A wide input voltage and high efficiency DC-DC converter for fuel cell applications

A reliable and highly efficient power-conditioning unit is fundamental for the commercial success of fuel cell systems. A DC/DC converter especially designed for grid parallel applications and capable of operating over a wide input voltage range is presented. The proposed converter operation principle is based on the slow transients required by the fuel cell stacks and on the possibility of using an unregulated DC-link to feed the inverter. According to these facts, the paper proposes a configuration that achieves high efficiency over the complete input voltage range by using a multi coil transformer. Experimental results for a 3 kW prototype are presented to verify the concept