| It is of great significance to simulate the magnetic properties of magnetic materials to improve the efficiency and performance of electrical equipment such as motor and transformer,accurately.Traditional one-dimensional test method only considers the single direction of magnetization characteristic,ignoring the anisotropic of the medium,it is different with the actual working condition.The new 3-D magnetic property measurement can be accurately measure the magnetic properties of the silicon steel laminated sheet in a variety of different excitation models,the magnetic field strength H and the magnetic induction intensity B are described by an indirect sensing structure.Therefore,optimization and compensation of the sensing structure are key factors for accurate measurement of magnetic properties of materials.The paper is supported by NSFC.It is aimed at anisotropy of the silicon steel laminations and other magnetic materials in the field of simulation,mainly.A novel three-dimensional dynamic magnetic property testing structure is designed in this paper,and the alternating and rotating magnetic properties of silicon sheet material are tested over wide frequency range.The sensing structure of the device is optimized.Thus,the magnetic characteristics of the material are studied more precisely.The main contents are as follows:(1)Aiming at the symmetry problem of 3-D magnetic circuit,dual array composite BH sensing coils and sensing box structure are designed and optimized.Various types of sensing structures are proposed,which can reduce the measurement error,effectively.The problem of measuring the magnetic characteristics of the local magnetic field of silicon steel lamination is emphatically solved.(2)The sensing coil calibration experiments are designed,and the DC excitation model and AC excitation model are put forward.The coefficients of the new sensing coils are calibrated by standard solenoid.It is proved that the influence of geomagnetic field in the DC excitation system should be considered,which can provide a reliable guarantee for 3-D magnetic measurement accuracy.(3)The measured data is corrected.The coordinate correction of the sensing structure and excitation structure is carried out by the method of rotating coordinate transformation.The air gap between the coil and the sample is compensated by the external interpolation method,a sample structure with uniform field pole boots can be used to measure the internal magnetic field of the sample more accurately.(4)The magnetic properties measurement of different excitation conditions of nonoriented silicon steel laminations(35WW270)is acquired based on the improved sensing structure.Moreover,it is analyzed the loss characteristics in detail,two models for calculating eddy current loss are also presented,which provide an important reference for the research of large electrical equipment. |
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