Interleaved Boost Converter for PV Cell Application Using DSPIC · 2018. 1. 24. · the PV system....

International Journal of Multidisciplinary Approach

and Studies ISSN NO:: 2348 – 537X

Volume 02, No.4, July-August, 2015

Pag

e : 7

5

Interleaved Boost Converter for PV Cell Application Using

DSPIC

Mr.V.Srimaheswaran*, Mr.V.J.Sivanagappa**and

Mr. B. Goutham***

*Assisant Professor, Department of EEE, Vivekanandha College of Engineering for Women, Tiruchegode

**Assisant Professor, Department of EEE, Anjalai Ammal Mahalingam Engineering College, Kovilvenni

***Assisant Professor, Department of EEE, Vivekanandha College of Engineering for Women,

Tiruchengode

ABSTRACT:

The PV power generation have low efficiency due to the various constrain, to utilize the

maximum power generated by the solar panel, it is required to match its internal resistance

with that of the load. This thesis gives a new proposed method to improve the performance of

the PV system. The PV cell is connected to the battery, interleaved boost converter. Battery

can be used as a backup power source when the photovoltaic system is incapable of

supplying power to the load. The proposed resonant circuit based interleaved boost converter

is to achieve high output voltage. A PWM technique is used to generate the PWM signal for

interleaved Boost switches. The purpose of boost converter is to step up the voltage. The

simulation results are validated for different duty cycle. The hardware is implemented with

the PV cell, battery, interleaved boost converter and DSPIC microcontroller. The DSPIC

microcontroller is used to generate the PWM signals for boost converter switches. The output

voltage of interleaved boost converter is given to the load. This topology increases the

performance of the dc to dc converter and reduces the ripples. The result obtained through

the simulation is verified with the hardware.

Key words — PV Array, Interleaved Boost Converter(IBC).

1. INTRODUCTION

DC-DC converters play an important role in interfacing the non-conventional energy sources

like photovoltaic current to useful DC or AC form. It is therefore necessary that the

interfacing converter should be highly efficient in transferring the power to ensure proper

load management. The boost topology is the most popular topology for getting constant value

of high DC output [14] as it’s simple power circuit leads to high efficiency and high

reliability at low cost.

In case of hard switching boost converters, due to overlapping of voltage and current

waveforms during switching and the reverse recovery of the diode with each switching cycle,

there is a high amount of switching loss associated with it. In order to address these

shortcomings, new power electronics circuits are designed based on resonant and soft-

switching technologies [11].




Pag

e : 7

6

In these cases, an increase in the efficiency of the system is accounted for, owing to non-

overlapping of the voltage and current waveforms during switching. This results in decreased

output ripple at higher values of frequencies [7]. Also, with an increase in frequency, it is

possible to use smaller values of inductors and capacitors, which results in the reduction of

the sizes of the components and thus increasing the power density [11]. However, the major

challenge still remains as the design of the converter, especially when the constraints such as

permissible stresses and conduction losses are stringent.

An interleaved boost converter usually combines more than two conventional topologies,

and the current in the element of the interleaved boost converter is half of the conventional

topology in the same power condition. Besides, the input current ripple and output voltage

ripple of the interleaved boost converter are lower than those of the conventional topologies.

The demand for renewable energy has increased significantly over the years because of

shortage of fossil fuels and greenhouse effect. Among various types of renewable energy

sources, solar energy and wind energy have become very popular and demanding due to

advancement in power electronics techniques. Photo-Voltaic (PV) sources are used today in

many applications as they have the advantages of being maintenance and pollution free.

Solar-electric-energy demand has grown consistently by 20%–25% per annum over the past

20 years, which is mainly due to the decreasing costs and prices. This decline has been driven

by the following factors: 1) an increasing efficiency of solar cells 2) manufacturing

technology improvements and 3) economics of scale [9].

2. MODELING OF THE SOLAR CELL

Thus the simplest equivalent circuit of a solar cell is a current in parallel with a diode. The

output of the current source is directly proportional to the light falling on the cell. During

darkness, the solar cell is not an active device; it works as a diode, i.e. a P-N junction. It

produces neither a current nor a voltage. However, if it is connected to an external supply

(large voltage) it generates a current Id, called diode current or dark current. The diode

determines the V-I characteristics of the cell.

Fig. 1. Equivalent Circuit of a Solar Cell

Fig. 1 shows the equivalent circuit of a solar cell, where, RS is the very small series

resistance and Rsh is the quite large shunt resistance. Dj is the ideal P-N diode, Iph expresses

as the photocurrent source generated proportionally by the surface temperature and

insolation. V and I represent the output voltage and output current of the solar cell,




Pag

e : 7

7

respectively. According to the physical property of the P-N semiconductor, the I-V

characteristics of PV module could be expressed.

