Analysis & Simulation of Different LLC Converter Topologies

Abstract

There is an expanding trend in electric vehicle (EV) technologies because of finite fuel sources and environmental concerns. One of the essential barriers in EVs commercialization is the charging of batteries. The inductor-inductor-capacitor (LLC) resonant converter appears the most appealing design due to its advantages, such as small electromagnetic interference, obtaining high-power density, ability to be designed at very high switching frequencies, operation for wide input and output voltage range with narrow switching frequency variation, and high efficiency. This study compares different topologies of LLC resonant converter that can be adapted as battery charger of electric vehicle. The schematics of topologies, detailed design calculation of the parameters, simulation results of topologies to show the circuit performance are presented, respectively. The simulation model is realized for whole examined topologies with a proportional integral controller to obtain constant output voltage using MATLAB. LLC resonant circuit is designed for the input voltage range of 305-345V, output voltage range of 36-58V, and output power of 700W. Analytical and simulation results are included in this study to illustrate the performance differences among the presented topologies of LLC resonant converter in terms of structure, efficiency, and dynamic response at sudden load changes.