International Journal of Engineering Trends and Technology (IJETT) – Volume 23 Number 7- May 2015
Hardware Realization of Single Axis Solar Tracking
System by Using a Cost Effective Microcontroller
Rajesh.K#1 and Kailash Krishna Prasad.B#2
#1
Assistant Professor, Department of EEE,
Assistant Professor, Department of EEE,
BITS, KURNOOL.
#2
Abstract — Solar based energy harvesting techniques have been
attaining enormous interest in recent years. There are basically
two ways of extracting energy from solar photovoltaic (PV)
panels. One is by employing single axis or dual axis tracking
technique and the other one is by Maximum Power Point
Tracking (MPPT) methods. The latter method is a bit complex
and implementation cost is high. Hence, it is convenient to use
single axis tracking method to ensure cost effective solution as it
very easy to design. A small Prototype has been developed by
using a low cost embedded microcontroller and the performance
is examined.
Keywords— single axis tracking, dual axis tracking, MPPT,
microcontroller, energy harvesting.
I. INTRODUCTION
Designing and implementing a real-time based solar
tracking system is considered to be an important task to meet
the energy demand. The MPPT based solar power extraction
[13],[14],[15] is considered to be one of the effective methods
to extract maximum power from solar photovoltaic (PV)
panels but its implementation cost is too expensive if it is
designed in digital domain by using a Digital Signal Processor
(DSP) (or) Field Programmable Gate Array (FPGA) systems
respectively [1],[2],[12],[16]. Hence, it is of utmost importance
to look for cost effective solution in order to build a real time
prototype of solar tracking kit. Since, most of the systems are
implemented in digital domain to acquire accurate results; it is
convenient to use a low cost microcontroller to achieve the
task of solar power collection.
Single axis (or) dual axis tracking methods is used
sometimes instead of MPPT based methods because of its
simplicity and possibility of low cost implementation. Few
researchers have already been worked in this area to show its
effectiveness [3],[4],[5],[6],[7],[8],[9],[10],[11]. But they have
used different microcontrollers which are a bit costly. Hence,
in this paper it has been shown the feasibility of utilizing
AT89S52 microcontroller for the purpose of collecting power
from solar PV panel. The AT89S52 is a low-voltage, highperformance CMOS 8-bit microcontroller with inbuilt 4K
bytes of Flash programmable memory embedded in it. In this
paper, single axis tracking method is selected and explained .
Even though dual axis tracking method is better method when
compared to single axis method, it is better option to consider
single axis tracking for low cost implementation.
ISSN: 2231-5381
II. HARDWARE DESCRIPTION
The major parts involved are microchip microcontroller,
oscillator, voltage regulator, photovoltaic (PV) cell, stepper
motor, parasitic elements, power electronic switches and
motor sensor accessories.
A. Block diagram of Hardware:
The schematic diagram of the complete hardware setup is
represented in Fig: 1.The stepper motor runs based on the
tracking sensor position. The software is dumped onto the
microcontroller by using Keil Micro Vision, an integrated
development environment which is used to create software to
be run on microcontroller.
Fig: 1. Hardware Block diagram
B. Software working description:
Software working operation can be divided into four major
parts. The first part is meant for initial positioning. Prior to the
powering up of the total system, the photovoltaic (PV) cell
must be manually set to a certain direction. Once manually
positioned, the tracking sensor will move to certain degree of
steps per second in the clockwise direction until a value of
light intensity greater than the preset threshold value is
detected. The second part of the system code deals with the
light tracking. This is considered to be the heart of the
program. Once the tracker has set its initial position to a
bright source of light i.e., sun, it is ready to align itself more
precisely and continue to track the light. The tracker first
measures the light intensity at its present location and then
moves counter clockwise (left) by certain degree of steps and
further takes another measurement. It, then moves clockwise
(right) to certain degree of steps and calculates the final
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International Journal of Engineering Trends and Technology (IJETT) – Volume 23 Number 7- May 2015
measurement. The software comparison subroutines compare
these values and position the tracker at the point of greatest
measurement. If any of the values are equal, the tracker will
return stand still position.
