Novel structure five-degree-of-freedom integrated hybrid magnetic bearing

Abstract

The application discloses a new structure five-freedom-degree integrated hybrid magnetic bearing, and solves the technical problems of mutual restriction of axial and radial parameters and common bias magnetic flux in a conventional five-freedom-degree integrated hybrid magnetic bearing. The hybrid magnetic bearing divides a rotor core into two parts of radial and axial directions by a magnetic isolation ring, two radial stator cores, six permanent magnet blocks and the radial part of the rotor core form a radial magnetic circuit, and an axial stator core, two annular permanent magnets, two L-shaped cores and the axial part of the rotor core form an axial magnetic circuit. The new structure five-freedom-degree integrated hybrid magnetic bearing has the advantages of no coupling between the axial and radial magnetic circuits, no correlation between the radial and axial parameters, short axial magnetic circuit, small rotor inertia, light weight, fast response speed, simple control, easy realization, small magnetic flux leakage and low power consumption.

Description

Technical Field

[0001] This invention relates to the field of magnetic levitation bearing technology, and specifically to a novel five-degree-of-freedom integrated hybrid magnetic bearing. Background Technology

[0002] To achieve stable rotor levitation in a magnetic bearing motor, constraints must be applied in all five degrees of freedom, which requires the use of magnetic bearings. Magnetic bearings are non-contact bearings that utilize magnetic force to levitate the rotor in space without contact. They are a new type of high-performance mechatronic bearing integrating mechanics, rotor dynamics, control theory, and electromagnetics. Compared to ordinary bearings, magnetic bearings possess a series of superior qualities, including frictionless operation, wear-free operation, no need for lubrication or sealing, high speed, high precision, long lifespan, and adjustable bearing stiffness and damping. Therefore, they have received widespread attention in the engineering field and are one of the cutting-edge research topics in mechanical and electrical control technologies.

[0003] Hybrid magnetic bearings utilize permanent magnets to provide bias flux and control windings to generate control flux. The two fluxes superimpose, resulting in an enhanced magnetic field in the air gap on one side of the rotor and a weakened magnetic field in the opposite direction, generating a radial force in the direction of the enhanced magnetic field, thus achieving stable rotor levitation. Currently, hybrid magnetic bearings are widely used in various high-performance transmission systems. However, to achieve stable rotor levitation, two radial hybrid magnetic bearings and one axial hybrid magnetic bearing are needed to support the rotor's five degrees of freedom, leading to excessively long axial length and low critical speed. Therefore, to address these issues, domestic and international researchers have developed various integrated hybrid magnetic bearings that achieve stable five-degree-of-freedom rotor levitation within a single unit. These integrate axial and radial levitation functions, using a common permanent magnet to generate radial and axial bias fluxes. These bias fluxes pass through both axial and radial air gaps, resulting in proportional constraints between multiple radial and axial parameters. Furthermore, achieving rotor levitation performance requires complex decoupling control strategies, leading to high control system costs and computational demands. Summary of the Invention

[0004] This invention proposes a novel five-degree-of-freedom integrated hybrid magnetic bearing with no correlation between axial and radial magnetic flux. Its radial and axial parameters are designed independently, resulting in a short axial magnetic circuit, simpler control, easier implementation, and low power consumption.

[0005] This invention is achieved through the following technical solution:

[0006] A novel five-degree-of-freedom integrated hybrid magnetic bearing includes a stator and a rotor. The stator comprises an axial stator core, two radial stator cores, left and right L-cores, and left and right annular permanent magnets. The two radial stator cores are symmetrically mounted inside the axial stator core. The left and right L-cores and the left and right annular permanent magnets are symmetrically mounted outside the axial stator core. Symmetrical axial control coils are wound inside the axial stator core. Three control magnetic poles and three bias magnetic poles are evenly distributed around the inner circumference of the radial stator cores, and radial control coils are wound on the control magnetic poles. The biased magnetic poles contain permanent magnets; the rotor is located inside the stator, consisting of a rotating shaft, a rotor axial core, a magnetic isolation ring, and a pair of rotor radial cores from the inside out; the magnetic isolation ring is embedded between the rotor axial core and the pair of rotor radial cores, the axial width of the rotor axial core is smaller than the axial width of the magnetic isolation ring, the pair of rotor radial cores are opposite to and equal in width to the two radial stator cores, and there is a radial air gap between them, the inner side of the axial stator core and the left and right L cores extend into the rotor, and there are upper axial air gaps and lower axial air gaps between them and the rotor axial core respectively.

[0007] Furthermore, the polarities of the connecting surfaces of the left and right annular permanent magnets and the axial stator core are the same.

[0008] Furthermore, the permanent magnet generates a radial bias magnetic flux, which forms a closed path between the control magnetic pole, the bias magnetic pole, the radial air gap, and the rotor radial core; the left and right annular permanent magnets generate an axial bias magnetic flux, which forms a closed path between the axial stator core, the left and right L cores, the rotor axial core, the upper axial air gap, and the lower axial air gap.

