| Electrical machine and power transformer are one of the most important electric and transmission equipments.Electrical machine comsumption accounted for 64%.Even if the power transformer is working under no load,its core loss is sigficant.If the power utilization rate increases by a small percentage point,a great wealth of the National Society will be saved.One of the key technologies of optimization design and efficiency calculation of the core magnetic circuit is the fine simulation technology of the core material of the electrical steel sheet.Aiming at the key problem of core loss measurement and fine simulation for electrical steel sheet,and based on the support of National Natural Science Foundation of China “Measurement of the three-dimensional magnetic properties for electrical magnetic materials and modeling of the tensor magnetic”,3D magnetic properties measurement skills including excitating structure and sensing structure optimization design,are explained in detail in this paper.Magnetic feedback method and fine simulation of electrical steel sheet are deeply researched.The main topic coves dynamic hysteresis model,vector hysteresis and magnetic anisotropy model,and their mathematical modeling,parameters identification,validation of the model,verification in the engineering problem.The emphasis and achievement of the paper mainly manifests in the following aspects:(1)The 3D magnetic circuit and sensing structure of 3D magnetic tester were studied by simulation.A simulation algorithm considering multi-sheet silicon steel and multi-eddy current domain were designed.Based on the algorithm,the 3D lattice shaped and 3D C-shaped excitating structures were compared.The former one had the drawback that there existed normal magnetic flux across the laminated steel around the lapped area and so it may produce local heating.The latter one overcomeed the defect and realized three symmetric excitation direction of 3D magnetic circuit.On the other hand,the size and position of the sensing coil of magnetic density and magnetic field strength were optimized.(2)The dynamic model of 3D magnetic property measurement system was built up.And,parameters of the system were experimental identified.Then,a novel frequency domain feedback control algorithm based on decoupling each axis of the excitation system was proposed.It improved the repeatability of measurement of the magnetic properties of soft magnetic materials.Due to the hysteresis and magnetic saturation,the 3D measurement system was interfered by the harmonics.By injecting the specific harmonic through feedback method,the harmonics the measurement system were compensated and weaken,and the measurement accuracy of loss was improved.(3)A dynamic inverse Preisach hysteresis model of electrical soft magnetic material is established,which describes the wide band(20Hz~1kHz)hysteresis loop of electrical steel sheet.The inverse Preisach hysteresis model is easy to be coupled with the electromagnetic finite element method based on the magnetic vector potential.The rotational transient loss model is established to predict the hysteresis loss under arbitrary trace.The model can describe the physical phenomena when the rotating magnetic density is close to saturation.The coupling of hysteresis model and electromagnetic finite element method is applied to the simulation design and analysis of electromagnetic device,which provides an accurate tool for the design of electromagnetic devices.(4)A magnetic anisotropy energy model based on energy was put forward.The model advantage is that the most hard magnetization axis of oriented electrical steel sheet with the rolling direction 55 degrees angle direction was described correctly.The model was realized by the finite element method,and was compared with a variety of magnetic anisotropy model.Furthermore,a standard three limb core model was designed in order to systematic test the proposed algorithm.The experimental results were compared with a variety of simulation models,so the validity of the proposed model was verified.In this paper,under the research background of energy saving and consumption reduction for the equipment of electric machine and power transformer,a novel 3D magnetic properties measurement system was built up;and the feedback method in frequency domain for 3D magnetic properties measurement was proposed;and the automatic measurement system for 3D rotating loss was fulfilled.The research for 3D magnetic measurement provided the experimental foundation for fine simulation of electrical steel sheet and a new loss evaluation system supporting new electrical soft magnetic material development and production quality control.In theory,a dynamic inverse Preisach hysteresis model and magnetic anisotropy based on energy were proposed,therefore the dynamic hysteresis loss and vector rotational loss and magnetic loci of magnetic anisotropy will be predicted more accurately.In summary,the research of 3D magnetic property measurement and modeling provide a more accurate and effective finite element simulation tool for design of electrical machine and power transformer. |
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