异极型径向磁轴承的非线性解析模型

针对异极型径向磁轴承（HeRMB）气隙磁密分布和电磁力的计算，建立等效磁路法和气隙磁导函数相结合的非线性解析模型.通过计算磁轴承磁路各部分的集中磁导，建立计及饱和效应的等效磁路.采用考虑齿槽效应和转子偏心的气隙磁导函数计算气隙磁密分布，得到作用在转子上的电磁力，利用有限元验证了该解析模型的计算精度. 利用建立的解析模型，研究偏置电流的影响和耦合效应.结果表明，偏置电流的变化对电磁力特性有很明显的影响；当转子无偏心时，X、Y 2个方向相互解耦，当转子有偏心时，2个方向之间会有耦合.

Nonlinear analytical model of heteropolar radial magnetic bearing

A nonlinear analytical model combining the equivalent magnetic circuit method and the air gap permeance function was developed in order to predict the air gap flux density distribution and electromagnetic force of a heteropolar radial magnetic bearing (HeRMB). The equivalent magnetic circuit considering the saturation effect was established by calculating the lumped permeance of each segment of the HeRMB. The air gap permeance function considering the slotting effect and rotor eccentricity was used to determine the air gap flux density distribution. Then the electromagnetic force was predicted. The accuracy of the developed analytical model was verified by the finite element method. The influence of bias current and the coupling effect between two directions were analyzed by the proposed model. Results show that the bias current significantly affects the electromagnetic force. The X and Y directions are decoupled without rotor eccentricity, and they are coupled when the rotor deviates from the center position.