关键词: 永磁轴承, 不平衡磁拉力, 径向刚度, 转子涡动, 临界转速

Abstract: To ensure that the rotor of an asynchronous motor has only micro-friction characteristics in the state of permanent magnetic levitation, it is necessary to ensure that the permanent magnet bearings have a stable high potential energy state. A mechanical spherical roller bearing was used to limit the axial displacement of its rotor. The unbalanced magnetic pul on the rotor was calculated based on the air-gap permeability and equivalent magnetic charge method, and the relationship between the stator-rotor air-gap of the permanent magnet bearing, the rotor offset, the division of the number of rings of the permanent magnet bearing, the position of the air-gap and the radial stiffness were given, and the above parameters were optimized in order to get the optimal radial stiffness of the permanent magnet bearing, so that the permanent magnet bearing could effectively balance the unbalanced magnetic pul on the motor rotor. The permanent magnet bearing levitation structure of asynchronous motor was verified to realize micro-friction levitation by analyzing rotor vortex trajectory and critical speed.

Key words: permanent magnet bearings, unbalanced magnetic pull ( UMP ), radial stiffness, rotor vortex, critical speed