A Novel 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 a isolated three-phase rectifier-type high-frequency-link (RHFL) bi-directional power converter. In conjunction with a back-end AC/AC converter operating with a novel patent-filed hybrid modulation scheme outlined in [1], [2] that reduces the number of hard-switched commutation per switching cycle , the proposed ZVZCS scheme can leads 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.