This document summarizes a research paper that proposes a photovoltaic water pumping system using a two inductor boost converter and PWM inverter. It consists of the following key components: 1) A PV array that provides a variable 18V input to the converter. 2) A MPPT controller that uses the perturb and observe algorithm to maximize power output from the PV array. 3) A two inductor boost converter that boosts the 18V PV output to a regulated 35V DC output. 4) A three-phase PWM inverter that converts the 35V DC to AC to power an induction motor for water pumping. Simulations and experimental results demonstrate the system's ability to boost the PV

1. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30-31, December, 2014, Ernakulam, India
197
IMPLEMENTATION OF TWO INDUCTOR BOOST
CONVERTER FOR AN AUTONOMOUS PHOTOVOLTAIC
WATER PUMPING SYSTEM
KRISHNAPRIYA C S1
, NITHIN S NAIR2
1
P G Scholar, Department of EEE Sree Narayana Gurukulam College of Engineering Kolenchery, India
2
Assisstant Professor, Department of EEE Sree Narayana Gurukulam College of Engineering, Kolenchery, India
ABSTRACT
This paper proposes a new converter- inverter drive system for induction motor. This system is mainly used for
water pumping purposes in areas like they do not have drinkable water for their consumption. In these places, the
unavailability of electric power rules out the pumping and water treatment through conventional systems. Use of
photovoltaic energy is one of the solution for this problem. Voltage from the PV array is the input to the converter. In the
converter-inverter system, It proposes a Dual Inductor Converter consisting of a resonant tank, voltage doubler rectifier
and a snubber circuit which act as a DC-DC boost converter. The output of the converter system is given to the inverter
system. SPWM control is used to trigger the IGBT’s in the inverter. But the voltage from the PV cell is not constant
which varies according to the solar radiation. MPPT control is provided; it maximizes the power output from a PV
module or array with varying operating conditions, and therefore maximizes the system efficiency. To obtain the
maximum power extracting efficiency perturb and observe maximum power point tracking algorithm is introduced for
the controlling of converter.
Keyword: PV cell, MPPT, Two inductor boost converter, PWM Inverter
I. INTRODUCTION
Water resources are essential for satisfying human needs, protecting health, and ensuring food production,
energy and the restoration of ecosystems, as well as for social and economic development and for sustainable
development. In this paper, a efficient photovoltaic water pumping system is presented [1]. Here the drive system is
typically composed of four main components: a PV cell, gives the input supply to the converter, a dc-dc converter that
converts low dc voltages to a required high dc voltage, an inverter that converts the high dc voltage to a three-phase ac
voltage, a MPPT controller that controls the PV cell at its maximum power point.
The simplified block diagram of a photovoltaic system is shown in Fig 1. This paper proposes a new high
efficiency, low cost converter for photovoltaic water pumping system without the use of storage elements, such as
batteries. The converter is designed to drive a three-phase induction motor directly from photovoltaic energy. The use of
three-phase induction motor presents a better solution to the commercial DC motor water pumping system. The proposed
system is based on a current-fed multi-resonant converter also known as Resonant Two Inductor Boost Converter (TIBC)
and a Full-Bridge Three-phase Voltage Source Inverter (VSI). The classic topology of the TIBC has features like high
voltage gain and low input current ripple. Maximum power point tracking (MPPT) is used in photovoltaic (PV) systems
to maximize the photovoltaic array output power, irrespective of the temperature and radiation conditions and of the load
electrical characteristics the PV array output power is used to directly control the dc/dc converter, thus reducing the
INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING &
TECHNOLOGY (IJEET)
ISSN 0976 – 6545(Print)
ISSN 0976 – 6553(Online)
Volume 5, Issue 12, December (2014), pp. 197-206
© IAEME: www.iaeme.com/IJEET.asp
Journal Impact Factor (2014): 6.8310 (Calculated by GISI)
www.jifactor.com
IJEET
© I A E M E

2. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30-31, December, 2014, Ernakulam, India
198
complexity of the system. The method is based on use of a P & O of the PV to determine an optimum operating current
for the maximum output power.
Fig 1. Simplified Block Diagram of the Proposed System.
The Two Inductor Boost converter has two inductors in the primary side and a voltage doubler in the secondary
side. Although, the current fed topologies are used here, it have some problems like high voltage spikes created due to
the leakage inductance of the transformers, and high voltage stress on the rectifying diodes. Thus, the converters adopt
resonant topologies to utilize the component parasitic characteristics and thereby achieve zero current switching (ZCS).
A snubber is connected in parallel with the whole system to overcome from and problems. The inverter is based on a
classic topology (three legs, two switches per leg). SPWM control method is used.
This In this paper, a PV array is modeled and simulated using MATLAB/Simulink .This PV model is coupled to
a TIBC converter. By changing the duty cycle of the converter the system implements the most popular MPPT method to
extract maximum power. The system is then connected to a Three-Phase Inverter. Finally the output is given to a Three-
phase induction motor.
II. PROPOSED SYSTEM
Fig 2. Simplified Block Diagram of the Proposed System.
Figure 2 shows the general block diagram of the proposed system. Each blocks are explained below,
A. PV Cell
Fig 3. Single Diode Model of a PV Cell

3. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30-31, December, 2014, Ernakulam, India
199
Photovoltaic cells convert sunlight directly to electricity. They are basically made up of a PN junction. In single
diode model, there is a current source parallel to a diode. The current source represents light generated current that varies
linearly with solar irradiation. This is the simplest and most widely used model as it offers a good compromise between
simplicity and accuracy.
B. MPPT Control
Photovoltaic (PV) energy is the most important energy resource since it is clean, pollution free, and
inexhaustible. In recent years, a large number of techniques have been proposed for tracking the maximum power point
(MPP). Maximum power point tracking (MPPT) is used in photovoltaic (PV) systems to maximize the photovoltaic array
output power, irrespective of the temperature and radiation conditions and of the load electrical characteristics the PV
array output power is used to directly control the dc/dc converter, thus reducing the complexity of the system. The
method is based on use of a Incremental conductance of the PV to determine an optimum operating current for the
maximum output power.
In perturb and observe method the array terminal voltage is always adjusted according to the MPP voltage it is
based on the incremental and instantaneous conductance of the PV module
Fig 4. MPPT Control
Figure shows that the slope of the P-V array power curve is zero at The MPP, increasing on the left of the MPP and
decreasing on the Right hand side of the MPP.
Fig 5. P&O Algorithm

4. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30-31, December, 2014, Ernakulam, India
200
C. Two Inductor Boost Converter
Fig 6. Proposed Two Inductor Converter Side Circuitry
It mainly consists of current fed converter block, voltage doubler and snubber circuitry. Current-fed converter
mainly consists of an inductor connected in series with the supply. The current source system thus obtained is normally
derived from the boost converter, having an inherent high step-up voltage ratio, which helps to reduce the needed
transformer turn ratio and it reduces the voltage stress to a large extend. But, it has disadvantages like high current
ripples. For that, two inductors are connected in the primary side. The voltage doubler in the secondary side is used to
double the input voltage to it, thereby using it for obtaining a wide output range. An isolation transformer is connected in
between them. Figure 6 shows the proposed converter circuitry. The single inductor of a general boost converter is
replaced by two inductors, L1 and L2. The MOSFET switches Q1 and Q2 are hard switched overlapped.ie, at least one of
the switches is on at any time. The parasitic components of the resonant tank include the magnetizing inductance Lm,
leakage inductance Lr and leakage capacitance Cr. The Do1, Do2, Co1and Co2 forms the voltage doubler circuit. The
output capacitors Co1 and Co2 are much larger than Cr, to clamp the resonant voltage. Ds1, Ds2 and Cs form the snubber
circuit. The topological operating stages for a half cycle includes two stages
1st stage: with both switches closed the primary winding is short circuited and the current increases linearly in the input
inductors according to the specified ripple. Energy is stored in the inductors while the output filter capacitor feeds the
load. The isolation transformer remains unaffected.
2nd stage: when the switch Q1 is turned-off, its current is commutated to the primary winding. The isolation transformer
gets involved due to the voltage difference between node 1 and node 2. As Q2 is turned on, Ds1 will start to conduct. At
this instant the current in Do2 reaches zero causing the resonance between Cr and Lm
D. Three-Phase PWM Inverter
Fig 7. Three-Phase PWM Inverter

5. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30-31, December, 2014, Ernakulam, India
201
The six step inverter is developed using SPWM strategy. In SPWM strategy, the peak of the sine modulating
waveform is always less than the peak of the triangle carrier voltage waveform. When the sinusoidal waveform is greater
than the triangular wave, the upper switch is turned on. Similarly, when the sinusoidal waveform is less than the
triangular waveform, the upper switch is off and the lower switch is on. The switches are controlled in pairs ((S1; S4),
(S3;S6), and (S5;S2)).
III. SIMULATION RESULTS AND ANALYSIS
The proposed system software is done in MATLAB/Simulink version 2013. Simulation of converter and the three
phase inverter is done and the waveforms are analyzed. PV cell and MPPT controller is simulated. An input 18V from
the PV cell is boosted to a constant DC 35 volt. It is fed to a three phase inverter. The inverter is controlled using SPWM.
a) PV Cell Simulation and MPPT Control
The Simulink model used for the implementation of the required solar cell and MPPT control system is as
shown. PV cell generate 18Volt.
Fig 8. PV cell Matlab/SIMULINK model
Fig 9. Voltage waveform

6. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30-31, December, 2014, Ernakulam, India
202
Fig 10. Matlab/Simulink model of MPPT control
Fig 11. Gating Pulses to
b) Inverter Simulation and Output Waveform
Fig 13. TIBC Converter Simulation
A dc input of 18 volt is given to the converter, which is boosted to 35 Volt.

7. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30-31, December, 2014, Ernakulam, India
203
Fig 14. Output Voltage of the TIBC Converter
c) Inverter Simulation And Line Voltage
Simulink model of 3-phase inverter is shown in figure 14. A 3-phase squirrel cage Motor rated 5.4 HP, 400 V,
50 Hz, 1430 rpm is fed by a 3-phase IGBT inverter. And a three phase filter is connected between them.
Fig 14. Simulink Model of 3-Phase Inverter.
Fig 15. Output and line voltage using SPWM method
Fig 16. Output of filter

8. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30-31, December, 2014, Ernakulam, India
204
Fig 17. Stator voltage
Fig 18. Torque
IV. EXPERIMENTAL STUDY
Fig 19. Block Diagram of the Experimental Set Up.
For the power supply unit, The 230V is first converted into 15V ac by using a step down transformer. Then the
ac supply is being changed into dc supply by implementing a bridge rectifier. The unwanted signals which are called as
harmonics is being eliminated using capacitor filter. This 12V dc supply is then fed into a voltage regulator and is

9. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30-31, December, 2014, Ernakulam, India
205
converted to 5V regulated supply. Then it is fed into the required components like driver circuit and PIC microcontroller.
We are using PIC16F877 for producing switching pulses to converter.
Fig 20. Power circuit diagram of TIBC Converter
Experimental results are shown for a TIBC converter. The pulses generated by the PIC controller are given to
the MOSFET through driver circuit. These pulses are shown below. The maximum output value of this TIBC converter is
60V.
Fig 21. Hardware Set Up Fig 22. Pulses for Q1
Fig 23. Pulses for Q2

10. Proceedings of the International Conference on Emerging Trends in Engineering and Management (ICETEM14)
30-31, December, 2014, Ernakulam, India
206
V. CONCLUSION
In this paper, a converter-inverter drive system using a photovoltaic array is implemented. The converter was
designed to drive a three-phase induction motor directly from PV solar energy, and was conceived to be a commercially
viable solution having low cost, high efficiency, and robustness. The TIBC converter used here has low input current
ripple, low cost and high step-up characteristics. The multi-resonant tank provides high voltage gain and absorbs the
parasitic parameters of the transformer. By employing the voltage doubler at the load side, the turns-ratio of transformer
could be halved. With this TIBC system, the input voltage of 18 Volts is boosted to 35 volts. The output of the converter
system is given to the inverter system. Here SPWM control is used. MPPT control is provided to operate the PV cell in
maximum power.
REFERENCES
[1] M.A. Vitorino, and M.B.R. Correa, "High performance photovoltaic pumping system using induction motor," in
Proc. 2009 Brazilian Power Electronics Conference, , pp.797-804.
[2] M. Cacciato, A. Consoli, and V. Crisafulli, "A high voltage gain DC/DC converter for energy harvesting in
single module photovoltaic applications," in Proc. 2010 IEEE International Symposium on Industrial Electronics
(ISIE), , pp.550-555.
[3] R. Faranda, and S. Leva, “Energy comparison of MPPT techniques for PV Systems”, WSEAS Transactions on
Power Systems, vol. 3, pp. 446-455, June 2008.
[4] D. Li, Bo Liu, Bo Yuan, Xu Yang, J. Duan, and J. Zhai, "A high step-up current fed multi-resonant converter
with output voltage doubler," in Proc. 2011 IEEE Applied Power Electronics Conference and Exposition
pp.2020-2026.
[5] Aishwarya P. Mulmule, Rambabu A. Vatti and Pratik M. Porwal, MPPT Technique To Improve Efficiency In
Wind-Solar Hybrid System” International Journal of Electrical Engineering & Technology (IJEET), Volume 4,
Issue 6, 2013, pp. 74 - 82, ISSN Print : 0976-6545, ISSN Online: 0976-6553.