This document describes a novel zero-current switching current-fed half-bridge isolated DC/DC converter that provides a simple solution for switching turn-off with zero-current switching without increasing component count. This reduces size, lowers cost, and improves efficiency. The document includes an abstract, keywords, block diagrams of the proposed and conventional converters, expected simulation results and figures, and references. It is presented as a potential topology for front-end DC/DC power conversion for fuel cell inverters.

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Novel Zero-Current Switching Current-Fed Half-Bridge Isolated
Dc/Dc Converterfor Fuel Cell Based Applications
ABSTRACT:
This paper presents a novel zero-currentswitching (ZCS) current-fed half-bridge isolated
dc/dcconverter. It is a potential topology for front-end dc/dc powerconversion for fuel cell
inverters. This proposed converter isunique, not reported in literature and provides a simple
solutionto switch turn-off problem with ZCS without increase incomponents count. This will
lead to reduced size, lower cost andhigher efficiency. Analysis, design and simulation results of
theproposed converter are reported in this paper. A comparisonwith existing active-clamped ZVS
current-fed half-bridgeconverter has been illustrated.
KEYWORDS:
1. Zero-current switching
2. Dc/Dc converter
3. Current-fed
4. Fuel cells
5. High efficiency
SOFTWARE:MATLAB/SIMULINK

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BLOCK DIAGRAM:
Fig. 1. Conventional hard-switched current-fed half-bridge dc/dc converter
Fig. 2 Active-clamped ZVS current-fed half-bridge dc/dc converter
Fig. 3.Proposed ZCS current-fed half-bridge dc/dc converter.

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EXPECTED SIMULATION RESULTS:
Fig. 4.Zero-current switching of primary-side switches.The ripple frequency of input current Iinis 200 kHz, which
is same twice the switching frequency fs. The transformer
Fig. 5.Zero-current turn-on of primary-side switches.V(S1) is voltage acrossswitch S1 and I(S1) is current through
switch S1. The current waveform isscaled for clarity.

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Fig. 6.Current-waveforms through the secondary-side switches.
Fig. 7.Zero-current turn-on of secondary-side switches.V(Sr1) is voltageacross switch Sr1 and I(Sr1) is current
through switch Sr1. The currentwaveform is scaled for clarity.

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Fig. 8.Current waveforms through input inductors L1 and L2.
Fig. 9. . Input current (Iin) and transformer current I(Ls) waveforms.

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REFERENCES:
[1] www.fossil.gov.in
[2] S. K. Mazumder, R. K. Burra, and K. Acharya, “A ripple-mitigatingand energy-efficient fuel
cell power-conditioning system,” IEEETransactions on Power Electronics, vol. 22, 2007, pp.
1437-1452.
[3] Jin-Tae Kim, Byoung-Kuk Lee, Tae-Won Lee, Su-Jin Jang, Soo-SeokKim, and Chung-Yuen
Won, “An active clamping current-fed halfbridgeconverter for fuel-cell generation systems,” in
Proceedings 2004IEEE Power Electronics Specialists Conference, pp. 4709-4714.
[4] S. Han, H. Yoon, G. Moon, M. Youn, Y. Kim, and K. Lee, “A newactive-clamping zero-
voltage switching PWM current-fed half-bridgeconverter,” IEEE Transactions on Power
Electronics, vol. 20, pp 1271-1279, 2006.
[5] S. J. Jang, C. Y. Won, B. K. Lee and J. Hur, “Fuel cell generationsystem with a new active
clamping current-fed half-bridge converter,”IEEE Trans. on Energy Conversion, vol. 22, pp.
332-340, June 2007.