An SiC-Based AC/DC CCM Bridgeless Onboard EV Charger With Coupled Active Voltage Doubler Rectifiers for 800-V Battery Systems

High voltage electric vehicle (EV) battery systems are gaining increasing attention in both industry and academia for their capability to reduce the charging time. This paper presents a novel single-stage onboard charger that consists of a CCM bridgeless boost converter integrated with an isolated CLL resonant converter and two magnetically coupled active voltage doublers. The proposed ac-dc charger achieves low THD and near unity power factor. The 800-V output voltage is regulated via variable switching frequency, with duty ratio control used to achieve PFC in the front-end CCM bridgeless boost circuit. The reduced number of semiconductor devices along with soft-switching operations enhance the overall circuit efficiency. Simulation results are given on both level 1 and level 2 charging systems with 2~5 kW, 120~240 Vac /800 Vdc to highlight the merits of the proposed converter. Experimental results are also given on a 120 Vac/800 Vdc prototype to support this work.