Wide Output Voltage Range Isolated Buck-Boost PFC Converter with Reconfigurable Rectifier

This paper presents a novel quasi single-stage isolated converter for ac-to-dc interfacing that provides galvanic isolation and wide output voltage range. These features became necessary is such applications as electric vehicle (EV) charging, where more and more models are entering the market with a variety of nominal battery voltage levels. Thanks to a buck-boost feature of the series-parallel resonant circuit, wider output voltage range can be achieved for the same input bridge semiconductor voltage stress, when compared to conventional topologies. Moreover, due to the presence of the series capacitor, a reconfigurable rectifier can be easily implemented for doubling the output voltage range. In this paper, an operating principle and design guidelines for achieving zero voltage/zero current switching (ZVS/ZCS) and optimizing semiconductor voltage stress, switching frequency and regulation range of the topology are presented. The findings are verified with a 5 kVA converter model with input voltage of 230 VAC, output voltage range of $200\ldots 800$ VDC and peak voltage across primary semiconductors below 800 V, potentially allowing the use of 900…1000 V discrete SiC MOSFETs.