A PWM full-bridge converter with natural input power factor correction

A PWM full-bridge power converter that simultaneously performs input power factor correction (PFC) and DC-DC power conversion is proposed in this paper. This converter is the same as the standard voltage-fed PWM full-bridge converter with a diode bridge/low pass filter front-end, but with a slight modification that results in an improved power factor. The proposed power converter is found to have lower voltage stress across the DC bulk capacitor, hold-up time capacity and very small low frequency (120 Hz) ripple in the output while satisfying the IEC 1000-3-2 limits on input current harmonics. A detailed simulation of the power converter operation is given and key performance curves are presented. Finally, a bread-board power converter is built to confirm the concept and to validate the simulation results.