ISSN: 2277-3754
ISO 9001:2008 Certified
International Journal of Engineering and Innovative Technology (IJEIT)
Volume 2, Issue 7, January 2013
High Voltage Gain Boost Converter Based On
Three State Switching Cell for Solar Energy
Harvesting
N.Prasad, T.Logeswaran, Dr.A.Senthil Kumar
Abstract: - In this paper a three state switching cell boost
converter for photovoltaic applications employing MPPT (perturb
and observe) algorithm is discussed. A three state switching cell
boost converter has advantages such as reduced size of boost
inductor and current sharing is performed between two switches
leading to the usage of low power rating switches. The maximum
power varies with respect to temperature and solar radiation.
MPPT algorithm is used to track the maximum power and thereby
improving the efficiency of the system. By manipulating the duty
cycle the system implements perturb and observe MPPT
algorithm.
The
simulation
is
performed
using
MATLAB/SIMULINK under various temperature and solar
radiation and waveforms are presented.
Index terms: - Three State Switching Cell Boost
Converter, Maximum Power Point Tracking (MPPT),
Photo Voltaic Power Generation System.
I. INTRODUCTION
Renewable energy attracts interest for power generation
since the non renewable energy like petrol, diesels etc are
diminishing and energy crisis is an important issue in most of
the nations. Energy production using solar energy could be a
solution for the increasing power demands. The photovoltaic
generation systems can either be operated as isolated systems
or connected to the grid as a part of an integrated system. One
of the major advantages of PV technology is that it has no
moving parts; it has a long lifetime and low maintenance
requirements and most importantly it is one solution that
offers eco friendly power. A maximum power point tracking
algorithm is absolutely necessary to increase the efficiency of
the solar panel as it has been found that only 30-40% of
energy incident is converted into electrical energy. Among all
the MPPT methods, Perturb & Observe (P&O) is most
commonly used because of its simple implementation [7].
Generally the efficiency of the system depends on the boost
converter too. To improve the efficiency of the converter soft
switching scheme is used [2] .The solar energy is directly
converted into the electric energy by the Photovoltaic (PV)
module. A PV module consists of a number of solar cells
which when connected in series increases the voltage and
when connected in parallel increases the module current.
Despite mechanically changing the position of the solar
panels, MPPT works automatically to keep the output at the
maximum power. The concept in Maximum power point
tracking is that when the source impedance matches with the
load impedance maximum power transfers from the source to
load [6], so the source impedance is varied by varying the
duty cycle. In this paper three state switching cell boost
converter is used even though conventional boost converters
can produce high voltage gain, the gain decreases as the duty
cycle approaches unity as proved in [1], when connecting
boost converters in series losses will increase due to increase
of devices [5]. Depending upon the surrounding conditions
such as temperature and irradiation, the output power of the
solar cell changes and hence its efficiency is low. Thus for the
transmission of the power from PV array to the load, high
efficiency is needed for the power conditioning systems
(PCS). Generally a single stage PV PCS is composed of two
conversion stages namely dc/dc conversion stage and dc/ac
conversion stage. The maximum power point tracking is
applied to the dc/dc converter topology. To solve this
disadvantage, three state switching cell boost converter [4] is
used because of its reduced ripple currents in both the input
and output circuits and hence there is a decrease in the boost
inductor magnetic volume. The power is equally divided
between two oppositely coupled inductor the stress across the
devices are much low so there is no need for any soft
switching scheme [10].
II. PV GENERATOR
A. Solar Panel
The simplest circuit of a solar cell is a current source
connected in parallel with a diode. A PV array consists of
several photovoltaic cells in series and parallel connections.
Series connections are required for increasing the voltage of
the module and the parallel connection is required for
increasing the current in the array. The PV module is self
protected which means even when the ends are short circuited
only short circuit current flows and will never make an issue
because of the short circuit.
102
Fig.1 Equivalent Circuit of the PV Cell
ISSN: 2277-3754
ISO 9001:2008 Certified
International Journal of Engineering and Innovative Technology (IJEIT)
Volume 2, Issue 7, January 2013
The equation that gives the voltage current characteristics of
When the voltage and the current characteristics are
a solar cell is given by
multiplied, the P-V characteristics is obtained as shown in
Figure.4
Where
IPH=light saturated current or photo current
Is=cell saturation of dark current
Q=charge of an electron (1.602×10-19)
K= Boltzmann‟s constant (1.38×10-23)
A=Ideal factor (2.15)
Tc=cell‟s working temperature
RSH=Shunt resistance
RS=Series resistance
The photocurrent mainly depend on temperature and solar
radiation given by the equation
Fig. 4 P-V Characteristics Curve of Solar Panel
Where
Isc=Cell‟s short circuit current
Ki=Cell‟s short circuit temperature coefficient
Tref=Cell‟s reference temperature
H=Solar radiation.
