Analysis and Design of Novel Single-Stage Isolated Cuk-derived Converter for 800-V Electric Vehicle Grid-to-Vehicle Onboard Charging

Recent advancements in battery electric vehicle (BEV) technology have led to the development of 800-V passenger BEVs, enabling rapid charging capabilities. However, these vehicles still require an onboard charger (OBC) to facilitate convenient and economical overnight charging from residential power supplies. Designing efficient and compact 800-V OBCs presents several challenges, including achieving a high voltage gain from 120-V or 240-V AC inputs, and managing increased costs due to the need for higher voltage components. While some 800-V OBC designs have been proposed, many involve a high component count. To address these challenges, this paper introduces a novel single-phase bridgeless Cuk-derived isolated OBC for 800-V BEVs. One unique feature of this design is its operation in discontinuous conduction mode (DCM) across the entire power range, naturally achieving power factor correction without the need for input voltage and current sensing. Detailed simulation results and experimental data from a 2-kW, 800-V hardware prototype validate the converter's performance, demonstrating a total harmonic distortion of 3.11%, near-unity power factor, and peak efficiency of 96.8%.