The Numerical Calculation Of Rotating Electromagnetic Field Based On Reluctivity Tensor

On the support of the Natural Science Foundation of Hebei Province, this paper selected"The Numerical Calculation of Rotating Electromagnetic Field Based on Reluctivity Tensor"as the subject of dissertation for Ph.D. It has important practical value.In most electromagnetic field analysis, the reluctivity of materials is treated as a scalar or a vector, and the results are acceptable. With the constant improvement of electrical apparatus design, the precision of electromagnetic field analysis is more and more important. In some cases, the result with reluctivity scalar or vector is unacceptable. In rotating electromagnetic field, the reluctivity becomes tensor. Most study of relucvitity tensor is two dimensional. Few three dimensional electromagnetic field analysis based on reluctivity tensor are reported.In this paper, by substitution of the three dimensional reluctivity tensor into curl-curl equation of three dimensional electromagnetic field, the finite element equations for four node tetrahedral element and six node triangular prism element are obtained. These equations contain every term of the three dimensional reluctivity tensor. A solving program is designed based on these finite element equations. Secondary development of FEMAP is carried out. The finite element analysis of three dimensional electromagnetic field based on reluctivity tensor is realized.A testing system that consists of a square coil and two iron plates is designed and simulated by FERT. When the reluctivity is treated as scalar, the calculation result is highly consistent with the result from ANSYS. When the reluctivity is treated as different tensor, the results differ from each other. The paper preliminarily discusses the off-diagonal term effect on the distribution of magnetic flux density.