考虑材料非线性及涡流影响的径向电磁轴承等效磁路建模  

Equivalent Magnetic Circuit Modeling of Radial Active Magnetic Bearing Considering Material Nonlinearity and Eddy Current Effects

作　　者：叶品州 李红伟[1] 于文涛[1] 仲慧[1] Ye Pinzhou;Li Hongwei;Yu Wentao;Zhong Hui(School of Electrical Engineering Shandong University,Jinan 250061 China)

机构地区：[1]山东大学电气工程学院,济南250061

出　　处：《电工技术学报》2020年第9期1858-1867,共10页Transactions of China Electrotechnical Society

摘　　要：电磁场分布特性的准确分析与计算是电磁轴承性能优化的基础,而目前电磁轴承磁场分析时较少同时考虑涡流和铁心磁导率的非线性这两个因素的影响。因此,该文利用指数方程拟合硅钢片的磁化曲线来考虑磁导率的非线性,引入动态相对磁导率来计及涡流对磁场的影响。建立了计及磁极边缘效应、定转子铁心磁阻、铁心磁导率非线性、涡流及实时控制电流在内的径向电磁轴承非线性等效磁路模型。采用该模型计算转子具有静态位移0.1mm时电磁轴承的气隙磁场分布,与有限元仿真结果吻合较好,在磁极正对处的气隙磁通密度的误差基本在3%以内。并分析了转子周期振动导致的铁心涡流对气隙磁通及电磁力的影响,考虑涡流后,磁通及电磁力都有一定程度的衰减,并且转子振动频率越高,衰减越大。The accurate analysis and calculation of the electromagnetic field distribution characteristics are the basis for the performance optimization of active magnetic bearing(AMB).At present,the influence of eddy current and the nonlinearity of material permeability were rarely both considered in the magnetic field analysis of AMB.Therefore,the exponential equation was used to fit the magnetization curve of the silicon steel sheet to consider the nonlinearity of magnetic permeability of the material,the dynamic relative magnetic permeability was introduced to account for the influence of the eddy current.Then a nonlinear equivalent magnetic circuit model(NEMC)of radial AMB was established with the edge effect,stator and rotor core reluctance,nonlinear magnetic permeability,eddy current influence and real-time control current.Using this model,the magnetic field distribution in the air-gap was calculated when the rotor had a static displacement of 0.1 mm.The results are in good agreement with the finite element simulation(FEM)results,and the relative error in the opposite of magnetic poles is basically less than 3%.In addition,the influence of eddy current caused by rotor period vibration on magnetic flux and electromagnetic force was analyzed.After considering the eddy current,the magnetic flux and the electromagnetic force decrease,and the higher the vibration frequency,the greater the attenuation.

关 键 词：电磁轴承 等效磁路法 磁导率非线性 涡流 转子振动 

分 类 号：TM14[电气工程—电工理论与新技术]