Multiple Input Bidirectional DC/DC Converter for Energy Supervision in Fuel Cell Electric Vehicles

A hybrid power system for fuel cell electric vehicles(FCEV) was proposed. The fuel cell and the battery and/or ultracapacitor are connected to the same voltage bus through an appropriate unidirectional dc-dc converter (UDC) and a buck/boost bidirectional DC/DC converter(BDC), respectively. The battery and the ultracapacitor are auxiliary energy source, which provides or absorbs the dynamic power when the load varies and the fuel cell cannot respond immediately, so the system dynamic characteristics are improved. A multiple input dc-dc converter (MIDC) devoted to combine the power flowing from combined on-board energy sources is presented; Finally, the analysis and design validation are verified through the simulation and experiment.