Design and Simulation of LLC Converter Based On-Board Battery Charger for Electric Vehicle Applications

Design of EV charger design is a most demanding and challenging aspect in the current power electronic industry. Lithium batteries are the best suited for battery vehicles. Onboard charger design using resonant inductor- inductor-capacitor (LLC) converter is discussed in this paper with validation of MATLAB simulation results. This converter is specially designed for all vehicle and battery conditions keeping input voltage of 400V to a variable output of 300-500V at 3 kW power for a 98% efficiency at peak. Battery possesses a nonlinear characteristic unlike resistive loads. Thus, unique features of LLC converter are mainly suited. Power losses can be reduced by implementation of ZVS at converter primary side. The design methodology steps are proposed and validated through MATLAB results. A simulation of a closed loop is replicated in MATLAB Simulink. Results are compared to support the validity of the suggested analytical solution.