A new ZVS-PWM full-bridge step-up/down converter

A novel zero-voltage-switching pulse-width-modulation (ZVS-PWM) full-bridge transformer-isolated step-up/down converter is proposed in this paper. The output voltage of the proposed converter can be larger or lower than the DC input voltage, depending on the instantaneous duty-cycle. This property is not found in the classical full-bridge transformer-isolated converter. Furthermore, in the proposed converter, besides operating at constant frequency, all semiconductor devices operate at soft-switching without additional voltage stress and current stress. An average approach is employed to analyze the system. A design example of 1000 W ZVS-PWM full-bridge converter is examined to assess the converter performance.