Distributed Winding AC Hybrid Magnetic Bearing

Abstract

The present invention discloses a distributed winding type AC hybrid magnetic bearing, wherein three stator suspension teeth and three offset teeth embedded with permanent magnets are distributed on the inner circumference of the stator core, the three suspension teeth are 120° apart from each other, and the axis of one suspension tooth is aligned with the +X axis; the three offset teeth are 120° apart from each other, and the axis of one offset tooth is aligned with the -X axis; the rotor comprises a rotor core and a rotating shaft; the rotor core has 6N diamond-shaped open inner slots evenly distributed along the circumference, and control windings are embedded in the diamond-shaped open inner slots; two control windings with a phase difference of 180° are short-circuited at one end, and the other end is connected to a commutator segment, and connected to a three-phase AC power supply through a carbon brush. The present invention provides bias magnetic flux by a permanent magnet, and provides control magnetic flux by passing a three-phase AC power through a control winding; the structure increases the effective area between the stator and rotor, increases the suspension force density, has a large degree of freedom and flexibility, has a large room for variable parameter adjustment, and has the advantages of large bearing capacity.

Description

Technical Field

[0001] The present invention relates to a non-mechanical contact magnetic bearing, in particular to a distributed winding AC hybrid magnetic bearing, which can be used as a contactless suspension support for high-speed transmission components such as flywheel systems, machine tool electric spindles, centrifuges, etc. Background Art

[0002] Magnetic bearings are electromagnetic devices that use electromagnetic force to achieve mechanical contact-free suspension support between the stator and rotor. High-speed motors supported by magnetic bearings can achieve greater power and higher speed operation, and have the advantages of no mechanical wear, low power consumption, low noise, long life, no lubrication and maintenance-free. Magnetic bearings can be divided into three types according to the magnetic force and the principle of suspension force generation: active magnetic bearings, passive magnetic bearings and hybrid magnetic bearings. Compared with active and passive hybrid magnetic bearings, hybrid magnetic bearings use permanent magnetic materials to generate bias magnetic fields, and the control current only provides control flux to balance the load or interference, which reduces the power loss of the magnetic bearings, reduces the volume of the magnetic bearings, and improves the suspension force density and carrying capacity.

[0003] Existing hybrid magnetic bearings all have stator teeth distributed along the circumference of the stator, and use concentrated windings wound on the stator teeth. The winding design of this structure involves the number of turns, the cross-sectional area of ​​the wire, the current density, etc., and occupies radial space, the radial magnetic pole area cannot be maximized, and the radial bearing capacity is small. In addition, the air gap magnetic density of this structure is limited by the saturation of the tooth part and cannot be increased as needed. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to propose a distributed winding AC hybrid magnetic bearing, in which the stator core has no winding and the winding is distributed in the inner slot of the rotor, which increases the effective area between the stator and the rotor, increases the suspension force density, has a greater degree of freedom and flexibility, has a large room for variable parameter adjustment, and has a compact structure.

[0005] Technical solution: The present invention discloses a distributed winding AC hybrid magnetic bearing, comprising a stator and a rotor, wherein the stator comprises a stator core, wherein the inner circumference of the stator core is provided with three stator suspension teeth A, B, C and three offset teeth X, Y, Z embedded with permanent magnets, wherein the stator suspension teeth A, B, C are mutually offset by 120°, and the axis of one of the stator suspension teeth is aligned with the +X axis; the offset teeth X, Y, Z are mutually offset by 120°, and the axis of one of the offset teeth is aligned with the -X axis; the rotor comprises a rotor core and a rotating shaft passing through the rotor core, the rotor core is in the shape of a disc ring, and 6N diamond-shaped open inner slots are evenly distributed along its circumference, wherein N is a positive integer greater than or equal to 1, and control windings are embedded in the diamond-shaped open inner slots; one end of two control windings with a difference of 180° is short-circuited, and the other end is connected to the commutator segments in the commutator, the number of the commutator segments is equal to the number of the diamond-shaped open inner slots, and every two commutator segments are connected through a carbon brush and then connected to a three-phase AC power supply; an air gap is arranged between the rotor core and the stator core.

