Active mitigation method of bearing voltage for motor drive system

The Pulse Width Modulation (PWM) technology is widely used in the industrial motor drive field because of its excellent control performance and high efficiency. However, the common-mode voltage of the PWM inverter can aggravate the bearing electric corrosion problem and shorten the bearing life. In this paper, the generation mechanism and coupling path of bearing voltage were studied. After that, the active mitigation method of bearing voltage in motor drive system was proposed, which included software and hardware suppression measures. The Active Zero State Pulse Width Modulation (AZSPWM) strategy was used to suppress the amplitude of common-mode voltage at the inverter output. Then, an Active Common-Mode Voltage Eliminator (ACMVE) installed between the motor and the inverter was proposed to further cancel the residual common-mode voltage. Finally, the mitigation effect of proposed method for the bearing voltage was verified by simulation.