Soft-switching dual full-bridge converter with reduced circulating loss and voltage stress of secondary rectifier

Abstract. This paper proposes a novel soft-switching dual full-bridge converter with shared lagging leg and dual outputs in series. Resonant clamp circuits are employed across the secondary rectifiers to reduce the voltage overshoots of the secondary rectifiers, as well as extinguish the primary current during the freewheeling interval. Full Zero-Voltage-Switching (ZVS) range of the lagging leg switches can be achieved based on the parallel full-bridge configuration. The dual outputs of the proposed converter are connected in series, and the whole output voltage can be regulated within the desired voltage range by the phase-shift control. Therefore, the proposed converter would be useful for high output voltage and high power applications. Steady state operation and distinctive features of the converter are explained and verified on a 1-kW hardware prototype, and experimental results validate the feasibility and performance of the proposed converter.