A Safety Enhanced High Step Up DCDC Converter for AC Photovoltaic Module Application

04/08/2023 FINAL REVIEW - ANNA UNIVERSITY 1

GUIDED BY: Ms. T.V. JINCYAsst. Professor

SUBMITTED BY: P.VENKATASUBRAMANIYAMDEPT: M.E – POWER ELECTRONICS & DRIVESBATCH: 2011 – 2013

A Safety Enhanced, High Step-Up DC–DC Converter for AC Photovoltaic Module Application


ABSTRACT

This paper proposes a converter that employs a floating active switch to isolate energy from the PV panel when the ac module is OFF.

This particular design protects installers and users from electrical hazards.

Without extreme duty ratios and the numerous turns-ratios of a coupled inductor, this converter achieves a high step-up voltage-conversion ratio.

The leakage inductor energy of the coupled inductor is efficiently recycled to the load.


ORGANISATION OF WORK

EXISTING SYSTEM PROPOSED SYSTEM MODES OF OPERATION OF PROPOSED SYSTEM SIMULATION OUTPUT OF PROPOSED SYSTEM REFERENCES CONCLUSION


EXISTING SYSTEM(HIGH STEP UP DC-DC CONVERTER)

DC Voltage Source Vin

Floating active switch S1

Primary Turns of Coupled Inductors N1

Secondary Turns of Coupled Inductors N2

Diodes D1 & D2

Capacitors C1 & C2

Rectifier diode D3

Output capacitor C3

Load R


INTERLEAVED HIGH STEP-UP DC-DC CONVERTER (PROPOSED SYSTEM )

DC Voltage Source Vin

Floating active switchS1 & S2

Primary Turns of Coupled Inductors N1 & N3

Secondary Turns of Coupled Inductors N2 & N4

Diodes D1, D2, D3 & D4

Capacitors C1, C2, C3 & C4

Rectifier diodeD5

Output capacitorC5

Load R


VOLTAGE AND CURRENT POLARITY IN PROPOSED CONVERTER

In order to simplify the circuit analysis the following assumptions are made The coupled inductor T1 & T2 are

represented as a magnetizing inductor Lm & Lm1.

Lk1 & Lk2 are Primary & Secondary Leakage Inductors of coupled inductor T1

Lk3 & Lk4 are Primary & Secondary Leakage Inductors of coupled inductor T2


CONTINUOUS CONDUCTION MODEMODE – I (T0 – T1)

CONDUCTING COMPONENTS CHARGING

CAPACITORSSWITCH DIODE

S1 & S2 D2 & D4 C2 & C4


MODE – I (T0 – T1)OPERATING PRINCIPLE

When S1 & S2 are at ON state the magnetizing inductor Lm & Lm1

continuously charges capacitor C2 & C4 through T1 & T2.

The source voltage Vin crosses the magnetizing inductor Lm , Lm1 and

primary leakage inductor Lk1 ,Lk3.

The magnetizing inductor Lm & Lm1 transfers its energy through coupled

inductor T1 & T2 to charge switched capacitor C2 & C4.

As a result the current ILm & ILm1 is decreases.

In this Mode the charging current ID2, ID4 and IC2 , IC4 decreases.

The Mode Ends When Ilk1 = Ilm & Ilk3 = Ilm1.


MODE – II (T1 – T2)



S1 & S2 D5 C5


MODE – II (T1 – T2)OPERATING PRINCIPLEThe source voltage Vin crosses the magnetizing inductor Lm ,Lm1,

primary leakage inductor Lk1 ,Lk3 and Primary winding N1 & N3 and

acts series with secondary winding N2 & N4 of coupled inductor T1 &

T2, Capacitor C1, C2, C3 & C4.

Magnetizing inductor Lm & Lm1 is also receiving energy from Vin.

The energy is finally discharged to Output Capacitor C5 and Load R.

As a result the current ILm & ILm1, Ilk1 & Ilk3, Rectifier Diode Current Id5

are increasing.

This mode ends when switch S1 & S2 are turned OFF.


