University of Mauritius
Faculty of Engineering
Department of Electrical and
Electronic Engineering
IMPLEMENTATION OF WATER
COOLING SYSTEM, MPPT AND P&O
WITH DUAL AXIS TRACKER AND STATIC
PANEL
MONEBAHAL Ali Asgar Ibne
Project submitted in partial fulfilment of the award of the degree of
B.Eng (Hons.) Mechatronics Engineering
Supervisor: Mr H. Shamachurn
JULY 15, 2022
Table of Contents
Table of Contents .......................................................................................................... i
List of Figures ............................................................................................................. vi
List of Tables................................................................................................................ x
Acknowledgement......................................................................................................xii
Declaration Form .......................................................................................................xii
Submission Form .......................................................................................................xii
Abstract ...................................................................................................................... xv
List of Abbreviations................................................................................................. xvi
1.0
Introduction .................................................................................................... 1
1.1 Aims and Objectives .......................................................................................... 3
1.2 Chapter Review .................................................................................................. 3
2.0 Literature Review................................................................................................. 4
2.1 PV cell ................................................................................................................ 4
2.1.1 Factors affecting PV cell ............................................................................. 4
2.1.2 Types of PV cell .......................................................................................... 5
2.2 Solar trackers ...................................................................................................... 7
2.2.2 Active Solar Tracker ................................................................................... 8
2.3 Solar Irradiance .................................................................................................. 9
2.4 Solar Radiation in Mauritius ............................................................................ 10
2.5 Mauritius Solar Path......................................................................................... 11
2.6 Control algorithms ........................................................................................... 16
2.7.1 Open-loop Control (OLC) ......................................................................... 16
2.7.2 Closed-loop control (CLC) ....................................................................... 16
Four LDRs Method ........................................................................................ 17
Extremum seeking control (ESC) .................................................................. 17
i
Perturb and Observe (P&O) ........................................................................... 17
2.8 Ways of Harnessing Energy from Solar Tracker ............................................. 18
2.9 Previous works ................................................................................................. 18
3.0 Methodology ....................................................................................................... 21
3.1 Proposed Methodology .................................................................................... 22
3.2 Apparatus ......................................................................................................... 22
3.3 Procedure.......................................................................................................... 23
3.4 Safety Precautions ............................................................................................ 23
4.0 Conceptual Design .............................................................................................. 24
4.1 Design Brief ..................................................................................................... 24
4.2 Mechanical Design ........................................................................................... 24
4.2.1 Specifications ............................................................................................ 24
4.2.2 Ideas and existing models ......................................................................... 25
4.2.3 Designing the mechanical Structure.......................................................... 27
Material Selection .......................................................................................... 27
Available Forms ............................................................................................. 28
Base Shape ..................................................................................................... 28
Motor Selection .............................................................................................. 29
Panel support frame........................................................................................ 31
4.2.4 Sizing of parts and Calculations ................................................................ 33
Modelling the Panel support frame ................................................................ 33
Modelling the Polar angle shafts .................................................................... 34
Modelling Supporting Beam .......................................................................... 37
Modelling the Elevation Shaft ....................................................................... 40
Base Modelling .............................................................................................. 42
Final Design ................................................................................................... 45
Static Panel Support ....................................................................................... 47
ii
Further Modifications..................................................................................... 48
4.2.5 Mechanical Components Costing ............................................................. 49
4.3 Electrical and Electronic design ....................................................................... 50
4.3.1 Specifications of Electrical and Electronic Components .......................... 50
Microcontroller selection ............................................................................... 51
Linear actuator sizing ..................................................................................... 52
Valves............................................................................................................. 53
Pyranometer ................................................................................................... 53
Motor drivers or Relays ................................................................................. 54
Real-Time Clock ............................................................................................ 54
Solar Panels .................................................................................................... 55
Data Acquisition System ................................................................................ 56
Temperature sensors....................................................................................... 57
Current and Voltage Sensors .......................................................................... 58
MOSFET Selection ........................................................................................ 60
Maximum Power Point Tracking ................................................................... 61
Supply ............................................................................................................ 61
Heat sink......................................................................................................... 62
Electrical Circuit ............................................................................................ 64
4.3.2 Electrical components costing .................................................................. 65
4.4 Software Design ............................................................................................... 66
4.4.1 LABVIEW Program ................................................................................. 66
4.4.2 Arduino Coding......................................................................................... 70
Perturb and Observe ....................................................................................... 70
Mathematical Modelling ................................................................................ 71
Water Cooling System ................................................................................... 74
5.0 Implementation and Testing ............................................................................. 75
iii
5.1 Problems faced and actions taken .................................................................... 75
Linear Actuator .............................................................................................. 75
Temperature Sensor ....................................................................................... 75
MPPT and Solar tracking ............................................................................... 75
Noisy current sensor output ........................................................................... 75
Unnoticeable changes in Power ..................................................................... 75
Additional Modifications ............................................................................... 76
Power consumed ............................................................................................ 76
5.2 Implementation ................................................................................................ 76
6.0 Data Collection, Results and Discussion .......................................................... 79
6.1 Ambient Conditions ......................................................................................... 79
6.2 P&O in Cloudy Conditions .............................................................................. 81
6.3 Mathematical Modelling in Cloudy Conditions ............................................... 84
6.4 P&O Sunny Weather without Water Cooling System ..................................... 86
6.5 P&O Sunny Weather with Water Cooling System .......................................... 88
6.6 Mathematical Modelling Sunny Weather without Water Cooling System ...... 90
6.7 Mathematical Modelling Sunny Weather with Water Cooling System ........... 92
6.8 Water Cooling System Efficiency.................................................................... 94
6.9 Overall Analysis of Efficiencies ...................................................................... 96
7.0 Conclusion and Recommendations................................................................... 98
8.0 References ........................................................................................................... 99
9.0 Appendices ........................................................................................................ 107
Appendix A: Relevant Information .................................................................. 108
Solar Energy Resource ................................................................................. 108
Photovoltaic cell ........................................................................................... 109
Control Algorithms .......................................................................................... 110
Extremum Seeking Control .......................................................................... 110
iv
Perturb and Observe Control........................................................................ 110
Appendix B: Datasheets of Electrical Components ........................................ 112
Appendix C: Datasheets of Mechanical Components ..................................... 154
Appendix D: Programming and Coding .......................................................... 157
1.
Full Perturb and Observe Control .......................................................... 157
2.
Mathematical modelling for elevation angle and Perturb and Observe for
polar angle ........................................................................................................ 161
3.
Water Cooling System ........................................................................... 166
4.
LABVIEW Program .............................................................................. 167
Appendix E: Realisation and Build-up ............................................................ 169
Appendix F: Synopsis and Progress Log ......................................................... 172
v
List of Figures
Figure 1 Power-Voltage characteristics curves ........................................................... 5
Figure 2 Appearance of different types of Solar panels [32] ...................................... 6
Figure 3 Single Axis trackers ....................................................................................... 7
Figure 4 Tilted Axis tracker ......................................................................................... 7
Figure 5 Polar Altitude (left) and Azimuth Altitude (right) Trackers .......................... 7
Figure 6 Passive Solar tracker [35] .............................................................................. 8
Figure 7 Types of Solar Radiation [42]........................................................................ 9
Figure 8 Winter month Solar Map [44]...................................................................... 10
Figure 9 Summer Month Solar Map [44]................................................................... 10
Figure 10 Azimuth and Altitude angles [45].............................................................. 11
Figure 11 Mauritius Solar path .................................................................................. 12
Figure 12 Cartesian coordinates of Mauritius Solar path........................................... 12
Figure 13 Hourly Solar Irradiance [46] ...................................................................... 14
Figure 14 Four LDRs system ..................................................................................... 17
Figure 15 Solar tracker 1st model .............................................................................. 25
Figure 16 Solar tracker 2nd model[56] ...................................................................... 25
Figure 17 Solar tracker 3rd model ............................................................................. 26
Figure 18 Solar Tracker 4th model[40] ...................................................................... 26
Figure 19 Base types .................................................................................................. 28
Figure 20 Preliminary design of Solar tracker ........................................................... 32
Figure 21 Rectangular tube Cross-section ................................................................. 33
Figure 22 Panel Support frame dimension ................................................................. 33
Figure 23 Moment on shaft for polar tracking ........................................................... 34
Figure 24 Moment of inertia for shaft ........................................................................ 34
Figure 25 Pillow case model and specifications [58]................................................. 36
Figure 26 Forces on rectangular beam ....................................................................... 37
Figure 27 Moments of rectangular beam ................................................................... 38
Figure 28 Improved design for polar actuator............................................................ 38
Figure 29 Moment of Inertia Dimensions .................................................................. 39
Figure 30 Compressive force exerted by elevation shaft ........................................... 40
Figure 31 Moment of inertia of shaft ......................................................................... 41
Figure 32 Base Modelling .......................................................................................... 43
vi
Figure 33 Final design ................................................................................................ 45
Figure 34 Final design Linear Actuators .................................................................... 45
Figure 35 Final design Pivots..................................................................................... 46
Figure 36 Final design bearings ................................................................................. 46
Figure 37 Static panel Support ................................................................................... 47
Figure 38 Solar tracker piping design ........................................................................ 48
Figure 39 Arduino Uno .............................................................................................. 51
Figure 40 Polar Linear actuator positioning and dimensions (full extension,
perpendicular, full retraction)..................................................................................... 52
Figure 41 Altitude Linear actuator positioning and dimensions (full extension,
perpendicular, full retraction)..................................................................................... 52
Figure 42 Solenoid Valve........................................................................................... 53
Figure 43 Pyranometer ............................................................................................... 53
Figure 44 Relay 4 Channel ......................................................................................... 54
Figure 45 Real-Time Clock ........................................................................................ 54
Figure 46 Modified Panel Support ............................................................................. 55
Figure 48 Modified Final Design ............................................................................... 56
Figure 49 NI myDAQ ................................................................................................ 57
Figure 50 LM35 Temperature Sensor ........................................................................ 57
Figure 51 Current Sensor HY 15-P ............................................................................ 58
Figure 52 Current sensor calibration circuit............................................................... 58
Figure 53 Current sensor Calibration graph 1 (HY 15-P) .......................................... 59
Figure 54 Current sensor Calibration graph 2 (HY 20-P) .......................................... 59
Figure 55 Current sensor Calibration graph 3 (HY 15-P) .......................................... 60
Figure 56 High power ................................................................................................ 60
Figure 57 MOSFET Calibration graph ...................................................................... 60
Figure 58 Final MPPT circuit .................................................................................... 61
Figure 59 Heat flow for MOSFET ............................................................................. 62
Figure 60 Parallel MOSFET connection .................................................................... 63
Figure 61 Detailed Microcontroller circuit ................................................................ 64
Figure 62 Overall System .......................................................................................... 66
Figure 63 MPPT flowchart......................................................................................... 67
Figure 64 Filtered and Unfiltered Signal for low current .......................................... 68
Figure 65 Filtered and Unfiltered Signal for high current ......................................... 68
vii
Figure 66 Perturb and Observe flowchart .................................................................. 70
Figure 67 Calibration of Elevation actuator ............................................................... 71
Figure 68 Calibration of Polar actuator ...................................................................... 71
Figure 69 Elevation actuator calibration vis a vis Elevation angle ............................ 71
Figure 70 Mathematical Modelling flowchart ........................................................... 72
Figure 71 Water cooling data ..................................................................................... 74
Figure 72 Water cooling program flowchart .............................................................. 74
Figure 73 Modified leg design ................................................................................... 76
Figure 74 Realised model vs designed model ............................................................ 76
Figure 75 Complete Set up......................................................................................... 77
Figure 76 Pyranometer Setup ..................................................................................... 77
Figure 77 Water Cooling Tracker .............................................................................. 78
Figure 78 Electrical Circuit Setup .............................................................................. 78
Figure 79 Water Cooling Static Panel ........................................................................ 78
Figure 80 Irradiance Sunny vs Cloudy Graph............................................................ 79
Figure 81 Temperature Sunny vs Cloudy Graph ....................................................... 79
Figure 82 P&O Cloudy Temperature and Irradiance Graph ...................................... 81
Figure 83 P&O Cloudy Power and Irradiance Graph ................................................ 81
Figure 84 P&O Modified Cloudy Power and Irradiance Graph ................................ 83
Figure 85 Mathematical Modelling Cloudy Temperature and Irradiance Graph ...... 84
Figure 86 Mathematical Modelling Cloudy Power and Irradiance Graph ................. 84
Figure 87 P&O Sunny Temperature and Irradiance Graph ....................................... 86
Figure 88 P&O Sunny Power and Irradiance Graph .................................................. 86
Figure 89 P&O Sunny Water Cooling Temperature and Irradiance Graph ............... 88
Figure 90 P&O Sunny Water Cooling Power and Irradiance Graph ......................... 88
Figure 91 Mathematical Modelling Sunny Temperature and Irradiance Graph ........ 90
Figure 92 Mathematical Modelling Sunny Power and Irradiance Graph .................. 90
Figure 93 Mathematical Modelling Sunny Water Cooling Temperature and
Irradiance Graph......................................................................................................... 92
Figure 94 Mathematical Modelling Sunny Water Cooling Power and Irradiance
Graph .......................................................................................................................... 92
Figure 95 Temperature of Water Cooling vs Without Graph (Morning)................... 94
Figure 96 Temperature of Water Cooling vs Without Graph (Afternoon) ................ 94
Figure 97 Efficiency of all systems chart ................................................................... 96
viii
Figure 98 Solar Panel Hierarchy[22] ....................................................................... 109
Figure 99 Solar Cell Working Principle .................................................................. 109
Figure 100 Pertrub and Observe system .................................................................. 111
Figure 101 Microcontroller Arduino circuit ............................................................ 166
Figure 102 LABVIEW Front Panel ......................................................................... 167
Figure 103 LABVIEW Block Diagram ................................................................... 167
Figure 104 Complete data collection and controlling circuit ................................... 168
Figure 105 Main Stand and Support Beam .............................................................. 169
Figure 106 Main Stand Welding .............................................................................. 169
Figure 107 Support Beam ........................................................................................ 169
Figure 108 Main Stand ............................................................................................. 169
Figure 109 Elevation Pivot ...................................................................................... 169
Figure 110 Solar Tracker ......................................................................................... 170
Figure 111 Complete Solar Tracker ......................................................................... 170
Figure 112 Panel Support Frame.............................................................................. 170
Figure 113 Static Panel ............................................................................................ 171
Figure 114 Tracker Water Cooling .......................................................................... 171
Figure 115 Temperature Sensors glued to Panel...................................................... 171
Figure 116 Valve ...................................................................................................... 171
Figure 117 LDR Setup ............................................................................................. 171
Figure 118 Pyranometer Setup ................................................................................. 171
ix
List of Tables
Table 1 Hourly Sun Position ...................................................................................... 13
Table 2 Material Comparison .................................................................................... 27
Table 3 Material Characteristics ................................................................................ 28
Table 4 Driver Comparison........................................................................................ 30
Table 5 Mechanical components Cost ....................................................................... 49
Table 6 Additional Mechanical Components Cost .................................................... 55
Table 7 MOSFET heat specifications ........................................................................ 62
Table 8 Electrical components costing ...................................................................... 65
Table 9 Logic control conditions ............................................................................... 73
Table 10 Efficiency of P&O in cloudy weather ......................................................... 82
Table 11 P&O Cloudy Maximum power ................................................................... 82
Table 12 P&O Cloudy Minimum Maximum and Average values ............................ 82
Table 13 Efficiency of P&O Modified in cloudy weather ......................................... 83
Table 14 Mathematical Modelling in Cloudy Condition ........................................... 85
Table 15 Mathematical Modelling Cloudy Maximum power.................................... 85
Table 16 Mathematical Modelling Cloudy Minimum Maximum and Average values
.................................................................................................................................... 85
Table 17 Efficiency of P&O in Sunny Conditions..................................................... 87
Table 18 P&O Sunny Maximum power..................................................................... 87
Table 19 P&O Sunny Minimum Maximum and Average values .............................. 87
Table 20 Efficiency of P&O Water Cooling in Sunny Conditions ............................ 89
Table 21 P&O Sunny Water Cooling Maximum power ............................................ 89
Table 22 P&O Sunny Water Cooling Minimum Maximum and Average values ..... 89
Table 23 Efficiency of Mathematical Modelling in Sunny conditions ...................... 91
Table 24 Mathematical Modelling Sunny Maximum power ..................................... 91
Table 25 Mathematical Modelling Sunny Minimum Maximum and Average values
.................................................................................................................................... 91
Table 26 Efficiency of Mathematical Modelling with Water Cooling in Sunny
Conditions .................................................................................................................. 93
Table 27 Mathematical Modelling Sunny Water Cooling Maximum power ............ 93
Table 28 Mathematical Modelling Sunny Water Cooling Minimum Maximum and
Average values ........................................................................................................... 93
x
Table 29 Water Cooling vs Normal data.................................................................... 95
Table 30 Cutting list ................................................................................................. 156
xi
Acknowledgement
First and foremost, I would like to thank God, the Almighty for granting me the
opportunity, knowledge, courage and health to accomplish this endeavour
satisfactorily, guiding me through the ups and downs and showing the solution for the
problems I faced.
Secondly, the credit goes to my parents who supported me unconditionally all the way
through my studies and making sure that I had everything I needed and for their
countless prayers, love and caring. Alongside my parents, I need to give special thanks
to my dearest sisters who never failed to help wherever they could. Also, much
appreciation goes to my dear partner for her moral support and company. I cannot but
mention my faithful friends for their ideas and experience.
Last but not least, I would like to thank my supervisor, Mr H. Shamachurn for his
usual assistance and cooperation who helped me all the way through my research work
and never failed to provide me with what was necessary in making this thesis a
success.
xii
Monebahal Ali Asgar Ibne
1811899
B.Eng (Hons.) Mechatronics Engineering
Implementation of water cooling system, MPPT and P&O with dual axis
tracker and static panel
Mr. H. Shamachurn
29/07/2022
xiii
Monebahal Ali Asgar Ibne
1811899
B.Eng (Hons.) Mechatronics Engineering
Implementation of Water cooling system, MPPT and P&O with dual axis tracker and static panel
12376
29/07/2022
xiv
Abstract
The attempt of this thesis is to work ameliorating the already existing solar trackers
which exist in various forms and of numerous tracking algorithms have already been
tried and tested.
The dual axis tracker, which is known to be the most efficient type of tracker, is
therefore be modified to not simply track the sun as previous trackers would tend to,
rather this innovative tracker is required to track the maximum irradiance available to
generate maximum power.
Also, the power generation was enhanced with the maximum power point tracking in
aspiration to optimize the output. The maximum power point tracking was
implemented with MOSFETs which acted as variable resistances.
Additionally, the need for water cooling systems on and off tracker for solar panels is
assessed in this thesis.
xv
List of Abbreviations
Abbreviations
Meaning
GHI
Global Horizontal Irradiance
POA
Plane of Array Irradiance
RTC
Real-time clock
PWM
Pusle Width Moderator
MPP
Maximum Power Point
MPPT
Maximum Power Point Tracking
ESC
Extremum Seeking Control
P&O
Perturb and Observe
DC
Direct current
USB
Universal Serial Bus
VSAT
Vertical Single Axis Tracker
AADAT
Azimuth Altitude Dual Axis Tracker
CLC
Closed Loop Control
OLC
Open Loop Control
GUI
Graphical User Interface
DAQ
Data Acquisition
LDR
Light Dependent Resistor
PC
Personal Computer
IDE
Integrated Development Environment
xvi
1.0 Introduction
Oil, Natural gas and Coal have been the heroes for nearly all the technological
advances up till now. But this has certainly cost us the health of the mother earth as
these have very certainly left a trail. Coal are said to have been used since the
prehistoric time as a source of heat but it has only contributed to modernization since
1750 [1]. Natural gas first commercial use trace up to the late 18th century where it
was used to light up streets and heat houses [2]. Oil is recorded to have been pumped
out in the mid-19th century where most of it would be turned to kerosene to fuel lamps
and later automobiles [3].
According to a recent study performed by the US Energy Information Administration,
if the consumption of oil keeps constant for the coming years, the latter will be
completely depleted by the year 2052 and therefore the whole global economy shall
rely on natural gas and coal whose depletion shall not be impeded if new energy
sources are not exploited [4].
The situation is becoming more and more alarming as years pass by, hence, much have
been done and emphasized to find suitable alternatives to cope with the energy
requirements of the world. Renewable sources could be the hero to save us against a
global blackout and scientists have been working to develop such sources to make
them more and more efficient [5].
Over the last decade, more productive and sustainable renewable systems have been
achieved and yet improvements are being to procure better results. Researchers have
been focusing mostly on eco-friendly energy generation methods as an attempt to limit
the damage already caused to the atmosphere. From industries to individuals, mostly
everyone is taking measures to create a healthy world and renewable energy sources
seems to be doing the job very well [7].
Among the various alternatives namely; hydroelectricity, bioenergy, wind and
geothermal energy, tidal power; solar energy takes precedence over the other sources
of energy despite all of the mentioned being renewable sources. This has been the case
since the solar photovoltaic(PV) energy is the most accessible all around the globe and
its high reliability [8]. Thanks to the countless researches on the PV modules, be it on
large scale or small scale basis, and further development, PV modules cost is
1
decreasing considerably. This has therefore lead to more residential uses alongside
industrial uses [9]. According to International Energy Agency (IEA), worldwide PV
capacity has grown at 40% on average per annum since the year 2000. This trend is
nowhere near ending as can be deduced in [10].
Photovoltaic have evolved a great amount since its discovery by Edmond Bequerel in
1839. Then decades later, scientist named Fritts found selenium to produce a steady
current of reasonable force when exposed to light. Nearly half a decade later, Bells
laboratory came to the conclusion that semiconductor material like silicon are more
efficient than selenium [11].
Various types of solar panel came into existence following above discoveries among
which are: monocrystalline type of PV which was discovered in 1941[12] followed by
poly-crystalline type in mid 1950s and last came the amorphous type also known as
thin-film discovered in the early 1950s [13]. These different types of solar panels have
each different efficiencies and characteristics and each hold distinct advantages and
drawbacks [14].
The solar energy, being the cheapest and most accessible anywhere, has been
enhanced and ways have been developed to obtain higher output from the PV cells.
Among such ways is the maximum power point tracking and solar tracking, the
concept of dual axis solar tracking was first introduced by Robert H Dold in 2007 and
has been modified and enhanced ever since [15]. The idea is simply to face the sun
more time in order to get maximum irradiance thus maximum power. Solar trackers
have been implemented in various ways be it single axis or dual axis. The first single
axis solar tracker proved to be 22% more effective than a fixed solar panel, study
performed by Naser Barsoum in 2010 [16].
Discrete methods of tracking the sun have been deployed and others have proven to
be more rewarding than others but that very well relied on the execution of the control
and response of the mechanisms. Of the most common ways is the use of Light
dependent resistors(LDRs) to track maximum sunlight and move the panel
accordingly.
2
1.1 Aims and Objectives
This thesis is therefore an attempt to contribute to the extensive researches performed
on PV modules by means of a dual axis solar tracker and the aforementioned types of
PV panels to see if they all react and display more or less same characteristics when
on or off a solar tracker and the efficiency variations of each one of them.
Objectives:

