Design and Implementation of a New ZVS Interleaved Forward-Flyback Converter Using an Integrated Transformer

This paper proposes an interleaved active-clamping zero-voltage-switching (ZVS) forward-flyback converter using a single magnetic core. The presented topology is composed of an active-clamping forward converter parallel with an active-clamping flyback converter. The main switch of any converter also acts as auxiliary switch for the other one, so only two switches are required and there is no need to additional switches to achieve ZVS operation. Because of interleaved operation of the converter, the output current ripple will be reduced Thus, the output choke and capacitor can be smaller. The transformers of converter are integrated into one magnetic core and center and outer legs are gapped Due to the mutual influence of the coupling between the two transformers, input current ripple also can be reduced According to the mentioned reasons, the proposed converter has high efficiency. Furthermore, the size of the converter is reduced and its power density increases. A prototype converter has been implemented and experimental results have been recorded with an ac input voltage of 85-135 V-rms, an output voltage 12V and output current 16A. Copyright (C) 2010 Praise Worthy Prize S.r.l. - All rights reserved.