(1)

In addition, the modules reverse saturation current Isat.

(2)

The Iph is expressed in (3) represents the photocurrent proportionally produced to the level of

cell surface temperature and radiation, where ISSO is the short-circuit current, Ki is the short-

circuit current temperature coefficient, and Si is the solar radiation in W/m2 [8].

(3)

2.1 V-I CHARACTERISTICS of PV CELL

Each solar cell has its own voltage-current (V-I) characteristic. Fig. 2 shows the V-I &

P-V characteristic of a typical photovoltaic cell. The problem with extracting the most

possible power from a solar panel is due to nonlinearity of the characteristic curve. The

characteristic shows two curves, one shows the behavior of the current with respect to

increasing voltage. The other curve is the power-voltage curve and is obtained by the

equation (P=I*V).

Fig. 2. Solar Panel V-I Characteristic and Power Curve

When the P-V curve of the module is observed, one can locate single maxima of power

where the solar panel operates at its optimum. In other words, there is a peak power that

corresponds to a particular voltage and current. Obtaining this peak power requires the solar

panel to be operated at or very near the point where the P-V curve is at the maximum [8].

3. INTERLEAVED BOOST CONVERTER

The interleaved boost converter will represent one of the most significant portions to get

maximum output. Ideally, the maximum power will be taken from the solar panels. In order




Pag

e : 7

8

to do so, the panels must operate at their optimum power point. The output of the solar panel

will be either shorted or open circuited through the opening or closing of a switch.

A basic boost converter converts a DC voltage to a higher DC voltage. Interleaving adds

additional benefits such as reduced ripple currents in both the input and output circuits.

Higher efficiency is realized by splitting the output current into two paths, substantially

reducing I2R losses and inductor AC losses. This advantages of interleaving, such as higher

efficiency and reduced input and output ripple, are also realized in the boost topology. Most

of the controllers used in these applications apply equally well when configured for use in an

interleaved boost application. As power densities continue to rise, interleaved boost designs

become a powerful tool to keep input currents manageable and increase efficiency, while still

maintaining good power density. With mandates on energy savings more common,

interleaved construction may be the only way to achieve design objectives.

The concept of interleaving, or more generally that of increasing the effective pulse

frequency of any periodic power source by synchronizing several smaller sources and

operating them with relative phase shifts, is not new. Interleaving technique actually exists in

different areas of modern technologies in different forms..In the field of power electronics,

application of interleaving technique can be traced back to very early days, especially in high

power applications. In high power applications, the voltage and current stress can easily go

beyond the range that one power device can handle. Multiple power devices connected in

parallel and/or series could be one solution. However, voltage sharing and/or current sharing

are still the concerns. Instead of paralleling power devices, paralleling power converters is

another solution which could be more beneficial. Furthermore, with the power converter

paralleling architecture, interleaving technique comes naturally. Benefits like harmonic

cancellation, better efficiency, better thermal performance, and high power density can be

obtained. In earlier days, for high power applications, in order to meet certain system

requirement, interleaving multi-channel converter could be a superior solution especially

considering the available power devices with limited performance at that time. One of such

example can be found in the application of Superconducting a Magnetic Energy Storage

System (SMES).The current stress of such application is extremely high, yet certain system

performance still need to be met.

3.1 OPERATION

Recently, high-performance dc–dc converters have been called for the increasing high step-

down ratios with high output current rating applications, such as VRMs of CPU boards and

battery chargers, and distributed power systems. For non isolation applications with low

output current ripple requirement, an interleaved boost converter (IBC) has received a lot of

attention due to its simple structure and low control complexity.

Here input is low voltage dc supply has been given and high voltage dc supply is derived.

Such as in between inversion, high frequency transformation & voltage doubler operation are

carried on.




Pag

e : 7

9

Low voltage dc supply is given to single phase inverter. In this topology the single phase

inverter as inductor (L1). Thereby by switching the two switches for positive half cycle &

another two switches for negative half cycle. Thus during shoot through state of two

switching sequence the inductor connected will be charged and it will be discharged during

negative half cycle. Because of this boosted ac voltage is acquired across the single phase

inverter.

Across the single phase inverter we are also used LC filter to remove the ripple free output at

the end of single phase inverter and we are using a special high frequency transformer for

switching that boosted ac signal at high frequency state.

Fig. 3. Circuit Diagram of Interleaved Boost Converter

Here by getting that high frequency boosted ac signal; the six stage three level voltage

doubler will derive the dc output level upto six times from the given high frequency boosted

ac signal. As we are using mur diodes and high power rated capacitors the output voltage and

power will be much higher than the normal dc-dc converter.

