ZVS-ZCS full-bridge DC-DC converter for voltage step-up in fuel cell distributed generation systems

This paper proposes a ZVS-ZCS full-bridge converter for voltage step-up applications, where only a few solutions have been proposed in the literature. A new auxiliary circuit is used on the high-voltage side of the proposed converter to achieve Zero Current Switching (ZCS) for one converter leg, while Zero Voltage Switching (ZVS) is achieved for the other leg by means of snubber capacitors. The principle of operation has been analyzed and verified on a 20 kW, 50 kHz prototype converter. The proposed converter can be a viable solution for fuel cell distributed generation systems, where voltage boost and efficiency are key issues.