CN114198403B - A five-degree-of-freedom hybrid magnetic bearing - Google Patents

Abstract

The invention discloses a five-degree-of-freedom hybrid magnetic bearing, which includes a pair of two-half-degree-of-freedom hybrid magnetic bearings, which are arranged axisymmetrically with the gap set in the middle, and the stator of each two-half-degree-of-freedom hybrid magnetic bearing includes a radial stator Iron core, permanent magnet, axial stator core. The radial stator core distributes N control poles and N permanent magnet poles embedded with permanent magnets along the circumference, and radial control windings are wound on the control poles; the inner surface of the axial stator core and the opposite part of the rotor core are distributed 2M The arc-shaped control core of the block-wound axial control winding; the radial stator core and the axial stator core are connected by a magnetic isolation material; the rotor core is opposite to the radial stator core, and forms a radial air gap with 2N magnetic poles, and 2M arc-shaped control cores form an axial air gap. The invention integrates the radial air gap of the rotor and the adjustable function of the axial single-side air gap into one body, has a large radial suspension force, and is used in pairs to support the stable suspension of the five-degree-of-freedom rotor of the motor.

Description

A five-degree-of-freedom hybrid magnetic bearing

technical field

The invention relates to the technical field of bearing manufacturing, in particular to a five-degree-of-freedom hybrid magnetic bearing with adjustable rotor radial air gap and axial single-side air gap.

Background technique

The magnetic levitation motor is a special motor that uses the electromagnetic force generated by the magnetic bearing to support the stable suspension of the motor rotor with five degrees of freedom. Because there is no mechanical contact between the stator and the rotor, the magnetic levitation motor can reach a very high operating speed, and has the advantages of no mechanical wear, low energy consumption, long life, no lubrication, no pollution, etc., especially suitable for high-speed or ultra-high speed applications. High speed direct drive field.

In order to achieve stable suspension of the motor rotor, multiple magnetic bearings must be used to form a five-degree-of-freedom magnetic levitation system to jointly support the high-speed motor rotor. At present, the five-degree-of-freedom magnetic levitation motor solution mainly includes two types, one is to use single-degree-of-freedom magnetic bearings, two-degree-of-freedom magnetic bearings and three-degree-of-freedom magnetic bearings to freely combine to support the high-speed motor rotor (CN201210472348.1 and CN201720195930.6 ); the other is to use an integrated magnetic bearing that can realize stable suspension of the motor rotor with five degrees of freedom in one unit to support the motor rotor (CN201610399378.2, CN202011015788.5). The first type of magnetic levitation motor has a large volume, long axial length, low critical speed, low levitation force density, and difficult coordinated control of multiple units; the second type of magnetic levitation motor has too long axial magnetic circuit, serious magnetic flux leakage, and axial The control winding current and power consumption are large. Therefore, how to design a magnetic bearing with a short magnetic circuit, a reasonable structure, and a high levitation force density is the basis for its industrial application. Half-degree-of-freedom hybrid magnetic bearings can be used in pairs to jointly support the motor rotor to form a five-degree-of-freedom magnetic levitation motor.

Contents of the invention

Purpose of the invention: In view of the problems existing in the prior art, the present invention provides a five-degree-of-freedom hybrid magnetic bearing, which can be used in pairs to support the stable suspension of the five-degree-of-freedom motor rotor, effectively reducing the five-degree-of-freedom magnetic levitation motor. The length of the magnetic circuit is small, the power consumption is low, the structure is compact, the critical speed is high, and the radial suspension force density is large.

