Zero-voltage-switching pulse-widthmodulation full-bridge transformer-isolated step-up/down converter

A novel zero-voltage-switching pulse-width-modulation (ZVS-PWM) full-bridge transformer-isolated step- up/down converter is proposed. The output voltage of the proposed converter can be higher or lower than the DC input voltage, depending on the instantaneous duty cycle. 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 analyse the system. A design example of 1000 W proposed ZVS-PWM full-bridge converter is examined to assess the converter performance.