To construct a fully functional dual axis solar tracker for real size modules

Using appropriate control to maximise power output of the solar tracker

Record data for all types of panels: fixed or on solar tracker

To implement a maximum power point tracker on the panels to derive
maximum power from fixed PV panel and tracker

Introduce a water cooling system
1.2 Chapter Review
Chapter 1: Introduction
• Background Information about thesis and source of the concept
• Aims and Objectives
Chapter 2: Literature review
• Information about PV panels and solar trackers and MPP trackers
Chapter 3: Methodology
• Procedure to attain objectives and selection of components/ softwares
Chapter 4: Conceptual Design
• Drawing solar tracker design based on data collected
• Simulation on softwares to verify correct functioning
Chapter 5: Implementation and Testing
• Building of solar tracker and assessing the need for changes
• Evaluation of Prototype
Chapter 6: Data collection, Results and Discussion
• Gathering data from prototype and different type of solar panel
• Results
Chapter 7: Conclusion and Recommendations
3
2.0 Literature Review
2.1 PV cell
2.1.1 Factors affecting PV cell
The efficiency of the PV panel is dependent on many factors, while some can be
avoided, others cannot. Among the main factors are:
1. Solar Irradiance
This is the light intensity that hits the surface of the panel. As explained
earlier, more light means more photons thus more electrons freed causing
higher current to flow through and does not affect the open circuit voltage.
[25] Cloudy weather and shadows are thus not appreciated.
2. Temperature
Temperature rise of the surface of the panel causes a voltage drop and a
slight current increase caused by the absorption of heat energy leading
more electrons to rise from the valence band to the conduction band.
However, the thermally generated electrons control the electrical
properties of the semiconductor thereby negatively affecting the open
circuit voltage. [26] The optimum working temperature of a solar panel is
25°C with a temperature coefficient of about -0.5%/°C. Thus, maintaining
the temperature near 25°C shall yield more energy. [65]
3. Maximum power point tracking (MPPT)
MPP tracking is to track and maintain the adequate load resistance that
matches with the internal resistance of the source to generate maximum
power as the maximum power transfer theorem. The internal impedance of
the solar panel is determined from the I-V (current-voltage) graph of the
cell and MPP occurs at the point where the product of IV is the maximum.
The I-V graph varies due to several reasons: non-uniform irradiance,
soiling, shading and temperature amongst others. [27]
4
Figure 1 Power-Voltage characteristics curves
The conventional method is the simple perturb and observe control but
algorithms like extremum seeking control displayed promising results in
terms of stability for large signal operation. [27]
4. Orientation
The more exposure to direct sunlight shall eventually prove advantageous
to the current generation. The power generated from a solar panel is thereby
dependent on the irradiation and the angle between the module and the sun.
[28]
2.1.2 Types of PV cell
PV cells are divided into many categories based on their chemical composition or their
manufacturing processes. Among the varying types, three are the most common:
1. Single/ Mono-crystalline solar cell
Suggested by the name, this type of solar cell is manufactured from single
crystals of silicon via the Czochralski Process. The silicon of high purity is
sliced from cylindrical ingots. The process requires high precision which
makes it the most expensive but higher efficiency of between 16-18%. [29]
2. Polycrystalline solar cell
Consists of different crystals linked to one another in a single solar cell. The
manufacture of this type is cheaper by cooling a graphite mould charged with
molten silicon and during the solidifying of the silicon, various crystal
5
structures are formed. This type of Solar panel is the most widespread [30]and
provides an efficiency of 12-14%.
The two above mentioned are known as the first generation solar cell and what
is to follow is from the second generation
3. Thin-film solar cell
These solar cells are more economical than the first generation silicon wafer
solar cells by having a light absorbing layer of 1µm compared to 350µm. these
can be divided into three categories: Amorphous Silicon (a-Si), Cadmium
Telluride (CdTe), Copper Indium Gallium Di-Selenide (CIGS) and have
efficiency under 12%. [31]
As their composition varies, so does their appearances:
Figure 2 Appearance of different types of Solar panels [32]
6
2.2 Solar trackers
Solar trackers were introduced so as to increase the amount of perpendicular sunlight
incident on the panel. Solar trackers can be either passive or active and exist mainly
in two types further divided into other categories.
Solar
trackers
Singe Axis
Tracker
Vertical
(VSAT)
Horizontal
(HSAT)
Dual Axis
Tracker
Tilted
Axis
Azimuth
Altitude
(AADAT)
Polar Axis
(PADAT)
Figure 3 Single Axis trackers
Figure 4 Tilted Axis tracker
Figure 5 Polar Altitude (left)
and Azimuth Altitude (right)
Trackers
7
2.2.1 Passive Solar trackers
Passive solar trackers trace the path of the sun without any mechanical drives. They
normally comprise of actuators and thermally active materials in form of fluids. [33]
Using the principle of thermal expansion and pressure imbalance between two points
at the ends of the tracker, when the sun is perpendicular to the panel, equilibrium is
reached and upon moving of one side, a difference in heat causes one to expand and
the other to contract leading to the panel rotation. [34]
Figure 6 Passive Solar tracker [35]
2.2.2 Active Solar Tracker
Contrary to passive solar trackers, these use the help of motors and sensors to track
the sun continuously [36]. As mentioned earlier, various ways of active solar tracking
exist while the most famous is the use of 4 LDRs to locate the sun but new ways of
solar tracking are also developing which are based on date and time and auxiliary
bifacial PV cells and others like maximum power seeking control. These systems are
controlled via a processor which processes the input for a convenient output. [37]
As shown above, various types of trackers exist. The efficiency of a VSAT was
investigated by Dian and al. based on GPS tracking which proved to be 22% more
rewarding than a fixed panel. [38]
The need of a dual axis solar tracker arises due to the fact that the sun does not move
about a single axis year round. The sun does move from east to west on a daily basis
but has a slight tilt angle throughout the year as it performs its daily routine.
8
2.3 Solar Irradiance
Radiant energy from the sun is earth’s primary energy source and is known as solar
irradiance. In brief, solar power is reported as irradiance and measured in Watts per
metre square (W/m2) and isolation is the cumulative amount of solar energy delivered
to a particular area measured in kilowatt hour per metre square (kWh/m2). Three types
of solar radiation exist: direct, diffuse and reflected while the rest are absorbed. Direct
Radiation is that which travels reaches the planet via a straight and the obstruction of
which causes shadows. While the diffuse radiation is scattered light by molecules and
particles which spreads in all direction. During clear weather, about 85-90% of light
consists of direct radiation. The third is the reflected radiation which is caused by
reflection of light from non-atmospheric things such as the surface of the earth known
as albedo. These affect solar panels the least and the latter are of often tilted away from
such radiation. [41]
Figure 7 Types of Solar Radiation [42]
9
2.4 Solar Radiation in Mauritius
Mauritius lies in the Indian ocean at 20.3484° S, 57.5522° E situated just above the
tropic of Capricorn and thereby enjoys mostly sunny weather year round, ideal
location for solar energy harvesting. In an attempt to hinder climate change, the
republic of Mauritius has taken the incentive to reach 35% of electrical production via
renewable sources and solar energy is the main target as it should be. [43]
Below are solar maps for a winter and summer month.
Figure 8 Winter month Solar Map [44]
Figure 9 Summer Month Solar Map [44]
10
It can be clearly seen that the irradiance in winter is much less, about 61%, than that
in summer as explained in [64].
2.5 Mauritius Solar Path
As mentioned earlier, the sun does not maintain the east to west rotation perfectly year
round, slight angle variations in the north south direction occur gradually during a
year. Thus, two angles need to be defined to locate the sun accurately namely:
elevation angle and azimuth angle.
Elevation angle is the angle between the local horizon and the sun. Also known as the
altitude, it refers to high the sun is with respect of the observer.
The Azimuth angle is the angle between a reference (normally north) in a clockwise
direction and the sun, lying in a horizontal plane. Thus this angle will be 90° when the
sun is at the east and 270° at the west.
Figure 10 Azimuth and Altitude angles [45]
11
The geometric location for the intended location of testing is 20.0177903 south and
57.5786805 east and the expected solar paths for different months is shown below.
The following data have been taken from [46]
Figure 11 Mauritius Solar path
The Cartesian coordinates of the solar path, where elevation is plotted in the y axis
and azimuth in the x axis, is represented in this graph
Figure 12 Cartesian coordinates of Mauritius Solar path
12
For better analysis, the values of expected month of experimentation are tabulated:
Table 1 Hourly Sun Position
Date:
14/04/2022 | GMT3
coordinates:
-20.0177903, 57.5786805
location:
-20.01779030,57.57868050
hour
Elevation
Azimuth
06:20:15
-0.833°
80.34°
7:00:00
8.31°
76.8°
8:00:00
21.84°
70.55°
9:00:00
34.76°
62.33°
10:00:00
46.52°
50.41°
11:00:00
55.88°
31.95°
12:00:00
60.43°
5.02°
13:00:00
58.06°
336.21°
14:00:00
49.97°
314.92°
15:00:00
38.82°
301.22°
16:00:00
26.19°
292.03°
17:00:00
12.82°
285.28°
17:59:32
-0.833°
279.85
According to the above table, the maximum change in the elevation angle is 68.76°
but the zenith has not been clearly identified and the maximum change in the azimuth
angle is therefore 331.19°. However, throughout the year, the maximum elevation
should be 90° and according to the yearly statistics, the maximum difference in the
azimuth angle is 344.79°. These values are relevant to azimuth altitude tracking but as
for polar altitude tracking, the tilt angle of the sun towards the north and south would
be more relevant and the maximum difference in that plane for a complete year is
between 45° and 120° read from the solar map above (fig 2.09). But since testing shall
be done over a short period of time only, and for specific hours of a day, having such
ranges might be unnecessary and shall raise the cost. Thus the altitude angle can be
limited to a smaller angle.
As for the hourly irradiance for the expected period of research, the graph is shown
below for a region close to research location
13
Figure 13 Hourly Solar Irradiance [46]
GHI: global horizontal irradiance
PoA: Plane of Array Irradiance
As it can be seen, the irradiance between 7.30 to 15.30 is great compared to other
times, thus tracking can be limited to this period for experimentation. However, for
energy harvesting, this would be considered a loss of resources. Consequently, the
maximum difference in elevation angle required is 140° deduced from the table.
Minimum range of motion= 180 - elevation angle at 7.30 - elevation at 15.30 =
180-14-32= 136° ←
It can be seen that the optimum operating time for the solar tracker will range from 8
in the morning till after 15 in the afternoon. The average wind speed for our country
lies between 20 and 30km/h and the temperature does not fall below 15°C and neither
exceeds 35°C. It also receives ample precipitation of 2302mm per annum. [47]
The solar path from east to west can be calculated by approximating the sun location
using mathematical formulas. Since the earth is said to rotate at an angular velocity of
15°/hour, it is easier to find the sunrise and sunset time though these also vary in
function to the day of the year. The basic definition of sunrise is when the sun first
appears and sunset is when the sun goes below the horizon. These can be calculated
using the hour angle,ꞷ
ꞷ= cos-1(-tanφtanδ)
Where φ= latitude of the location
δ= declination angle
the latter can be found using
14
Eq (2)
δ=23.45sin((284+n)×
𝟑𝟔𝟎
𝟑𝟔𝟓
)
Eq (2)
n= number of days taking the 1st of January as 1.
This approximation was derived based on the research by P.I. Cooper in 1969. The
sunrise and sunset times are thus calculated by subtracting and adding, respectively,
the hour angle to 12. [48]
15
2.6 Control algorithms
Solar tracking is done via controllers in which control algorithms are written and
execution signal is given to actuators. There are basically two types of control
algorithms namely open-loop control(OLC) and closed-loop control(CLC). These
main difference between these is the absence of feedback in the OLC.
2.7.1 Open-loop Control (OLC)
Open loop control is an easy way to control any system but due to the lack of feedback,
the system cannot rectify any mistake or adapt to a new situation. It therefore follows
the same pattern unless the control algorithm changes. This technique is based on
mathematical models and the sun is tracked according to the results.
An example for this model is what have been derived by K.K Chong and C.W Wong
based on the aforementioned formulae.
Some also use time and date to pre-calculation the sun’s orientation depending
geographic rotation as in [47]. This type of system is cheaper and easier to implement.
2.7.2 Closed-loop control (CLC)
Closed loop control refers to the feedback that the system takes in as input to modify
the output to provide better results or taking inputs from sensors to find greatest
irradiance. Such systems adapt and react to any changes and correct errors making
them independent and more efficient by staying safe from the effect of disturbances
or straying from the reference.
16
Four LDRs Method
Of the famous of them is the use of 4 LDRs adjacent to each other forming a square
with an opaque separation between them. Shadows will be cast by the separation on
some while some shall get direct sunlight. A comparison control is done using the
analogue values of the 4 LDRs by pairs for azimuth and tilt angle via a controller and
the solar panel is moved accordingly. The main ordeal of this system is cloudy weather
where there is no difference in intensity between the four LDRs causing the system to
remain idle.
Figure 14 Four LDRs system
Extremum seeking control (ESC)
Extremum seeking control is an equation-free controller/ adaptive which does not
require a model of the system and can adapt to slowly changing parameters. Its main
purpose is to find the local maximum or minimum in a modelled or un-modelled
system.
Perturb and Observe (P&O)
Perturb and Observe is another type of system which tracks the highest output. As the
name suggests, it consists of perturbing the system and observing the reaction. If a
positive response is obtained, then the system continues to move in the same direction.
On the other hand, if the response is negative, it returns to the original position and
tries to track the maximum power in another direction.
17
2.8 Ways of Harnessing Energy from Solar Tracker
Two distinct methods are used to draw current and voltage from a solar panel namely
PWM and MPPT. The former being the cheaper drags the voltage of the panel to
nearly 12V i.e. the battery voltage levels away from the MPP. The working principle
is that it sends pulses of voltage to a battery and measures the voltage level of the
battery and accordingly varies the pulse width until eventually battery is full giving it
its rightful name Pulse Width Modulation. This system is not suitable for this research
since it eventually stops the current flow when the battery is fully charged blocking us
from determining the actual amount of energy harnessable.
As for the MPPT, it tries to match its internal resistance to that of the solar panel
characteristic resistance offering greater power and efficiency. It is of a known fact
that MPPT are 30% more efficient than PWM but these might vary under certain
conditions. Below are the reasons to go for an MPPT:
-
It can deal with any voltage generated by the panel (PWM deals only with 12V
or slightly above)
-
Uses the entire output of solar panel without passively dropping the voltage to
battery level voltage
-
More efficient even in low light/cloudy conditions or when panel heats up
However, MPPTs are bigger and costlier than PWM. [61]
2.9 Previous works
Of the papers worth mentioning is the multipurpose dual-axis solar tracker with two
tracking strategies. The two strategies used are normal tracking method and daily
adjustment tracking method. The results showed that the normal strategy keeps smaller
tracking errors but however the alternate method facilitates the tracking method by
setting the primary axis before the tracking starts and moves the panel in the east west
direction at the same rate of the relative motion between sun and earth of 15°/hour.
The normal tracking system has tracking error less than 0.15% and 23.6% more
efficient than fixed panels but however, the daily adjustment method proves to be more
efficient with a considerable 31.8% or above. [52]
18
Another type of hybrid solar tracker is the one designed by Ferdaus in [53]. This
tracker focuses mainly on using time as a tracking factor for more economical
tracking. One motor adjusts for the seasonal motion of the sun i.e. in the north south
direction once per month while the other motor tracks the east west direction thereby
saving much energy with respect to the continuous tracker which operates both motor
year round. Upon comparing with fixed solar panel, it yields upto 25.6% more energy
than a static panel while lagging behind by roughly 4% against a continuous dual axis
tracker but compensates for that lack by consuming 44.4% less energy than the
continuous dual axis tracker.
Another low cost Azimuth Altitude dual axis tracker was designed by two university
students in 2010 which produced considerable results. Upon experimenting, the dual
axis tracker came out nearly 49% more successful than an immobile panel under same
conditions and the tracker consumed significantly less energy than the solar energy
gathered given that the error was only up to 1.5° during clear weather. Of the things
that could have been improved, they found the use of stepper motors for less expenses
and use of a single battery for powering and storing charge. Cloudy weathers caused
noticeable misalignment with respect to the sun. This could be solved by
implementing by using time-based logarithm and location to guess the location of the
sun while tracker adjusts for more accurate alignment. They also came up with the
idea of auto-calibration of the sensors by the microcontroller. [53]
Recently, a novel sensor-less dual axis tracker has been designed and tested to show
great results. Having both the pros of sensor-based and sensor-less tracking, it
dismisses their drawbacks with an accuracy of 0.11° and increase by 28-43%
efficiency depending on seasonal changes. It differs to sensor-less systems which are
open-loop systems which uses solar maps, estimated solar path equations which lead
to inaccurate data and useless information under cloudy conditions. Maximum power
point tracking is also implemented and the sun is tracked according to deviations of
the azimuth and altitude angle to extract maximum power. [54]
In a research study performed in 2019, a student compared the different types of static
PV panels under various conditions and positions and came to various deductions
among which are: the linear decrease of maximum power under partial uniform
shading, the tolerance of amorphous Silicon under shading is greater than thin film
19
then followed by polycrystalline. Of the great conclusions is the optimum tilt angle
for maximum power was found to be 20° towards the north for Mauritius. This
correlates to the research of K.A Sado and al. who deduced that the yearly optimum
angle average is the latitude of the location [55]. Further improvements included using
higher power modules as the ones used was classified as mini modules and thus noise
in the current affected the results and the use of more analogue inputs could have
helped for better results while a pyranometer could have been used for better
measurement of solar radiation to better understand the relation of maximum power
to solar irradiance. [55]
Mr Mooraby tried to implement a new concept in solar tracking by not tracking the
sun itself, but rather the tracking the maximum power, even if that means facing away
from the sun in cloudy conditions. Using extremum seeking control, he succeeded in
realizing the idea. He deducted that the MPP is not a specific point rather a region and
varies depending on weather conditions and panel efficiency as clouds would cause
shifting of MPP region, and wrong calibration of sensors may cause lower efficiency
than static panel and ESC and P&O work nearly the same for this purpose. Due to
budget, two different PV panels could not be obtained for simultaneous experimenting
for more accurate results. In further development he added the use of 3D mapping for
faster convergence, testing year round for wider overview, uses of filters and advanced
logic for stabilized tracking. The mechanical design limited the tracking in the vertical
axis and vibrations lead to imprecise results which was also the result of poor
measuring hardware. [40]
Another dual axis tracker model and testing was carried out in 2019 by a student which
showed an efficient design but results in terms of energy harnessed yet showed room
for improvement. A 100W mono-crystalline solar panel was used to track the sun by
means of a camera for feedback and control. Data like solar irradiance and current
voltage have not been gathered for better analysis and understanding. This thesis shall
therefore complement above past studies for a more explicit examination. [56]
20
3.0 Methodology
Mainly, the dual axis tracker is to be designed which is made up of three parts:
1. The controller design
A controller needs to be chosen to suit all the needs and can be easily programmed to
output required functions and simulations. An appropriate tracking algorithm shall be
incorporated in it or linked to it. Data will be collected via data collecting software
and various simulations will be carried out before implementing the system directly to
the solar tracker
2. Electrical and Electronic design
This is mainly the wiring of the systems linking the sensors, meters, actuators and
controlling chip. All of the latter shall be either designed or selected to fit required
purpose e.g. motor needs to be sized according to applied load. A good and reliable
power source also needs to be chosen to supply the entire system while the need for a
battery to store charge is to be debated.
3. Mechanical design
It consists of the physical appearance of the tracker, its size, shape, the different
materials it will be made of, the actuator and sensors positioning. It also includes the
designing of specific parts like gears and shafts. The weight also plays and important
role in the mechanical design.
21
3.1 Proposed Methodology
1. A dual axis solar tracker is to be designed after deep research with appropriate
mechanics
2. Control system is to be designed and adjusted or simulated if deemed necessary
3. MPPT are implemented to both types of panels and values of power and current
are recorded to calculate power received from both panel.
4. Prototype is realised and tested, troubleshot or modified if necessary.
5. The fully functional dual axis solar tracker is used for the experimentation while
another panel of same type is kept stationary at an angle of 20° facing the north
for maximum power according to Mr Ruchpaul. [55]
5. Values of both panels are read and compared for analysis
All the above steps shall help to realise the aim and objectives of the thesis.
Different control algorithms shall also be tested and compared like the hybrid solar
tracker using time to estimate the sun location or using a fully time-based control
algorithm.
Note: Since the purpose of this thesis is only for testing, the power shall not be
stored in a battery rather directed to any load.
3.2 Apparatus
 PC for logging data and appropriate software for comparison
 Solar tracker
 Measuring devices for current and voltage or other required quantities
 Controller
 Sensors
 Panels
 Drivers
22
3.3 Procedure