MODE – III (T2 – T3)

CONDUCTING COMPONENTS CHARGING CAPACITORS

SWITCH DIODE

All SWITCHES ARE IN OFF STATE D1, D3, D5 C1, C3 & C5


MODE – III (T2 – T3)OPERATING PRINCIPLEAs the switches S1 & S2 are in OFF state

Energy of secondary leakage inductor Lk2 & Lk4 is series

connected with C2 & C4 to charge output capacitor C5 and the

load R.

Energy stored in Primary leakage inductor Lk1 & Lk3 flows

through diode D1 & D3 to charge capacitor C1 & C3.

Ilm & Ilm1 are increasing because magnetizing inductor Lm and

Lm1 is receiving energy from Lk1 & Lk3.

Diode D1 and D3 are conducting

This Mode ends when Leakage Current ILk2 & ILK4 decreases to zero.


MODE – IV (T3 – T4)



All SWITCHES ARE IN OFF STATE

D1, D2, D3 & D4 C1, C2, C3 & C4


MODE – IV (T3 – T4)OPERATING PRINCIPLEThe leakage energy from the Leakage inductor Lk1 & Lk2 flows through the

diodes D1 & D3 keeps charging capacitor C1 & C3 as a result Currents ILk1,

ILK3 and ID1, ID3 are continually decreasing.

The Lm & Lm1 is delivering its energy through T1 ,T2 and D2, D4 to charge

capacitor C2 & C4.

Diodes D1, D2, D3 & D4 are conducting.

The energy stored in output capacitor C5 is constantly discharged to the

load R.

These energy transfers result in decrease of ILk1, ILK3 and ILm, ILm1 but

increases in ILk2 & ILk4 .

This mode ends when current ILk1 and ILK3 reaches zero.


MODE – V (T4 – T5)



All SWITCHES ARE IN OFF

STATE D2 & D4 C2 & C4


MODE – V (T4 – T5)OPERATING PRINCIPLE Magnetizing inductor Lm & Lm1 are constantly releasing its

energy to C2 & C4. Diode D2 is conducting The magnetizing inductor energy flows through the secondary

winding of the coupled inductor N2 ,N4 and D2, D4 continues to charge capacitor C2. As a result the iLm & iLm1 are decreasing.

The energy stored in capacitor C3 is constantly discharged to the load R.

This mode ends when switch S1 is turned ON.


WAVEFORM OF PROPOSED CONVERTERS AT CCM OPERATION


WAVEFORM OF PROPOSED CONVERTERS AT CCM OPERATION




S1 & S2 D5 C5

DISCONTINUOUS CONDUCTION MODEMODE – I (T0 – T1)


MODE – I (T0 – T1)OPERATING PRINCIPLEThe source voltage Vin crosses the magnetizing inductor Lm ,Lm1,

primary leakage inductor Lk1 ,Lk3 and Primary winding N1 & N3 and

acts series with secondary winding N2 & N4 of coupled inductor T1 &

T2, Capacitor C1, C2, C3 & C4.

Magnetizing inductor Lm & Lm1 is also receiving energy from Vin.

The energy is finally discharged to Output Capacitor C5 and Load R.

As a result the current ILm & ILm1, Ilk1 & Ilk3, Rectifier Diode Current Id5

are increasing.

This mode ends when switch S1 & S2 are turned OFF.


MODE – II (T1 – T2)

CONDUCTING COMPONENTS CHARGING CAPACITORS

SWITCH DIODE

All SWITCHES ARE IN OFF STATE D1, D3, D5 C1, C3 & C5


MODE – II (T1 – T2)OPERATING PRINCIPLEAs the switches S1 & S2 are in OFF state

Energy of secondary leakage inductor Lk2 & Lk4 is series

connected with C2 & C4 to charge output capacitor C5 and the

load R.

Energy stored in Primary leakage inductor Lk1 & Lk3 flows

through diode D1 & D3 to charge capacitor C1 & C3.

Ilm & Ilm1 are increasing because magnetizing inductor Lm and

Lm1 is receiving energy from Lk1 & Lk3.

