Analysis, design and implementation of an improved two‐switch zero‐current zero‐voltage pulse‐width modulation forward converter

In this study, an improved two‐switch zero‐current zero‐voltage switching pulse‐width modulation (ZCZVS‐PWM) forward converter, which employs a simple resonant lossless snubber circuit, is introduced. A simple resonant snubber circuit consists of a capacitor, an inductor and two diodes. In proposed converter, switch Q 1 operates under exactly zero‐current switching at turn‐on, and exactly zero‐voltage switching (ZVS) at turn‐off, and switch Q 2 operates under exactly ZCZVS at turn‐on, and ZVS at turn‐off, and the all‐passive semiconductor devices operate under soft‐switching at turn‐on and turn‐off. The proposed converter has no current and voltage spikes in the switches in comparison with the hard‐switching forward converter counterpart and is suitable for high switching frequency and high‐power operation. The proposed converter is analysed and various operating modes of the improved two‐switch ZCZVS‐PWM forward converter are discussed. Analysis and design considerations are presented and the prototype experimental results of a 160 W (32 V/5 A) proposed converter operating at 300 kHz switching frequency, confirm the validity of theoretical analysis.