Common-mode voltage elimination technique for an open-end winding induction motor using carrier based PWM

Common-mode voltage (CMV) generated by pulse width modulated (PWM) inverters is the root cause for the premature bearing failures and electromagnetic interference in motor drives. This CMV can be eliminated by switching zero CMV states only. This paper proposes a carrier based method for the elimination of CMV for a 3-level inverter using open-end winding (OEW) configuration for induction motor. Switching sequences and timing signals for this method are derived from the two virtual PWM patterns. In this scheme only active switching states are used to control inverter. The proposed method is free from neutral point fluctuations and clamping diodes in comparison with CMV elimination methods for conventional 3-level inverter topologies.