A novel three-phase high-power soft switched DC/DC converter for low voltage fuel cell applications

An efficient DC/DC converter is needed as the interface between a low-voltage fuel cell source and a high-voltage bus for inverter operation. In this paper, a three-phase transformer-isolated DC/DC converter utilizing phase-shift modulation is proposed. The converter must be able to boost the voltage significantly and operate at current levels above 240 amps on the source side. Key features of the proposed converter include: reduced transformer turns-ratio by a factor of two while maintaining the same output voltage, reduced the size of passive components including output filter and input DC bus capacitor using three-phase interleaving, eliminated inductor current ripple at phase-shift angles above 120/spl deg/, and achieved soft switching over a wide load range without auxiliary circuitry. The proposed converter has been analyzed, simulated and implemented in hardware. An efficiency of above 96% was achieved using the prototype unit. Experimental results were used to verify all design and analysis.

[1]  Ivo Barbi,et al.  A three-phase ZVS PWM DC/DC converter with asymmetrical duty cycle for high power applications , 2005 .

[2]  F. Lee,et al.  Zero voltage and zero current switching full bridge PWM converter using secondary active clamp , 1996, PESC Record. 27th Annual IEEE Power Electronics Specialists Conference.

[3]  Fred C. Lee,et al.  A soft-switched, full-bridge boost converter employing an active-clamp circuit , 1996, PESC Record. 27th Annual IEEE Power Electronics Specialists Conference.

[4]  Milan M. Jovanovic,et al.  An improved full-bridge zero-voltage-switched PWM converter using a saturable inductor , 1993 .

[5]  G. Cho,et al.  A zero-voltage and zero-current switching full bridge DC-DC converter with transformer isolation , 2001 .

[6]  F.C. Lee,et al.  Design considerations for high-voltage high-power full-bridge zero-voltage-switched PWM converter , 1990, Fifth Annual Proceedings on Applied Power Electronics Conference and Exposition.

[7]  Fred C. Lee,et al.  Zero voltage and zero current switching full bridge PWM converter using secondary active clamp , 1996 .

[8]  Jih-Sheng Lai,et al.  Modeling and Control of a Novel Six-Leg Three-Phase High-Power Converter for Low Voltage Fuel Cell Applications , 2006, IEEE Transactions on Power Electronics.

[9]  Dong-Wook Yoo,et al.  Novel zero-voltage and zero-current-switching (ZVZCS) full bridge PWM converter with low output current ripple , 1997, Proceedings of Power and Energy Systems in Converging Markets.

[10]  Youhao Xi,et al.  Analysis and design considerations of a load and line independent zero voltage switching full bridge DC/DC converter topology , 2002 .

[11]  Hans B. Puttgen,et al.  Distributed generation: Semantic hype or the dawn of a new era? , 2003 .

[12]  Dong-Wook Yoo,et al.  Novel zero-voltage and zero-current-switching (ZVZCS) full bridge PWM converter using transformer auxiliary winding , 1997, PESC97. Record 28th Annual IEEE Power Electronics Specialists Conference. Formerly Power Conditioning Specialists Conference 1970-71. Power Processing and Electronic Specialists Conference 1972.