A novel wide voltage range bi-directional series resonant converter with clamped capacitor voltage

Bi-directional DC-DC converters become more and more important in the applications of future plug-in hybrid electric vehicles (PHEV's) charging stations and distributed renewable power generations as the interface with battery energy storage system. Maintaining high power efficiency in wide voltage range is required since the battery pack voltage varies a lot. Based on previous study, the series resonant converter with clamped capacitor voltage exhibits excellent characteristics in forward mode operation, such as high efficiency, high power density and fault current limiting capability; but very limited study has been performed for reverse mode operation. In this paper, the power stage design based on efficiency optimization for forward mode has been proposed to meet specifications of 750 V input, 300 V-600 V/35 kW output and 50 kHz switching frequency. For reverse mode operation, the advanced control strategy with three phase-shift angles has been proposed, since simple phase-shift control cannot reverse power flow. The proposed control strategy is successfully verified by a 15 kW prototype.