A double-coil axial spherical pure electromagnetic bearing

Abstract

A double-coil axial spherical pure electromagnetic bearing is mainly composed of a stator system and a rotating shaft. The stator system mainly includes: an upper stator core, a lower stator core, and an excitation coil. The invention adopts upper and lower spherical magnetic bearings, so that the electromagnetic force on the rotating shaft always passes through the center of the sphere. When the sphere center of the rotating shaft coincides with the center of mass, the torque generated by the electromagnetic force relative to the rotating shaft is zero, thereby eliminating the impact of radial torsion on the axial direction. translational disturbance. In addition, the upper and lower stator cores adopt the pole shoe structure, which makes the magnetic field distribution on the circumference more uniform. The excitation coils of the upper and lower stator cores adopt a double coil structure, and the number of turns of the two coils is different, and the current of the coil with fewer turns can be controlled , the current of the coil with a large number of turns remains unchanged, and the current response rate is improved compared with the single-coil structure. The controllable current adopts a differential form, which further improves the control accuracy of the magnetic bearing.

Description

Technical field [0001] The invention relates to a non-contact magnetic suspension bearing, in particular a spherical pure electromagnetic magnetic bearing, which can be used as a non-contact support of rotating parts in a small spacecraft, and is particularly suitable for non-contact support of a magnetic suspension flywheel. [0002] technical background [0003] With the development of aerospace technology, spacecraft such as satellites and space stations have higher and higher requirements for attitude control accuracy, and traditional mechanical momentum wheels can no longer meet the requirements. The magnetic levitation flywheel is supported by magnetic bearings, which eliminates the wear caused by mechanical bearings and improves the accuracy and stability of the control torque. [0004] In the existing magnetic levitation flywheel structure, generally a single degree of freedom axial magnetic bearing or a three degree of freedom axial magnetic bearing is used. No matter which...

AI Technical Summary

Problems solved by technology

However, when the rotor deflects, the magnetic air gap between the stator and rotor of the magnetic bearing is uneven, resulting in uneven electromagnetic force in the magnetic pole surface, thereby generating a torsional moment relative to the center of mass of the rotor, that is, the translation control produces an interference torque to the torsion control

The magnetic pole surfaces of the permanent magnet bias axial magnetic bearings described in Chinese patent application numbers 200510011272.2 and 200710098749.4 are all cylindrical. When the magnetic bearing deflects, there is an uneven air gap between the stator and the rotor, resulting in a large torsional negative torque. , increasing the load on the torsional bearing of the flywheel

Thereby reducing the control precision and control torque precision of the flywheel rotor

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