Based on the above shown equations a MATLAB
/SIMULINK model was designed as shown below
The simulation is carried out for a cell surface temperature
of 50° C, 20 solar cells in series and 2rows of solar cells in
parallel. The irradiation varies from 250 Watt per sq. cm. to
1000 Watt per sq. cm,. The simulation is run for a total of 1
second, with the irradiation taking up a new value every 0.25
seconds.
Fig. 5 Plot of Output Voltage, Current and Power of PV Panel
Fig 2. MATLAB/SIMULINK model of a solar PV array
Fig. 3 I-V Characteristics of a Solar Panel
B. MPPT algorithm
Numerous techniques have been proposed so far to realize
MPP. These MPPT methods vary in complexity, sensors
required, convergence speed, cost, range of effectiveness,
implementation hardware, popularity, and in other respects.
Among them the Perturb-and Observe (P&O) method, is the
most common. The P&O algorithm is mostly used, due to its
ease of implementation. Module Voltage, current and power
measured at kth instant .Module Voltage, current and power
calculated at k+1th instant. ∆P is calculated by ∆P=P
(k+1)-P(k) and ∆Vis calculated by ∆V=V(k+1)-V(k). Based
on the values of ∆V and ∆P the duty cycle is varied. If ∆P>0
and ∆V>0 then D=D- ∆D. If ∆P>0 and ∆V<0 then D=D+ ∆D.
If ∆P<0 and ∆V <0 then D=D+ ∆D. If ∆P<0 and ∆ V>0 then
D=D- ∆D. Where D= duty cycle and ∆D is perturbation
103
ISSN: 2277-3754
ISO 9001:2008 Certified
International Journal of Engineering and Innovative Technology (IJEIT)
Volume 2, Issue 7, January 2013
A .Operation
Fig. 8 First and Third Operating Stage
Fig. 6 P&O Algorithm
Fig. 9 Second Operating Stage
Fig.10 Fourth Operating Stage
Fig. 7 MATLAB/SIMULINK Model Of Perturb and Observe
Algorithm
III. THREE STATE SWITCHING CELL BOOST
CONVERTER
A three state switching cell boost converter is an efficient
dc –dc boost converter providing high voltage gain by means
of voltage multiplier stages. It reduces the input ripple by
means of oppositely coupled inductor and reduces output
ripple by means of output capacitor. A three state switching
cell boost converter has a high voltage gain and high
efficiency. In three state switching cell boost converter the
duty cycle has to be more than 0.5 for nominal operation of
the converter circuit. There are two low power rating switches
in the converter.
The first and third stage as shown in Figure.8 is that the
switches S1, S2 are turned on so that the supply charges the
input inductor. The second operating stage as shown in
Figure.9 is that S1 is still turned ON and S2 is turned OFF so
that the diode Dm2 and D1 are forward biased. The current
through the winding Np2 divides into two paths so that in one
path the current discharges the capacitor C2 and supplies the
load through diode D1 and thereby charging the capacitor Co.
The second path through diode Dm2 and charges the
capacitor C1 and the circuit close through the switch S1.The
first path adds the input voltage with the energy stored in the
boost inductor along with the charge in the capacitor C2
thereby boosting the input voltage. The fourth stage as shown
in Figure.10 is that the switch S2 is turned ON and the switch
S1 is OFF so that the current through the transformer winding
Np1divides into two paths so that in first path the current
discharges through the capacitor and flows through the diode
D2 and the load.
104
ISSN: 2277-3754
ISO 9001:2008 Certified
International Journal of Engineering and Innovative Technology (IJEIT)
Volume 2, Issue 7, January 2013
By substituting the values in the above said formulas the
values obtained is as follows
Parameters
Symbol
Value
Boost inductor
Lb
66.5 µH
Duty cycle
D
0.58
C1
4.6 µH
C2
2.3 µH
C3
1.2 µH
Output Capacitor
Cout
680uF
Resistance of Load
R
20 Ω
Multiplier capacitor
Fig.11 Switching Pulses for Switch S1, S2
IV. PROPOSED MODEL
The three state switching cell boost converter obtained by
substituting the above values is as follows
Fig.12 Proposed Model of the Project
A three state switching cell boost converter with high
voltage gain to about 9.5 can be obtained as the input voltage
is 42V and the obtained output voltage is nearly 400V and the
parameters for designing this converter is as follows
Duty cycle
Fig.13 Three State Switching Cell Boost Converter
Boost inductor
Multiplier capacitor
The maximum power is transferred when the source
impedance matches with the load impedance. For matching
the matching the impedances the duty cycle is varied in the
converter. The switches are synchronized by the following
method.
