A Soft-Switching Scheme for an Isolated DC/DC Converter With Pulsating DC Output for a Three-Phase High-Frequency-Link PWM Converter

Abstract

This paper outlines a soft-switching mechanism based on zero-voltage-zero-current-switching (ZVZCS) principle for the front-end isolated DC/DC converter of an isolated three-phase rectifier-type high-frequency-link bidirectional power converter. In conjunction with a back-end DC/AC converter operating with a novel patent-filed hybrid modulation scheme outlined in , , and that reduces the number of hard-switched commutation per switching cycle, the proposed ZVZCS scheme can lead to less overall switching losses than other conventional switching schemes. The proposed ZVZCS scheme is effective for various load conditions, operates seamlessly with a simple active-clamp circuit, and is suitable for applications where low-voltage dc to high-voltage three-phase ac power conversion is required.