Install the dual axis solar tracker and fixed solar panel at a known and specific
coordinate at which all the experimentation shall be done.

Use the MPP tracker to extract the maximum power from both static and
tracker. MPP is set to change at regular intervals depending on maximum
voltage and current.

Values of current, voltage and MPP is recorded at pre-set intervals to calculate
power generated

The duration of one test should be long enough, at least 3 hours, for better
comparison and the compared data should obviously have the same start and
end time
Note: The comparison has to be done the same day or next day if two panels of
same type are not available. In case of different weather condition the next day,
then the closest similar day shall be tested. Moreover, since the irradiance is
symmetrical around the solar noon, data in the afternoon can be compared with
data in the morning provided the same weather conditions are maintained. [63]
3.4 Safety Precautions
i.
The roof top should be secured and well surrounded
ii.
Proper water drainage should be in place to prevent water accumulation which
leads to slippery floor
iii.
Electric parts should be properly ground to prevent damage to parts
iv.
Ensure safe environment around tracker
v.
Experiments not to be carried under cyclonic conditions like heavy rain and
strong winds
vi.
The structure should be safe i.e. no sharp edges, stable and strong to prevent
toppling and harming anybody.
23
4.0 Conceptual Design
4.1 Design Brief
The main instrument for testing and experimentation is a dual axis solar tracker to
harvest maximum solar energy possible under most weather conditions while tracking
the maximum available power with the help of drives and sensors. The tracking shall
be dictated by an appropriately designed control algorithms.
4.2 Mechanical Design
4.2.1 Specifications
The Dual axis tracker should (be):

Built from scratch

Corrosion resistant for longer lifetime

Resist moderately strong wind condition not exceeding 50km/h

Stable, reliable and Safe

Consist of tracking algorithm

Work under both direct and diffuse type of radiation, the latter often
accompanied by rain, thus should resist rain

Off-grid for better

Roof mounted

Operate with ease under any ambient local temperature since freezing point is
not reached in Mauritius

Should have required angle freedom for faithful solar tracking in both
directions.

Cost under Rs12,000

Easily maintained
24
4.2.2 Ideas and existing models
Various dual axis solar trackers have been designed and implemented and mostly all
possible configurations have been tried out which makes future designing easier by
modifying or complementing one with another.
The first one to be considered is an azimuth-altitude solar tracker with a circular rotary
base and fixed stand with an axis at its top for elevation angle.
Pros

Simple design

Stable

Very Robust

Wide Range of motion
Cons
×
Too much material thus
higher cost
×
Huge torque required
×
Voluminous
Figure 15 Solar tracker 1st model
A second example would be that of Mr Rugooputh, who designed a polar-altitude solar
tracker. With the use of two linear actuators, he successfully executed the project built
for a 100W panel with a camera as a tracking apparatus.
Pros
 Inexpensive
 Space Efficient
 Light
 Low
energy
consumption
Cons
×
Not Stable
×
Limited Range
Figure 16 Solar tracker 2nd model[56]
of motion
25
Below is another design which moves the tracker with help of gears for azimuth and
altitude tracking. Gear set 1 is powered by a rotary motor coupled to a gear to rotate
the panel along the east west path while the other gear set powered similarly by a great
torque motor is used to track the seasonal changes.
Figure 17 Solar tracker 3rd model
Pros
Cons
 Expensive drivers required to
 Full range motion
provide such high torque
 Consumes much energy
 Consumes less floor space
 Stable
Another prototypes using the same basics of the
latter was designed by Mr Mooraby who used
linear actuators instead of motors, at the very
cost of limited range of motion for less expenses.
Figure 18 Solar Tracker 4th model[40]
From these alternatives, Mr Rugooputh’s design stands out due to its simplicity and
effectiveness though further improvements can still be made in terms of the stability
and other mechanical features which shall be modified.
26
4.2.3 Designing the mechanical Structure
Four things need to be considered when designing the mechanical structure, by
priority:
1.
Material and its available forms
2. Base as this will determine its stability
3. Types of actuators/motors to be used
4. The panel holding frame
Material Selection
Two metals are considered for the manufacture of this prototype: Coated aluminium
and Mild steel as both are readily available and other materials such as plastic or wood
might not resist the outdoor weather conditions and stresses. However, it also needs
to fulfil the requirements listed below:
Table 2 Material Comparison
ALUMINIUM
MILD STEEL
STRENGTH
1
3
CORROSION
3
1
1
3
JOINTS RELIABILITY 1
3
1
3
COST
2
3
TOTAL
9
16
RESISTANT
WEIGHT
DEFORMATION
RESISTANCE
Where 1=poor, 2=fair, 3=good
Mild steel is considered the better option since it will provide much stability due to
its weight and strength of the welding joints with a reasonable price. As for the
corrosion resistant, steel can be galvanised which shall increase the cost.
However, Aluminium still poses as a good solution for the panel support since strong
joints are not necessary and its light weight can be beneficial.
27
The characteristics of both materials are tabulated below [57]:
Table 3 Material Characteristics
Material
Mild Steel
Aluminium
Young’s Modulus Yield Stress (s), Pa
(E), Pa
200 × 109
250 × 106
70 × 109
95 × 106
Density, p
Kg/m3
7860
2710
Note: the yield stress is taken into consideration instead of other stresses, as no plastic
deformation should occur.
Available Forms
Mild steel can be divided into 3 forms: sheets, square/rectangular tube, circular tubes,
solid forms
As for our case, sheets are not to be used and solid forms shall be used only for the
shafts. Square tubes is preferred over round for ease of joining.
Base Shape
Comments
Stable on mostly any type
of ground
Fairly easy to make
Moveable
Affordable
Comments
Very stable but requires a
completely flat floor
Heavy thus not easily
displaced
Costly
Comments
Very stable even on
uneven ground
Easy to manufacture as
single joint needed for
each leg
Ideal weight
Affordable cost
Aesthetic
Figure 19 Base types
Based on the above comparison, option 3 is selected for its better characteristics
28
Motor Selection
Drives and motors are required for any automated mechanical movement and a
plethora of those are available, each having its very own characteristics.
Here is a list of them:
Ac motors
Servo motors
DC motors
Stepper Motors
Electromagnetic
Linear Actuators
•
•
•
•
•
continuous rotation
Speed controlled via Variable frequency drive (Vfd)
low maintenance
Adjustable torque and speed
Exists in two types: Synchronous and Induction
• Uses closed-loop control(feedback) to drive motor
• Very accurate control of motion for limited ranges
• PWM can be used for precise control and zero steadystate error
• Stable Operation
• Speed controlled by varying flux, resistance and
voltage applied
• Continuous rotation
• Rugged
• Has many types including shunt, brushless, etc
•
•
•
•
•
•
Rotates with fixed step angle triggered by a pulse
Controlled speed and positioning
Consist of coils known as phases which vary step size
No feedback for easier control
Can resist static load
Good stop start mechanism
• Rotary motion trnnslated into linear motion by means
of gearbox and a lead screw.
• Limited range of motion
• Forward and reverse movement is driven by
clockwise and anticlockwise rotation of motor
• Static load resistant
Motor Requirements:
o Swift and controlled motion
o Accurate positioning
o Static load resistant
o Appropriate for halting and starting intermittently with minimal wear and tear
o Reverse and forward motion
29
o High torque and Low speed for stability
o Adequate range of motion
Table 4 Driver Comparison
Weight Ac
Servo
DC
Stepper
Linear
motor
motor
motor
Motor
Actuator
2





3





load 3





1





Reverse and 2





Controlled
Motion
Accurate
Positioning
Static
resistant
Intermittent
working
forward
High torque
3





