Suppression of vibration and common-mode voltage of dual three-phase motor under improved PWM methods

Abstract:
The variable switching frequency modulation can effectively reduce the harmonic peak value of the inverter output current, thereby reducing the mechanical vibration and noise of the motor. Among these strategies, random pulse width modulation (RPWM) is a traditional and effective variable switching frequency modulation method, and its frequency change is completely random. It can effectively reduce high-frequency current harmonics and vibration. As an improved period modulation method, Uniform Distributed Pulse Width Modulation (UDPWM) is preferred to reduce the current total harmonic distortion (THD). For the dual three-phase motors, reverse winding pulse width modulation (RWPWM) can theoretically eliminate common-mode voltage (CMV). In this paper, the novel RW-RPWM and RW-UDPWM are proposed by combining the above PWM methods, which can achieve the suppression of both CMV and vibration. Among them, RW-RPWM has better vibration reduction performance, and RWUDPWM has less influence on current THD.