[0009] Furthermore, the axial control coils are connected in series in the same direction to form an axial suspension winding, and are driven by a DC switching power amplifier to generate axial control flux, forming a closed path between the axial stator core, the upper axial air gap, and the rotor axial core; the radial control coils are connected in a star configuration and are driven by two three-phase inverters to generate radial control flux, forming a closed path between the three control poles, the radial air gap, and the rotor radial core.

[0010] Furthermore, the left and right annular permanent magnets and the permanent magnet material are rare earth permanent magnet materials, the magnetic shielding ring material is aluminum, the two radial stator cores and the rotor radial core are made of silicon steel sheets; the rotor axial core, the axial stator core, and the left and right L cores are integrally machined from magnetically conductive materials, and the shaft is made of non-magnetically conductive materials.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] First, the axial and radial parameters are designed independently and are unrelated to each other. Therefore, it is only necessary to design the radial and axial parameters by giving the order of the maximum levitation forces in the radial and axial directions, and the design of the two parts is unrelated.

[0013] Second, the axial magnetic circuit is independent of the radial magnetic circuit, the levitation force is generated without coupling, there is no constraint relationship between the axial and radial magnetic pole areas and the maximum axial and radial levitation forces, the control is simple and easy to implement;

[0014] Third, the rotor axial core can be made very short, resulting in a short axial control magnetic circuit, low leakage flux, and low power consumption. Attached Figure Description

[0015] Figure 1 Axial cross-sectional view of a novel five-degree-of-freedom integrated hybrid magnetic bearing;

[0016] Figure 2 Axial magnetic circuit diagram of a novel five-degree-of-freedom integrated hybrid magnetic bearing;

[0017] Figure 3 Radial section diagram of a novel five-degree-of-freedom integrated hybrid magnetic bearing;

[0018] Figure 4 Radial magnetic circuit diagram of a novel five-degree-of-freedom integrated hybrid magnetic bearing. Detailed Implementation

[0019] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] This invention is achieved through the following technical solution:

[0022] like Figure 1The diagram shows a novel five-degree-of-freedom integrated hybrid magnetic bearing, comprising a stator and a rotor. The stator includes an axial stator core 1, two radial stator cores 2 and 3, left and right L-cores 4 and 5, and left and right annular permanent magnets 6 and 7. The two radial stator cores 2 and 3 are symmetrically installed inside the axial stator core 1. The left and right L-cores 4 and 5 and the left and right annular permanent magnets 6 and 7 are symmetrically installed outside the axial stator core 1. Symmetrical axial control coils 8 and 9 are wound inside the axial stator core 1. Three control magnetic poles 10 and 11 and three bias magnetic poles 12 and 13 are evenly distributed on the inner circumference of the radial stator cores 2 and 3. Radial control coils 14 and 15 are wound on the control magnetic poles 10 and 11, and permanent magnets 16 and 17 are provided in the bias magnetic poles 12 and 13.

[0023] The rotor is housed inside the stator, consisting of, from the inside out, a shaft 18, an axial rotor core 19, a magnetic isolation ring 20, and radial rotor cores 21 and 22. The magnetic isolation ring 20 is embedded between the axial rotor core 19 and the pair of radial rotor cores 21 and 22. The axial width of the axial rotor core 19 is smaller than the axial width of the magnetic isolation ring 20. The radial rotor cores 21 and 22 are opposite to and of equal width to the two radial stator cores 2 and 3, and are separated by radial air gaps 23 and 24. The inner side of the axial stator core 1 and the left and right L-cores 4 and 5 extend into the rotor, and are separated from the axial rotor core 19 by upper axial air gaps 25 and 26 and lower axial air gaps 27 and 28, respectively. The polarities of the connecting surfaces of the left annular permanent magnet 6 and the right annular permanent magnet 7 to the axial stator core 1 are the same. The design of this magnetic bearing can achieve independence of radial and axial parameters and no coupling between axial and radial suspension forces, solving a series of problems in traditional hybrid magnetic bearings, such as mutual constraints between radial and axial parameters, coupling of axial and radial suspension forces, complex control and high power consumption.

[0024] The left and right annular permanent magnets 6 and 7 and permanent magnets 16 and 17 are all made of rare earth permanent magnet materials. The magnetic shielding ring 20 is made of aluminum. The two radial stator cores 2 and 3 and the rotor radial cores 21 and 22 are made of silicon steel sheets. The rotor axial core 19, the axial stator core 1, and the left and right L cores 4 and 5 are integrally machined from magnetic materials. The rotating shaft 18 is made of non-magnetic materials.

