Design of a Halbach Array Permanent Magnet Damping System for High Speed Compressor With Large Thrust Load

Many magnetically suspended compressors operate above the first bending critical speed, which gives rise to high vibration problems and introduces complications in designing controllers for radial magnetic bearings; besides, a significant axial load always exists in high-speed compressors, which requires a high load capacity in the thrust bearings and introduces complications in designing axial magnetic bearings. In this paper, a passive damper with the Halbach magnet array is proposed. The Halbach damper can provide radial damping force without control system, and can also provide a large axial force to reduce the burden of axial bearing. Firstly, the effect of the location of dampers on response amplitude is studied and the optimum convenient location is obtained. Then, an analytical model of the Halbach damper is established and the effects of some important structure parameters on the system performance are discussed. Finally, a design example for a high-speed compressor with flexible rotor and a large thrust load is given. The analytical and design results, which are verified by the finite element result, show that the Halbach damper can provide the required axial force, and it is effective in controlling the first bending vibration of the flexible rotor.