短转子永磁偏置轴向径向磁轴承耦合特性分析

Analysis Forcoupling Performance of a Short Rotor Permanent Magnet Biased Axial Radial Magnetic Bearing

永磁偏置轴向径向磁轴承能够实现转子的三自由度悬浮,结构紧凑、功耗低,但3个自由度之间易耦合。对一种短转子永磁偏置轴向径向磁轴承进行了研究,它的轴向定子位于径向定子之上,为短转子结构。根据二维仿真结果进行等效磁路分析,对径向控制磁路进行解耦分析,设计径向力为400 N的磁轴承进行三维有限元仿真分。并通过三维网格图对轴向径向悬浮力进行耦合分析。研究结果表明,在平衡位置附近,轴向径向间彼此解耦,悬浮性能优良。

The permanent magnet biased axial-radial magnetic bearing（PARMB） can achieve the rotor levitation with three degrees of freedom which has many advantages as the compact structure and low power loss. However, there always exists couplings among three degrees of freedom. A PARMB with the short rotor was studied. Its axial stator was located outside of its radial stator, thus its axial length of rotor could be quite short. Its radial-control flux path was analysed in theoretically, The equivalent magnetic circuit was established based on the two-dimensional simulation results. A magnetic bearing with 400 N radial force was designed and investigated with the three-dimensional simulation. The coupling analysis between the axial and radial forces was also completed via the three-dimensional finite-element meshes. Research results show that the flux control is decoupled in the two radial directions, the axial and radial forces control are decoupled near the balancing position, thus the control of the proposed magnetic bearing is quite flexible.