Operation analysis of high-frequency AC link three-phase DC-AC converter applying phase-shift PWM control in secondary side

Abstract

Soft-switching power supplies and their related application systems have attracted because soft-switching scheme has remarkable advantages such as lowered switching loss, reduced dynamic electrical stresses, reduced EMI noise and so on. However most of soft-switching power conversion systems include some inherent difficulties. For example, power conversion efficiency is lowered by conduction losses caused by significant circulating current and resonant current due to soft-switching operation. To solved their difficulties, authors have proposed a new phase-shift PWM control scheme and have already reported before about quasi-resonant high-frequency AC link DC-DC converter and single phase DC-AC converter applied for proposed control scheme. They have some features such as circulating current reduction, lowered conduction losses and easily achieved soft-switching and so on.In this paper, authors apply a proposed control scheme to a quasi-resonant high-frequency AC link three-phase DC-AC converter. Its new operation principle based on time shared space vector theory is proposed and unique features are described. Operating performance and evaluation of THD (Total Harmonic distortion) of this three-phase DC-AC converter in steady-state are illustrated by means of simulating results.