Common-Mode Voltage Mitigation for Back-to-Back Current-Source Converter With Optimal Space-Vector Modulation

Common-mode voltage (CMV) problem is one of the most important issues for back-to-back current-source converters. In this paper, the theoretical analysis is presented to clarify that the system CMV mainly depends on the CMV difference between a rectifier and an inverter. And then, a new CMV mitigation technique is proposed. Different from the existing methods, the proposed method coordinates the active and zero vectors of both rectifier and inverter in the back-to-back current converter, instead of eliminating zero vectors or optimal selection of a zero vector. In this way, the CMV difference between a rectifier and an inverter is minimized. Consequently, the system CMV can be significantly mitigated. Finally, the experimental tests are carried out on a 10-kVA back-to-back current-source converter, and experimental results verify the effectiveness of the proposed method.