Cost
1





of 1





2
12
4
12
15
Range
motion
Total
16
For these reasons, linear actuators are the most commonly used for small scale solar
tracking and experimentation. These linear actuators are available in all sizes with
different speeds and force specifications and are relatively inexpensive compared to
other motors. However, owing to its limited range of motion, the design might become
more complex since rotary motion is the principle of motion of both degrees of
freedom.
30
Panel support frame
Comments
Strong and well
supported
Accomodate for
various panel sizes
Easy to
manufacture
Panel bolted on
support
Cost more than
two others
Comments
Panel is well
supported by two
angle bars but limits
the sizes
Strong and Reliable
Comments
Less material
required thus
cheaper but not
very strong
Much tension on
bolts since no side
support available
Option 1 is selected for its versatility and accommodation of different panel sizes
alongside actuator positioning space
31
Based on the above conclusions, the approximate design of the tracker is drawn
West
North
East
South
Figure 20 Preliminary design of Solar tracker
32
4.2.4 Sizing of parts and Calculations
To ensure a safe and reliable structure, several calculations have been carried out for
dimensioning and modelling parts which can be found below. The size and weight of
the panels have been slightly overestimated for safety after a brief analysis of the
available real-size panels.
Modelling the Panel support frame
Since most of the stresses, compressions and moments will be dependent on the weight
of the system since ideally no external forces will be made to apply on the tracker. The
solar panel frame support is expected to be built from steel due to wide availability of
sizes. The mass of that totality can be calculated by basic formulas. The cross-section
is shown below.
Area= Length (m) × width (m)
Eq (3)
Therefore, cross-sectional area= 40×20 38×18= 116mm2 ←
Figure 21 Rectangular tube Cross-section
Volume= Cross-sectional Area (m2) × total length (m)
Eq (4)
= 0.000116× (1.3×2 + 0.82×3)
= 0. 58696 × 10-3 m3 ←
Hence mass of the panel frame support is
Mass= Volume(m3) × Density(kg/m3) Eq (5)
= 0. 58696 × 10-3 × 7860
= 4.61kg ←
Now, the total mass of the frame and components; 2
rail support and one linear actuator bracket is
Figure 22 Panel Support frame
dimension
= 1.59 + 2 × 0.037 + 0.050
= 4.7375kg
33
∴ Since Weight = Mass × Gravity
Eq (6)
Total weight= 1.714 × 9.81= 46. 47 N ←
Modelling the Polar angle shafts
The total weight acting upon the two shafts is the above value added to the mass of
the solar panels which is not beyond 12kg. According to Equation 4, the net weight of
the panel and frame is 163.96N.
Figure 23 Moment on shaft for polar tracking
This can be further simplified for better analysis.
81.98N
81.98N
40
40
Figure 24 Moment of inertia for shaft
The minimum radius of the shaft can be calculated by the moment of inertia given by
dmax=
where,
d = deflection
F= Force
L= Perpendicular distance from Force
E= Young’s Modulus
I= Inertia
34
𝐹𝐿3
3𝐸𝐼
Eq (7)
Taking the maximum deflection to be 1mm and the length exaggerated to a 40mm, the
moment of inertia is
81.98 ×0.04 3
Inertia=
3 ×(200 × 109 )×0.001
= 8.7445 × 10 -12 m4 ←
Now that the minimum moment of inertia is obtained, the minimum radius of the shaft
can be calculated since, where r is the radius
Moment of Inertia of circle, I =
4
∴ r= √
𝜋𝑟 4
4
m4
Eq (8)
4 × 8.7445 ×10−12
π
= 1.8267 × 10-3 m ←
Thus a shaft of diameter 3.653mm shall be enough to allow motion without failure of
the tracker but the safety factor needs to be considered and moreover shafts and
associated components are not available for such small diameters, thus the closest
available diameter shaft will be used that is 10mm.
The maximum bending stress can be calculated by using the above results and
Equation 6:
Maximum
bending
stress,
s
,
(Pa)
𝑀𝑎𝑥𝑖𝑚𝑢𝑚 𝑀𝑜𝑚𝑒𝑛𝑡(𝑁𝑚) × 𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑜𝑓 𝑛𝑒𝑢𝑡𝑟𝑎𝑙 𝑎𝑥𝑖𝑠 𝑓𝑟𝑜𝑚 𝑒𝑑𝑔𝑒(𝑚)
𝑀𝑜𝑚𝑒𝑛𝑡 𝑜𝑓 𝐼𝑛𝑒𝑟𝑡𝑖𝑎 (𝑚4 )
Maximum bending stress, s =
=
Eq (9)
81.98 ×0.04 ×0.005
𝜋×0.0054
4
= 33.402 × 106 Pa ←
From the value above, the safety factor, which is compared to the yield stress, can be
calculated:
35
Safety Factor =
𝑌𝑖𝑒𝑙𝑑 𝑆𝑡𝑟𝑒𝑠𝑠 (𝑃𝑎)
𝐴𝑐𝑡𝑢𝑎𝑙 𝑆𝑡𝑟𝑒𝑠𝑠 (𝑃𝑎)
=
Eq (10)
250 × 106
33.402× 106
= 7.485 ←
Thus the 10 mm steel rod as a shaft can be approved and further components like
pillow cases of same bore diameter are to be evaluated.
Selecting Pillow-type bearing
The available pillow type bearing for 10mm shaft is:
Figure 25 Pillow case model and specifications [58]
The static load is denoted by COr and is 1950N which leads to a safety factor of
Safety Factor =
𝑀𝑎𝑥𝑖𝑚𝑢𝑚 𝐹𝑜𝑟𝑐𝑒 (𝑁)
𝐴𝑐𝑡𝑢𝑎𝑙 𝐹𝑜𝑟𝑐𝑒 (𝑁)
36
Eq (11)
=
1950
81.98
= 23.79 ←
Modelling Supporting Beam
Next, the rectangular frame upon which the pillow type bearings are mounted is to be
sized. This is done by using moment of inertia.
Figure 26 Forces on rectangular beam
As it can be seen, the right side of the tracker has got more forces causing an imbalance
about the pivot point in a clockwise direction. The linear actuator shall compensate by
applying a counter force to reach equilibrium. The weight of the linear actuator support
is made from mild steel and its weight is estimated by Equation 1, 2, 3 and 4 which
gives:
Cross-sectional Area=25×25 - 21×21= 184mm2
Volume= 0.000184 × 0.67 = 0.0001233 m3
Mass= 0.969 kg
Total mass (Bracket and linear actuator weight added) = 0.969 + 0.05 + 1.19 = 2.209kg
Weight = 21.67N ←
37
A simpler representation is shown below:
Figure 27 Moments of rectangular beam
The moment caused by the linear actuator and the support can be eliminated by
translating the entire bundle to the centre. This will also create swifter motion since
the polar linear actuator will act between the two pillow cases which was not the case
with previous designs thereby causing vibrations in the system.
Hence,
Figure 28 Improved design for polar actuator
Taking the maximum deflection to be 1mm, and using equation 5, the moment of
inertia is
=
81.98 × 0.293
3 ×(200×109 ) × 0.001
= 3.332 × 10-9 m4 ←
38
As for the rectangular tube’s size, the outer dimensions are 75x40mm and is available
in two thicknesses: 1.5mm and 2.5mm. The calculations shall be made for the 1.5mm
for safer results but 2.5mm might be used in case of constraints.
Moment of Inertia of rectangular hollow tube, Ixx (about x axis)
=
=
𝐵𝐷3
12
−
𝑏𝑑3
Eq (12)
12
0.075 × 0.0403
12
−
0.072 × 0.0373
12
= 9.608 × 10 -8 m4 ←
This moment of inertia is greater than the
minimum moment of 3.332 × 10-9, thus can be
used.
Figure 29 Moment of Inertia Dimensions
The maximum bending stress is found through equation 7:
=
81.98 ×0.29 ×0.020
9.608 × 10−8
= 4.949 × 10 6 Pa ←
∴ Safety Factor =
250 × 106
4.949 × 106
= 50.5 ←
Weight of the pillow cases, rail supports and shaft have not been considered due to
their negligible sizes which shall be compensated by the huge safety factor.
39
Modelling the Elevation Shaft
As for the azimuth tracking, the panel shall be pivoted in the stand by means of a shaft.
The entire weight of the panel, supporting frame, rectangular tube and components
shall fall on the shaft who in turn rests on the two sides in a hole primarily and the
welded rail supports. The compressive force, i.e. the weight of the above mentioned
things shall generate a stress which is calculated below:
The weight of the shaft, metal
plate and bracket is taken as a
safe N to be added to the
previous calculated weight
Net weight= 163.96+21.67+4
= 189.63 N
Figure 30 Compressive force exerted by elevation shaft
This entire will be acting on
two half circles of assumed radius of 6mm of certain thickness to be calculated thereby
having surface area = Circumference × Thickness
=2×
𝜋
2
×r×t
= 0.0188× t m2
Compressive stress, s (Pa) =
𝐹𝑜𝑟𝑐𝑒 (𝑁)
𝐴𝑟𝑒𝑎 (𝑚2 )
189.63
∴ Minimum area = 𝑀𝑎𝑥𝑖𝑚𝑢𝑚 𝑐𝑜𝑚𝑝𝑟𝑒𝑠𝑠𝑖𝑣𝑒 𝑠𝑡𝑟𝑒𝑠𝑠
Eq (13)
= 0.7585 × 10-6 m2
(250 𝑀𝑃𝑎)
Leading to minimum thickness, t (m)=
0.7585 ×10−6
0.0188
= 0.0403 mm ←
Since such small thicknesses are not available, it would be advisable to use the 2.5
mm thickness standard size and it shall also provide swifter and more stable motion
and shall be safer. Moreover, the weight of the 2.5mm tube will improve stability.
∴ The safety factor is calculated as done before and fount out to be = 62.1 ←
40
As for the minimum shaft diameter, the maximum deflection is taken as 0.1 mm, since
a slight bending might lead to resistant motion. The model is pictured below:
Figure 31 Moment of inertia of shaft
Applying equations 5 and 6, the minimum radius of the shaft can be found:
190 ×0.02253
Inertia=
3 ×(200 × 109 )×0.0001
= 5.41 × 10-11 m4
4
Radius=
√
4 × 5.41 ×10−11
π
= 2.88 mm ←
A 12 mm shaft will be used for safer and more reliable performance
Thus maximum bending stress is obtained via Equation 7
Maximum bending stress =
190 ×0.0225 ×0.006
𝜋×0.0064
4
= 25.2 × 106 Pa ←
Safety factor (Equation 8) =
41
250 × 106
25.2× 106
= 9.92 ←
Base Modelling
The dimension of the base is also of great significance since it shall determine the
stability of the entire tracker. The main cause of imbalance is the wind and design can
be modified for better wind resistance.
The centre of gravity of the tracker is vital in determining its tipping force, and for that
the weight of several parts and their respective centres of gravity have to be determined
with the assumption that the centre of gravity of each part lies in a single vertical axis
thus having similar x and z coordinates:
As for the main stand made of 50x50mm tube of thickness 2.5mm and length 0.95m
and with added components the centre of gravity acts at safely 0.45m off the ground
with a weight of 61.6N taking into account the linear actuator and its extension
support.
As for the solar panel and frame structure with components, the weight has already
been calculated previously and found to be 190N assumed to be acting at the elevation
pivot which is at 0.930. (P.s the centre of gravity shall be slightly off the vertical axis
since panel is at the right of it but deflection is negligible)
Centre of gravity =
𝛴 [(𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑝𝑎𝑟𝑡𝑠)(𝑟𝑒𝑠𝑝𝑒𝑐𝑡𝑖𝑣𝑒 𝑐𝑒𝑛𝑡𝑟𝑒 𝑜𝑓 𝑔𝑟𝑎𝑣𝑖𝑡𝑦)]
𝛴 (𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑝𝑎𝑟𝑡𝑠)
Eq (14)
=
[61.6×0.45]+[190×0.93]
61.6+190
=0.8125m ←
The legs have not been taken into consideration, since their length is to be
calculated and then weight to be determined. Moreover, since the legs shall add
weight to the tracker and cause greater clockwise moment to balance the wind
load.
42
West
East
Figure 32 Base Modelling
This model is simplified for better analysis below.
The coefficient of friction for steel to concrete (as in this case) contact is experimented
to be 0.57.
Since
Friction= Coefficient of friction (µ) × Perpendicular force
Eq (15)
Friction = 0.57 × 277 = 157.89N
As for the wind resistance, the solar tracker should be able to resist upto 50km/h
(14m/s) wind speed.
Wind Load =
1
2
× 𝑎𝑖𝑟 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 (
𝑘𝑔
𝑚
𝑚
𝑠
2
2
3 ) × 𝑤𝑖𝑛𝑑 𝑠𝑝𝑒𝑒𝑑 ( ) × 𝐴𝑟𝑒𝑎 (𝑚 )
43
Eq (16)
The air density in tropical regions is 1.225 kg/m3[59] and the surface area of the panel
of length 1.3m and width 0.9m is 1.17m2. However, the efficient area is 1.17cos(10)
as the panel is tilted at 10°, the latter being the closest achievable position to the
vertical axis. Thus area= 1.15m2
Wind load (N) = 0.5 × 1.225 × 142 × 1.15
= 138 N
Since the wind load is less than the frictional force, the tracker shall not be displaced
from the ground. Thus only possible motion is rotary about pivot point.
As for the length of the legs, it can be obtained via equilibrium of moments:
𝛴 𝑐𝑙𝑜𝑐𝑘𝑤𝑖𝑠𝑒 𝑚𝑜𝑚𝑒𝑛𝑡 = 𝛴 𝑠𝑢𝑚 𝑜𝑓 𝑎𝑛𝑡𝑖𝑐𝑙𝑜𝑐𝑘𝑤𝑖𝑠𝑒 𝑚𝑜𝑚𝑒𝑛𝑡𝑠 Eq (17)
Taking parallel (to force) length of leg as x,
252 × x = 138 × 0.93
x = 0.509m←
The ground length of the leg should thus be 0.509 but since it shall be slightly inclined
at 15° making the legs 526mm.
Note: Slight design changes might occur in the realisation due to manufacturing
limitations or other unforeseen circumstances. Yet, these shall be compensated by the
safety factors.
44
Final Design
Here is the final design, taking into consideration previous modifications (some
improvements based on further development shall also be made)
Figure 33 Final design
Figure 34 Final design Linear Actuators
45
Figure 35 Final design Pivots
Figure 36 Final design bearings
46
Static Panel Support
As for the fixed panel, a simple mild steel structure shall suffice to hold the panel at
20° facing the north. The panel can be bolted or secured in any suitable way and due
to the inclination, wind of 50km/h shall not cause any trouble as it shall be on the floor.
Figure 37 Static panel Support
However, such frame might not be necessary as the panel maybe simply rested on an
elevated base to the required angle without requiring the need to invest more money.
The efficient area shall be 1.17cos(70) = 0.4m2 and therefore wind load at 50km/h is
48N. The mass of the panel only is about 15kg and weight of 147N and therefor
friction between concrete and steel should be 83N, sufficient to resist the wind.
47
Further Modifications
As mentioned earlier, solar panels work better under ambient temperatures. However,
due to the sun exposure at peak hours, the panel’s temperature rises without fail
thereby negatively affecting the efficiency. The solution is as simple as implementing
a cooling system which detects the temperature rise and causes water to run over the
panel for some time by means of a pump. To avoid wastage of resources, the water is
collected and recirculated in a tank. The piping on the panel is as shown below
Figure 38 Solar tracker piping design
The black pipes are for water dispensing and the white for water collection. However,
due to the change in orientation of the tracker, drain hoses will have to be placed at
each corner and lead to a single tank for water recirculation. This can lead to tangling
of hoses or additional resistances to the motion of the tracker. Moreover, since
different sizes of panels are expected to be tested, a fixed draining system will not be
possible. This leading to a simple water cooling system which sprays water upon
temperature rise.
48
4.2.5 Mechanical Components Costing
Table 5 Mechanical components Cost
Component
Mild steel tube 2”x2”
Mild steel tube 2”x1”
𝟏
Mild steel tube 3”x1𝟐”
Mild steel tube 1”x1”
Flat mild steel 5mm
thickness
Mild steel shaft dia
10mm
Mild steel shaft dia
12mm
Mild steel bar ¾"
Length/mm
1260 mm
1710 mm
600 mm
Price/Rs
298
327
164
3580 mm
125 x 100 mm
65 x 150 mm
140 mm
394
50
70 mm
20
1150 mm
Quantity
bearing 2
Pillow type
10mm
Flange bearing 12mm
𝟏
M6 hex bolts 1𝟐”
Linear
Actuator
brackets
Piping
Pipe fittings
Total
30
100
75
2
12
75
3
4
10
10 m
-
300
300
2459
49
4.3 Electrical and Electronic design
Before diving into the components selection, the specifications pertaining to the
