High-efficiency and low-stress ZVS-PWM bidirectional DC/DC converter for battery charger

A new zero-voltage-switching (ZVS) pulsewidth-modulated (PWM) bidirectional DC/DC converter for battery charger using the Reflex™ method with high efficiency and low stress is presented in this paper. The proposed bidirectional DC/DC converter uses a new ZVS-PWM auxiliary commutation circuit to provide soft-switching function on all switches. Except for the auxiliary switches, all active and passive semiconductor devices in the proposed bidirectional DC/DC converter operate at ZVS turn on and turn off. The auxiliary switches operate at zero-current-switching (ZCS) turned-on and turned-off. Besides operating at constant frequency, the proposed bidirectional DC/DC converter has no additional voltage and current stresses on the main switch compared to the hard switching bidirectional DC/DC converter counterpart. Auxiliary components rated at very small current are used. The principle of operation, theoretical analysis, and experimental results of the new bidirectional DC/DC converter are provided in this paper to verify the performance.