GaN-based High Frequency 6.6kW Bi-directional DC/DC Converter for OBC Application

DAB (Dual-active-bridge) and CLLC are two common isolated bidirectional DC/DC converters, but they are limited by soft switching and gain adjustment range respectively, and cannot meet the requirements of high-efficiency, bidirectional, wide range, and full power transmission of products. Boost-SRC is a combination of the advantages of the two, using vary frequency and phase-shift control method, meet the soft switch, the higher gain and suitable for wide output voltage regulation applications. In this paper, firstly, the working principle of the topology is introduced, and the time domain analysis is carried out based on the phase-plane analysis method. Secondly, the general engineering design steps and system control methods are given. Finally, a 6. 6kW bidirectional DC/DC prototype was built using Navitas Nano-Toll packaging GaN devices, and the charge and discharge efficiency curves were measured, the highest switching frequency up to 900khz, which verified the feasibility of GaN devices application in high-power vehicle products.