Shaft voltage suppression for inverter-driven induction motor applying SHEPWM

In order to reduce the common mode (CM) voltage and shaft voltage for induction motor driven by inverter, an Improved Selective Harmonics Elimination Pulse Width Modulation (ISHEPWM) method was proposed in this paper. First ISHEPWM eliminates certain low order components of common mode voltage (CMV) generated by inverter. Secondly the high order components of the CMV were attenuated by a well-designed passive CM filter. Based on a three-level neutral-point-clamped (3L NPC) platform, the experimental results with and without CM filter were analyzed in detail, and the former obtained a much lower CMV and shaft voltage at the motor terminal compared with the latter, which verify the validity of the SHEPWM scheme proposed in this paper.