[0006] Furthermore, the commutator includes a base, which is made of insulating material, on which a commutator cylinder is provided, the commutator segments are distributed on the surface of the commutator cylinder, the segments are insulated from each other, and the commutator segments are insulated from each other, the two ends of each carbon brush are aligned with the outer sides of the two corresponding commutator segments, and the chord length width is equal to the width of the two commutator segments plus the insulation width between the two, and the 6N commutator segments are divided into U phase, V phase, and W phase. When the rotor rotates, the carbon brushes do not move, and the control winding sequentially enters and leaves the phase where the commutator segment is located, and the number of commutator segments corresponding to the carbon brushes remains unchanged, and each commutator segment is connected to a three-phase AC power supply through its corresponding carbon brush.

[0007] Furthermore, the insulation width between the commutator segments is equal to the width of the commutator segments.

[0008] Furthermore, the arc of the stator suspension teeth A, B, and C is less than 80°, the arc of the offset teeth X, Y, and Z is less than 40°, and the arc of the stator suspension teeth is twice the arc of the offset teeth, and the air gap bias flux density under the offset teeth is the saturation value B s , the air gap bias flux density under the stator suspension tooth is B s / 2.

[0009] Furthermore, taking N=2, the rotor core has 12 rhombus-shaped open inner slots evenly distributed along its circumference, and the control windings R1-R 12 For suspension control, the control windings R1 and R7, R2 and R8, R3 and R9, R4 and R 10 , R5 and R 11 , R6 and R 12The other end is connected in series with the corresponding commutator segment in the commutator. The four commutator segments connected to the control windings R1, R2, R7, and R8 in the inner slot of the diamond opening are U phase, and the control windings R3, R4, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, R26, R27, R28, R29, R30, R31, R32, R33, R34, R35, R36, R37, R38, R39, R40, R41, R42, R43, R44, R45, R46, R47, R48, R49, R50, R51, R52, R53, R54, R5 10 The four commutator segments are V phase, connected to the control windings R5, R6, R 11 , R 12 The 4 commutator segments are W phase.

[0010] Furthermore, the diamond-shaped open inner slot control winding R1-R 12 A three-phase inverter is used to provide control current. When a three-phase AC power supply is input, a magnetic flux distribution corresponding to the bias magnetic flux is generated.

[0011] Furthermore, the stator core and the rotor core are made of a whole piece of magnetic conductive material, and the permanent magnet is made of rare earth permanent magnet material. Beneficial Effects

[0012] The present invention proposes a distributed winding AC hybrid magnetic bearing. The stator core of the AC hybrid magnetic bearing with this structure has no winding, and the winding is distributed in the inner slot of the rotor, which increases the effective area between the stator and the rotor, increases the suspension force density, has a large degree of freedom and flexibility, has a large room for variable parameter adjustment, and has a compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a connection diagram of a distributed winding AC hybrid magnetic bearing commutator of the present invention;

[0014] Figure 2 A wiring diagram of a distributed winding AC hybrid magnetic bearing of the present invention;

[0015] Figure 3 The present invention discloses a distributed winding AC hybrid magnetic bearing axial segmentation and suspension flux diagram.

