径向磁力轴承磁极布置对磁场和磁力的影响

Efeects of Magnetic Pole Arrangement on Magnetic Field and Force in Radial Magnetic Bearings

使用有限元方法对8极径向磁力轴承的磁场进行了建模,计算了气隙磁通密度和磁力,对比分析了在转子不同的偏心情况下两种磁极布置形式(NSNS交替磁极布置和NNSS成对磁极布置)的磁力轴承的气隙磁通密度和磁力,并通过实验测试验证了有限元磁场建模和计算的准确性。结果表明,在同样大小的电流激励下,NSNS布置比NNSS布置的气隙磁通密度大,偏心时产生的磁力也较大,适合小尺寸的磁力轴承,而NSNS布置磁极之间的磁耦合比NNSS布置形式强,增加了控制系统的复杂性。研究结论对磁力轴承的结构设计和控制系统设计具有一定的指导意义。

Magnetic field of an 8--pole radial magnetic bearing was modeled through finite element method （FEM） and the magnetic flux lines were presented. The air gap magnetic flux density and magnetic forces with different rotor eccentricity were calculated and compared under NSNS alternating arrangement and NNSS paired arrangement. The magnetic hearing＇s magnetic field model and calculation were verified with measurements. Results show that air gap magnetic flux density and magnetic force of NSNS arrangement are greater than the ones of NNSS arrangement with same input currents. So the NSNS arrangement always gives smaller magnetic bearings. However, it is with stronger magnetic field coupling between adjacent pole pairs of NSNS arrangement than that of NNSS arrangement, NSNS arrangement will result in more complicated coil current control. It is significative to use the conclusion of this paper in magnetic bearing design.