中文摘要：

为了识别出永磁同步电机的噪声来源,该文对常见的机械噪声和不同影响因素下的电磁噪声特点进行研究。首先分析了滚动轴承产生的噪声阶次特征,识别出了滚珠内外圈通过频率对应的分数阶噪声。其次通过麦克斯韦应力张量法推导了理想条件下作用于定子内表面的径向力波的频率阶次,结合实测电流谐波分析了不同电流谐波类型下的径向力波特征,通过引入偏心修正系数分析了转子动态偏心对径向力波的影响,从而识别出了不同影响因素下的电磁噪声源。并且建立了永磁同步电机的有限元模型,通过模态试验对定子铁芯和绕组的等效进行验证,由电机约束模态分析获取了电机在实际安装条件下的模态参数,对实测的共振噪声来源进行解释。最后分析了各影响因素产生的噪声对总体噪声的贡献量,指出电机的主要噪声源。该研究可以识别出永磁同步电机的每一阶次噪声和共振噪声的来源,为进一步的减振降噪奠定基础。

英文摘要：

The noise source of permanent magnet synchronous motor（PMSM） was identified in this paper. Firstly, the noise signal in the acceleration process was tested and the short time Fourier transform（STFT） was used to perform the time-frequency analysis. Main noise characteristics including frequency order and resonance region were obtained. Then, the order feature of rolling bearing was studied and the fractional order noise produced by ball pass frequency was recognized. Based on the Maxwell stress tensor method, the frequency order of radial electromagnetic force acting on the teeth surface was derived. The characteristics of the ideal radial force under sinusoidal current with no rotor eccentricity were derived. The influence of current harmonics on the radial force was discussed. Current in the acceleration process was monitored and STFT was used to analyze the type of current harmonics. It was found current harmonics could be divided into 2 types： 1） current harmonics which were multiples of the fundamental current frequency and 2） current harmonics which were close to the switching frequency. The force order produced by the first type of current harmonics was the same as that in the ideal condition and the second type of current harmonics produced force harmonics around the switching frequency. By introducing the eccentricity correction factor the force harmonic due to rotor dynamic eccentricity was analyzed. It was found that rotor dynamic eccentricity induced extra space and frequency harmonics. Especially, low space harmonic which contributed most to the overall noise level was produced in the eccentricity case. In order to obtain the modal parameters in the resonance region, the finite element（FE） model of stator was established. The material anisotropy of stator core and winding was considered according to the actual structure of stator and modal shape. Modal tests of stator core and stator assembly were conducted to validate the equivalent model of stator core and winding, respectively. Th