Analysis of Integrated on-Board Charger for 400 V and 800 V EV Battery Using Dual-Mode Three-Leg LLC Resonant Converter

Electric vehicle technology is rapidly advancing to achieve higher power density and cost-effectiveness. On-board chargers (OBC) are evolving to support new power ratings and battery technologies, focusing on higher power and voltage capabilities to enhance power density and reduce recharge times. This paper proposes a novel three-leg LLC (TL-LLC) resonant converter for an On-board EV charger, designed to charge different EV models efficiently. By adopting a variable DC-link voltage as input, the converter tracks a wide battery voltage range, ensuring optimal efficiency. It operates in two modes: voltage doubler for 800-V charger and current doubler for 400-V charger at 10 kW power rating. MATLAB/Simulink simulations verify the converter's performance for both battery types at 10 kW power level.