A novel soft-switching buck-boost type AC-DC converter with high power efficiency, high power factor and low harmonic distortion

This paper presents the novel soft-switching buck-boost type AC-DC power converter with high power efficiency and high power factor. In this AC-DC power converter, the power factor and harmonic distortion are improved by using the third winding of the energy-storage reactor, and high power efficiency is achieved by the soft-switching operations of the main power switch and output rectifier diode. The equivalent circuit model with DC voltage sources is derived and the performance characteristics are analysed by this model. The analytical results are confirmed by experiments. As a result, it is clarified that the proposed AC-DC power converter satisfies the maximum limits of the input current harmonics distortion in IEC 1000-3-2 Class D and that its power efficiency is 95% at the rated load current.