Technical solution: The present invention provides a five-degree-of-freedom hybrid magnetic bearing, including a pair of two half-degree-of-freedom hybrid magnetic bearings, a pair of two half-degree-of-freedom hybrid magnetic bearings with a gap in the middle, and a pair of two half-degree-of-freedom hybrid magnetic bearings. The half-degree-of-freedom hybrid magnetic bearings all take the gap in the middle as the axis, and the left and right axes are symmetrically arranged. Each of the two half-degree-of-freedom hybrid magnetic bearings includes a stator and a rotor. The stator includes a radial stator core, a permanent magnet, an axial Stator core; the radial stator core is evenly distributed with 2N magnetic poles along its inner circumference, wherein, N magnetic poles control magnetic poles, and the remaining N magnetic poles are respectively embedded with permanent magnet magnetic poles of the permanent magnets, and N said control poles The magnetic poles are spaced apart from N permanent magnetic poles; radial control windings are wound on the N control magnetic poles; 2M arc-shaped control cores are evenly distributed radially along the circumference of the inner surface of the axial stator core; the arc-shaped control Axial control windings are wound on the core; the radial stator core is connected to the axial stator core through a magnetic isolation material; the rotor includes a rotor core and a rotating shaft, and the rotor core is opposite to the radial stator core. And form a radial air gap with 2N magnetic poles, and form an axial air gap with the arc-shaped control core.

Further, the circular arc length of the control pole is twice that of the permanent magnet pole, the air gap bias flux density under the control pole is B _s , and the bias flux density under the permanent magnet pole is 2 B _s .

Further, N=4, the radial control windings wound on the four control poles are used for two-degree-of-freedom control of radial levitation, and the opposite two-pole windings are connected in reverse series or in parallel.

Further, taking N=3, the radial control windings wound on the three control poles are used for radial two-degree-of-freedom levitation control, and are connected as star windings.

Further, take M=1 or 2 or 3; the axial control winding wound on the arc-shaped control core of the 2M block is used for axial half-degree-of-freedom levitation control, and the opposite two windings are connected in reverse series or reverse After parallel connection, they are connected in series or in parallel to form a winding.

Further, the N permanent magnets have a block structure, and their magnetization direction is same polarity magnetization along the radial direction.

Further, the radial stator core, the axial stator core, and the rotor core are all made of magnetically permeable materials, and the permanent magnets are all made of rare earth permanent magnet materials.

Beneficial effect:

The two-half-degree-of-freedom hybrid magnetic bearing mentioned in the present invention has the characteristics of adjustable radial two-degree-of-freedom air gap and axial single-side air gap, which realizes 2.5-degree-of-freedom suspension control and can be used in pairs to support high-speed motor rotors. A five-degree-of-freedom magnetic levitation motor is formed. Compared with the existing five-degree-of-freedom magnetic levitation motor, it has the advantages of small size, short axial length, high critical speed, short magnetic circuit, low power consumption, small magnetic flux leakage, and high levitation force density. features. The circular arc length of the radial portion of the control magnetic pole of the present invention is twice that of the permanent magnetic pole, which increases the levitation force.

Description of drawings

Fig. 1 is a structural diagram of a hybrid magnetic bearing with two half-degrees of freedom in the present invention;

Fig. 2 is a right-view levitation magnetic flux diagram of the five-degree-of-freedom hybrid magnetic bearing of the present invention;

Fig. 3 is a radial levitation magnetic flux diagram of the hybrid magnetic bearing with two half degrees of freedom in the present invention.

Among them, 1-radial stator core, 2-permanent magnet, 3-axial stator core, 4-control magnetic pole, 5-permanent magnetic pole, 6-radial control winding, 7-control disc, 8-axial control Winding, 9-rotor core, 10-rotating shaft, 11-radial air gap, 12-axial air gap, 13-bias magnetic flux, 14-radial suspension control magnetic flux, 15-axial suspension control magnetic flux, 16-Magnetic isolation material.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in Figures 1-3, the present invention discloses a five-degree-of-freedom hybrid magnetic bearing, which includes a pair of two-half-degree-of-freedom hybrid magnetic bearings, and a gap is set between a pair of two-half-degree-of-freedom hybrid magnetic bearings. A pair of two half-degree-of-freedom hybrid magnetic bearings take the gap in the middle as the axis, and the left and right axes are symmetrically arranged. Each two-half-degree-of-freedom hybrid magnetic bearing includes a stator and a rotor. The stator includes a radial stator core 1 and a block permanent magnet. 2. Axial stator core 3. Radial stator core 1 distributes 2N magnetic poles uniformly along its inner circumference, among which N are control magnetic poles 4, N are permanent magnetic poles 5 embedded with block permanent magnets 2, N control magnetic poles 4 and N permanent magnetic poles 5 are set at intervals, N is usually 3 or 4, and N=4 in this embodiment, see Figure 1 and Figure 3, radial control windings 6 are wound on four control poles 4 . On the inner surface of the axial stator core 3, 2M arc-shaped control cores 7 are evenly distributed radially along the circumference. In this embodiment, M=2, and 4 arc-shaped control cores 7 are evenly distributed along the circumference. Axial control windings 8 are wound on four arc-shaped control cores 7, see Fig. 1 .

