Investigation On Calculation And Analysis Of Electromagnetic Vibration And Noise In Permanent Magnet Synchronous Motors

It is well known that acoustic noise and vibration of a motor are the very important standards used to estimate operation performance of this motor, and also are directly related to its quality and life. Nowadays, unfortunately, there is relatively little investigation that focuses on vibration and noise of Permanent Magnet Synchronous Motors (PMSM). In this paper, electromagnetic noise and vibration of PMSM are illustrated specifically, of which the contents include several parts as following:Firstly, air-gap magnetic field of 18.5kW Disc PMSM (DPMSM) is evaluated based on 3D Finite Element Method (FEM) in the condition of different switching frequencies of pulsewidth modulation (PWM) converters and sinusoidal current respectively. And then, comparison between the air-gap magnetic flux density and the exciting force wave existed on the surface of the stator teeth while operation currents are different is presented through spectrum analysis. As a result, the interaction between harmonic current and exciting force wave is developed. Especially, it is shown that there would be several new peaks of exciting force around switching frequencies.What's more, using 3D transient acoustic field analysis, the electromagnetic noise, vibration displacement, speed and acceleration are also evaluated when the exciting forces mentioned above are applied as loads. Finally, it is well illustrated that both noise and vibration would have new components around switching frequencies just because of the interaction between the fundamental and the harmonic currents. Moreover, the distribution principle of these new components is developed further, and also it can be concluded that various switching frequencies enormously influence acoustic noise and vibration of DPMSM. In the end, the calculation results are compared with the relevant experimental results, which are basically coincident with each other, and so the reliability of these calculation results and conclusions has been proved. Finally, the influence of various structural parameters on acoustic noise is also investigated. Specifically, through calculating 2D magnetic field and acoustic field of 850W PMSM, various structural parameters including slot/pole combination, shapes of magnetic poles and stator teeth chamfering are investigated in order to obtain their effects on acoustic noise. And these research results can provide reliable reference for the noise reduction and optimization design of PMSM.