Abstract:Magnetic field distribution and its parameters of salient machine are closely related to position angle. The calculation work will increase sharply if the model is established at every position. The rotor and the air surrounding it, stator and the air around it, are divided into two different sub-regions using gap midline as region boundary line. In order to distribute the nodes evenly and make the nodes exist in a separate sub-area respectively, the meshing of finite element method(FEM) is adopted for the air gap. If the degree of freedom(DOF) of nodes is coupled correspondingly, the field of the rotor at a certain position can be solved. On the contrary, decoupling these DOFs and further coupling it at another position, the rotor can be regarded as another location and finally it can be solved too. On basis of above analysis, the machine achieves the solution of “rotation”, which is using the state of “rest” to replace of the “motion” state. This method is called “motion replaced by rest”(MRR). In this paper, doubly salient machine is selected as a prototype. The rules of inductance variation of prototype are solved using MRR FEM. After that, combing with the control circuit of this motor, the current of armature windings can be obtained. Eventually, Fourier transform is used to obtain the composition of the current harmonics, and the eddy current losses can be calculated. The internal demagnetization effect of the silicon steel sheet can be ignored because it is thin enough. Then, the total loss of eddy current can be solved. According to the constitution of the total losses from the testing, the hysteresis loss of the iron core about the prototype can also be solved. At the same time, the coefficient of hysteresis loss of the silicon steel sheet can be calculated. Based on above analysis, the losses under different speed and winding current are calculated and measured. According to the comparison of the calculated results and measured ones, the error is within 15%. It is shown that the field problem of rotating machine can be solved by MRR FEM conveniently and quickly. The proposed approach is not only suitable for all rotating and moving equipment, but also can be used in other subjects, i.e., it has a wide range of universality.
王世山,虞振洋,谢仁和,龚敏,秦海鸿. 以静代动有限元原理及其在凸极类电机中的应用[J]. 电工技术学报, 2014, 29(1): 68-76.
Wang Shishan,Yu Zhenyang,Xie Renhe,Gong Min,Qin Haihong. Finite Element Method of Motion Replaced by Rest and Its Application in Salient Machines. Transactions of China Electrotechnical Society, 2014, 29(1): 68-76.
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