[0025] The left and right annular permanent magnets 6 and 7, the axial stator core 1, the left and right L-cores 4 and 5, and the rotor axial core 19 constitute the axial section, serving as the control magnetic circuit and bias magnetic circuit for the axial section. The bias magnetic circuit consists of the left and right annular permanent magnets 6 and 7 generating axial bias fluxes 31 and 32, which form closed paths between the axial stator core 1, the left and right L-cores 4 and 5, the rotor axial core 19, the upper axial air gaps 25 and 26, and the lower axial air gaps 27 and 28. The control magnetic circuit consists of axial control coils 8 and 9 connected in series in the same direction as an axial suspension winding, driven by a DC switching power amplifier, generating an axial control flux 33, which forms a closed path between the axial stator core 1, the upper axial air gaps 25 and 26, and the rotor axial core 19.

[0026] The permanent magnets 16 and 17, control poles 10 and 11, bias poles 12 and 13, and rotor radial cores 21 and 22 constitute the radial section, serving as the radial control and bias magnetic circuit. The bias magnetic circuit consists of permanent magnets 16 and 17 generating radial bias fluxes 29 and 30, which pass through control poles 10 and 11, bias poles 12 and 13, radial air gaps 23 and 24, and rotor radial cores 21 and 22. The control magnetic circuit consists of radial control coils 14 and 15 connected in a star configuration and driven by two three-phase inverters to generate radial control fluxes 34 and 35, forming a closed path between the three control poles 10 and 11, radial air gaps 23 and 24, and rotor radial cores 21 and 22.

[0027] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A novel five-degree-of-freedom integrated hybrid magnetic bearing, characterized in that: The system includes a stator and a rotor. The stator comprises an axial stator core (1), two radial stator cores (2, 3), left and right L-cores (4, 5), and left and right annular permanent magnets (6, 7). The two radial stator cores (2, 3) are symmetrically installed inside the axial stator core (1). The left and right L-cores (4, 5) and the left and right annular permanent magnets (6, 7) are symmetrically installed outside the axial stator core (1). Symmetrical axial control coils (8, 9) are wound inside the axial stator core (1). Three control magnetic poles (10, 11) and three bias magnetic poles (12, 13) are evenly distributed around the inner circumference of the radial stator cores (2, 3). Radial control coils (14, 15) are wound on the control magnetic poles (10, 11), and permanent magnets (6, 7) are provided in the bias magnetic poles (12, 13). 16, 17); The rotor is located inside the stator, and from the inside out are the rotating shaft (18), the rotor axial core (19), the magnetic isolation ring (20) and a pair of rotor radial cores (21, 22); The magnetic isolation ring (20) is embedded between the rotor axial core (19) and the pair of rotor radial cores (21, 22). The axial width of the rotor axial core (19) is smaller than the axial width of the magnetic isolation ring (20). The pair of rotor radial cores (21, 22) are opposite to and equal in width to the two radial stator cores (2, 3), and there is a radial air gap (23, 24) between them. The inner side of the axial stator core (1) and the left and right L cores (4, 5) extend into the rotor, and there are upper axial air gaps (25, 26) and lower axial air gaps (27, 28) between it and the rotor axial core (19).

2. The novel five-degree-of-freedom integrated hybrid magnetic bearing according to claim 1, characterized in that: The left annular permanent magnet (6), the right annular permanent magnet (7) and the axial stator core (1) have the same polarity.

3. The novel five-degree-of-freedom integrated hybrid magnetic bearing according to claim 1, characterized in that: The permanent magnets (16, 17) generate radial bias magnetic fluxes (29, 30), which form closed paths between the control poles (10, 11), bias poles (12, 13), radial air gaps (23, 24), and rotor radial cores (21, 22). The left and right annular permanent magnets (6, 7) generate axial bias magnetic fluxes (31, 32), which form closed paths between the axial stator core (1), left and right L cores (4, 5), rotor axial core (19), upper axial air gaps (25, 26), and lower axial air gaps (27, 28).

4. The novel five-degree-of-freedom integrated hybrid magnetic bearing according to claim 1, characterized in that: The axial control coils (8, 9) are connected in series in the same direction to form an axial suspension winding, and are driven by a DC switching power amplifier to generate axial control flux (33), forming a closed path between the axial stator core (1), the upper axial air gap (25, 26) and the rotor axial core (19); the radial control coils (14, 15) are connected in a star configuration and are driven by two three-phase inverters to generate radial control flux (34, 35), forming a closed path between the three control poles (10, 11), the radial air gap (23, 24), and the rotor radial core (21, 22).

5. The novel five-degree-of-freedom integrated hybrid magnetic bearing according to claim 1, characterized in that: The left and right annular permanent magnets (6, 7) and the permanent magnets (16, 17) are all made of rare earth permanent magnet materials. The magnetic isolation ring (20) is made of aluminum. The two radial stator cores (2, 3) and the rotor radial cores (21, 22) are made of silicon steel sheets. The rotor axial core (19), the axial stator core (1), and the left and right L cores (4, 5) are made of magnetically conductive materials. The shaft (18) is made of non-magnetically conductive materials.

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