Modified Bidirectional LLC Converter for Electric Vehicle Application

This paper proposes a modified bidirectional Half-Full Bridge LLC resonant Converter with a control strategy for EV charging applications. With the topology shown, every switch is capable of soft switching, which is operated by zero voltage switching (ZVS). The modified LLC uses fewer switches than a conventional LLC converter, which greatly reduces reverse power and turn-off losses while also allowing for significantly higher conversion efficiencies. The system achieved bidirectional power flow for a proposed isolated converter. The converter always operates with a discontinuous resonant current. Clamping diodes were added to the converter to minimize the initial inrush current. Additionally, the working principle and design aspects are presented. Closed loop PID control is used to control an EV battery's charging and discharging modes. To evaluate the effectiveness of the converter and controller, the 3.3kW system is simulated in MATLAB/Simulink with 96% efficiency, and the expected results are obtained.