Wide Bandgap Semiconductor Based High Performance Bidirectional Resonant Converter for Electric Vehicle Application

In this paper, a bidirectional capacitor-inductor-inductor-inductor-capacitor (CLLLC) resonant converter based on a wide bandgap (WBG) transistor is designed and analyzed at MHz-level switching frequency to accomplish high power density and high efficiency. A discrete-time Proportional-Integral-Derivative (PID) controller based on phase shifted pulse width modulation (PWM) technique has been developed for the closed-loop control of the aforementioned CLLLC converter. The converter is designed with WBG switching devices to accomplish fast switching with minimal switching losses, and it is also compared to Si-based switching devices. For the proper thermal design of the converter, a precise power loss model of the switching devices has been developed. A 5 kW CLLLC converter with 400-450V DC input and 250-465V DC output with an operating frequency of 1 MHz has been designed and simulated under a variety of loading conditions. The maximum conversion efficiency achieved with Gallium Nitride (GaN)-based devices was 97.2 percent in forward mode and 97 percent in reverse mode.