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

在本研究中，考虑到涡流在叠片铁芯的非线性磁场分析的有效性进行了验证模型。此外，为了改进该方法，研究了利用微磁学仿真的磁滞建模。主要研究结果如下：1.叠片铁心模型的验证本研究提出了叠片铁心模型的验证模型。结果表明，当励磁电流为1 kHz时，应考虑铁心钢板中的涡流。在50 Hz时，计算结果与实测结果吻合较好，但在1 kHz时，计算结果与实测结果不一致。这个问题是未来的工作。并将叠片铁心模型应用于真实的磁轴承系统。计算结果表明，不仅要考虑钢板中的涡流，还要考虑铁心表层的涡流。本研究还开发了精确的测量系统.基于微磁学仿真的磁滞回线建模研究了基于微磁学的磁滞回线建模方法。提出了用最小模型表示磁滞现象的方法。结果表明，微磁学参数可以改变磁滞曲线的形状。此外，还提出了利用微磁学表征铁磁材料大尺度磁畴结构的方法。首先，为了减少用于确定每个单元中的磁化方向的迭代次数，研究了在没有Landau-Lifshitz-吉尔伯特方程的情况下用于修改磁化的方法。此外，为了模拟大尺度磁畴，提出了通过改变微磁学参数来实现大单元尺寸的方法。最后，它表明，大规模的磁畴可以表示所提出的方法。

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.