Analysis of the Extended Forward Converter for Fuel Cell Applications

The source voltage of high-power fuel cells shows strong load dependence at comparatively low voltage levels. In order to provide the voltage of 750 V on the DC-link for feeding electrical energy into the mains via a three-phase inverter a step- up converter with a large step ratio is required. The efficiency of this converter must be as high as possible and the cost must be as low as possible. To meet these requirements a new circuit of the DC/DC-converter is proposed. In this paper this circuit of the DC/DC-converter was compared with another circuits. This paper presents also a mathematical analysis of this DC/DC-converter and the simulation results to fit into a 5 kW electrical fuel cell system.