electronic design is to be listed. A microcontroller is used to be used for the controlling
of the solar tracker with the help of sensors and linear actuators.
4.3.1 Specifications of Electrical and Electronic Components
The components should be/use:
 Easy to interface with each other
 Available locally or reachable within time frame
 Within budget limit
 Compatible with microcontroller and vice versa for the development of a
functional system
 For better power tracking, a single battery/power source
 Able to output data to a data acquisition software for deeper analysis and
behaviour
The electrical/electronic system shall be divided into 2 categories: one in charge of
data acquisition while the other for controlling movement of the tracker. The relation
between these two shall be the power consumption and generation of the tracker
measured by the data acquisition system. Furthermore, two control algorithms shall be
executed, one for the Maximum Power Point tracking and the other for tracking the
maximum irradiance achievable by re-orientating the solar panel.
50
The controlling part of the solar tracker is first discussed.
Microcontroller selection
The most popular type is the Arduino Uno which is the most affordable and versatile.
However, before opting for the latter, several criteria need to be analysed:
Power efficiency: Draws 46.5mA at 5V which is not very efficient but might not cause
too much of a problem for our scenario
Temperature tolerance: Between -40°C and 85°C for proper functioning. Thus the
board shall be enclosed in a connection box to prevent damage
Security: security is not of any issue as the purpose is for low-scale research
Hardware architecture: Size is not of any problem as much space is available
Processing power: Atmega328 processor operating at 16MHz
Memory: 32KB of program memory which is amply enough
Hardware interface: supports USB cable and connection to PC and motor drivers
which are the only 2 interfacing requirements. Has 14 digital I/O pins and 6 analogue
inputs sufficient for our task
Software architecture: Simple and adaptive coding
Cost: The most affordable and available
Reliability: Reliable if well secured
From all the above details, it can be concluded that the Arduino Uno shall be the most
suitable selection for this research, mainly for its price and easy programming with
some minor trade-offs like power efficiency.
Figure 39 Arduino Uno
51
Linear actuator sizing
As for the linear actuators, the main requirement is the stroke length as the latter shall
limit the motion and allow the sun to be tracked faithfully. As deduced earlier (fig
2.09, 2.10), the elevation angle range should be 140° and polar angle range of 75°.
The length of the linear actuators shall be determined by locus drawing and trial and
error. For cost reduction, the design shall make use of the smallest possible stroke for
the linear actuators. Taking into consideration availability and other aforementioned
factors, a 400mm stroke for elevation tracking and 300mm stroke for polar tracking
are required.
Note that: the mounting length of each actuator is 140mm + stroke length.
Figure 40 Polar Linear actuator positioning and dimensions (full extension, perpendicular, full retraction)
Figure 41 Altitude Linear actuator positioning and dimensions (full extension, perpendicular, full retraction)
52
Valves
The cooling system shall operate on temperature rise and thus water flow is controlled
by a 12V solenoid valve operated by means of a relay and 5V Arduino signal.
Figure 42 Solenoid Valve
Pyranometer
The only available pyranometer is the DP 053 thermopile pyranometer which will be
used for the solar irradiance measurement. This can prove very fruitful when data
plotting and deeper analysis. Such a device shall allow us to determine when a cloud
has passed over the panel and of what opacity it has been, thus any fluctuation in power
at that particular time can be related to the cloud passing. This device however, uses
its own Arduino-based data logger using a battery as power source and configured via
its own software.
The Pyranometer outputs a very small voltage, 10-15 µV, per unit change in the
irradiance. Thus, for the data to be readable by the Arduino analogue pin, having 10bit resolution, the signal has to be amplified using an operational amplifier.
Figure 43 Pyranometer
53
Motor drivers or Relays
Drivers exist in different sizes for different purposes accommodating for one or more
motors. Since the linear actuators are of considerable length subjected to counter
forces and generate torque, a robust motor driver/relay shall be needed with high
enough current tolerance. As for motor drivers, these form an ideal solution when
speed needs to be controlled, which is not required in our case. Thus, the cheaper and
more effective option shall be a 4-channel 5V relay which shall be used to extend and
retract two linear actuators and additionally two more is required for the solenoid
valves.
Figure 44 Relay 4 Channel
Real-Time Clock
An RTC is required for keeping track of the time as the sun shall also be tracked based
on mathematical modelling. The available and most affordable RTC with good
accuracy was the RTC DS3231 accompanied with a small battery cell.
Figure 45 Real-Time Clock
54
Solar Panels
These shall be lent by local solar companies of real size components with two of each
kind to allow faithful comparison between solar tracking and fixed panel. The
specification sheets of the panel are found in the appendix. Since the solar panels shall
not be available in a single dimension, the panel frame support shall be modified to
accommodate for various panel sizes due to limited resources. Below is the modified
design
Figure 46 Modified Panel Support
This modification is heavier by the previous design but since the safety factors are also
greater than 5, this weight increase might not be of any problem. The weight increase
is of about 3kg to the support being 4.6kg. The following components are to be added
Table 6 Additional Mechanical Components Cost
Component
Length/mm
Price/Rs
8
7
M12 hex nuts
2
100
Bolt
160
Mild steel flat bar 2mm 50 x 2480mm
thickness
Rs 316
Total
The total costing for mechanical components thus amounts to 2775.
55
The final design thus looks like this
Figure 47 Modified Final Design
The second part pertains to the means of gathering data.
Data Acquisition System
The Data acquisition system consists of two parts, the hardware and software. The
available software is LABVIEW which has high processing speed using Graphical
User Interface (GUI) and can perform multiple collection of data with several DAQ
hardware simultaneously. As for the hardware, this research would need 8 input pins
with 2 output pins.
The 8 inputs correspond to:
1. Voltage and current generated by fixed system (2)
2. Voltage and current generated and consumed by dual axis solar tracker panel
(4)
3.
Temperature of both panels (2)
56
As for the 2 output pins, these correspond to setting the gate voltage of the mosfet for
the MPPT. Since only NI myDAQs are available consisting of 8 digital outputs/inputs,
two of those will be needed for the data collection connected to a PC via USB port.
Figure 48 NI myDAQ
Temperature sensors
IC LM35s are used for detecting the level of temperature for the cooling system
selected for its ease of use, good linearity and connection to Arduino. These are
mounted at the back of the panel via Omegatherm thermal paste to allow reliable
thermal conductivity for faithful measurements. For further details, see [60].
As for the ambient temperature measurement for data collection, J-type thermocouples
will be used with their data logger for better and more accurate results for analysis.
Figure 49 LM35 Temperature Sensor
57
Current and Voltage Sensors
The voltage can be measured with the NI myDAQ device itself having a range of 060V. The maximum voltage that can be generated is 59V in an open circuit condition
which is not planned to be encountered. Thus voltage will be well below the upper
limit of the device.
As for the current sensors, since much accuracy, precision and linearity is demanded
for researches, 2 HY-15P and 1 HY20-P sensors shall be used for current measuring.
These have been calibrated by means of a current supply and accurate ammeter. The
calibration is done to 9A as the maximum current shall be well below that. Given
that…
Figure 50 Current Sensor HY 15-P
Figure 51 Current sensor calibration circuit
58
Figure 52 Current sensor Calibration graph 1 (HY 15-P)
Changing axes will give: A=3.888V-0.0505
Figure 53 Current sensor Calibration graph 2 (HY 20-P)
Changing axes will give: A=5.1393V-0.0167
59
Figure 54 Current sensor Calibration graph 3 (HY 15-P)
Changing axes will give: A=3.8625V+0.027
MOSFET Selection
An adequate high power MOSFET is needed as much power shall be dissipated and a
robust design is demanded with suitable voltage and current characteristics. The
selection was very narrowed by the fact that only the APT5010JN MOSFET was
available and hence
used.
Figure 55 High power
MOSFET APT5010JN
Figure 56 MOSFET Calibration graph
60
Maximum Power Point Tracking
The second part being the Maximum Power Point Tracking (MPPT) shall be copied
from previous research performed by the University of Mauritius which implemented
the system using MOSFET and calibrated voltage and current sensors linked to a data
acquisition hardware. The MPPT circuit is found below:
Figure 57 Final MPPT circuit
The gate-source voltage of the MOSFET is varied according to the values of current
and voltage obtained to extract maximum power.
Supply
Since all drivers i.e. linear actuators and solenoid valves are rated 12V, a 12V power
supply with sufficient current capacity is selected for the supply which shall be
powered by local 230V rms.
61
Heat sink
Heat flow from component to ambient follows the below order
Figure 58 Heat flow for MOSFET
From the datasheet of the MOSFET, the values of thermal resistance of junction to
case and case to sink is of 0.30°C/W altogether as can be seen below.
Table 7 MOSFET heat specifications
The Junction to Ambient thermal resistance determines the rate at which total heat
dissipation shall take place and is the sum of RθJC, RθCS and RθSA (Thermal resistance
of sink to ambient) Thus,
RθSA = RθJA(max) - (RθJC + RθCS)
Eq (18)
The maximum Junction to Ambient thermal resistance, RθJA(max), is found using the
equation below:
TJ(max) = TA + (P × RθjA(max))
Eq (19)
Where TJ → Junction temperature
TA → Ambient temperature
P → Power to be dissipated
The power of the panel shall not exceed 90W under standard conditions of 25°C,
1000W/m2 and air mass 1.5 spectrum. These conditions are not easily attained in
outdoor conditions simultaneously and thus power harnessed is usually 15% less than
rated under the most favourable outdoor conditions. [62]
Thus 76.5W of power should be able to get dissipated without attaining the maximum
junction temperature of 150°C (Tj(max)) with an ambient of 31°C.
Hence,
RθJA(max)=1.556 °C/W
62
Leading to,
RθSA=1.256 °C/W←
Being the size of the heat sink required. However, to maintain a good working
performance the temperature of the MOSFET must not reach its limit, the heat sink
will thus be placed in water.
Also for bigger panels, two MOSFETs will need to be put in parallel to share the heat
dissipation as shown below.
Figure 59 Parallel MOSFET connection
63
Electrical Circuit
Figure 60 Detailed Microcontroller circuit
The microcontroller is powered by a USB cable from the PC loaded with LABVIEW.
The code is downloaded in the Arduino for its controlling algorithm and receives and
generates signal accordingly. The drivers all need 12V and since the Arduino can only
output small current and 5V, relays are used, two for each linear actuator namely for
extension and retraction and two for the solenoid valves. Two Arduino Unos have
been used as the analogue input pins were not enough and since the formers were
readily available for borrow, they have been opted for instead of a bigger
microcontroller. The power generated value is scaled down in the LABVIEW program
and fed into the Arduino Uno pin A0 for processing.
64
4.3.2 Electrical components costing
Table 8 Electrical components costing
Component
Quantity
Linear Actuator 400mm 1
Linear Actuator 300mm 1
2
Solenoid Valve 12V
70
Jumper Wires
2
Mini Breadboard
10
Dominos
HY 15P & 20P current 2
sensor
2
MOSFET APT5010JN
2
Solar Panel CdTe
Monocrystalline Solar 2
Panel
1
Relay 4-channel
1
Relay 2-channel
2
NI myDAQ
2
Heat sink
1
RTC DS3231
1
LDR sensor
2
Arduino UNO
Pyranometer + Data 1
logger
Thermocouple + Data 1
logger
Wires and Cables
Total
The total cost of the project thus amounts to Rs 11800.
65
Price + Shipping /Rs
2186 + 1987
2030 + 1987
295
2
75
5
On Loan
On Loan
On Loan
On Loan
On Loan
On Loan
On Loan
On Loan
On Loan
On Loan
On Loan
On Loan
On Loan
200
9025
4.4 Software Design
The software design is divided into two categories: MPPT tracking and linear actuator
control for tracking the sun. The first part shall be programmed in LABVIEW which
also allows data collection and the second part shall be programmed via the Arduino
IDE.
Solar
Panel
Actuators
Sensors/
Transduc
er
Microcontroller
NI
myDAQ
LABVIE
W and
MPPT
Figure 61 Overall System
4.4.1 LABVIEW Program
The MPP tracking, as mentioned before, is the variation of the resistance across the
solar panel to exhort the panel to output maximum power. This is done with the help
of a MOSFET whose resistance can be varied by wavering the gate-source voltage.
The program thus outputs a voltage to the gate of the MOSFET according to the
Perturb and Observe algorithm. The required input data are the voltage and current
which are multiplied to obtain the power, whose fluctuations are tracked and
monitored by the algorithm to increase or decrease the outputted voltage.
With the help of the NI myDAQ, the program reads the voltage across the solar panel
via the differential multi-meter and also the voltage signal generated by the current
sensor which is then processed to obtain the current value. All the values are plotted
66
on a real time chart and stored in an array which can be retrieved after the program is
stopped.
This process is the same for both the solar panels, on and off tracker.
Figure 62 MPPT flowchart
Since, the current sensor output voltage was very noisy and unstable, a filter had to
allow only the low frequency signals to pass through (0.01Hz) and attenuate the higher
frequency values. The downfall of that system is the significant delay of 6 seconds
caused by the low-pass filter to smoothen the waveform. Hence a moving average
system was opted for since the noise could be observed oscillating about the true value.
The moving average filter selected is the Henderson’s 23 points for its responsiveness
and smoothness.
67
𝑀−1
1
∑ 𝑥 [𝑛 − 𝑙 ]
𝑀𝑜𝑣𝑖𝑛𝑔 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 =
𝑀
𝐸𝑞 (20)
𝑙=0
where M is the number of points.
