A single stage power factor corrected AC/DC converter

This paper presents a single-stage isolated power converter topology to achieve a regulated DC output voltage having no low frequency components and a high input power factor. The topology is derived from the basic two-switch forward power converter, but incorporates an additional transformer winding, an inductor and a few diodes. The proposed circuit inherently forces the input current to be discontinuous and AC modulated to achieve high input power factor. The power converter´s output is operated in the discontinuous mode to minimize the bulk capacitor voltage variations when the output load is varied. Analysis of the power converter is presented and performance characteristics are given. Further, design guidelines to select critical components of the circuit are presented. Finally, experimental results on a 160 W, universal input, 54 VDC output power converter are given which confirm the high efficiency and high power factor features of the proposed topology