磁悬浮主被动飞轮和被动磁轴承轴向力设计分析

针对现有商业卫星用磁悬浮飞轮存在发射成本高、体积大、重量大、功耗大、结构复杂和控制难度大等缺陷，提出了采用三自由度自稳定被动磁轴承代替原有磁轴承方案的磁悬浮主被动飞轮。分别介绍了飞轮和被动磁轴承结构、工作原理；通过等效磁荷法对被动磁轴承轴向力和轴向力刚度进行了数学建模；采用数值分析法，对被动磁轴承不同高宽比和气隙宽度的轴向力—位移曲线进行分析比较，并基于工程实际，选用高宽比为2和气隙宽度为1mm的被动磁轴承模型；采用有限元法，对飞轮在仅轴向偏移、径向偏移扰动、径向扭转扰动和同时发生径向偏移扰动与径向扭转扰动四种工作状态下轴向力自稳定性进行了分析。研究结果表明，轴向自稳定性满足性能需求，该自稳定被动磁轴承为商业航天卫星的磁悬浮飞轮的性能提升与成本降低提供了新的思路。

Design and Axial Force Analysis of Passive Magnetic Bearing for Maglev Active and Passive Flywheel

Aiming at the defects of the existing magnetic levitation flywheel for commercial satellites such as high launching cost, large volume, heavy weight, high power consumption, complex structure and difficult control, a magnetic levitation active-passive flywheel using three-degree-of-freedom self-stabilized passive magnetic bearings instead of the original magnetic bearing scheme is proposed. The flywheel and passive magnetic bearing structure and working principle are introduced respectively. The axial force and axial force stiffness of passive magnetic bearing are modeled mathematically by equivalent magnetic charge method. The axial force-displacement curves of passive magnetic bearing with different aspect ratio and air gap width are analyzed and compared by numerical analysis method, and the passive magnetic bearing model with aspect ratio of 2 and air gap width of 1mm is selected based on the engineering practice which the finite element method is used. Based on the engineering practice, a passive magnetic bearing model with an aspect ratio of 2 and an air gap width of 1 mm is selected. The finite element method is used to analyze the axial force self-stability of the flywheel under four operating conditions: axial offset only, radial offset disturbance, radial torsional disturbance and radial offset disturbance and radial torsional disturbance at the same time. The analysis results shown that the axial self-stability meets the performance requirements, and its self-stabilized passive magnetic bearing provides a new method for the performance improvement and cost reduction of the magnetic levitation flywheel for commercial space satellites.