Below are the charts for the filtered and unfiltered signals for low and high current.
Figure 63 Filtered and Unfiltered Signal for low current
Figure 64 Filtered and Unfiltered Signal for high current
Low-pass filter → cut-off frequency 0.2
Low-pass filter 2 → cut-off frequency 0.02
The former is more responsive to the cost of fluctuations while the second being
delayed. The 9-points moving average is quite similar to the first low-pass filter but
68
still noisy as can be seen from Figure 67. Thus, the 23-points moving average is opted
for. However, since there shall still remain some minor fluctuations in the current, the
P&O systems compensates for that error by demanding changes greater than 0.02W
instead of 0.
69
4.4.2 Arduino Coding
The linear actuators and valves shall be controlled via Arduinos. Three different
programs are written in the IDE: two pertaining to the linear actuator control and one
for the valves. These can be found in Appendix D.
Perturb and Observe
Where both the actuators rely on the P&O algorithm having as input the potentiometer
value and power value from the NI myDAQ. The actuators shall extend in discrete
steps and thus the speed of the actuator was determined to maintain 1° or 2° steps.
Figure 65 Perturb and Observe flowchart
70
Mathematical Modelling
In this system, the polar actuator is controlled by the P&O algorithm and the elevation
actuator by mathematical modelling i.e. the date and time obtained from the RTC is
used to calculate the sun elevation angle and determine accordingly the length of the
actuator based on equation 1 and 2. The relation between the potentiometer reading
and actuator length was found in order to extend the actuator to the correct length and
also the relation between the length of the actuator to the elevation angle which is
found via AutoCAD.
Figure 66 Calibration of Elevation actuator
Figure 67 Calibration of Polar actuator
Figure 68 Elevation actuator calibration vis a vis Elevation angle
The values obtained from AutoCAD were plotted in Matlab and a curve of best fit
with known equation was found.
71
Figure 69 Mathematical Modelling flowchart
72
Table 9 Logic control conditions
Power→
NB
NS
ZE
PS
PB
NB
PB
PB
PS
NB
NB
NS
PB
PS
NB
NS
NB
ZE
PS
PS
ZE
NS
NS
PS
NB
NS
PB
PS
PB
PB
NB
NB
NS
PB
PB
Potentiometer↓
NB→ negative big
NS→ negative small
ZE→ zero
PS→ positive small
PB→ positive big
Coding can be found in Appendix D.
73
Water Cooling System
The testing is to be done in winter with ambient temperature not exceeding 25°C in
midday. Therefore, the panel temperature can be maintained near the ambient for
maximum power harnessing.
The water cooling system would act by opening and closing a valve, the amount of
time to keep the valve opened is deduced by cooling the panel for 3 seconds at several
intervals and the graph below is plotted.
The water cooling shall be
activated when the temperature
reaches 30°C and therefore, it
shall take about 70 seconds to
reach the ambient temperature.
(obtained from graph)
Figure 70 Water cooling data
Figure 71 Water cooling program flowchart
74
5.0 Implementation and Testing
5.1 Problems faced and actions taken
Linear Actuator
The elevation linear actuator stopped extending while drawing very high current under
supposedly no load. Upon investigation it was found that a gear got stuck and therefore
it was removed and relocated. Unfortunately, the potentiometer with the actuator
stopped working after the unmounting process. Therefore, it was replaced by the
potentiometer of the polar actuator as it was more needed in the elevation for the
mathematical modelling. The feedback of the polar actuator was hence removed and
the Arduino coding would keep up the P&O algorithm by keeping track of the last
motion.
Temperature Sensor
The lm35 sensor seemed to be giving varying outputs for same temperature. After
troubleshooting, the reason seemed to be the additional resistance of the long wires to
the sensor. Hence, a single lm35 was placed on the back of the tracker’s panel
responsible for opening a single valve to cool both panels.
MPPT and Solar tracking
The motion of the linear actuators appeared unjustified depending on the sun location.
This was due to the simultaneous tracking of the maximum power point and the
maximum irradiance. As a solution, anytime the actuator would move, the MPPT
tracker would temporarily stop.
Noisy current sensor output
This problem has already been discussed in the section 4.4.1.
Unnoticeable changes in Power
The extension and retraction were initially set to steps of 3mm which did not bring
about any consequent power change given the current sensor noises, thus the steps had
to be increased to more than 10mm jeopardizing the precision of the solar tracking.
75
Additional Modifications
Another modification shall be the leg design, for more secure system the prototype
can be bolted down but shall require flat legs.
Figure 72 Modified leg design
Power consumed
The actuators move for discrete small time intervals which are difficult to record via
sensors accurately, thus the count of the extensions and retractions are kept in the
Arduino serial monitor. The actuator is rated 12V and consumes 0.5A which is helpful
in finding the energy consumed.
5.2 Implementation
Figure 73 Realised model vs designed model
76
Pyranomete
r
Camp
Solar Tracker
Static Panel
Figure 74 Complete Set up
Figure 75 Pyranometer Setup
77
Figure 76 Water Cooling Tracker
Figure 78 Water Cooling Static Panel
MOSFET
NI-myDAQ
Current sensor
4-relay
NI-myDAQ
RTC
2 Arduino
MOSFET
Current sensor
2-relay
Figure 77 Electrical Circuit Setup
78
09:11:30
09:15:32
09:19:34
09:23:36
09:27:38
09:31:40
09:35:42
09:39:44
09:43:46
09:47:48
09:51:50
09:55:52
09:59:54
10:03:56
10:07:58
10:12:00
10:16:02
10:20:04
10:24:06
10:28:08
10:32:10
10:36:12
10:40:14
10:44:16
10:48:18
10:52:20
10:56:22
11:00:24
11:04:26
11:08:28
11:12:30
11:16:32
11:20:34
11:24:36
11:28:38
11:32:40
11:36:42
11:40:44
11:44:46
11:48:48
11:52:50
11:56:52
12:00:54
12:04:56
12:08:58
Temperature/°C
09:11:30
09:16:24
09:21:18
09:26:12
09:31:06
09:36:00
09:40:54
09:45:48
09:50:42
09:55:36
10:00:30
10:05:24
10:10:18
10:15:12
10:20:06
10:25:00
10:29:54
10:34:48
10:39:42
10:44:36
10:49:30
10:54:24
10:59:18
11:04:12
11:09:06
11:14:00
11:18:54
11:23:48
11:28:42
11:33:36
11:38:30
11:43:24
11:48:18
11:53:12
11:58:06
12:03:00
12:07:54
Irradiance/Wm-2
6.0 Data Collection, Results and
Discussion
All the tests have been done using 50W monocrystalline panel at single location of
20.0177903 south and 57.5786805 east.
6.1 Ambient Conditions
The temperature and irradiance of cloudy and sunny weathers are first analysed before
proceeding
Irradiance Sunny and Cloudy vs Time
1400
1200
1000
800
600
400
200
0
Time
Sunny
Ambient Sunny
Tracker Sunny
Cloudy
Figure 79 Irradiance Sunny vs Cloudy Graph
50
Temperature Sunny and Cloudy vs Time
45
40
35
30
25
20
15
10
5
0
Time
Static Sunny
79
Ambient Cloudy
Tracker Cloudy
Figure 80 Temperature Sunny vs Cloudy Graph
Static Cloudy
Observations
-
The temperature of the cloudy weather is far lower than sunny for all three
categories: Ambient, static and tracker.
-
The cloudy weather temperature has greater variations and the sunny weather
is pretty stable and increasing.
-
The cloudy temperature rarely exceeds 35°C and stays pretty low, therefor not
requiring the water cooling system.
-
The irradiance in the cloudy weather exceeds the irradiance of sunny weather
at its peaks.
For each condition, three tables are listed:
1. Efficiency of algorithm in specific weather condition
2. The maximum power recorded for the tracker and static panel and conditions
at that time
3. The minimum, maximum and average values recorded for each data set
80
09:16:01
09:20:51
09:25:41
09:30:31
09:35:21
09:40:11
09:45:01
09:49:51
09:54:41
09:59:31
10:04:21
10:09:13
10:14:03
10:18:53
10:23:43
10:28:33
10:33:23
10:38:13
10:43:03
10:47:55
10:52:45
10:57:35
11:02:25
11:07:15
11:12:05
11:16:55
11:21:45
11:26:35
11:31:25
11:36:15
11:41:05
11:45:55
11:50:45
11:55:35
12:00:25
12:05:15
12:10:07
12:14:57
Power/W
40
30
25
800
20
600
15
5
0
Ambient
Tracker
Tracker
Static
50
45
40
10
5
0
Static
the ambient temperature
81
Irradiance/Wm-2
45
35
1000
30
25
800
20
600
15
400
Irradiance/Wm-2
09:16:01
09:21:35
09:27:09
09:32:43
09:38:17
09:43:51
09:49:25
09:54:59
10:00:33
10:06:09
10:11:43
10:17:17
10:22:51
10:28:25
10:33:59
10:39:33
10:45:09
10:50:43
10:56:17
11:01:51
11:07:25
11:12:59
11:18:33
11:24:07
11:29:41
11:35:15
11:40:49
11:46:23
11:51:57
11:57:31
12:03:05
12:08:39
12:14:15
°
Temperature/ C
6.2 P&O in Cloudy Conditions
Date: 09 July 2022
Temperature and Irradiance vs Time
1400
35
1200
1000
10
400
200
0
Time
Irradiance
Figure 81 P&O Cloudy Temperature and Irradiance Graph
Power and Irradiance vs Time
1400
1200
200
0
Time
irradiance
Figure 82 P&O Cloudy Power and Irradiance Graph
Observations
The recorded temperatures vary with the irradiance with least effect being on
-
The power generated follows faithfully the irradiance except for acute peaks
of irradiance as at 9:43:01. This is due to the time taken for the MPPT to reach
its required value.
-
Since all the values are not recorded on a single platform, some time
misalignment occurred
-
The power drops to nearly zero every time a cloud blocks the sun. This is due
to the system short circuiting as the Vgs was high for maximum power
generation in high irradiance and the irradiance drop caused by the sudden
cloud causes short circuit before the Vgs drops.
Table 10 Efficiency of P&O in cloudy weather
Total Energy
Generated
Consumed
Efficient
Energy/J
Energy/J
Energy/J
Tracker
187947.3
-6381
181566.3
Static
171954.7
0
171954.7
Efficiency
105.5%
Table 11 P&O Cloudy Maximum power
Tracker
ambient
Time
Temp/
Static
Irradiance Temp/ Voltage Current Power/ Temp Voltage Current Power/
/Wm-2
°C
11:01:11 22.91
1063.4
31.52 16.937 2.6382 44.684 28.75 13.313 1.9532 26.003
12:16:01 25.82
1205.4
33.08 20.509 0.7479 15.340 35.95 14.769 2.6350 38.919
°C
/V
/A
W
/°C
/V
/A
W
Table 12 P&O Cloudy Minimum Maximum and Average values
Tracker
Ambient Irradiance/ Temp/
Temp/
Wm-2
Static
Voltage/ Current/ Power/ Temp/ Voltage/ Current/ Power/
°C
V
A
W
°C
V
A
W
23.1
0.11561 0.222
0.1096 23.88 0.0906
0.2367 0.0322
38.2
21.3769 2.83261 44.684 39.58 21.157
2.6423 38.919
°C
Minimum
20.79
130.2
Maximum
26.89
1222.3
Average
23.7044 630.722
31.761 16.3562 1.06398 17.086 31.222 13.2638 1.17822 15.632
82
The efficiency appeared too low, thus some parameters were altered and tested again
under only overcast weather.
Date: 25 July 2022
45
40
35
30
25
20
15
10
5
0
1000
800
600
400
200
Irradiance/Wm-2
1200
0
09:58:01
09:58:35
09:59:09
09:59:43
10:00:17
10:00:51
10:01:25
10:01:59
10:02:33
10:03:07
10:03:41
10:04:17
10:04:51
10:05:25
10:05:59
10:06:33
10:07:07
10:07:41
10:08:15
10:08:49
10:09:23
10:09:57
10:10:31
10:11:05
10:11:39
10:12:13
10:12:47
10:13:21
10:13:55
10:14:29
Power/W
Power and Irradiance vs Time
Time
Tracker
Static
Irradiance
Figure 83 P&O Modified Cloudy Power and Irradiance Graph
Table 13 Efficiency of P&O Modified in cloudy weather
Total Energy
Generated
Consumed
Efficient
Energy/J
Energy/J
Energy/J
Tracker
5402.683
-520.7
4881.9
Static
3857.528
0
3857.528
Efficiency
126.55%
Observations
-
The efficiency improved by 21.05% but unfortunately the cloudy condition did
not last longer for more data to be collected.
-
Both panels share similar responsiveness.
83
12:39:27
12:43:57
12:48:27
12:53:01
12:57:33
13:02:05
13:06:39
13:11:11
13:15:45
13:20:17
13:24:49
13:29:23
13:33:55
13:38:27
13:43:01
13:47:33
13:52:07
13:56:39
14:01:11
14:05:45
14:10:15
14:14:47
14:19:21
14:23:53
14:28:27
14:32:59
14:37:31
14:42:05
14:46:37
14:51:09
14:55:43
15:00:15
15:04:49
15:09:21
15:13:53
15:18:27
15:22:59
15:27:31
15:32:05
15:36:37
15:41:11
Power/W
45
40
35
30
25
20
15
10
5
0
800
600
400
Ambient
Tracker
Tracker
Static
50
45
35
30
20
15
5
0
Static
conditions. This can be observed in the P&O cloudy also.
84
Irradiance/Wm-2
1000
1000
25
800
600
400
Irradiance/Wm-2
12:39:27
12:45:09
12:50:57
12:56:45
13:02:33
13:08:19
13:14:07
13:19:55
13:25:43
13:31:29
13:37:17
13:43:05
13:48:53
13:54:39
14:00:27
14:06:15
14:12:01
14:17:47
14:23:35
14:29:23
14:35:11
14:40:57
14:46:45
14:52:33
14:58:21
15:04:07
15:09:55
15:15:43
15:21:31
15:27:17
15:33:05
15:38:53
Temperature/ °C
6.3 Mathematical Modelling in Cloudy Conditions
Date: 09 July 2022
Temperature and Irradiance vs Time
1400
1200
200
0
Time
Irradiance
Figure 84 Mathematical Modelling Cloudy Temperature and Irradiance Graph
Power and Irradiance vs Time
1400
40
1200
10
200
0
Time
Irradiance
Figure 85 Mathematical Modelling Cloudy Power and Irradiance Graph
Observations
The tracker power generated clearly outstrips the static power by much under
sunny conditions though it does not appear to be the case under cloudy
-
It was also observed for both cloudy weathers that the tracker would keep
facing the sun until the irradiance was well below 400Wm-2 which require
thick clouds.
Table 14 Mathematical Modelling in Cloudy Condition
Total Energy
Tracker
Static
Generated
Energy/J
224369.6
194786.9
Consumed
Energy/J
-2613
0
Efficient
Energy/J
221756.6
194786.9
Efficiency
113.8 %
Table 15 Mathematical Modelling Cloudy Maximum power
Tracker
ambient
Temp
/°C
15:01:37 25.34
13:53:17 25.8
Time
Static
Irradianc Temp/ Voltage Current Power/ Temp Voltage Current Power/
e/Wm-2 °C
/V
/A
W
/°C /V
/A
W
764.8
847.5
37.28
38.87
15.781 2.798 44.161 36.35 15.218 1.9403 29.528
20.082 0.8607 17.284 40.48 16.898 1.9005 32.117
Table 16 Mathematical Modelling Cloudy Minimum Maximum and Average values
Tracker
Static
Ambient Irradiance/ Temp/ Voltage/ Current/ Power/ Temp/ Voltage/
Temp/ Wm-2
°C
V
A
W
°C
V
°C
Minimum
21.05
89.9
22.01 0.13874 0.13155 0.0619 23.08 0.0906
Maximum
27.12
1221.5
41.39 21.4463 2.81166 44.161 42.26 20.5967
Average
24.3337 596.295
33.0134 15.8988 1.3161 20.397 34.119 13.5342
85
Current/ Power/
A
W
0.15217 0.0690
2.13103 32.117
1.30582 17.707
09:11:30
09:16:10
09:20:50
09:25:30
09:30:10
09:34:50
09:39:30
09:44:10
09:48:50
09:53:30
09:58:10
10:02:50
10:07:30
10:12:10
10:16:50
10:21:30
10:26:10
10:30:50
10:35:30
10:40:10
10:44:50
10:49:30
10:54:10
10:58:50
11:03:30
11:08:10
11:12:50
11:17:30
11:22:10
11:26:50
11:31:30
11:36:10
11:40:50
11:45:30
11:50:10
11:54:50
11:59:30
12:04:10
12:08:50
Power/W
45
40
-
35
900
30
25
800
20
700
15
10
600
5
0
Ambient
Tracker
Tracker
Static
45
40
35
30
25
20
15
10
5
0
Static
morning
86
Irradiance/Wm-2
50
800
600
400
Irradiance/Wm-2
09:11:30
09:17:58
09:24:26
09:30:54
09:37:22
09:43:50
09:50:18
09:56:46
10:03:14
10:09:42
10:16:10
10:22:38
10:29:06
10:35:34
10:42:02
10:48:30
10:54:58
11:01:26
11:07:54
11:14:22
11:20:50
11:27:18
11:33:46
11:40:14
11:46:42
11:53:10
11:59:38
12:06:06
Temperature/ °C
6.4 P&O Sunny Weather without Water Cooling System
Date: 16 July 2022
Temperature and Irradiance vs Time
1100
1000
500
400
Time
Irradiance
Figure 86 P&O Sunny Temperature and Irradiance Graph
