A ZVS Three-Port DC-DC Converter Based on Coupled Inductor for Fuel Cell Vehicle

In fuel cell vehicle power systems, a power electronic interface is required to manage the power flow between the fuel cell, battery, and the high-voltage DC bus. For this application, a novel zero voltage switching (ZVS) three-port converter (TPC) is proposed in this paper, which has fewer components compared with multiple discrete converters. Phase-shift and duty cycle modulation provides two degrees of freedom to decouple the power flow so that independent energy transfer among different power ports can be achieved. In the primary sides, the input current ripple is greatly reduced thanks to the interleaved structure, which is beneficial for prolonging the service life of the fuel cell stack. In the secondary side, the coupled inductor technique is adopted to boost the step-up ratio. Moreover, zero voltage switching (ZVS) can be realized among all the MOSFETs in wide voltage and load range while ensuring low current stress thanks to the multiple degrees of freedom modulation. A 4-kW three-port DC-DC prototype is designed and experimental results are presented to verify the merits of the proposed converter topology.