Vibration reduction method in SRM with a smoothing voltage commutation by PWM

Vibration and acoustic noise generated by the excitation force at radial direction (radial force) of Switched Reluctance Motors are the most critical issue. Due to these unfavorable characteristics of SR motors, the application for the industry machine has been delayed. The main factor of the vibration in the driving condition is caused by an electromagnetic force in the radial direction. The radial force is generated when the voltage instantly turned off, this instantaneous voltage change makes all of resonant frequency of the motor excite. This paper considers that a relationship between a variation of the input voltage and the generated vibration to establish a low vibration and low acoustic noise driving method. A new method to reduce them by adding a smoothing voltage modulated by PWM is proposed in this paper, the method is compared with the conventional single pulse operation by experimental results.