A Novel Soft-Switching Scheme for an Isolated Dc/Dc Converter with Pulsating Dc Output for a Three-Phase High-Frequency-Link PWM Converter

摘要

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.