考虑谐波及集肤效应的电工钢片旋转异常损耗计算与测量

Measurement and calculation of rotating anomalous loss in electrical steel sheets considering harmonics and skin effect

为了准确计算电工钢片的旋转异常损耗,根据谐波分析原理对建立的电工钢叠片有限元模型进行时步有限元仿真;基于旋转铁心损耗计算模型,通过考虑涡流集肤效应对旋转损耗系数的影响结合钢片在中低频率下的损耗测试获得叠片损耗计算的关键系数,间接求得电工钢片中旋转异常损耗的计算式。利用构建的新型三维磁特性测试系统对典型电工钢叠片样品进行椭圆形旋转与交变励磁方式下的宽频铁耗实验测量,并定量地进行了对比与分析。结果表明:2种励磁方式下叠片损耗的变化规律相类似,但其椭圆形旋转各损耗都要比交变时的对应损耗大,必须认真考虑谐波、集肤效应和旋转励磁等对材料特性的影响;所计算出的旋转异常损耗也是相对较小,在1 k Hz时也未占到旋转总铁耗的5%。从而验证了所推导出的计算式和测量手段的正确性与可行性。

In order to accurately calculate the rotating anomalous loss in electrical steel sheets, sheets finite element model was simulated by adopting time-stepping finite element method based on Fourier analysis. Then, the key loss coefficients of the sheets were obtained by experimental measurement at low to medium frequencies with considering the influence of eddy current skin effect to the loss coefficients on the basis of rotating core losses calculation model. So, the calculation formula of rotating anomalous loss in electrical steel sheets was deducd indirectly. By using a novel 3-D magnetic properties testing system, the total broadband core losses under elliptical rotation and alternating excitations were carried out for a typical electrical steel laminated specimen. Meanwhile, losses characteristics of the two excitation modes were compared and analyzed quantitatively. The results show that both the losses variations are analogous, but varieties of elliptical rotation excitation losses are bigger than the corresponding alternating losses, so it is necessary to consider the influences of harmonic, skin effect and rotating excitation, etc, to the materials properties seriously. The calculation of rotating anomalous loss is relatively small and is not accounted for 5% of the total rotating core losses up to 1k Hz. Thus, it validates the correctness and feasibility of the calculation formula and measurement means.