3.2 ADVANTAGES

High voltage gain

Reduces the voltage stress of both active switches and diodes

Conduction loss is less

Used for higher power ratings at high voltage ratings.

Easy control method is employed for switching devices without complex circuits.

4. SIMULATION MODEL & RESULTS

Proteus Professional-software for automated design of electronic circuits. The package is a

system of circuit simulation, based on the models of electronic components in PSPICE. A

distinctive feature of the package Proteus Professional is the possibility of modeling of the

programmable devices: microcontrollers, microprocessors, DSP and others. Additionally, the

package of Proteus Professional is a system design of printed circuit boards. Proteus

Professional can simulate the following microcontrollers: 8051, ARM7, AVR, PIC. In this

project, interleaved boost converter for PV application is modeled using Proteus7.7 software.

The simulated result is discussed with the switching pulse; input voltage and output voltage

are analyzed.




Pag

e : 8

0

Fig. 4. Simulation Model of Interleaved Boost Converter

4.1 SIMULATION RESULT FOR 25% DUTY CYCLE

Fig. 5. Switching Pulses for Boost Convverter

Fig 5 shows the switching pulses for interleaved boost converter that are generated using

single pulse width modulation. The pulse is given to the MOSFET switch is turned on at a

correct sequence to obtain the output.

Fig. 6. Input and Output Waveforms of High Frequency Transformer




Pag

e : 8

1

Fig 6 shows the input and output waveforms of high frequency transformer. The transformer

primary and secondary voltages are 3.7V and 37V (Peak – Peak). The output of transformer

is given to the six stage three level voltage doublers rectifier.

Fig.7. Input and Output waveform of Interleaved Boost Converter

Fig 7 shows the input and output waveform of interleaved boost converter. Channel B

and Channel C is connected to the input and output. The input has the voltage of 12V.The

output voltage has pulse which occurs due to the grounding. In order to show the value of the

DC output voltage it has been grounded. Here we have obtained 4 quadrant of 105V.

4.2 SIMULATION RESULT FOR 50% DUTY CYCLE

Fig. 8. Switching Pulses for Boost Converter

Fig 8 shows the switching pulses for interleaved boost converter that are generated using

single pulse width modulation. The pulse is given to the MOSFET switch is turned on at a

correct sequence to obtain the output.




Pag

e : 8

2

Fig. 9. Input and Output Waveforms of High Frequency Transformer

Fig 9 shows the input and output waveforms of high frequency transformer. The transformer

primary and secondary voltages are 7.2V and 72V (Peak - Peak). The output of transformer is

given to the six stage three level voltage doubler rectifier.

Fig.10. Input and Output waveform of Interleaved Boost Converter

Fig 10 shows the input and output waveform of interleaved boost converter. Channel B and

Channel C is connected to the input and output. The input has the voltage of 12V.The output

voltage has pulse which occurs due to the grounding. In order to show the value of the DC

output voltage it has been grounded. Here we have obtained 4 quadrant of 196V.

5. EXPERIMENTAL ANALYSIS

The hardware of Solar panel with Interleaved Boost converter is implemented and the output

is fed to the load. The DC supply from the battery is given to the interleaved boost converter.

The boosted voltage is then given to the load. The microcontroller is used to produce control

signals based on pulse width modulation technique for the gates of the MOSFET. The

hardware results are input voltage, gate pulses, input voltage of transformer and output

voltage of converter. These result measured using Digital Storage Oscilloscope (DSO).




Pag

e : 8

3

Fig. 11. Hardware Circuit for Interleaved Boost Converter

Fig 11 shows the hardware circuit for interleaved boost converter. The gate pulses for

interleaved boost converter are generated using PIC microcontroller.

Fig.12 Input Voltage Waveform

Fig 12 shows the input voltage of 9V which is obtained from the solar panel is then given to

the interleaved boost converter.

Fig. 13. Switching Pulse for Interleaved Boost Chopper




Pag

e : 8

4

Fig 13 shows the switching pulses for interleaved boost converter. The switching pulses are

generated using DSPIC microcontroller and are given to the switches. The pulses supplied

from the DSPIC have the amplitude of 5V which is not enough to drive the MOSFET

switches and therefore optocoupler IC’s are employed to regulate the voltage. The switches

S1, S2, S3 and S4 are turned on at a correct sequence.

Fig. 14. High Frequency Transformer Input Voltage Waveform

Fig 14 shows the transformer pulsating input voltage waveform of 80V (Peak - Peak) which

is given to the voltage doublers rectifier circuit.

