Technology Research Of Noise And Vibration Source Identification Of Permanent Magnet Synchronous Motor

The research on sources of noise and vibration of Motor originated the 1940's. Main work oriented towards induction motors, DC motors and synchronous motors. Since Rare Earth Permanent Magnet Synchronous Motor (PMSM) is a new and high efficiency specialty motor, PMSM is widely used. But the study on the sources of noise and vibration of PMSM is rare. Like ordinary motors, noise and vibration of PMSM are also important performance indicators. Therefore, it is very meaningful to study noise and vibration source of PMSM.As a time-frequency analysis method, Wavelet Transform has ability of exhibit characterization of signals in the time-frequency domain. Through a flexible window of time-frequency transform, it can highlight the different characteristics of the signal. In this paper, the development process, basic principles and practical applications of Wavelet Transform were expounded. Because Wavelet Transform in signal processing has merit, noise and vibration signals of the motor are analyzed and processed by the Wavelet Transform as a signal processing tool in this paper.The study of source of noise and vibration of the motor is as the followings:Electromagnetic vibration of PMSM in sinusoidal supply has been studied. The electromagnetic vibration on the motor core is excited by electromagnetic force generated in air-gap magnetic field. The electromagnetic vibration plays an important role in PMSM. In this paper, air-gap magnetic field and the electromagnetic exciting force in PMSM are analyzed. The spectra of electromagnetic exciting forces are gained.Noise of PMSM in inverter supply is studied. Experiments of noise and vibration of PMSM fed by inverter are completed. Signal processing of motor was conducted by Wavelet Transform. The current harmonics characteristics and noise changes with switching frequency of the motor fed by Inverter were listed. The source of noise and vibration of PMSM fed by inverter are identified. Reasons of resulting in noise and vibration in high-frequency was revealed. The mechanism and signal characteristics of mechanical vibration of motor are set forth. The vibration signal of the ball bearing of motor was recognized. In this paper, the wavelet decomposition of the signal of the vibration was processed. And then, demodulation and zoom analysis by Hilbert Transform was processed. Identification of Noise and vibration resulting from bearing can be completed.