Analysis of Iron Loss in Magnetic Material using Time-Periodic Finite Element Method Taking Account of Hysteresis and Eddy Current

为了建立准确分析电机铁损的三维非线性磁场分析方法，提出了三维时间周期有限元法和磁滞回线建模技术。此外，还对模型铁心的通量和铁损进行了分析和测量。将可直接获得交流稳态现象的时间周期法引入到基于边缘元的三维有限元方法中。在此基础上，开发了在实际CPU时间内求解三维交流稳态磁场的代码。提出了利用逆分布函数的改进Preisach模型，使磁场强度可以由给定磁通密度直接求得。采用该方法，在考虑磁滞的磁场分析中，CPT时间可以大大缩短。3 .磁滞环的测量由于磁场分析中需要直流磁滞环，利用H线圈输出的数字积分，提出了小于0.01Hz的极低频磁滞环测量方法。分析了模型铁芯内的磁通分布，研究了由计算得到的磁滞回线计算磁滞和涡流损耗的方法。并将通量和铁损的分析结果与实测值进行了比较。

3-D time-periodic finite element method and modeling technique of hysteresis loop are developed in order to establish 3-D nonlinear magnetic field analysis method for the accurate analysis of iron loss in electric machines. Moreover, the flux and iron loss in model core are also analyzed and measured.1. Development of 3-D Time-Periodic Finite Element MethodThe time-periodic method which can directly obtain the ac steady state phenomenon is introduced to 3-D finite element method using edge element. Then, a code for solving 3-D ac steady state magnetic field within a practical CPU time can be developed.2. Development of Modeling Technique of Hysteresis LoopThe modified Preisach model using the inverse distribution function is conceived so that the magnetic field strength can be directly obtained from the given flux density. By using this method, the CPT time can be considerably reducedin the magnetic field analysis taking account of hysteresis.3.Measurement of Hysteresis LoopAs the dc hysteresis loop is necessary in magnetic field analysis, the magnetic measurement method under the extremely low frequency less than 0.01Hz is developed by utilizing the digital integration of the output of an H coil.4. Analysis of Flux and Iron Loss of Core and MeasurementsThe flux distribution in model core is analyzed, and the method for calculating the hysteresis and eddy current losses from the calculated hysteresis loop is investigated. The analyzed results of flux and iron loss are compared with measured ones.