Design of a GaN-Based Reconfigurable Resonant Converter for High Frequency On-Board Charger of Battery Electric Vehicles

In this paper, a reconfigurable resonant converter for On-board Chargers (OBCs) and its' design consideration is proposed. This approach allows high frequency operation with maximum efficiency and Zero-Voltage Switching (ZVS) for all primary switches over a wide range of load conditions. The proposed converter is a combination of a Full Bridge LLC (FB-LLC) and an LCL compensator to form a high order resonant network. Constant Current (CC) and Constant Voltage (CV) charging profiles can be implemented automatically by reconfiguring the resonant network on the secondary side. In this design, GaN-FETs and a high frequency planar transformer are employed to further take advantage of high frequency operation. A 300kHz-3.3kW hardware prototype was built. Simulation and experiment results are provided with a maximum efficiency of 97%.