考虑定子铁心片间短路时的涡流及涡流损耗的有限元分析

FEM Analysis of Eddy Current and Associated Losses Considering Interlamination Short-Circuits in Stator Core

对于定子铁心中发生片间短路时的涡流及涡流损耗计算的问题,提出了一种基于低频下的均质化方法,且该均质化方法利用有限元方法进行分析。直接模拟方法需要对每个叠片进行非常细致的剖分,因此会导致巨大的计算上的未知。为了避免对每个叠片进行模拟,本文使用等效电导率的连续体模型代替大量的叠片。应用上面提出的方法对一台发生片间短路的大型异步电机的定子通过使用T,Ψ-Ψ方程的三维有限元软件进行计算验证,并将引入各向异性电导率的连续体模型下获得的结果与实际叠片下获得的精确解进行对比分析,可知在各向异性电导率的连续体模型下获得的故障点分析可以有效地满足实际的精度要求。

A homogenization method is presented to compute the eddy current and associated loss in stator core which hold the interlamination short-circuits based on the finite element method at low frequency. The direct modeling method needs a fine mesh within each sheet and consequently results in large number of unknowns. To avoid modeling individually each sheet, a continuum model with an equivalent conductivity is used to substitute for a number of sheets. As an example of application of the method developed above, the eddy current and resultant losses in a large asynchronous machine core with interlamination short-circuit are computed by using the aid of a 3D finite-element packet which utilizes the T, Ψ-Ψ formulation. The calculation, based on the continuum model by introducing anisotropic conductivity and on the real lamination model, respectively, are analytical comparison. The results of the comparison display the stator faults analyzed by the continuum model with the isotropic conductivity can satisfy the actual accuracy requirement.