Power and Irradiance vs Time
1200
1000
200
0
Time
Irradiance
Figure 87 P&O Sunny Power and Irradiance Graph
Observations
Two small clouds passed by around 9:38 and 9:44 which caused two short-
lived power drops in both powers.
The tracker provides a more constant and stable power throughout the sunny
-
The average of the static follows the irradiance curve with much fluctuations,
the cause of the latter being the current sensor noises.
-
The temperature of both the panels rise with the irradiance with the tracker
being higher than the static temperature before the latter caught up and
exceeded the tracker temperature. This is due the fact that the tracker at times
moves away from the sun to find maximum power and the static staying
completely still. However, in the early morning, the tracker enjoys more
benefit of direct heat despite its motion.
Table 17 Efficiency of P&O in Sunny Conditions
Total Energy
Tracker
Static
Generated
Energy/J
375972.4
240278.9
Consumed
Energy/J
-5058
0
Efficient
Energy/J
371914.4
240278.9
Efficiency
154.4%
Table 18 P&O Sunny Maximum power
Tracker
ambient
Time
Temp/
°C
12:08:10 27.19
11:49:02 28
Static
Irradianc Temp/ Voltage Current Power/ Temp Voltage Current Power/
e/Wm-2 °C
/V
/A
W
/°C /V
/A
W
1005.1
1000.8
40.55
43.31
15.398 2.6729 41.159 44.12 15.834 2.1707 34.372
14.818 2.4761 36.694 45.1 15.767 2.5675 40.482
Table 19 P&O Sunny Minimum Maximum and Average values
Ambient Irradiance/
Temp/ Wm-2
°C
Minimum
24.35
394.1
Maximum
29.29
1007.4
Average
27.0054 862.434
Tracker
Static
Temp/ Voltage/ Current/ Power/ Temp/ Voltage/ Current/ Power/
°C
V
A
W
°C
V
A
W
35.64
0.10424 0.20273 0.6221 28.83 0.08554 0.16313 0.0509
43.36
20.7279 2.71331 41.159 45.64 20.0926 2.56756 40.482
39.4669 15.0375 2.30747 34.735 39.071 16.2514 1.37907 22.149
87
6.5 P&O Sunny Weather with Water Cooling System
Date: 25 July 2022
45
1400
40
1200
1000
30
25
800
20
600
15
400
10
5
200
0
0
09:12:49
09:18:19
09:23:49
09:29:19
09:34:49
09:40:21
09:45:51
09:51:21
09:56:51
10:02:21
10:07:53
10:13:23
10:18:53
10:24:23
10:29:53
10:35:25
10:40:55
10:46:25
10:51:55
10:57:25
11:02:55
11:08:25
11:13:55
11:19:25
11:24:55
11:30:25
11:35:55
11:41:25
11:46:55
11:52:25
11:57:57
12:03:27
12:08:57
12:14:27
12:19:57
Tenperature/°C
35
Irradiance/Wm-2
Temperature and Irradiance vs Time
Time
Tracker
Static
Ambient
Irradiance
Figure 88 P&O Sunny Water Cooling Temperature and Irradiance Graph
60
1400
50
1200
1000
40
800
30
600
20
400
10
Irradiance/Wm-2
Power/W
Power and Irradiance vs Time
200
0
09:51:01
09:55:41
10:00:21
10:05:03
10:09:43
10:14:23
10:19:03
10:23:43
10:28:23
10:33:03
10:37:45
10:42:25
10:47:05
10:51:45
10:56:25
11:01:05
11:05:45
11:10:25
11:15:05
11:19:45
11:24:25
11:29:05
11:33:45
11:38:25
11:43:05
11:47:45
11:52:25
11:57:07
12:01:47
12:06:27
12:11:07
12:15:47
12:20:27
0
Time
Tracker
Static
Irradiance
Figure 89 P&O Sunny Water Cooling Power and Irradiance Graph
Observations
-
The weather was mostly sunny as from 10:14 with passing clouds causing
fluctuations in the powers.
-
A delay varying from 30sec to 1min is needed for the MPPT to catch up with
the irradiance depending on the opacity of the clouds.
-
Effective water cooling system
88
-
Low panel temperatures during low irradiance.
Thus two different efficiencies are calculated to compensate for the clouds. This is
done by taking on the values for the irradiance above 600W/m-2.
The valve used was spring-return which as a result consumed much energy to operate.
It would thus be more appropriate to use latching valves for better economy. The
consumption of the valve was 6W which is consequent over extended period of time
and thus not included in calculating efficiency as better option is available.
Table 20 Efficiency of P&O Water Cooling in Sunny Conditions
Total Energy
>600Wm-2
Tracker
Static
Tracker
Static
Generated
Energy/J
285945.8
195107
133160.6
89357.93
Consumed
Energy/J
-4791
0
-3981.4
0
Efficient
Energy/J
281154.8
195107
129179.2
89357.93
Efficiency
144.1%
144.6%
Table 21 P&O Sunny Water Cooling Maximum power
Tracker
ambient
Time
Temp/°
C
11:31:31 28
11:41:57 27.81
Static
Irradianc Temp/ Voltage Current Power/ Temp Voltage Current Power/
e/Wm-2 °C
/V
/A
W
/°C /V
/A
W
1159.3
1073.6
25.38
27.41
15.514 3.2695 50.724 24.2 14.526 2.3602 34.286
18.874 1.9347 36.517 25.07 18.348 2.0872 38.298
Table 22 P&O Sunny Water Cooling Minimum Maximum and Average values
Tracker
Ambient Irradiance/ Temp/ Voltage/ Current/
Temp/° Wm-2
°C
V
A
C
Minimum
24.89
136.4
23.74 0.10424 0.14185
Maximum
29.29
1264
35.36 21.5389 3.27649
Average
27.3961 871.261
29.8619 16.0208 1.87446
89
Static
Power/ Temp/ Voltage/ Current/ Power/
W
°C
V
A
W
0.0439 23.69 0.04083 0.03074 0.0561
50.724 33.22 21.825
2.46999 38.298
30.98
0.98842 21.138
27.561 17.697
12:35:01
12:39:29
12:43:57
12:48:25
12:52:53
12:57:21
01:01:49
01:06:17
01:10:45
01:15:13
01:19:41
01:24:09
01:28:37
01:33:05
01:37:33
01:42:01
01:46:29
01:50:57
01:55:25
01:59:53
02:04:21
02:08:49
02:13:17
02:17:45
02:22:13
02:26:41
02:31:09
02:35:37
02:40:05
02:44:33
02:49:01
02:53:29
02:57:57
Power/W
50
45
40
35
30
25
20
15
10
5
0
800
600
400
Ambient
Tracker
Tracker
Static
50
45
40
35
30
25
20
15
10
5
0
1000
800
600
400
Static
90
Irradiance/Wm-2
1000
Irradiance/Wm-2
12:35:01
12:39:29
12:43:57
12:48:25
12:52:53
12:57:21
01:01:49
01:06:17
01:10:45
01:15:13
01:19:41
01:24:09
01:28:37
01:33:05
01:37:33
01:42:01
01:46:29
01:50:57
01:55:25
01:59:53
02:04:21
02:08:49
02:13:17
02:17:45
02:22:13
02:26:41
02:31:09
02:35:37
02:40:05
02:44:33
02:49:01
02:53:29
02:57:57
Temperature/°C
6.6 Mathematical Modelling Sunny Weather without Water
Cooling System
Date: 25 July 2022
Temperature and Irradiance vs Time
1400
1200
200
0
Time
Irradiance
Figure 90 Mathematical Modelling Sunny Temperature and Irradiance Graph
Power and Irradiance vs Time
1400
1200
200
0
Time
Irradiance
Figure 91 Mathematical Modelling Sunny Power and Irradiance Graph
Observations
Weather similar to P&O cloudy with water cooling and so are the observations.
Table 23 Efficiency of Mathematical Modelling in Sunny conditions
Tracker
Static
Tracker
>600Wm-2
Static
*For clouds compensation
Total Energy
Generated
Energy/J
269114.4
209489
126838.3
99002.72
Consumed
Energy/J
-2004.6
0
-1767
0
Efficient
Energy/J
267109.8
209489
125071.3
99002.72
Efficiency
127.5%
126.3%
Table 24 Mathematical Modelling Sunny Maximum power
Tracker
ambient
Temp/°
C
13:54:47 24.02
13:42:49 24.28
Time
Static
Irradianc Temp/ Voltage Current Power/ Temp Voltage Current Power/
e/Wm-2 °C
/V
/A
W
/°C /V
/A
W
1061.3
1015.6
38.74
42.89
14.818 3.0599 45.345 40.44 17.544 1.4833 26.024
14.355 2.7846 39.973 44.38 16.985 2.3378 39.708
Table 25 Mathematical Modelling Sunny Minimum Maximum and Average values
Ambient Irradiance/
Temp/° Wm-2
C
Minimum
22.87
158.1
Maximum
28.39
1195.4
Average
25.0306 840.958
Tracker
Static
Temp/ Voltage/ Current/ Power/ Temp/ Voltage/ Current/ Power/
°C
V
A
W
°C
V
A
W
33.89
0.10424 0.31283 0.0422 35.63 0.16378 0.16378 0.0688
43.52
20.7279 3.10559 45.345 44.92 20.6514 2.46351 39.708
39.6433 15.2382 2.05904 30.616 41.266 16.0393 1.40461 23.832
91
6.7 Mathematical Modelling Sunny Weather with Water
Cooling System
Date: 16 July 2022
Temperature and Irradiance vs Time
50
1100
45
1000
900
35
30
800
25
700
20
15
600
Irradiance/Wm-2
Tempeature/°C
40
10
500
5
0
12:30:53
12:36:57
12:43:01
12:49:05
12:55:09
01:01:13
01:07:17
01:13:21
01:19:25
01:25:29
01:31:33
01:37:37
01:43:41
01:49:45
01:55:49
02:01:53
02:07:57
02:14:01
02:20:05
02:26:09
02:32:13
02:38:17
02:44:21
02:50:25
02:56:29
03:02:33
03:08:37
03:14:41
03:20:45
03:26:49
400
Axis Title
Ambient
Tracker
Static
Irradiance
Figure 92 Mathematical Modelling Sunny Water Cooling Temperature and Irradiance Graph
50
45
40
35
30
25
20
15
10
5
0
1200
800
600
400
Irradiance/Wm-2
1000
200
0
12:30:53
12:36:23
12:41:53
12:47:23
12:52:53
12:58:23
01:03:53
01:09:23
01:14:53
01:20:23
01:25:53
01:31:23
01:36:53
01:42:23
01:47:53
01:53:23
01:58:53
02:04:23
02:09:53
02:15:23
02:20:53
02:26:23
02:31:53
02:37:23
02:42:53
02:48:23
02:53:53
02:59:23
03:04:53
03:10:23
03:15:53
03:21:23
03:26:53
Power/W
Power and Irradiance vs Time
Time
Tracker
Static
Irradiance
Figure 93 Mathematical Modelling Sunny Water Cooling Power and Irradiance Graph
Observations
-
Two small glitches occurred in the tracker power which might have been due
to the tracker moving too far away from the sun
-
A consequent glitch also happened in the static power which was due to the
current sensor noises.
92
-
The static power is again seen to follow the irradiance curve as in the P&O
sunny weather.
-
The effect of the water cooling system can be seen on the temperature graph
with two abnormal peaks of 40°C before the system stabilized.
Note: Energy consumed by the valve has not been taken into account for
aforementioned reason.
Table 26 Efficiency of Mathematical Modelling with Water Cooling in Sunny Conditions
Total Energy
Tracker
Static
Generated
Energy/J
407374.7
306562.8
Consumed
Energy/J
-2761
0
Efficient
Energy/J
404613.5
306562.8
Efficiency
131.98%
Table 27 Mathematical Modelling Sunny Water Cooling Maximum power
Tracker
ambient
Temp/°
C
12:41:49 25.01
13:00:15 24.11
Time
Static
Irradianc Temp/ Voltage Current Power/ Temp Voltage Current Power/
e/Wm-2 °C
/V
/A
W
/°C /V
/A
W
1003.1
995.3
29.54
34.67
17.831 2.4685 44.017 27.27 17.533 1.9137 33.554
15.745 2.7065 42.616 29.52 17.320 2.6444 45.803
Table 28 Mathematical Modelling Sunny Water Cooling Minimum Maximum and Average values
Ambient Irradiance/
Temp/° Wm-2
C
Minimum
22.87
545.8
Maximum
28.39
1015.6
Average
25.1368 856.266
Tracker
Static
Temp/ Voltage/ Current/ Power/ Temp/ Voltage/ Current/ Power/
°C
V
A
W
°C
V
A
W
27.44
0.10424 0.2276 0.0904 25.69 11.6315 0.13857 2.8586
40.29
21.0755 2.77006 44.017 36.98 20.7297 2.64444 45.803
32.5469 15.2808 2.43229 37.483 29.323 15.7557 1.81045 28.207
93
6.8 Water Cooling System Efficiency
The weather for the tests were unfortunately not quite comparable, thus could not be
compared directly. Thus, only the high values of irradiance, due to passing clouds,
were considered for which the ratio of power to irradiance were calculated and average
found and compared.
Ratio=
𝑃𝑜𝑤𝑒𝑟/𝑊
𝐼𝑟𝑟𝑎𝑑𝑖𝑎𝑛𝑐𝑒/𝑊𝑚−2
× 100
Eq (21)
50
45
40
35
30
25
20
15
10
5
0
09:51:00
09:54:56
09:58:52
10:02:48
10:06:44
10:10:40
10:14:36
10:18:32
10:22:28
10:26:24
10:30:20
10:34:16
10:38:12
10:42:08
10:46:04
10:50:00
10:53:56
10:57:52
11:01:48
11:05:44
11:09:40
11:13:36
11:17:32
11:21:28
11:25:24
11:29:20
11:33:16
11:37:12
11:41:08
11:45:04
11:49:00
11:52:56
11:56:52
12:00:48
12:04:44
12:08:40
Temperature/°C
Temperature Water Cooling and Normal vs Time
Time
Tracker
Static
Tracker Water Cooling
Static Water Cooling
Figure 94 Temperature of Water Cooling vs Without Graph (Morning)
50
45
40
35
30
25
20
15
10
5
0
12:35:01
12:39:07
12:43:13
12:47:19
12:51:25
12:55:31
12:59:37
01:03:43
01:07:49
01:11:55
01:16:01
01:20:07
01:24:13
01:28:19
01:32:25
01:36:31
01:40:37
01:44:43
01:48:49
01:52:55
01:57:01
02:01:07
02:05:13
02:09:19
02:13:25
02:17:31
02:21:37
02:25:43
02:29:49
02:33:55
02:38:01
02:42:07
02:46:13
02:50:19
02:54:25
02:58:31
Temperature/°C
Temperature of Water Cooling and Normal vs Time
Time
Tracker
Static
Tracker Water Cooling
Static Water Cooling
Figure 95 Temperature of Water Cooling vs Without Graph (Afternoon)
94
Table 29 Water Cooling vs Normal data
Average Temperature/°C
Without
With
Water
Water
Difference
Cooling
Cooling
P&O Tracker
39.46
29.86
9.6
Mathematical Modelling Tracker
39.64
32.54
7.1
Static
39.07
27.56
11.51
41.26
29.32
11.94
Average of Power-Irradiance Ratio
Without
With
Efficiency Efficiency
Water
Water
Increase/% increase/%/°C
Cooling
Cooling
4.2128
4.008071
5.1079
0.532
4.506
4.351616
3.5477
0.4997
3.071675
3.353268
2.862347
3.157565
7.3132
6.1979
0.635
0.519
It can hence be confirmed that the efficiency of solar panels varies by about 0.5%/°C
of temperature rise which confirms [65].
95
6.9 Overall Analysis of Efficiencies
The efficiencies of the systems are displayed in the chart below from maximum to
minimum
Overall Efficiency
180.00%
160.00%
140.00%
120.00%
100.00%
80.00%
60.00%
40.00%
20.00%
0.00%
P&O Sunny
P&O Sunny P&O Sunny Mathematical Mathematical P&O Cloudy Mathematical Mathematical P&O cloudy
Water Cooling Water Cooling Sunny Water Modelling
Modified
Modelling
Modelling
>600Wm-2
Cooling
Sunny
Sunny
Cloudy
>600Wm-2
Figure 96 Efficiency of all systems chart
The P&O system proves to be more efficient in all the conditions: sunny, water cooling
and cloudy. The maximum efficiency recorded is 54.7% more than the static panel.
The maximum efficiency of dual axis tracker recorded yet is 82.12%. [66]
The maximum power reached exceeded the rating of the panel being 50.724W under
the P&O with water cooling and the highest average being 37.483W for the
mathematical modelling with water cooling. This clearly shows the effect brought by
the water cooling.
Better results could have been achieved if not limited by the below mentioned reasons:
1. Testing could not be done during summer
2. Several tests could not be done for single algorithm due to time constraint
3. Noisy current sensor. Smaller extensions and retractions of the actuator would
have been possible with a better sensor since small changes could be read
thereby being more precise in finding maximum power
4. The MPPT adjusts itself every 2 seconds which could have been reduced for
better responsiveness
5. Delay before MPPT catches up with irradiance
6. Also the Vgs could be varied in smaller steps to optimize the resistance for
maximum power harnessing.
96
The last point is very critical as under overcast weathers it should be increased and
decreased in sunny conditions as the power fluctuations are very small in the former.
Also, the tested panel was relatively small in size rated at 50W, however the tracker
can accommodate for much bigger panels up to 150W with no significant rise in the
consumption, leading to more efficiency.
As for the water cooling system, the results correlate to previous findings and shall
therefore be more economical on larger power generation farms, where rain could be
collected and sprayed over, than single panels.
97
7.0 Conclusion and Recommendations
All the aims and requirements of the thesis have been successfully met with the
exception of testing different types of panels due to the unavailability of other types
of panels. Despite the listed limitations, an efficiency of 154.4% have been achieved
which is very promising start for a not yet fully enhanced algorithm. The P&O system
proved to be more efficient than the calculation method during winter season under
mostly all weather conditions. The MPPT also held up great except for the issue of
noisy current signal. As a whole, all the systems, mechanical, electrical and software
functioned appropriately and in harmony. The water cooling system also yielded
promising results although the climate was cool.
Below are recommendations for further works:

