Mathematical Modeling and Optimization of a Bidirectional Resonant Converter for Onboard Electric Vehicle Charging

Abstract As electric vehicle (EV) adoption accelerates, there is an increasing demand for efficient and compact onboard charging systems. This work introduces a bidirectional AC/DC LCLC resonant converter that inherently achieves power factor correction (PFC) without the need for a separate PFC stage. Unlike traditional resonant converters where low power factor is a concern, the proposed design combines the PFC and resonant operations within the same switching network, resulting in a more integrated and space efficient architecture. A bridgeless rectifier configuration is also implemented to reduce the overall component count and improve efficiency. The converter is based on an enhanced LLC topology, where a capacitor is added in parallel with the magnetizing inductance to create an LCLC structure. This modification leads to improved power conversion efficiency while minimizing the size of passive components. The system maintains output voltage regulation through switching frequency control, allowing it to adapt effectively to dynamic load variations. Additionally, the single stage topology ensures zero voltage switching (ZVS) for the power devices, further minimizing switching losses. With its ability to support both grid to vehicle (G2V) and vehicle to grid (V2G) power transfer, the proposed solution is well suited for next generation EV charging applications.