Asymmetric PWM converter for high load current application

Abstract

A soft switching converter using low voltage and low current stresses of power components is presented for high input voltage and high output current applications. Two input capacitors and four power MOSFETs are adopted at high voltage side in order to reduce the voltage stress of power switches. Thus, the voltage stress of MOSFETs is clamped at V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in</sub> /2. Two flying capacitors are adopted at the AC side of two half-bridge converter legs to balance input two capacitor voltages. Three center-tapped rectifiers are used at low voltage side in order to share load current and reduce the size of magnetic core and current stress of passive components. Asymmetric pulse-width modulation is used to generate the gate signals of power MOSFETs and regulate output voltage. Based on the resonant behavior at the transition interval, all power switches can be turned on under zero voltage switching. Finally, experiments are provided to verify the effectiveness of the proposed converter.