Whole year testing

Water cooling implementation on larger scale to better evaluate efficiency

Controller:
o Use fuzzy logic controller for more precise and economic tracking
o Vary parameters of MPPT to find optimum setup for sunny and
overcast conditions
o Reduce intervals for MPPT to 1 second

Mechanical:
o The range covered for tracking can be increased for year round tracking

Electrical:
o Use more accurate and stable sensors
o Instead of losing the power to the MOSFET as heat, it could be stored
and used more productively
98
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106
9.0 Appendices
107
Appendix A: Relevant Information
Solar Energy Resource
The sun has been keeping us alive since the first dawn and it still has more to offer.
Solar energy is the radiant emitted light from the sun and heat generated that is used
to generate electricity or for heating purposes. The solar energy now can be
considered as the road to an eco-friendlier tomorrow.
The solar energy is produced by nuclear reactions that occur within the sun itself and
travels through space via electromagnetic radiation. Solar energy is normally
measured by the amount of solar energy that travels through one square metre of
space perpendicular to the direction of travel of the radiation at an average distance
between the earth and the sun, this is known as the solar constant and is
approximately 1367W/m2 according to the World Energy Council. Considering
absorption and scattering of the radiation by clouds and other particles, a rough
amount of 1.08 x 108 GW of solar flux reaches the surface causing a colossal
3,400,000 EJ (x 1018) of energy received by earth each year. To put things into
perspective, this number is approximately 7000 times more than annual global
primary energy consumption. [17] Thus solar energy that hit the surface of the earth
for one hour is enough to supply all human needs for a year. Yet, the main issue
about solar energy remains on the efficiency of harnessing this resource.
Technologies are still lacking beyond nature in terms of efficiency of capturing
sunlight like photosynthesis. [18]
Of the major advantages of solar energy amongst being free and widely available, is
that solar energy can be obtained directly from sunlight vis very small photovoltaics.
This also means that major labour costs are saved compared to the conventional
energy generation technologies. Thus solar energy is considered as the future of the
developing world. [19]
Exploitation of the solar energy is done by two ways: Solar thermal and solar
photovoltaic (PV). As the name suggests, the first one is mostly related to the heat
aspect of the solar energy and used for water heating, desalination and more while
the solar photovoltaic is the generation of electricity powered by the natural light of
the sun. [20]
108
Photovoltaic cell
The generally accepted definition of a PV cell or Solar cell is an electronic device
which converts light energy directly to electrical energy by the photovoltaic effect. A
PV module is that which consists of several cells connected in series while arrays are
that which link modules to one another in series or parallel. [21]
Figure 97 Solar Panel Hierarchy[22]
A PV cell comprises of a semiconductor material upon which light is incident. The
former, normally Silicon, absorbs the light particles, also known as photons, and its
electron is freed leaving behind a hole. The electron thus moves from holes to holes
to cause current flow. To ensure flow in a specific direction, silicon doped with more
free electrons and the other with more holes are joined thus called a p-n junction.
Electrons are freed in the depletion region and thus flow towards the positive side of
the field, thereby creating an electric current. [23]
Figure 98 Solar Cell Working Principle
109
Control Algorithms
Extremum Seeking Control
The working principle of ESC is that a sinusoidal waveform is added to a best guess
for which the output is maximum or minimum. The sinusoidal waveform causes
fluctuations in the output which is filtered to obtain only the high frequency (thereby
eliminating the constant output) and the new waveform is multiplied by the
sinusoidal again to get a totally positive graph or totally negative. The latter is added
by integration to the best guess with a possible gain and the best guess is therefore
increased or decreased to match the maximum output. The system reaches
equilibrium after locating the local maximum or minimum output which might vary
over time. [48] The major drawback is the inability to track the global maximum or
minimum.
ESC has various applications among which are: Antilock braking system, Impedance
Matching in Semiconductor Plasma Processing Chamber, swarm tracking, wind
turbine control and power converter optimization, resource allocation problems,
optimization of robotic systems, price seeking in dynamic markets, dynamic tolling
for transportation systems, and traffic light control, to just name a few [49] [50] but
it can be used to track maximum power as proven by M. Mooraby in [40].
Perturb and Observe Control
This control algorithm is widely used in MPP tracking. An issue with this system is
that if the perturbations are not small enough, it might not track the peak accurately
as the values of output of both sides of the peak might be the same. Though if the
steps are too small, it will take much time before reaching optimum point.
110
Figure 99 Pertrub and Observe system
Example: for the same y=100, x has got 2 values. If the perturbation step is too big,
it can move from x=215 to x=85 while the output is same and thereby not locating
the peak precisely. But since the sun is continuously moving, this might not be too
much of a problem for a dynamic system as compared to a static one.
The last two systems focus mainly on harvesting maximum power from the sun
while the 4 LDRs system concentrates on positioning the solar panel perpendicular
to the sun for more irradiance and direct sunlight and consequently more power but
the problem arises during cloudy weather. The LDRs read the same intensity and no
comparison can be made causing the solar tracker to remain idle when more power
could have been generated via diffuse radiation. Recently, scientists have proved that
the maximum power does not come by facing the sun during cloudy weathers [51].
This is definitely a waste of resources especially during recurring cloudy days.
Another issue with LDRs is that the system can be disturbed by surrounding moving
lights
However, P&O and ESC are not affected by weather conditions for they will keep
tracking until the maximum output is reached, even if that means not facing the sun.
Very few researches and experimentation have been done with these control
algorithms for tracking maximum irradiance by orientation of solar panel compared
to researches done using these algorithms to track MPP.
111
Appendix B: Datasheets of Electrical Components
112
113
114
115
116
117
118
119
120
121
122
Link: http://www.dept.aoe.vt.edu/~aborgolt/aoe3054/manual/inst3/MyDAQ.pdf
123
124
Link: https://www.electronicsdatasheets.com/manufacturers/lem/parts/hy-15-p
125
126
127
128
Link: https://datasheetspdf.com/datasheet/APT5010JN.html
129
130
131
132
133
134
135
136
137
138
139
140
141
Link; https://datasheetspdf.com/pdf/49860/NationalSemiconductor/LM35/1
142
143
Link for complete datasheet: https://www.lsilastem.com/MANUAL/INSTUM_01388_en.pdf
144
145
146
147
Link for complete datasheet:
https://datasheets.maximintegrated.com/en/ds/DS3231.pdf
148
Linear actuators
--Input: 12/24V DC.
--Stroke Length: 16inch/ 400mm (Extension Length).
--Potentiometer: 1K/ 5K/ 10K (Available).
--Load Capacity: 1000N/ 100KGS/ 225LBS.
--No-Load Speed: 10mm/s.
--Mounting Hole Size: 6.5mm.
--Mini Install Length: 140+Stroke=540mm.
--Max Install Length: 140+StrokeX2=940mm.
--Limit Switches: Built-In (Not Adjustable).
149
Same for both save stoke, 300mm.
150
Arduino
Microcontroller
ATmega328
Operating Voltage
5V
Input Voltage (recommended)
7-12V
Input Voltage (limits)
6-20V
Digital I/O Pins
14 (of which 6 provide PWM output)
Analog Input Pins
6
DC Current per I/O Pin
40 Ma
DC Current for 3.3V Pin
50 Ma
Flash Memory
32 KB (ATmega328) of which 0.5 KB used
by bootloader
SRAM
2 KB (ATmega328)
EEPROM
1 KB (ATmega328)
Clock Speed
16 MHz
Link for datasheet: https://docs.arduino.cc/resources/datasheets/A000066datasheet.pdf
151
152
153
Appendix C: Datasheets of Mechanical Components
154
Link for full datasheet:
https://basco.com.pe/pdf/fyh/fyh_unit_bearings_catalog_3310_us.pdf
155
Cutting List
Table 30 Cutting list
Component
Mild steel tube 2”x2”
Mild steel tube 2”x1”
𝟏
Mild steel tube 3”x1𝟐”
Mild steel tube 1”x1”
Flat mild steel 5mm
thickness
Mild steel shaft dia
10mm
Mild steel shaft dia
12mm
Mild steel bar ¾"
Mild steel flat bar 2mm
thickness
Length/mm
950
310
550
250
600
Quantity
1
1
1
2
1
1240
550
125 x 100
65 x 50
70
2
2
1
3
2
70
1
550
10
50 x 1240
2
5
2
156
Appendix D: Programming and Coding
1. Full Perturb and Observe Control
const
const
const
const
const
int
int
int
int
int
signal
extpol
retpol
extele
retele
=
=
=
=
=
8;
9;
10;
11;
12;
int curpotele;
int prevpotele;
int curpowele;
int prevpowele;
int curpowpol;
int prevpowpol;
int difpowele;
int difpotele;
int difpowpol;
int difpotpol;
int a1000;
int a1500;
void setup() {
pinMode(signal, OUTPUT);
pinMode(extele, OUTPUT);
pinMode(retele, OUTPUT);
pinMode(extpol, OUTPUT);
pinMode(retpol, OUTPUT);
Serial.begin(9600);
difpotpol=25;
difpotele=70;
curpotele = 0;
prevpowele = 0;
curpowele = 0;
curpowpol = 0;
prevpowpol = 0;
a1000=0;
a1500=0;
digitalWrite(signal, HIGH);
offacts();
delay(10000);
}
void loop() {
for (int x = 0; x < 6 ; x++) {
digitalWrite(signal, LOW);
&&
curpowele = readpower();
difpowele = curpowele - prevpowele;
if (
(
difpowele < -2 && difpotele <= -60)
|| ( difpowele < - 13 && difpotele > -60 && difpotele < -30)
|| ( difpowele >= -2 &&
difpowele <= 2 && difpotele > 30
difpotele < 60)
|| ( difpowele > 13 && difpotele > 30 && difpotele < 60 )
|| ( difpowele > 2 && difpotele >= 60)
) {
difpotele=70;
if (readpotele()<785){
digitalWrite(extele, LOW);
157
digitalWrite(retele, HIGH);
delay(1500);
a1500++;
offacts();
delay(500);
&&
}
else {
offacts();
}
}
else if (
( difpowele > 2 && difpotele <= -60)
|| ( difpowele >= -2 && difpowele <= 2 && difpotele > -60
difpotele < -30)
|| ( difpowele > 13 &&
difpotele > -60 && difpotele < -
30)
|| (
difpowele < - 13 &&
difpotele > 30 &&
difpotele <
60)
|| (
difpowele < -2 &&
difpotele >= 60)
){
difpotele=-70;
digitalWrite(extele, HIGH);
digitalWrite(retele, LOW);
delay(1500);
a1500++;
offacts();
delay(500);
}
else if (
( difpowele >= -2 &&
difpowele <= 2 && difpotele <= -60)
|| ( difpowele >= - 13 &&
difpowele < -2 && difpotele > 60 && difpotele < -30)
|| (
difpowele < -2 && difpotele >= -30 && difpotele <=
30)
|| ( difpowele > 2 &&
difpowele <= 13 && difpotele > 30
&& difpotele < 60)
)
{
difpotele=35;
if (readpotele()<815)
{
digitalWrite(extele, LOW);
digitalWrite(retele, HIGH);
delay(1000);
a1000++;
offacts();
}
else {
offacts();
}
}
else if (
( difpowele > 2 &&
difpowele <= 13 && difpotele > -60
&& difpotele < -30)
|| ( difpowele > 2 && difpotele >= -30 && difpotele <= 30)
|| ( difpowele >= - 13 &&
difpowele < -2 && difpotele > 30
&& difpotele < 60)
|| ( difpowele >= -2 &&
difpowele <= 2 && difpotele >=60 )
) {
difpotele=-35;
158
digitalWrite(extele, HIGH);
digitalWrite(retele, LOW);
delay(1000);
a1000++;
offacts();
}
else {
offacts();
}
prevpowele = curpowele;
delay(1000);
}
digitalWrite(signal, HIGH);
delay(60000);
for (int j = 0; j < 6; j++) {
digitalWrite(signal, LOW);
curpowpol = readpower();
difpowpol = curpowpol - prevpowpol;
if (
(
difpowpol < -2 && difpotpol <= -20)
|| ( difpowpol < - 13 && difpotpol > -20 && difpotpol < 10)
|| ( difpowpol >= -2 &&
difpowpol <= 2 && difpotpol > 10
&& difpotpol < 20)
|| ( difpowpol > 13 && difpotpol > 10 && difpotpol < 20 )
|| ( difpowpol > 2 && difpotpol >= 20)
) {
digitalWrite(extpol, LOW);
digitalWrite(retpol, HIGH);
difpotpol=25;
delay(1500);
a1500++;
offacts();
delay(500);
}
else if (
( difpowpol > 2 && difpotpol <= -20)
|| ( difpowpol >= -2 &&
difpowpol <= 2 && difpotpol > -20
&& difpotpol < -10)
|| ( difpowpol > 13 && difpotpol > -20 && difpotpol < 10)
|| (
difpowpol < - 13 && difpotpol > 10 && difpotpol < 20)
|| (
difpowpol < -2 && difpotpol >= 20)
) {
digitalWrite(extpol, HIGH);
digitalWrite(retpol, LOW);
delay(1500);
a1500++;
difpotpol=-25;
offacts();
delay(500);
&&
}
else if (
( difpowpol >= -2 &&
difpowpol <= 2 && difpotpol <= -20 )
|| ( difpowpol >= - 13 &&
difpowpol < -2 && difpotpol > -20
difpotpol < -10)
|| ( difpowpol < -2 && difpotpol >= -10 && difpotpol <= 10)
159
&&
&&
&&
|| ( difpowpol > 2 && difpowpol <=
difpotpol < 20)
) {
digitalWrite(extpol, LOW);
digitalWrite(retpol, HIGH);
delay(1000);
a1000++;
difpotpol=12;
13 &&
difpotpol > 10
offacts();
}
else if (
( difpowpol > 2 &&
difpowpol <= 13 && difpotpol > -20
difpotpol < -10)
|| ( difpowpol > 2 && difpotpol >= -10 && difpotpol <= 10)
|| ( difpowpol >= - 13 &&
difpowpol < -2 && difpotpol > 10
difpotpol < 20)
|| ( difpowpol >= -2 &&
difpowpol <= 2 && difpotpol >=20 )
) {
digitalWrite(extpol, HIGH);
digitalWrite(retpol, LOW);
delay(1000);
a1000++;
difpotpol=-12;
offacts();
}
else {
offacts();
}
prevpowpol = curpowpol;
delay(1000);
}
digitalWrite(signal, HIGH);
if (readldr()>=18){
delay(60000);
}
else{
delay(120000);
}
Serial.print("a1000=");
Serial.println(a1000);
Serial.print("a1500=");
Serial.println(a1500);
}
int readpower(void) {
return analogRead(A0);
}
int readpotele(void){
return analogRead(A1);
}
int readldr(void){
return analogRead(A3);
}
void offacts() {
digitalWrite(extele, HIGH);
digitalWrite(retele, HIGH);
digitalWrite(extpol, HIGH);
digitalWrite(retpol, HIGH);
}
160
2. Mathematical modelling for elevation angle and Perturb and
Observe for polar angle
#include<Wire.h>
#define RTCAddress 0x68
const int signal= 8;
const int extpol = 9;
const int retpol = 10;
const int extele = 11;
const int retele = 12;
int curpotele;
int prevpotele;
int difpotele;
int prevpowpol;
int difpowpol;
int difpotpol;
int curpowpol;
int difele;
int a1500;
int a1000;
int a300;
int x;
void setup() {
Wire.begin();
Serial.begin(9600);
//setTime(0, 7, 9, 6, 9, 7, 22);
pinMode(extele, OUTPUT);
pinMode(retele, OUTPUT);
pinMode(extpol, OUTPUT);
pinMode(retpol, OUTPUT);
pinMode(signal, OUTPUT);
offacts();
digitalWrite(signal, HIGH);
delay(10000);
prevpotele = 0;
curpotele = 0;
curpowpol = 0;
prevpowpol = 0;
difpotpol = 25;
difpowpol = 0;
difele = 0;
a1500=0;
a1000=0;
a300=0;
int i=0;
while (i<40) {
i++;
curpotele = readpotele();
difele = calcpotvalue() - curpotele;
if (difele > 15 && curpotele<840) {
digitalWrite(extele, LOW);
digitalWrite(retele, HIGH);
delay(300);
a300++;
offacts();
161
}
else if (difele < -15) {
digitalWrite(extele, HIGH);
digitalWrite(retele, LOW);
delay(300);
a300++;
offacts();
}
else {
offacts();
}
}
}
void loop() {
for (int j = 0; j < 7; j++) {
digitalWrite(signal, LOW);
curpowpol = readpower();
difpowpol = curpowpol - prevpowpol;
if (
(
difpowpol < -2 && difpotpol <= -20)
|| ( difpowpol < - 13 && difpotpol > -20 && difpotpol < 10)
|| ( difpowpol >= -2 &&
difpowpol <= 2 && difpotpol > 10
&& difpotpol < 20)
|| ( difpowpol > 13 && difpotpol > 10 && difpotpol < 20 )
|| ( difpowpol > 2 && difpotpol >= 20)
) {
digitalWrite(extpol, LOW);
digitalWrite(retpol, HIGH);
difpotpol=25;
delay(1500);
a1500++;
offacts();
delay(500);
&&
}
else if (
( difpowpol > 2 && difpotpol <= -20)
|| ( difpowpol >= -2 &&
difpowpol <= 2 && difpotpol > -20
difpotpol < -10)
|| ( difpowpol > 13 && difpotpol > -20 && difpotpol < -
10)
|| (
difpowpol < - 13 && difpotpol > 10 &&
|| (
difpowpol < -2 && difpotpol >= 20)
) {
digitalWrite(extpol, HIGH);
digitalWrite(retpol, LOW);
delay(1500);
a1500++;
difpotpol=-25;
difpotpol < 20)
offacts();
delay(500);
}
else if (
( difpowpol >= -2 &&
difpowpol <= 2 &&
162
difpotpol <= -20 )
|| ( difpowpol >= - 13 &&
difpowpol < -2 && difpotpol > -20
difpotpol < -10)
|| ( difpowpol < -2 && difpotpol >= -10 && difpotpol <= 10)
|| ( difpowpol > 2 && difpowpol <= 13 && difpotpol > 10
difpotpol < 20)
) {
digitalWrite(extpol, LOW);
digitalWrite(retpol, HIGH);
delay(1000);
a1000++;
difpotpol=12;
&&
&&
offacts();
}
else if (
( difpowpol > 2 &&
difpowpol <= 13 && difpotpol > -20
difpotpol < -10)
|| ( difpowpol > 2 && difpotpol >= -10 && difpotpol <= 10)
|| ( difpowpol >= - 13 &&
difpowpol < -2 && difpotpol > 10
difpotpol < 20)
|| ( difpowpol >= -2 &&
difpowpol <= 2 && difpotpol >=20 )
) {
digitalWrite(extpol, HIGH);
digitalWrite(retpol, LOW);
delay(1000);
a1000++;
difpotpol=-12;
offacts();
}
else {
offacts();
}
prevpowpol = curpowpol;
delay(1000);
&&
&&
}
digitalWrite(signal, HIGH);
delay(100000);
byte second, minute, hour, day, date, month, year;
readTime(&second, &minute, &hour, &day, &date, &month, &year);
x=minute%10;
int k=0;
while (k<40) {
k++;
if (x>=6) {
curpotele = readpotele();
difele = calcpotvalue() - curpotele;
if (difele > 15 && curpotele<840) {
digitalWrite(extele, LOW);
digitalWrite(retele, HIGH);
delay(300);
a300++;
offacts();
}
else if (difele < -15) {
digitalWrite(extele, HIGH);
digitalWrite(retele, LOW);
delay(300);
a300++;
163
offacts();
}
else {
offacts();
}
}
else {
offacts();
}
}
delay(50000);
Serial.print("a300=");
Serial.println(a300);
Serial.print("a1000=");
Serial.println(a1000);
Serial.print("a1500=");
Serial.println(a1500);
}
int readpower(void) {
return analogRead(A0);
}
int readpotele(void) {
return analogRead(A1);
}
void offacts() {
digitalWrite(extele, HIGH);
digitalWrite(retele, HIGH);
digitalWrite(extpol, HIGH);
digitalWrite(retpol, HIGH);
}
byte bcd2dec(byte val) {
return ((val / 16 * 10) + (val % 16));
}
byte dec2bcd(byte val) {
return ((val / 10 * 16) + (val % 10));
}
void setTime(byte second, byte minute, byte hour, byte day, byte
date, byte month, byte year) {
Wire.beginTransmission(RTCAddress);
Wire.write(0);
Wire.write(dec2bcd(second));
Wire.write(dec2bcd(minute));
Wire.write(dec2bcd(hour));
Wire.write(dec2bcd(day));
Wire.write(dec2bcd(date));
Wire.write(dec2bcd(month));
Wire.write(dec2bcd(year));
164
Wire.endTransmission();
}
void readTime (byte *second, byte *minute, byte *hour, byte *day,
byte *date, byte *month, byte *year) {
Wire.beginTransmission(RTCAddress);
Wire.write(0);
Wire.endTransmission();
Wire.requestFrom(RTCAddress, 7);
*second = bcd2dec(Wire.read() & 0x7F);
*minute = bcd2dec(Wire.read());
*hour = bcd2dec(Wire.read() & 0x3F);
*day = bcd2dec(Wire.read());
*date = bcd2dec(Wire.read());
*month = bcd2dec(Wire.read());
*year = bcd2dec(Wire.read());
}
int calcpotvalue(void) {
double delta;
double w;
double pi = 3.14159;
double a;
int length;
int pot;
byte second, minute, hour,
readTime(&second, &minute,
delay(1000);
if (month == 7) {
delta = 23.45 * sin((284
}
if (month == 6) {
delta = 23.45 * sin((284
}
day, date, month, year;
&hour, &day, &date, &month, &year);
+ 181 + date) * (0.9863) * (pi / 180));
+ 151 + date) * (0.9863) * (pi / 180));
w = (acos(-tan(-20.0177903 * (pi / 180)) * tan(delta * (pi /
180)))) * (180 / pi);
a = ((((hour * 60) + minute) - (720 - ((w / 15) * 60))) / (2 * ((w
/ 15) * 60))) * 180;
length = -0.0001 * pow(a, 3) + 0.0133 * (pow(a, 2)) + 2.809 * a +
497.17;
pot=2.1*length - 1026;
return round(pot);
}
165
3. Water Cooling System
const int valve=8;
void setup() {
pinMode(valve, OUTPUT);
offacts();
}
void loop() {
delay(1000);
if (temp()>70){
delay(10000);
if (temp()>70){
digitalWrite(valve, LOW);
delay(100000);
offacts();
}
}
}
int temp(void) {
return analogRead(A0);
}
void offacts() {
digitalWrite(valve, HIGH);
}
Figure 100 Microcontroller Arduino circuit
166
4. LABVIEW Program
Figure 101 LABVIEW Front Panel
Figure 102 LABVIEW Block Diagram
167
Figure 103 Complete data collection and controlling circuit
168
Appendix E: Realisation and Build-up
Figure 104 Main Stand and Support Beam
Figure 105 Main Stand Welding
Figure 108 Elevation Pivot
Figure 106 Support Beam
Figure 107 Main Stand
169
Figure 110 Complete Solar Tracker
Figure 111 Panel Support Frame
Figure 109 Solar Tracker
170
Figure 112 Static Panel
Figure 113 Tracker Water Cooling
Figure 114 Temperature Sensors glued to Panel
Figure 115 Valve
Figure 117 Pyranometer Setup
Figure 116 LDR Setup
171
Appendix F: Synopsis and Progress Log
UNIVERSITY OF MAURITIUS
FACULTY of ENGINEERING
ANNEX 1
PROJECT PROPOSAL/SYNOPSIS
Department: Mechatronics Engineering
Academic Year: 4
Students are hereby informed that they should submit this document
(approximately 200 words) to their respective Module/Project Co-ordinators
by one month as from the beginning of Semester I at latest.
Student's Name: MONEBAHAL Ali Asgar Ibne
Student ID: 1811899
Title of dissertation: Efficiency of different types of PV modules with and
without solar tracker
Aims and Objectives:
To determine power generation capacity of 3 different types of PV modules at
maximum power point and on a solar tracker
To calculate the efficiency of the Solar Tracker with respect to its power
consumed
To find out which proves to be more efficient and reliable
Proposed Methodology (tentative):
The procedure will be to investigate the electricity production of the 3
different types of solar panels at a fixed point and on a solar tracker while
tracking the current consumption of the motors for the solar tracker.
Data needs to be collected over an adequate period of time to allow a correct
conclusion to be drawn.
172
An efficient and feasible solar tracker is to be built to experiment and take
values.
Expected Output
A fully functional solar tracker to record data and the conclusion is expected
to be that the solar tracker will be more effective
Frequency to meet supervisor
Start of Project:
Weekly
End of Project:
Weekly
Comments, if any:
Meetings and communications will be mostly limited to online sessions and
call as Covid-19 preventive measures.
GANTT CHART
Research
Literature Review
Design Solar
Tracker
Realisation
Data Acquisition
Testing and
Evaluation
Discussion
Thesis Writing
Nov
✓
✓
Dec
Jan
✓
✓
✓
✓
Feb
Mar
✓
✓
Apr
May
Jun
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
✓
Student's Signature: …………
Supervisor's Name: Mr H. Shamachurn
Date:23 Nov 2021
Supervisor’s Signature:.…………………
Date: 24 Nov 2021
173
UNIVERSITY OF MAURITIUS
FACULTY OF ENGINEERING
PROGRESS LOG
Student Name : MONEBAHAL Ali Asgar Ibne
Student ID : 1811899
Department : Engineering
Programme : B.Eng (Hons.) Mechatronics Engineering
Title of Dissertation : Efficiency of different types of PV modules on and off dual
axis solar tracker with MPPT (P&O) tracking
Supervisor : Mr H. Shamachurn
Project Coordinator :
• Your Progress Log serves as a record of your transferable skills and participation
and attainment as a student for dissertation purposes.
• Its purpose is to help you to plan your own dissertation and to record the outcomes.
• As well as gaining valuable skills, you will find that the information accumulated
in this Log will prove helpful during the write up of the dissertation.
• The document belongs to you and it is your responsibility to keep it up to date.
• It is your responsibility to ensure your supervisor is aware of the dissertation
activities you have undertaken.
You should sign the appropriate statement below when you submit your
Progress Log:
I confirm that the information I have given in this Log is a true and accurate record:
Signed: ………………………………………
174
Date: 29 Jul 2022
RECORD OF STRATEGIC MEETINGS WITH SUPERVISOR
Meetings Date
Topics/Theme s
(If any)
Discussed
1
16/10/21 Project Aims
2
02/02/22 Panel Sizing
3
04/04/22 Ordering of
Comments Supervisor’ Student’s
s Initials
Components
4
18/04/22 MPPT circuit +
water cooling
5
29/04/22 MOSFET power
dissipation
6
10/05/22 Data collection
7
05/06/22 Current Sensors
and troubleshoot
8
10/06/22 Pyranometer and
thermocouple
Supervisor Mr H. Shamachurn
Signature ……………………
Date…………….
175
Initials