一种新型结构的永磁偏置径向磁轴承

A New Permanent Magnet Biased Radial Magnetic Bearing

提出了一种新型永磁偏置径向磁轴承结构,通过第二气隙形成电磁磁路,与现有Heteropolar结构的磁轴承相比,定子磁极个数由8个减少为4个,可使转子高速旋转时的涡流损耗降低3倍,利用等效磁路法以及有限元法对该永磁偏置径向磁轴承进行分析,得出了最大承载力、电流刚度以及位移刚度的数学表达式,给出了主要参数的设计与计算方法。理论研究和仿真分析表明,所提出的新型径向磁轴承结构通过合理设计第二气隙的大小,可使永磁体产生的位移刚度减小,特别适用于磁悬浮反作用飞轮,以减小对飞轮的扰动,同时减小了飞轮的最大起动力矩,大大提高了飞轮的控制精度,在无轴承电动机、其他飞轮系统等场合具有广阔的应用前景。

A new permanent magnet biased radial magnetic bearing is proposed. The control flux passes through the second air gap. The magnetic bearing has four stator pole pieces compared to the heteropolar bearing which has eight stator pole pieces, so the new magnetic bearing can reduce the eddy loss three times. The radial magnetic bearing is analyzed and calculated by using equivalent magnetic circuit and 3D finite element method （FEM）. The math expression and some equations are given for maximum carrying capacity, current stiffness and displacement stiffness. Some parameters design and calculation method are presented. The theory analysis and simulation show that this radial magnetic bearing is of little displacement stiffness produced by permanent magnet by means of designing the second air gap. It is useful to reduce perturbance, the stiction torque and improve control accuracy of reaction flywheels. It has wide application in bearingless motor, other flywheel systems, and so on.