CMV Suppression Method for Back-to-Back Three-level NPC Converter

Common mode voltage (CMV) is a common problem in multi-level converter. It will hurt the bearing of the AC motor. This paper proposed a new CMV suppression method using zero-sequence voltage (ZSV) injection. When this method is used in the back-to-back three-level NPC converter, the CMV will be reduced from 1/3 to 1/6 of the DC link voltage. Simulation and Experiments have been carried out in the laboratory, and the results verify the effectiveness of the proposed CMV suppression method.