大型异步电动机定子振动与模态分析

Vibration and Modal Analysis of Stator of Large Induction Motors

预测电机的振动和噪声需准确计算电机定子结构的固有频率及定子的响应特性。文中利用3D有限元软件研究了定子模态和固有频率,分析了定子叠片结构、绕组对大型异步电机定子固有频率和振动模态的影响;用有限元分析和实验测量确定正交各向异性叠片结构和绕组的材料属性,并与实测结果进行了比较。研究表明,对于大型异步电机,定子绕组对固有频率影响很大,其弹性模量远低于实体铜,有效部分绕组和端部绕组不能简单地以附加质量形式计算固有频率;端部绕组质量和刚度对固有频率的影响大体相互抵消,所以端部绕组对固有频率的影响相对很小。

Accurate calculation of the stator natural frequencies and harmonic response of an electrical machine is essential to the prediction of acoustic noise and vibration. In this paper, the 3D finite element analysis is used to study on the stator modal shapes and natural frequencies of large induction motor. The influence of laminated core and winding on the natural frequencies and modal shapes of the stator are investigated. Both finite element analysis and experimental measurement are used to determine the material properties of anisotropy laminated stator core and windings. The study by comparing 3D finite element prediction with measurement shows that the stator windings have a significant effect on the natural frequencies of large induction motor, and the Young＇s modulus of the winding is much lower than that of the solid copper. It is concluded that the active part and end part of the stator winding cannot be treated simply as an additional mass. Since the mass and stiffness of the end part winding have contrary influences which appear to be counteracted each other, the influence of the end part winding on the natural frequencies is relatively small.