SOFT SWITCH DC-DC CONVERTER FOR ELECTROLYZER

APPLICATION

BATCH NO:08

BATCH MEMBER

SUNDARRAJAN S G

GOKULNATH R

MOHAMED ASHIQ A

SATHESKUMAR K

PROJECT GUIDE

Mr. K DINESH M.E,

AP/EEE

OBJECTIVES

• Switching transition occur under favorable condition-device voltage or current is zero

• Reduce switching loss, switching stress, easy thermal management

• high frequency operation is possible

APPLICATION REQUIREMENTS

• Vin=40v• Vout=60v• Pout=2.4kw• Fs=100kHz• Duty cycle ratio=0.85

LITERATURE SURVEY

• R.L.STEIGERWALD- increase the efficiency and further increase the switching frequency while reducing cost, size and electromagnetic interference problem.

• A. K.S BHAT-analysis the LCL type resonant converter in 1994

• A.K.S BHAT-fixed-frequency LCL SRC with an INDUCTIVE output filter, loss of input voltage problem in 1997

SOFT SWITCHING CIRCUITS

FIXED FREQUENCY SRC FIG(1)

FIXED FREQUENCY PRC FIG(2)

FIXED FREQUENCY SPRC FIG(3)

LCL SERIES RESONANT DC-TO-DC CONVERTER WITH AN INDUCTIVE OUTPUT FILTER FIG(4)

FIXED-FREQUENCY PHASE-SHIFTED ZVS PWM DC-TO-DC FULL-BRIDGE

CONVERTERFIG (5)

LCL SERIES RESONANT DC-TO-DC CONVERTER WITH AN CAPACITIVE OUTPUT FILTER FIG(6)

ZVT BOOST CONVERTER

OPERATIONAL CIRCUIT

DESIGN VALUE

THEORETICAL EFFICIENCY

DESIGN EQUATIONS FOR LCL SRC WITH CAPACITIVEOUTPUT FILTER

Base values:

VB = Vin ,min, ZB = (Lr /Cs )1/2 , IB =VB /ZB .

Converter gain: M = Vo ’/VB , Vo ’ = nt Vo .

NORMALIZED LOAD CURRENT: J = (Id /nt )/IB .

Normalized switching frequency:

F = ωs /ωr = fs /fr , ωr =1/(LrCs )1/2 .

The values of Lr and Cs are calculated using the following

equations

Lr =(M · J · V B2/Po)(F/2 · π · fs)

Cs =(F · Po/2 · π · fs ·M · J · VB2)

Lr /Lp , the ratio of series resonant inductor Lr to parallel inductor

Lp (= L’t = nt2Lt );

Then, the transformer turns ratio

nt = (Deff )(Vin )/Vo = 0.567.

The output filter inductor is

Lo =[(Vin/nt ) − Vo ](Deff )/[(ΔId)(2fs )] =∼ 7.5 μH.

The value of Lr is given By

Lr =(ntVin) (1 − Deff )/[(4Id )(fs )]= 0.212 μH.