Permanent-magnet bias outer rotor radial AC hybrid magnetic bearing

Abstract

The invention discloses a permanent-magnet bias outer rotor radial AC hybrid magnetic bearing. A stator core is arranged in the middle of the rotor core; the stator core is provided with 6 identical stator core magnetic poles, which are uniformly distributed in the circumferential direction and extend outwards in the radial direction; the three stator core magnetic poles, which are mutually isolated, are respectively provided with an slot; identical cuboid permanent magnets, which are used for providing static bias flux, are respectively embedded in the slots; the S pole of each permanent magnet faces the stator core, and the N pole faces the rotor core; the other 3 stator core magnetic poles, which are mutually isolated, are respectively wound by identical control coils; the top end of each stator core magnetic pole is provided with a groove; identical position sensors are arranged in the grooves; and control fluxes are formed among the stator core, radial air gap and rotor core. The invention reduces the magnetic resistance of the control magnetic circuit, lowers the coil copper loss and power amplification loss, has the advantages of small size and light weight and enhances the working efficiency of the magnetic bearing.

Description

technical field [0001] The invention relates to a non-mechanical contact magnetic bearing, in particular to a permanent magnet bias outer rotor radial AC hybrid magnetic bearing with small volume and low power consumption, which can be used as a five-degree-of-freedom magnetic levitation high-speed machine tool spindle, a bearingless motor and Non-contact suspension support for rotating parts in mechanical equipment such as flywheel energy storage systems and spacecraft such as satellites and space stations. Background technique [0002] Since the rapid development of magnetic bearing technology in the 1970s, due to the advantages of reducing control current and loss, hybrid magnetic bearings that provide static bias magnetic flux by permanent magnets and control magnetic flux by DC signals have been developed. It has become a research hotspot, but this type of magnetic bearing cannot meet the requirements of low production cost and low power consumption. On the one hand, d...

AI Technical Summary

Problems solved by technology

[0002] Since the rapid development of magnetic bearing technology in the 1970s, due to the advantages of reducing control current and loss, hybrid magnetic bearings that provide static bias magnetic flux by permanent magnets and control magnetic flux by DC signals have been developed. It has become a research hotspot, but this type of magnetic bearing cannot meet the requirements of low production cost and low power consumption

On the one hand, due to the use of DC control, the DC power amplifier is expensive and bulky, and a radial magnetic bearing usually requires four unipolar or two bipolar power amplifier circuits, which directly leads to the large size and high cost of the power amplifier. , which greatly limits the application fields of magnetic bearings, especially in aerospace and military applications

On the other hand, the permanent magnet bias external rotor radial AC hybrid magnetic bearings currently researched internationally are divided into heteropolar and homopolar structures: the magnetic force lines of the heteropolar structure magnetic bearings are perpendicular to the rotor axis, and the axial length can be made The magnetic bearings with the same polarity are shorter, but hysteresis loss will be generated; the magnetic force lines of the magnetic bearings with the same polarity structure are parallel to the rotor axis, and the generated hysteresis loss is greatly reduced, but the occupied axial space is relatively large, which cannot meet the needs of spacecraft such as satellites and space stations. The required small size and light weight are not conducive to the increase of the critical speed of the rotor

In addition, for some heteropolar magnetic bearings, the permanent magnet is directly placed in the control magnetic circuit, and the control magnetic flux must pass through the permanent magnet. Since the permanent magnet has a large reluctance, it is necessary to increase the control coil to generate the corresponding control magnetic flux. The excitation current increases the power consumption of the magnetic bearing, causing serious heating of the coil; some magnetic bearings with the same polarity structure directly connect the permanent magnet to the stator laminated core, so that the p

Images