The radial stator core 1 and the axial stator core 3 are connected through a magnetic isolation material 16; the rotor includes a rotor core 9 and a rotating shaft 10, and the rotating shaft 10 runs through the rotor core 9, and the rotor core 9 is opposite to the radial stator core 1, and is opposite to the 8 A magnetic pole forms a radial air gap 11, and forms an axial air gap 12 with the arc-shaped control core 7, see accompanying drawing 2.

The arc length of the control pole 4 is twice that of the permanent magnet pole 5, and the air gap bias flux density under the control pole 4 is B _s , so the bias flux density under the permanent magnet pole 5 is 2 B _s .

The magnetization directions of the four block permanent magnets 2 are radial magnetization with the same polarity. In this embodiment, the four block permanent magnets 2 are all magnetized in a direction of 45° to provide radial bias magnetic flux.

The radial control windings 6 wound on the four control poles 4 are used for radial two-degree-of-freedom levitation control, and the opposite radial two-pole windings are connected in reverse series or in parallel.

The axial control windings 8 wound on the four arc-shaped control cores 7 are used for axial half-degree-of-freedom levitation control, and the opposite two-pole windings are connected in reverse series or parallel, after the opposite radial two-pole windings are connected in reverse series or parallel. Connected in series or in parallel as a winding.

The radial stator core 1 , the axial stator core 3 and the rotor core 9 are all made of materials with magnetic permeability. The block permanent magnets 2 are all made of rare earth permanent magnet materials.

When a five-degree-of-freedom hybrid magnetic bearing is required to realize the active control of the axial displacement of 10 degrees of freedom of the rotating shaft, for the above-mentioned two-half-degree-of-freedom hybrid magnetic bearing, only two identical two-half-degree-of-freedom hybrid magnetic bearings need to be Used in pairs with magnetic bearings.

One of the two half-degree-of-freedom block permanent magnets 2 of the hybrid magnetic bearing provides bias magnetic flux 13 to the radial stator core 1, referring to the accompanying drawing 3, the magnetic circuit of the bias magnetic flux 13 is: the magnetic flux flows from the permanent magnet 2 Starting from the N pole of the permanent magnet pole 5, the radial stator core 1 yoke, the control pole 4, the radial air gap 11, the rotor core 9, the radial air gap 11, and returning to the S pole of the permanent magnet 2. The block permanent magnet 2 of another two-half-degree-of-freedom hybrid magnetic bearing provides the bias magnetic flux 13 to the radial stator core 1, which is the same as that in FIG. 3 , and will not be repeated here.

The radial levitation control magnetic flux 14 generated by the radial control winding 6 of one of the two half-degree-of-freedom hybrid magnetic bearings is energized, and its magnetic circuit is: control magnetic pole 4, radial stator core 1 yoke, radial air gap 11, The rotor core 9 forms a closed path. The magnetic circuit of the radial levitation control magnetic flux 14 generated by the radial control winding 6 of the other two half-degree-of-freedom hybrid magnetic bearing is the same as the above, and will not be repeated here.

The axial suspension control magnetic flux 15 generated by the energization of the axial control winding 8 of one of the two half-degree-of-freedom hybrid magnetic bearings has a magnetic circuit between the axial air gap 12 and the arc control core 7, and the side of the rotor core 9 form a closed path. The magnetic circuit of the axial levitation control magnetic flux 15 generated by the energization of the axial control winding 8 of the other two half-degree-of-freedom hybrid magnetic bearings is the same as the above, and will not be repeated here.

