| The subject is from the National Natural Science Fund Project, that is"The fine simulation of comprehensive electromagnetic properties of the electrical steel sheet and its composite structures in the computational electromagnetics"Fund Number: 50777042). In ferromagnetic materials, electrical steel sheets are widely used as iron core material of various types of motors and electrical apparatus to form the main magnetic circuit.Therefore, the magnetic properties measurement and simulation of electrical steel sheet receive much concern. As we all know, cold-rolled oriented electrical steel sheet is more often used in large power transformers. With the traditional method, only the magnetic property in the rolling direction or both in the rolling and transverse direction are considered for the electromagnetic field analysis. The results show that the deviation between calculated and actual magnetic flux density is rather large when using this method, which is mainly due to the anisotropy of electrical steel sheet. The cold-rolled non-oriented electrical steel sheets are used in motors as the iron core. Experiments show that the magnetic property of non-oriented electrical steel sheet is actually also not isotropic.In this paper, the anisotropy of electrical steel sheet is measured by the traditional Epstein Frame Method. Because Epstein Frame Method is one of one-dimensional measurement methods, namely, the magnetic properties of electrical steel sheet are measured along length direction of samples, and the excitation of Epstein Frame Method is in one direction, so that the anisotropy of magnetic materials can not be measured for the case of rotating magnetized. To overcome the shortcomings of the Epstein Frame Method, some improvements are made in this paper. The silicon steel sheets are cut along eleven directions, which are 0°, 10°, 20°, 30°, 40°, 50°, 55°, 60°, 70°, 80°, and 90°from rolling direction respectively. Then the magnetic property measurements are done for the eleven samples to simulate the anisotropy of silicon steel sheet in the case of rotating magnetized by making electrical steel sheet rotating.A novel method for simulating anisotropy is proposed in this paper. The experimental data of the magnetic properties of electrical steel sheet in different directions are used to analyze magnetic field and set magnetic property model. Then the finite element discretizing formulation is derived according to the model, and the finite element analysis and magnetic field calculation are completed by the self-written Fortran program. To verify the validity of this method, a three-phase transformer model is made. Exciting current and secondary side induced voltage of the model are measured. And the local average magnetic flux density in a period at some points is measured by setting induction coils at the corner and T-junction of the model.The magnetic field of this model is calculated is by the proposed method in this paper, and the calculation results of local magnetic flux density at specified points are compared with measured results. The calculation results obtained by traditional method, in which the magnetic properties of only rolling and transverse directions are considered, are also compared with the measured ones. The comparison proves that the new method for simulating anisotropy proposed in this paper is effective.
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