A Wide Output LLC Converter Based on Full Bridge and Half Bridge Topology Morphing Method Using Trajectory Transition

This paper presents a LLC resonant converter using full bridge and half bridge topology morphing method to achieve wide output and high efficiency. The trajectory control method is proposed to avoid current and voltage overshoot during mode transition. In order to verify the effectiveness of trajectory transition method, a 1.4 kW prototype using SiC devices is developed. The output voltage of prototype can vary from 180V to 540V with 600V DC input, and a maximum efficiency 98.5% is achieved. Both simulation and experimental results verify the effectiveness of the method conducted in the paper.