LAUSR

Paralleled inverters are widely employed in permanent magnet synchronous machine (PMSM) drives to increase system capacity and reliability. Due to the discrepancy of paralleled inverters, the differential-mode circulating current (DMCC) is a major concern in paralleled inverters fed PMSM drives. The DMCC would result in current unbalance and efficiency reduction. To address this issue, a low-frequency DMCC suppression considering dead time compensation is proposed in this article, which can be effective in the suppression of both DMCC and zero-sequence circulating current. In detail, the DMCC due to the discrepancy of control settings, such as dead time and switching period, is eliminated by a proposed dead time compensation. Besides, the DMCC owing to the hardware differences, including device voltage drops, device turn-on/off delays, and filter inductances, is suppressed by a proposed regulation of phase conduction time, being free of disturbing the command voltage of drive system. Finally, the effectiveness of the proposed method is experimentally validated under both two-level and three-level space vector modulations.