Bi-directional multi-level converter with DC link switches for charging and discharging battery

This paper proposes a 3 kW single-phase bi-directional multi-level converter (MLC) for charging/discharging an electric vehicle. The proposed topology is based on an H-bridge structure with four switches connected to DC-link. Based on a POD (phase opposition disposition) modulation method, a PWM method which requires only one carrier signal is used. The switching sequence to balance the capacitor voltage is also considered. Operating principle of the proposed converter is verified through simulation and experiment.