[0016] Among them, 1-stator core, 2-permanent magnet, 3-air gap, 4-rotor core, 5-static bias flux, 6-radial suspension control flux, 7-base, 8-rotating shaft, 9-commutator segment, 10-carbon brush. DETAILED DESCRIPTION

[0017] Specific implementation method Figure 1-3 As shown, the present invention discloses a distributed winding AC hybrid magnetic bearing, including a stator and a rotor. The stator includes a stator core 1, and the inner circumference of the stator core 1 is distributed with three stator suspension teeth A, B, C and three offset teeth X, Y, Z embedded with permanent magnets 2. The three stator suspension teeth A, B, C are 120° apart from each other. Figure 3, the axis of the stator suspension tooth A is aligned with the +X axis; the three offset teeth X, Y, and Z are 120° apart from each other, and the axis of the offset tooth Y is aligned with the -X axis; the arcs of the stator suspension teeth A, B, and C are twice the arcs of the stator teeth X, Y, and Z; the rotor includes a rotor core 4 and a rotating shaft 8 that penetrates the rotor core 4; the rotor core 4 is a disc ring, and 6N diamond-shaped open inner grooves are evenly distributed on its surface along its circumference, where N is a positive integer greater than or equal to 1, and the control winding is embedded in the diamond-shaped open inner groove; one end of the two control windings that are 180° apart is short-circuited, and the other end is connected to the commutator segments 9 in the commutator, and the number of commutator segments 9 is equal to the number of diamond-shaped open inner grooves. Every two commutator segments 9 are connected to a carbon brush 10 and then connected to a three-phase AC power supply. An air gap 3 is provided between the rotor core 4 and the stator core 1. The stator core 1 and the rotor core 4 are made of a whole piece of magnetic conductive material. The permanent magnet 2 is made of rare earth permanent magnet material.

[0018] In this embodiment, the arc of the stator suspension teeth A, B, C is less than 80°, the arc of the offset teeth X, Y, Z is less than 40°, and the arc of the stator suspension teeth is twice the arc of the offset teeth, and the air gap bias flux density under the offset teeth is the saturation value B s , the air gap bias flux density under the suspended tooth is B s / 2.

[0019] The commutator includes a base 7, which is an insulating material, on which a commutator cylinder is provided, and commutator segments 9 are distributed on the surface of the commutator cylinder. The segments are insulated from each other, and the commutator segments 9 are insulated from each other. The two ends of each carbon brush 10 are aligned with the outer sides of the two corresponding commutator segments 9, and the chord length width is equal to the width of the two commutator segments 9 plus the insulation width between the two. The 6N commutator segments 9 are divided into U phase, V phase, and W phase. When the rotor rotates, the carbon brush 10 does not move, and the control winding sequentially enters and leaves the phase where the commutator segment 9 is located, and the number of commutator segments 9 corresponding to the carbon brush 10 remains unchanged. Each commutator segment 9 is connected to a three-phase AC power supply through its corresponding carbon brush 10.

[0020] The insulation width between the commutator segments 9 is equal to the width of the commutator segments 9 .

[0021] 6N diamond-shaped open inner slot windings, in this embodiment, N=2, that is, 12 diamond-shaped open inner slots are used as an example, then the number of commutator segments 9 is 12, recorded as commutator segments c1-c 12 , 12 diamond-shaped open inner slots control winding R1-R 12 For suspension control, in the position shown in the figure: the commutator segment 9 connected to the control windings R1, R2, R7, and R8 in the inner slot of the diamond opening is the U phase, and the commutator segment 9 connected to the control windings R3, R4, R9, and R 10 The commutator segment 9 is V phase, connected to the control windings R5, R6, R 11 , R 12The commutator segment 9 is W phase, and the control windings R1 and R7, R2 and R8, R3 and R9, R4 and R 10 , R5 and R 11 , R6 and R 12 The other end is connected to the commutator segment 9 in the commutator, and then connected to the three-phase AC power supply through the carbon brush 10. For detailed connection, please refer to the attached Figure 2 .

[0022] The 12 commutator segments U, V, and W are connected to the three-phase power supply through six carbon brushes 10. When in the position shown in the figure: the control windings R3 and R4, R9 and R 10 , R1 and R2, R7 and R8, R5 and R6, R 11 With R 12 Six carbon brushes 10 are placed at relative positions on the corresponding commutator segments 9, respectively denoted as carbon brushes af. The two ends of each carbon brush 10 are aligned with the outer sides of the two corresponding commutator segments 9, and the chord length width is equal to the width of the two commutator segments 9 plus the insulation width therebetween. In the present embodiment, the insulation width between the commutator segments 9 is equal to the width of the commutator segments 9, so the chord length width of each carbon brush 10 is equal to the width of three commutator segments 9.

