一种轴向电磁轴承的结构优化与有限元分析

给定转子推力盘直径和转子芯轴直径,设计一种传统结构的轴向电磁轴承。保持定子内孔与转轴之间的径向漏磁气隙不变,采用有限元软件仿真定子线槽结构参数对轴向电磁轴承的磁场分布及承载力的影响,并从磁路理论角度对结果进行误差分析。在承载力最大的线槽结构参数下,只改变芯轴直径,仿真分析径向漏磁气隙对轴向电磁轴承的磁场分布及承载力的影响。研究结果表明:随着定子线槽轴向长度与径向长度比(长宽比)的增加,承载力先增大后减小;当长宽比为5~10时,漏磁不是最小,但承载力较大且基本不受长宽比变化的影响,最大电磁力为理论电磁力的88.7%;随着径向漏磁气隙与轴向气隙比(气隙比)的增加,承载力增加,但增量越来越小,当气隙比为13.3时,仿真电磁力达到理论电磁力的97.0%,当气隙比大于13.3后,承载力随气隙比的增加非常有限。

Structural optimization and finite element analysis of a type of axial AMBs

One typical structure of axial active magnetic bearings(AMBs)was designed with the given diameters of the shaft and rotor thrust. The influence of the slot structure dimensions on the magnetic field distribution and the bearing force of axial AMB was simulated by using an electromagnetic finite element software when the radial airgap between the stator inner hole and the shaft was unchanged. And the error analysis was given by constructing a magnetic circuit model of the axial AMB. Given the chosen optimized slot dimensions, the influences of the radial airgap of the stator on the magnetic field distribution and the bearing force were analyzed with different rotor shaft diameters. The results showed that the bearing force increased first and then decreased with the increase of the ratio of the axial length to the radial length of the slot. The radial magnetic flux leakage was not the smallest when the ratio was between 5 and 10 but the bearing force was large and stable, and the biggest force was about 88.7% of the theory. With the increase of the ratio of the radial airgap to the axial suspended airgap(airgap ratio), the bearing force increased, but the increment was getting smaller. When the airgap ratio was 13.3, the simulated bearing force was 97.0% of the theory. When the airgap ratio was more than 13.3, the increment of the bearing force was very limited, so the impact was not significant.