Finite element solution of nonlinear eddy current problems with periodic excitation and its industrial applications.
Finite element solution of nonlinear eddy current problems with periodic excitation and its industrial applications.
复制标题
DOI：
10.1016/j.apnum.2013.04.007
复制
发表时间：
2014-05
影响因子：
2.8
通讯作者：
Preis, Kurt
中科院分区：
文献类型：
--
作者：
Biro, Oszkar;Koczka, Gergely;Preis, Kurt
关键词：
在分析三维涡流问题时，提出了一种有效的考虑磁性材料非线性的有限元方法。该问题是用基于边缘和节点的有限元基函数近似的矢量和标量势来表示的。伽辽金技术的应用导致了一个大的、非线性的时域常微分方程组。假设激励是时间周期的，我们只关心稳态周期解。这要么在频域表示为有限傅立叶级数，要么在时域表示为每个有限元自由度在一个周期内的一组离散时间值。前一种方法是（连续的）谐波平衡方法，而在后一种方法中，离散傅里叶变换将会导致离散谐波平衡方法。由于非线性，所有的谐波，无论是连续的还是离散的，都是相互耦合的。因此，采用一种特殊的非线性迭代技术，即不动点法，通过选择与时间无关的磁导率分布，即在每个非线性迭代步骤中选择不动点磁导率，将方程线性化。这将导致这些步骤中的不耦合谐波。在工业应用方面，对大型电力变压器进行了分析。第一个例子是单相变压器电磁场的时域计算，并与传统时间步进方法的计算结果进行了比较。在第二种应用中，采用谐波平衡法在频域分析了同一变压器的改进模型，研究了高次谐波的存在对损耗的影响。最后，第三个例子处理了单相变压器线圈中直流偏置的情况。
An efficient finite element method to take account of the nonlinearity of the magnetic materials when analyzing three-dimensional eddy current problems is presented in this paper. The problem is formulated in terms of vector and scalar potentials approximated by edge and node based finite element basis functions. The application of Galerkin techniques leads to a large, nonlinear system of ordinary differential equations in the time domain. The excitations are assumed to be time-periodic and the steady-state periodic solution is of interest only. This is represented either in the frequency domain as a finite Fourier series or in the time domain as a set of discrete time values within one period for each finite element degree of freedom. The former approach is the (continuous) harmonic balance method and, in the latter one, discrete Fourier transformation will be shown to lead to a discrete harmonic balance method. Due to the nonlinearity, all harmonics, both continuous and discrete, are coupled to each other. The harmonics would be decoupled if the problem were linear, therefore, a special nonlinear iteration technique, the fixed-point method is used to linearize the equations by selecting a time-independent permeability distribution, the so-called fixed-point permeability in each nonlinear iteration step. This leads to uncoupled harmonics within these steps. As industrial applications, analyses of large power transformers are presented. The first example is the computation of the electromagnetic field of a single-phase transformer in the time domain with the results compared to those obtained by traditional time-stepping techniques. In the second application, an advanced model of the same transformer is analyzed in the frequency domain by the harmonic balance method with the effect of the presence of higher harmonics on the losses investigated. Finally a third example tackles the case of direct current (DC) bias in the coils of a single-phase transformer.
登录
查看更多内容
影响因子：
2.1
作者：
Biro, Oszkar;Koczka, Gergely;Preis, Kurt
通讯作者：
Preis, Kurt
影响因子：
2.1
作者：
ALBANESE, R;COCCORESE, E;RUBINACCI, G
通讯作者：
RUBINACCI, G
影响因子：
1.4
作者：
Biro, O.;Augerhofer, S.;Seitlinger, W.
通讯作者：
Seitlinger, W.
影响因子：
2.1
作者：
Koczka, Gergely;Ausserhofer, Stefan;Preis, Kurt
通讯作者：
Preis, Kurt
DOI：
10.1108/03321640910959107
发表时间：
2009-01-01
影响因子：
0.7
作者：
Koczka, Gergely;Ausserhofer, Stefan;Preis, Kurt
通讯作者：
Preis, Kurt