Study on method of nonlinear magnetic field analysis taking into account eddy current and hysteresis phenomena in laminated core

在本研究中，利用验证模型验证了考虑层压铁芯涡流的非线性磁场分析的有效性。此外，为了改进该方法，还研究了微磁仿真的磁滞建模方法。所得结果总结如下：1。本研究提出了层压岩心模型的验证模型。结果表明，当励磁电流为1kHz时，应考虑层压铁芯钢板内的涡流。虽然计算和测量结果在50Hz时很吻合，但在1kHz时出现差异。这个问题是今后的工作。并将层合铁心模型应用于实际磁轴承系统。结果表明，不仅要考虑钢板内部的涡流，还要考虑层芯表层的涡流。本研究还开发了精密测量系统。利用微磁模拟技术建立磁滞模型研究了磁滞模型在磁场分析中的应用。提出了用最小模型表示迟滞现象的方法。结果表明，微磁参数可以改变磁滞曲线的形状。此外，还提出了用微磁学表征铁磁材料大尺度磁畴结构的一些技术。首先，为了减少在每个单元中确定磁化方向的迭代次数，研究了不使用Landau-Lifshitz-Gilbert方程的磁化修正方法。此外，为了模拟大尺度的磁畴，本文还提出了通过改变微磁参数使大单元尺寸成为可能的方法。最后，证明了该方法可以表示大尺度的磁畴。

In this research, the validity of nonlinear magnetic field analysis taking into account eddy current in laminated core is verified using verification model. Moreover, in order to improve the method, the hysteresis modeling using micromagnetics simulation is investigated. The obtained results are summarized as follows:1. Verification of laminated core modelingThe verification model is proposed in this research. It is shown that the eddy currents in steel plates of laminated core should be considered when exciting current is driven at 1kHz. Although both results obtained from calculation and measurement are good agreement with each other at 50Hz, the discrepancies occur at 1kHz. This problem is the future work. Moreover, the laminated core modeling is applied to real magnetic bearing system. It is shown that not only eddy current in steel plates but also the surface layer of laminated core should be considered. The accurate measuring system is also developed in this research.2. Hysteresis modeling using micromagnetics simulationThe hysteresis modeling using the micromagnetics for the magnetic field analysis is investigated. The method for representing hysteresis phenomena by minimum modeling is proposed. It is shown that the shape of hysteresis curve can be changed by the parameters of micromagnetics. Moreover, some techniques for representing large scaled magnetic domain structure of ferromagnetic material using micromagnetics are also proposed. First, in order to reduce the number of iterations for determining the direction of magnetization in each cell, the method for modifying magnetization without the Landau-Lifshitz-Gilbert equation is investigated. Moreover, in order to simulate large scaled magnetic domain, the method for making it possible to use large cell size by modifying parameter of micromagnetics. Finally, it is shown that large scaled magnetic domain can be represented by a proposed method.