Shaft Voltage Elimination Method to Reduce Bearing Faults in Dual Three-Phase Motor

This paper proposes a method of eliminating common-mode voltage (CMV) and shaft voltage in dual three-phase motors using the carrier phase shift of space vector pulse width modulation (SVPWM). SVPWM for the dual three-phase motor is simply implemented using two traditional three-phase SVPWM structures. The representative work of the study is to eliminate the shaft voltage by applying the carrier phase shift method due to the cancellation of CMV. It was verified that the proposed method could reduce the shaft voltage with a simple technique, rather than applying a complex algorithm to reduce it. Also, the motor current and torque behaviors are analyzed to confirm that the proposed method does not affect the motor characteristics. The proposed method has been analyzed based on an equivalent circuit model and it has been verified through the experiment that the shaft voltage is simply eliminated by applying the proposed method.