Suspension principle: The static bias magnetic flux 13 interacts with the radial suspension control magnetic flux 14 in the radial direction, so that the air gap magnetic field on the same side as the radial eccentric direction of the rotor is superimposed and weakened, while the air gap magnetic field in the opposite direction is superimposed and strengthened. A force opposite to the direction of rotor deflection is generated on the rotor, pulling the rotor back to the radial equilibrium position. The axial direction is acted by the axial levitation control magnetic flux 15. When the rotor moves in the reverse direction under the disturbance force, the axial air gap 12 becomes larger. At this time, the axial control winding 8 is fed with a control current to generate a control magnetic flux, and the rotor Pull back to original position.

The above-mentioned embodiments are only for illustrating the technical concept and characteristics of the present invention, and its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and not to limit the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit of the present invention shall fall within the protection scope of the present invention.

Claims (7)

1. The five-degree-of-freedom hybrid magnetic bearing is characterized by comprising a pair of two half-degree-of-freedom hybrid magnetic bearings, wherein a gap is arranged between the pair of two half-degree-of-freedom hybrid magnetic bearings, the pair of two half-degree-of-freedom hybrid magnetic bearings are arranged in a left-right axial symmetry mode by taking the gap between the two half-degree-of-freedom hybrid magnetic bearings as an axis, each half-degree-of-freedom hybrid magnetic bearing comprises a stator and a rotor, and the stator comprises a radial stator core (1), a permanent magnet (2) and an axial stator core (3); the radial stator core (1) is uniformly distributed with 2N magnetic poles along the inner circumference, wherein the N magnetic poles are control magnetic poles (4), the rest N magnetic poles are permanent magnetic poles (5) respectively embedded into the permanent magnet (2), and the N control magnetic poles (4) and the N permanent magnetic poles (5) are arranged at intervals; radial control windings (6) are wound on the N control magnetic poles (4); 2M arc-shaped control iron cores (7) are uniformly distributed on the inner side surface of the axial stator iron core (3) along the circumferential radial direction; axial control windings (8) are wound on the arc-shaped control iron cores (7); the radial stator core (1) is connected with the axial stator core (3) through a magnetism isolating material (16); the rotor comprises a rotor iron core (9) and a rotating shaft (10), wherein the rotor iron core (9) is opposite to the radial stator iron core (1), a radial air gap (11) is formed between the rotor iron core and 2N magnetic poles, and an axial air gap (12) is formed between the rotor iron core and the arc-shaped control iron core (7).

2. The five degree-of-freedom hybrid magnetic bearing according to claim 1, wherein the control pole (4) has twice the circumferential arc length than the permanent magnet pole (5), and the air gap bias flux density under the control pole (4) isB _s The bias flux density under the permanent magnetic pole (5) is 2B _s 。

3. The five-degree-of-freedom hybrid magnetic bearing according to claim 1, wherein N =4,4 radial control windings (6) wound on the control magnetic poles (4) are taken for radial suspension two-degree-of-freedom control, with opposite two-pole windings being connected in series or in parallel in an inverted manner.

4. The five degree-of-freedom hybrid magnetic bearing according to claim 1, characterized in that N =3,3 radial control windings (6) wound on the control poles (4) are taken for radial two degree-of-freedom levitation control and connected as a star winding.

5. The five degree-of-freedom hybrid magnetic bearing of claim 1, wherein M =1 or 2 or 3; and 2M axial control windings (8) wound on the arc-shaped control iron core (7) are used for axial half-freedom suspension control, and are connected in series or in parallel after two opposite windings are connected in series or in parallel in the opposite direction to form one winding.

6. The five-degree-of-freedom hybrid magnetic bearing according to claim 1, wherein the N permanent magnets (2) are of a block-shaped structure and the magnetization direction thereof is in radial homopolar magnetization.

7. The five-degree-of-freedom hybrid magnetic bearing according to claim 1, wherein the radial stator core (1), the axial stator core (3) and the rotor core (9) are made of materials with magnetic permeability, and the permanent magnets (2) are made of rare earth permanent magnet materials.

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