A soft-switching single-stage AC-to-DC converter with low harmonic distortion-analysis, design, simulation and experimental results

A 1-φ high frequency transformer isolated soft switching single stage AC-DC converter with low line-current harmonic distortion is presented. Its operation is explained with equivalent circuits for the various intervals. The converter is analyzed including its snubber capacitance and design curves are obtained. An optimization parameter is introduced and a systematic design procedure is illustrated with a design example. Detailed SPICE simulation and experimental results of a 250 W converter with load and line voltage variation are given to verify theory. The proposed converter employs a zero voltage transition network to ensure zero voltage switching at all loads