This thesis outlines an accurate design procedure for the CLLC converter in the DC charging stations, which is suitable for First-Harmonic-Approximation (FHA) assumption. It works closely to the resonant frequency in a narrow switching frequency interval above it in both operating conditions, with ZVS and a reasonable operating voltage range for a DC bus in the DC microgrid. To enable G2V operation, a closed-loop voltage controller and a closed-loop current controller to achieve constant voltage (CV) charging and constant current (CC) are implemented. Instead, the discharging mode (V2G) operates with soft-start under constant voltage (CV) operation, and a voltage closed loop controller is implemented.