Precise Calculation Method of Vector Dwell Times for Single-Stage Isolated Three-Phase Buck-Type Rectifier to Reduce Grid Current Distortions

摘要

Since the dc side current of the single-stage isolated three-phase buck-type rectifier (1S-ITBR) is discontinuous, the conventional current space vector pulsewidth modulation presents a poor grid current characteristics. In this article, the expressions of the instantaneous grid current of 1S-ITBR and the amplitudes of various-order grid current harmonics are originally derived. These results reveal the essential reason for causing t low-order current harmonics. Then, the improved calculation method of dwell times of the effective current space vectors with the goal of eliminating the grid current distortion is proposed to improve the grid current quality. The correctness of the harmonics analysis and the feasibility and validity of the proposed improved method are experimentally verified.