An Integrated Onboard EV Charger With Wide Voltage Range Compatibility

Abstract

Electric vehicles (EVs) typically employ separate onboard chargers and traction inverters for battery charging and motor operation, respectively. This paper proposes a bidirectional integrated onboard charger (BIOC) that utilizes a single power converter to perform both functions, thereby reducing cost, improving system compactness, and supporting fast charging. The proposed BIOC architecture is implemented using a totem-pole power factor correction (PFC) stage combined with an additional coupling unit. This configuration supports a wide range of battery voltages and is compatible with both AC and DC grid inputs. The BIOC incorporates active power decoupling (APD) to minimize voltage ripple at the battery terminals during high-voltage (HV) battery charging. Leakage current analysis of the totem-pole PFC stage confirms compliance with safety standards, and a detailed switch loss calculation procedure is presented. A comprehensive controller design is developed using State-Space Averaging (SSA) and Small Signal Modelling (SSM), followed by a K-factor method to ensure optimal performance across various operating modes. The proposed system is validated through simulations on a 2 kW Simulink model and experimental testing on a 400 W scaled-down prototype, demonstrating effective charging of an EV battery across a wide voltage range from both AC and DC grids. This work offers a unified, efficient, and cost-effective solution for integrated onboard EV charging. © 2013 IEEE.