Voltage Mitigation for Back To Back Source Converter

Common-mode voltage 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 common mode voltage mainly depends on the common mode voltage difference between rectifier and inverter. And then, a new common mode voltage 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 common mode voltage difference between rectifier and inverter is minimized. Consequently, the system common mode voltage can be significantly mitigated. Finally, the experimental tests are carried out on a back-to-back current source converter, and experimental results verify the effectiveness of the proposed method.