变频器供电对永磁电机振动噪声源的影响研究

Study on source of vibration and acoustic noise of permanent magnet machines by inverter

为了研究变频器供电时永磁电机振动噪声源的特征频率,采用有限元法计算变频器供电时永磁电机的气隙磁场并进行频谱分析,通过与实测气隙磁场的对比分析总结出变频器供电时气隙磁场的主要谐波频率表达式。根据麦克斯韦定律计算出作用在电机定子表面的电磁激振力,并加载到定子表面用来计算变频器供电时永磁电机的三维声场。对计算出的噪声声压级进行频谱分析,推导出变频器供电时气隙磁场谐波频率与电机振动噪声频率的对应关系表达式并进行实验进行验证。实验结果表明利用所得到的解析表达式可以预估出永磁电机在变频器供电条件下的主要振动噪声峰值频率。

In order to research on the characteristic frequency of vibration and acoustic noise of permanent magnet （PM） machines by inverter, the finite element method （FEM） is employed to compute the air-gap magnetic field of PM machine by inverter and the spectra of air-gap magnetic field are analyzed. So the expression of main air-gap magnetic field＇s frequency is obtained through comparison and analysis with the measured one. The electromagnetic force on the stator is computed by Maxwell＇ s law, with which the 3D sound field by inverter is computed. Analyzing the spectra of the noise pressure level, the expression of air-gap field＇ s frequency by inverter and acoustic noise＇ s frequency is gained. The computing results are compared with the experiment results, which are basically coincident with each other. The experiment results indicate the frequencies of vibration and noise of PM machines by inverter are predicted with the expression.