A Novel Soft-Switching Single-Phase AC–DC–AC Converter Using New ZVS–PWM Strategy

This paper proposes a novel soft-switching single- phase ac-dc-ac converter to give high input power factor and low current distortion on the rectifier side and provide clean and stable ac voltage on the inverter side. The proposed converter uses a new zero voltage switching (ZVS) strategy to get ZVS function. Besides operating at constant frequency, all semiconductor devices operate at soft-switching without additional voltage stress. A significant reduction in the conduction losses is achieved, since the circulating current for the soft switching flows only through the auxiliary circuit and a minimum number of switching devices is involved in the circulating current path, and the rectifier in the proposed converter uses a single converter instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter. An average-current-mode control is employed in the rectifier side of proposed converter to detect the transition time and synthesize a suitable low harmonics sinusoidal waveform for the input current. The sinusoidal pulsewidth modulation (SPWM) control strategy is employed in the inverter of proposed converter to achieve good dynamic regulation. A design example of 1000 W soft-switching single-phase ac-dc-ac converter is examined to assess the converter performance.