A ZVS-PWM Single-phase inverter using a ZVS transformer-isolated step-up/down dc link

A zero-voltage switching (ZVS) pulse-width-modulation (PWM) single-phase inverter using a ZVS transformer-isolated step-up/down dc link is presented in this paper. The proposed ZVS transformer-isolated step-up/down dc link not only makes the switches in single-phase inverter can operate at ZVS condition, but it has a step-up/down input voltage function and it provides an isolation function. Moreover, the switches in itself also operate at ZVS. Except for the switch in the ZVS-PWM auxiliary circuit of the proposed ZVS transformer-isolated step-up/down dc link, all power semiconductor devices in proposed inverter operate at ZVS turn on and turn off. The switch in the ZVS-PWM auxiliary circuit of proposed ZVS transformer-isolated step-up/down dc link operates at zero-current-switching (ZCS) turn-on and turn-off. Thus, the switching losses can be reduced. The proposed ZVS-PWM inverter operates at constant frequency. The voltage stress and current stress on the main semiconductors in the proposed ZVS-PWM inverter are the same them in conventional hard switching inverter. The analysis of operation principle and experimental results of the proposed ZVS-PWM inverter, rated 2kW and operated at 40 kHz, are provided in this paper to verify the performance.