Highly Efficient Soft-Switched Quasi-Single-Stage AC-DC resonant Converter for EV Charging

The paper presents a current-fed AC-DC resonant converter witb regulated output voltage, zero input current ripples, and almost unity power factor for electric vehicle (EV) charging. A Dual Quadrant Voltage Bidirectional (DQVB) switch is employed between tbe voltage doubler circnit and tbe resonant inductor on tbe secondary side of tbe converter to accomplish tbese objectives. The presence of tbe DQVB switch sets tbe duty ratio D of tbe primary side switches at 50%, hence eliminating ripples in tbe input current. Consequently, no input filler is required for tbe designed converter. Moreover, ali switches are eitber ZVS tumed on or ZCS tumed off at 50 kHz due to tbe converter's resonance operation. Therefore, incurs very little switching loss witb high efficiency and power density. A 1.2 kW prototype was designed and tested to demonstrate tbe viability of tbis approach.