Implementation of an Interleaved AC/DC Power Converter with ZVS/ZCS

This paper presents an interleaved pulse-width modulation (PWM) AC/DC converter to achieve power factor correction in the front stage and to implement zero voltage switching (ZVS) turn-on for power switches and zero current switching (ZCS) turn-off for rectifier diodes in the DC/DC converter. Interleaved boost converters with boundary conduction mode (BCM) are used in the front stage to achieve ZCS turn-on for power switches and reduce the ripple currents at the input and output capacitors. Thus the input and output capacitances can be reduced and the size of boost inductors is also decreased. In the DC/DC converter, three identical series resonant converters are operated in an interleaved PWM scheme to reduce the input and output ripple currents, decrease the output capacitance, achieve ZVS turn-on for switches and implement ZCS turn-off for rectifier diodes. Thus the switching losses of MOSFETs are decreased and the reverse recovery losses of fast recover diodes are eliminated. The proposed converter is suitable for high efficiency applications such as industrial power supply unit, LCD-TV power unit and power supply unit of server and data storage systems. Laboratory experiments with a 1200W (48V/25A) prototype, verifying the effectiveness' of the proposed converter, are described. Copyright (C) 2011 Praise Worthy Prize S.r.l. All rights reserved.