Fig. 15. Output Voltage for Interleaved Boost Converter

Fig 15 shows the interleaved boost converter output voltage of 240V. The input 9V is boosted

to 240V.




Pag

e : 8

5

Fig. 16. Expérimental Set up

6. CONCLUSION

This Project gives the clear idea about the interleaved boost converter topology for PV cell.

The voltage level is improved by using the interleaved boost chopper. The proposed method

adds additional benefits such as reduced ripple currents in both the input and output circuits.

The circuit topology and the operational principle of the proposed converter are analyzed in

detail. The simulation results are validated for the different duty cycle. The hardware is

implemented with Solar panel, interleaved boost converter and DSPIC microcontroller. Boost

converter can be used to step up the voltage. The pulses are generated and it is given to the

switches by using pulse width modulation technique (PWM). Simulation and experimental

results shows the proposed interleaved converter topology structure. The results obtained

through the simulation are verified by using the hardware.

REFERENCES

i. B.Chitti Babu, S.R.Samantaray, M.V.Ashwin Kumar, “Design and Implementation of

Low Power Smart PV Energy System for Portable Applications Using Synchronous

Buck Converter”, Journal of Low Power Electronics, American Scientific publishers,

Vol.08, Issue.02, pp.: 1-10, 2012.

ii. Prasanna, U.; Rathore, A.; , "Extended Range ZVS Active-Clamped Current-Fed

FullBridge Isolated Dc/Dc Converter for Fuel Cell Applications: Analysis, Design

and Experimental Results," IEEE Transactions on Industrial Electronics, , Vol.

59,No:12., pp.1, 2012.

iii. Jee-Hoon Jung, and S. Ahmed, “Model Construction of Single Crystalline

Photovoltaic Panels for Real-time Simulation,” IEEE Energy Conversion Congress &

Expo, September 12-16, 2010, Atlanta, USA.

iv. E..H. Kim and B.H. Kwon, “Zero-voltage- and zero current-switching full-bridge

converter with secondary resonance,” IEEE Trans. On Industrial Electronics, vol. 57,

no. 3, pp. 1017-1025, March 2010.




Pag

e : 8

6

v. S.H. Park, G.R. Cha, Y.C. Jung and C.Y. Won, “Design and application for PV

generation system using a soft switching boost converter with SARC,” IEEE Trans.

on Industrial Electronics, vol. 57, no. 2, pp515-522, February (2010).

vi. K..N. Hasan.; et al. “An improved maximum power point tracking technique for the

photovoltaic module with current mode control” In: Proc. of 19th Australian

university power engineering conference (AUPEC), pp. 1-6, 2009.

vii. MiroslawLuft, ElzbietaSzychta and LeszekSzychta, “Method of designing ZVS boost

converter,” Power Electronics and Motion Control Conference 2008 (EPEPEMC

2008), Poznan(Poland), September 2008.

viii. Kuei-Hsiang Chao, Ching-Ju Li and Sheng-HanHo, “Modeling and Fault Simulation

of Photovoltaic Generation Systems Using Circuit Based Model”, in proceedings on

IEEE-ICSET Annual Meeting, Taichung, Taiwan, 2008, pp 290-294.

ix. Juan Manuel Carrasco, Leopoldo Garcia Franquelo, “Power Electronic Systems for

the Grid Integration of Renewable Energy Sources: A Survey”, IEEE Transactions

on Power Electronics, Vol.53, No.4, pp 1002-1016, Aug 2006.

x. J.Santos, F. Antunes, A. Chehab and C. Cruz, “A maximum power point tracker for

PV systems using a high performance boost converter,” Solar Energy, vol. 80, pp.

772-778, 2006.

xi. S.Wang, “Design and hardware implementation of a soft-switched converter for fuel

cell applications”, M.S.Thesis, University of Texas, Arlington. May 2006.

xii. R. Gurunathan and A. K. S. Bhat, “A zero-voltage transition boost converter using a

zero-voltage switching auxiliary circuit,” IEEE Trans. on Power Electronics, vol. 17,

no. 5, pp. 658-668, September 2002.

xiii. HacyBodur and A. FarukBakan, “A new ZVT-PWM DCDC converter,” IEEE Trans.

on Power Electronics, vol. 17, no. 1, pp. 40-47, January 2002.

xiv. N. Jain,”A Zero Voltage Switching Boost Converter using a Soft Switching Auxiliary

Circuit with reduced conduction losses”, M.S.Thesis, Concordia University, Montreal,

Canada. December 2000.

Date post:	01-Sep-2020
Category:	Documents
Upload:	others
View:	6 times
Download:	0 times

Interleaved Boost Converter for PV Cell Application Using DSPIC · 2018. 1. 24. · the PV system....

Documents