Low light detection is the third portion of the software
routine. This works in conjunction with the tracking routine.
The last portion of the software routine allows the tracker
to reset itself at the end of the day. After every motor
movement, a register is incremented or decremented
subsequently so that, the net position of the tracker can be
known at any given point of time.
C. Prototype:
The complete hardware prototype is depicted in Fig: 2.
Fig: 3 Plot of Voltage (Volt) and Time (hour)
TABLE I
OUTPUT VALUES IN THE FORM OF VOLTAGE (V) AND TIME (HOUR)
Time
6.00
6.30
7.00
7.30
8.00
8.30
9.00
9.30
10.00
10.30
11.00
11.30
12.00
Fig: 2. Hardware prototype
III. DESIGN ANALYSIS AND RESULTS
The hardware and software portions consist of light detection,
motor driving, software tracking, and software enhancement.
Also, a comparison has been made with the tracking PV panel
and a stand still panel. There exists improved efficiency when
the PV panel is rotating when compared to flat panel. Fig: 3
clearly show the enhanced efficiency and increased voltage
rating with respect to time. Table: I represent the plot data.
An experiment conducted to demonstrate the
working procedure of the developed prototype. In this
prototype, there exist two light sensors namely: LDR1 and LDR2
which are connected to the top side and bottom side of the PV
panel. If the light intensity at LDR1 is higher than LDR2, then
the PV panel rotates in anticlockwise direction. Similarly if
the light intensity at LDR1 is less than LDR2, then the Panel
rotates in the clockwise direction. Furthermore, if the light
intensities of the both the light sensors are equal, then the
panel remains stand still without rotating respectively.
ISSN: 2231-5381
Flat
Panel
Voltage
0
0.5
1.1
1.5
2.3
2.8
3.5
3.9
4.5
4.9
5.3
5.6
5.8
Tracking
Panel
Voltage
0
1.2
1.8
2.4
3.5
3.9
4.3
4.8
5.5
5.9
6
6
6
Time
Flat
Panel
Voltage
6
5.9
5.3
4.5
4
3.3
2.8
2.2
1.6
1.3
0.8
0
-------
12.30
1.00
1.30
2.00
2.30
3.00
3.30
4.00
4.30
5.00
5.30
6.00
------
Tracking
Panel
Voltage
6
6
6
6
6
6
6
5.6
4.3
3.9
2.1
0
--------
TABLE III
ROTATION OF PV PANEL
Light Intensity of Sensors
Rotation
LDR1 intensity is greater
than LDR2 intensity
LDR1 intensity is less than
LDR2 intensity
Light intensities at LDR1 and
LDR2 are equal
Anti-clockwise rotation
Clockwise rotation
Stand still i.e. constant position
The Table: II show the rotation positions of the panel with
respect to the light intensities of the two sensors. The stepper
motor rotates in steps and the panel tracks the sun light. Hence,
the process of extraction becomes simple and easier.
IV. CONCLUSION
This paper clearly illustrated the effectiveness of tracking
of solar power by considering the rotation of the PV panel.
Specifically, it demonstrates a working model for maximizing
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International Journal of Engineering Trends and Technology (IJETT) – Volume 23 Number 7- May 2015
solar PV cell output by positioning a solar array at the point of
maximum light intensity. This paper also demonstrated about
a low cost embedded microcontroller. Thus, single axis
tracking method can be effectively utilized to extract the solar
power in order to improve the efficiency of the extraction.
Comparison has been clearly shown in this paper regarding
the improved voltage profile after utilizing this single axis
tracking method.
Microcontroller Based Maximum Power Point Tracking of PV
Array‖, International Journal of Engineering Trends and Technology
(IJETT) – Volume 21 Number 7 – March 2015.
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