Diode D1 and D3 are conducting

This Mode ends when Leakage Current ILk2 & ILK4 decreases to zero.


MODE – III (T2 – T3)



All SWITCHES ARE IN OFF STATE

D1, D2, D3 & D4 C1, C2, C3 & C4


MODE – III (T2 – T3)OPERATING PRINCIPLEThe leakage energy from the Leakage inductor Lk1 & Lk2 flows through the

diodes D1 & D3 keeps charging capacitor C1 & C3 as a result Currents ILk1,

ILK3 and ID1, ID3 are continually decreasing.

The Lm & Lm1 is delivering its energy through T1 ,T2 and D2, D4 to charge

capacitor C2 & C4.

Diodes D1, D2, D3 & D4 are conducting.

The energy stored in output capacitor C5 is constantly discharged to the

load R.

These energy transfers result in decrease of ILk1, ILK3 and ILm, ILm1 but

increases in ILk2 & ILk4 .

This mode ends when current ILk1 and ILK3 reaches zero.


MODE – IV (T3 – T4)



All SWITCHES ARE IN OFF

STATE D2 & D4 C2 & C4


MODE – IV (T3 – T4)OPERATING PRINCIPLE Magnetizing inductor Lm & Lm1 are constantly releasing its

energy to C2 & C4. Diodes D2 & D4 are conducting The magnetizing inductor energy flows through the secondary

winding of the coupled inductor N2 ,N4 and D2, D4 continues to charge capacitor C2. As a result the ILm & ILm1 are decreasing.

The energy stored in capacitor C3 is constantly discharged to the load R.

This mode ends when switch S1 is turned ON.


MODE – V (T4 – T5)



All THE COMPONENTS ARE IN OFF STATE


MODE – V (T4 – T5)OPERATING PRINCIPLE

All active components are turned OFF.

Only the energy stored in OUTPUT capacitor C5 is continued to be

discharged to the load R

This mode ends when switch S1 & S2 are turned ON


WAVEFORM OF PROPOSED CONVERTERS AT DCM OPERATION


WAVEFORM OF PROPOSED CONVERTERS AT DCM OPERATION


SIMULATION CIRCUIT DIAGRAM


SIMULATION OUTPUTINPUT VOLTAGE


INPUT CURRENT


OUTPUT VOLTAGE


INPUT VOLTAGE (VS) OUTPUT VOLTAGE

INPUT VOLTAGE OUTPUT VOLTAGE THD%

15V 45V 61.86%

30V 75V 61.65%

45V 110V 61.03%

60V 140V 61.53%


REFERENCESSL No Topic Submitted by

Submitted Year

1Long-lifetime power inverter for photovoltaic ac modules

C. Rodriguez and G. A. J. Amaratunga

2008

2

Switched-capacitor/ switched- inductor structures for getting transformerless hybrid dc–dc PWM converters

B. Axelrod, Y. Berkovich, and A. Ioinovici

2008

3High boost converter using voltage multiplier

J. W. Baek, M. H. Ryoo, T. J. Kim, D. W. Yoo, and J. S. Kim

2005

4

Flyback-type single-phase utility interactive inverter with power pulsation decoupling on the dc input for an ac photovoltaic module system

K.Wada , T. Shimizu, , and N.Nakamura

2006

5High-efficiency, high step-up dc–dc converters

Q. Zhao and F. C. Lee 2003

6Review of non-isolated high-step-up dc/dc converters in photovoltaic grid-connected applications

W. Li and X. He 2011

7Soft-switched interleaved boost converters for high step-up and high power applications

Y. Park, S. Choi,W. Choi, and K. B. Lee

2011


CONCLUSIONThe proposed converter achieves high

step-up voltage gain, of up to 3 times the level of input voltage.

The energy of the coupled inductor’s leakage inductor has been recycled.

The improvements to the efficiency of the proposed converter have been achieved.


THANK Y

OU

Date post:	30-Oct-2014
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A Safety Enhanced High Step Up DCDC Converter for AC Photovoltaic Module Application

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