ZVZCS single-stage PFC AC-to-DC half-bridge converter

A zero-voltage- and zero-current-switched single-stage AC-to-DC half-bridge converter with high power factor is presented to reduce the switching losses and to achieve sinusoidal, unity power factor input currents. The single-stage approach, which combines a boost converter used as power-factor correction with a half-bridge converter used as DC-to-DC conversion into one power stage, has a simple structure and low cost. At the same time, the switching losses could be considerably reduced, because the switches of the proposed converter are designed to be turned on at zero voltage and off at zero current. Detailed analysis and experimental results are presented on the proposed converter, which is operated at constant switching frequency and in discontinuous conduction mode.