基于气隙磁通边缘效应的轴向混合磁轴承承载力解析计算

Calculation of electromagnetic force of axial hybrid magnetic bearing based on fringe effect of magnetic flux

为了研究单自由度轴向混合磁轴承轴向主动悬浮和径向被动悬浮的特性,对提出了基于气隙磁通边缘效应的磁轴承承载力解析计算方法。首先建立了轴向混合磁轴承基于气隙磁通边缘效应的磁路模型,利用分割磁场法推导各部分磁通管的磁导,根据其串并联关系,得到磁路的总磁导,由虚位移法推导了轴向力和径向力的解析表达,得到了轴向力与径向力随轴向气隙和径向位移的变化关系,并分析了轴向力与径向力的耦合特性,为磁悬浮系统轴向和径向的解耦控制提供了理论依据。利用有限元方法对轴向力和径向力进行仿真计算,仿真结果与模型计算结果基本吻合。

Axial and radial magnetic force is produced by axial hybrid magnetic bearing（ HMB）,which supports the rotor suspended actively in axial direction and passively in radial direction. In order to obtain the analytical expression of axial and radial magnetic force,the method based on fringe effect of gap magnetic flux was presented. Magnetic circuit model of axial HMB was created by considering fringe effect of gap magnetic flux. Based on magnetic field division,magnetic permeance of each magnetic flux tube was calculated. The permeance of whole magnetic circuit was obtained by considering the series and parallel connection in magnetic circuit model. Mathematical analytical model of axial and radial magnetic force was deduced by using virtual displacement method. The axial and radial magnetic force dependence on axial gap and radial displacement was analyzed. Coupling between axial and radial magnetic force was studied,which provided theoretical results for designing axial and radial decoupling control system. The model of axial HMB was simulated by finite-element method and the simulation results were basically in agreement with the calculated results.