Research On The Two-Dimensional Magnetic Property Measurement Of Electrical Steel Sheets

This thesis is supported by National Natural Science Foundation of China——The accurate modeling of electromagnetic property of electrical steel sheet and its composite structure in computational electromagnetics(under Grant 50777042). Measurement and modeling of three-dimensional hysteresis property of ferromagnetic materials(under Grant 50807039).As we all know, electrical steel sheet, which has complex magnetic properties including anisotropy, is widely used in electrotechnic products. In order to analyze dynamic characteristic of electrical machines and apparatus, decrease power loss and improve performance of electromagnetic equipment, it is highly significant to model the magnetic properties of electrical steel sheets precisely in the actual running state of electrical equipment. The prerequisite of achieving that modeling is to have reliable and effective measurement data. Therefore, it is important to measure the magnetic property of electrical steel sheets accurately. At present, there are two methods to measure the magnetic properties of electrical steel sheets, one-dimensional magnet i c prpertry measurement, and two-dimensional magnetic property measurement. The method of two-dimensional magnetic property measurement is a hot research point currently, and is also the main content in this paper. The primary task of this paper is described as follows.Firstly, the current development status of the magnetic property measurement of electrical steel sheets are summarized, and the advantages and disadvantages of three kinds of 1D measurement methods are analyzed. Then the principles of 2D magnetic property measurement are researched. Based on those researches, the model of 2D measurement is made, and the characteristics of three models, developed by our group, are compared with each other.Then, based on the 2D measurement system, a 2D feedback control of measurement system is designed. For one thing, percentages of each harmonic component of B, the magnetic flux density, versus fundamental harmonic are gained by fast Fourier transform (FFT) in rolling direction and transverse direction, and the feedback control of B waveform in rolling direction and transverse direction is realized separately with this system. The 30ZH120 grain-oriented electrical steel sheet is selected as samples, and the feedback control are achieved in rolling direction and transverse direction at the same time with the method and experience of the feedback controlling in single direction. The measurement data of electrical steel sheets in rotating magnetic field are also achieved.