High Power Density DC-DC Converter for 800V Fuel Cell Electric Vehicles

In this paper, a low-cost 63kW/L DC-DC converter operated at 300kHz is proposed for 800V fuel cell electric vehicles. Four modules of Dual Floating Output Boost Converter (DFOBC) are adopted to process 100kW power from the FC stack. For each module, an inverse coupled inductor and ZVT cells are employed. Advantages of the proposed converter over the Conventional Interleaved Boost Converter (CIBC) which is usually used in the previous FDC are found to be: 1) Planar core with PCB winding can be used for the main inductor; 2) Tall film capacitors are replaced by a low-profile ceramic capacitor; 3) Only a single discrete SiC mosfet is needed for the main switch of a 25kW module. A 25kW prototype of proposed converter is built and tested. The peak and full-load efficiencies confirm at 99% and 97.7%, respectively.