A Soft Switching Single Stage Isolated Three Phase Bidirectional PFC Converter for Electric Vehicles charging

This paper proposes a bidirectional three phase single stage ac-dc converter for applications like Electric Vehicle (EV) chargers. AC side of the proposed converter consists of current fed half bridge converter for each of the three phases and the DC side has three phase full bridge converter. The primary and secondary side of the converter are connected through star connection of high frequency transformer. The proposed converter achieves zero current switching (ZCS) of primary side switches and zero voltage switching (ZVS) for secondary side devices, while feeding power from grid to the dc side. The converter has soft switching on the primary side switches when transferring power from the dc side to the grid. The paper also presents a novel modulation and control scheme for the bidirectional power flow. The converter is evaluated using PSIM simulation tool for its operation in all the four quadrants of the PQ plot. The design of the converter, control strategy and the results are presented for a 10KVA converter for EV charger.