A single-stage power-factor-corrected AC/DC converter

This paper presents a single-stage isolated converter topology designed to achieve a regulated de output voltage having no low-frequency components an d a high-input power factor. The topology is derived from the basic two-swi tch forward converter, but incorporates an additional transformer winding, inductor, and a few diodes, The proposed circuit inherently forces the inpu t current to be discontinuous and ac modulated to achieve high-input power factor. The converter output is operated in discontinuous mode to minimize the bulk capacitor voltage variations when the output load is varied, Analy sis of the converter is presented, and performance characteristics are give n. Design guidelines to select critical components of the circuit are prese nted, Experimental results on a 150-W 50-kHz universal input (90-265 V) 54. 75-Y output ac/dc converter are given which confirm the predicted performan ce of the proposed topology.