A novel common-neutral single-stage single-phase ac/dc/ac converter with high input power factor

Abstract

This paper proposes novel common-neutral single-stage 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 ac/dc/ac converter has a common arm between the rectifier and inverter, and adopts an appropriate switching strategy. The proposed ac/dc/ac converter can not only provide regulation of the output ac voltage magnitude but provide variable output ac voltage frequency. A significant reduction in the conduction losses is achieved, since 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 pulse-width modulation (SPWM) control strategy is employed in the inverter of proposed converter to achieve well dynamic regulation. A design example of 1000W soft-switching single-stage single-phase ac/dc/ac converter is examined to assess the converter performance.