Improved soft switching dual switch forward converter

Abstract

An improved soft switching dual-switch forward converter topology is proposed in this paper. Compared with conventional dual-switch forward converter, the proposed converter employs an auxiliary switch and a clamp capacitor to instead of two reset diodes. Therefore, its duty cycle can exceed 0.5 to achieve wide range input voltage, also soft switching can be achieved for all switches. Especially, voltage stress across main switches can be clamped at 1/2V_in, voltage stress across auxiliary switch can be clamped at V_in. In addition, due to clamp capacitor series with the transformer, duty ratio can be extended with equation V_o = {V_in(1-D)D}/N. Thus, as a kind of better cost-effective approach, it is very attractive for high input, wide range and high efficiency application.