ECE 442 Power Electronics1 Series Resonant Inverter with Bidirectional Switch.

ECE 442 Power Electronics 1

Series Resonant Inverter with Bidirectional Switch

ECE 442 Power Electronics 2

Turn Q1 ON at t = 0

A “resonant” pulse of current flows, charging C to VC1, Q1 turns OFF

ECE 442 Power Electronics 3

C charges to VC1, Q1 turns OFF

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C discharges via D1 and Vs

• For t > t1

– The capacitor acts as a voltage source

– Current io reverses, and flows via D1 to VS

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V1220 V

D2DIODE_VIRTUAL

L120uH

C12uF

3

0

D1DIODE_VIRTUAL

1

2

“Idealized Version”

ECE 442 Power Electronics 6

ECE 442 Power Electronics 7

Half-Bridge Series Resonant Inverter

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Turn Q1 ON, Resonant Pulse of current appears.

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Turn Q2 ON, Resonant Pulse of current appears in the opposite direction, and goes to zero.

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Waveform Summary

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Overlapping and Non-Overlapping modes

• Non-Overlapping Mode– Firing of the switching device is delayed until the last

current oscillation through the diode is completed

ECE 442 Power Electronics 12

Overlapping and Non-Overlapping modes

• Overlapping Mode– Firing of the switching device occurs before the last

current oscillation through the diode is completed.– This increases the output frequency and the output

power

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MultiSim Simulation

D2DIODE_VIRTUAL

L

20uH

C

2uF

D1DIODE_VIRTUAL

V1110 V

V2110 V

J11 V 0mV

J21 V 0mV

XFG1

D3

DIODE_VIRTUAL

D4

DIODE_VIRTUAL

Rsample

1 Ohm

XSC1

A B

G

T

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Non-Overlapping Mode

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Overlapping Mode

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Full-Bridge Series Resonant Inverter

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Frequency Response of

Series-Resonant Inverters

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Series-Loaded Inverter

• Load Resistor in series with L and C

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0

0

0

( )( )

1( )

1( )

11

1

1( )

1

o

i

o

s

ss

V j RG j

V j R j Lj C

G jL

j jR RC

LCL

QR

G jQj jQ

ECE 442 Power Electronics 20

0

0

0

0

0

2 2

1( )

1

1( )

1

1( )

11 ( )

1( )

11 ( )

ss

s

s

s

G jQj jQ

G j

jQ

u

G jjQ u

u

G j

Q uu

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Frequency Response

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Parallel-Loaded Case

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2

0

0

2

20 0

1

1( )

( )( ) 1

1

1( )

1

1

1

1( )

1

o

s

s

Rj C

RV j j C

G jV j

Rj C

j LR

j C

G jL

LC jR

LCR

QQ L

G jQ

j

ECE 442 Power Electronics 24

2

20 0

2

0 0

0

2

2

2 2

1( )

1

1( )

1

1( )

1

1( )

(1 )

G jQ

j

G j

jQ

u

G ju

u jQ

G ju

uQ

ECE 442 Power Electronics 25

Frequency Response

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Series-Parallel Loaded Case

ECE 442 Power Electronics 27

Frequency Response