Output capacitor
Where
Vo = Output voltage
Vi = Input voltage
Gv = voltage gain
D = duty cycle
Mc = number of multiplier stages
Fs = switching frequency
Fig. 14 PWM Generation for Switches S1, S2
105
ISSN: 2277-3754
ISO 9001:2008 Certified
International Journal of Engineering and Innovative Technology (IJEIT)
Volume 2, Issue 7, January 2013
Photovoltaic Systems”, IEEE Applied Power Electronics
Here V2 is 1800 phase shifted from V1 and both are carrier
Colloquium (APEC), pp. 22-27, 2011.
frequency which is compared by the common voltage Vc. The
output power waveform obtained through the maximum [7] N. Femia, G. Petrone, G. Spagnuolo, and M. Vitelli,
power point tracking algorithm is shown below.
“Optimization of perturb and observe maximum power point
tracking method,” IEEE Trans. Power Electron., vol. 20, no. 4,
pp. 963–973, Jul. 2005.
[8] O. Abutbul, A. Gherlitz, Y. Berkovich and A. Ioinovici, “Boost
converter with high voltage gain using a switched capacitor
circuit”, Proceedings of the 2003 International Symposium on
Circuits and Systems (ISCAS 2003), vol. 3, pp. 296-299,
May2003.
[9] R. J. Wai, W. H. Wang, and C. Y. Lin, “High-performance
stand-alone photovoltaic generation system,” IEEE Trans. Ind.
Electron., vol. 55,no. 1, pp. 240–250, Jan. 2008.
[10] R. P. T Bascopé, et al., “A generalized high voltage gain boost
converter based on three-state switching cell,” Proceedings of
the 32nd IECON, pp. 1927-1932, Sept. 2006.
[11] Samuel Vasconcelos Araújo,, Rene P Torrico- Bascope and
Grover V Torrico- Bascope “High efficient high step up
converter for fuel cell processing based on three state
commutation cell” IEEE transactions on industrial
electronics,vol 57,no 6,2010.
Fig.15 Output Power of PV Panel
V. CONCLUSION
The simulation results of solar panel, three state switching
cell boost converter are presented. The maximum power point
tracking algorithms namely perturb and observe algorithm
used. All simulations are performed in matlab/simulink
modeling and simulation platform. The output voltage and
output power of the PV panel are obtained. The source
impedance is matched with the load impedance for maximum
power transfer from source to load and high voltage gain is
obtained through this three state switching cell boost
converter.
REFERENCES
[1] N. Mohan, T. M. Undeland and W. P. Robbins, Power
Electronics: Converters, Applications and Design, 2nd ed.,
New York: John Wiley & Sons, Inc., 1995, pp. 177-178.
[2] Doo-Yong Jung, Young-Hyok Ji, Sang-Hoon Park,
Yong-Chae Jung, and Chung-Yuen Won (2011) „Interleaved
Soft-Switching
Boost
Converter
for
Photovoltaic
Power-Generation System‟, IEEE Transactions on Power
Electronics, Vol. 26, No. 4, pp: 1137-1145.
[12] W. Xiao and W. G. Dunford, “A modified adaptive hill
climbing MPPT method for photovoltaic power systems,” in
Proc. IEEE PESC, 2004, pp. 1957–1963.
AUTHOR’S PROFILE
N.Prasad received his BE degree in Electrical and Electronics Engineering
in 2009 and he is currently doing ME (Applied electronics) in Kongu
Engineering College. His area of interest includes applications of power
electronics in renewable energy.
T.Logeswaran is with the Kongu Engineering College, Perundurai,
Tamilnadu in the Department of Electrical and Electronics Engineering as
Assistant Professor. He received his BE degree in Electrical and Electronics
Engineering in 2002 and ME degree in 2007.He is pursuing his research
work in area of Electrical Engineering.
Dr.A.Senthil kumar is with Dr.Mahalingam College of Engineering and
Technology as Professor and Head in the Department of Electrical and
Electronics Engineering, Pollachi. He received his BE degree in 1995 and
ME degree in 2001 and Ph.D in VLSI in 2009. He has published 5 Papers in
International Journals in the area of Low power VLSI design. He has
received Academic Excellence award from Bharathidasan University for the
outstanding performance in ME
[3] G. V. T. Bascopé and I. Barbi, “Comparison of the high current
boost converters generated with three-stage switching cell,”
Proceeding of the 9th Brazilian Power Electronics Conference,
2003.
[4] Grover victor torrico - bascope, Ivo Barbi “A single phase PFC
based on three state switching cells” 35th IEEE power
electronics specialists conference, Germany, 2008.
[5] J. W. Baek, M. Ryoo, T. Kim, D. Yoo and J. Kim, “High boost
converter using voltage multiplier”, Proceedings of the 31st
IECON, Nov. 2005.
[6] Mei Shan Ngan and Chee Wei Tan, “A Study of Maximum
Power Point Tracking Algorithms for Stand-Alone
106