[0023] Commutator and carbon brush 10 principle: Figure 1 The commutator is placed on one side of the rotor core 4, one end of the control winding is connected to the commutator segment 9, the commutator segment 9 is fixed on the shaft 8 and rotates with the shaft 8, the carbon brush a corresponds to the commutator segments c1 and c2, the carbon brush b corresponds to the commutator segments c3 and c4, the carbon brush c corresponds to the commutator segments c5 and c6, the carbon brush d corresponds to the commutator segments c7 and c8, and the carbon brush e corresponds to the commutator segments c9 and c10. 10 , carbon brush f corresponds to commutator segment c 11 、c 12 The carbon brush is fixed in space. When the shaft 8 rotates, an AC voltage is applied to the end of the carbon brush 10, and the electric energy is transmitted to the control winding through the commutator. After conversion by the three-phase inverter, it can be ensured that the current in the two control winding sides under each carbon brush 10 is always in the same direction, and the number of commutator segments 9 under the carbon brush 10 remains unchanged.

[0024] When the rotor rotates, the six carbon brushes 10 remain in place, and the control winding sequentially enters and leaves the phase where the commutator segment 9 is located, and the number of the commutator segments 9 corresponding to the carbon brushes 10 remains unchanged.

[0025] Diamond-shaped open inner slot control winding R1-R 12 A three-phase inverter is used to provide control current. When a three-phase AC power supply is input, a magnetic flux distribution corresponding to the bias magnetic flux is generated.

[0026] The permanent magnet 2 provides a static bias flux 5 , and the magnetic circuit of the static bias flux 5 is: the flux starts from the N pole of the permanent magnet 2 , the air gap 3 , the rotor core 4 , the air gap 3 , the stator suspended teeth, the stator core 1 , and returns to the S pole of the permanent magnet 2 .

[0027] Diamond-shaped open inner slot control winding R1-R 12 The radial suspension control magnetic flux 6 generated by power-on has a magnetic circuit of: the stator core 1, the air gap 3, the rotor core 4, and the stator core 1 forming a closed loop.

[0028] Suspension principle: The radial static bias flux 5 interacts with the radial suspension control flux 6, so that the air gap magnetic field on the same side as the radial eccentricity of the rotor is superimposed and weakened, while the air gap magnetic field in the opposite direction is superimposed and enhanced, generating a force on the rotor opposite to the rotor offset direction, pulling the rotor back to the radial equilibrium position.

[0029] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above-mentioned technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also regarded as the protection scope of the present invention.

Claims

1. A distributed winding AC hybrid magnetic bearing, comprising a stator and a rotor, characterized in that: The stator comprises a stator core (1), wherein the inner circumference of the stator core (1) is spaced apart with three stator suspension teeth A, B, C and three offset teeth X, Y, Z embedded with permanent magnets (2), wherein the stator suspension teeth A, B, C are mutually offset by 120°, and the axis of one of the stator suspension teeth is aligned with the +X axis; the offset teeth X, Y, Z are mutually offset by 120°, and the axis of one of the offset teeth is aligned with the -X axis; the rotor comprises a rotor core (4) and a rotating shaft (8) penetrating the rotor core (4), wherein the rotor core (4) is ) is in the shape of a disk ring, and has 6N rhombus-shaped open inner slots evenly distributed along its circumference, wherein N is a positive integer greater than or equal to 1, and control windings are embedded in the rhombus-shaped open inner slots; one end of two control windings with a phase difference of 180° is short-circuited, and the other end is connected to a commutator segment (9) in the commutator, the number of the commutator segments (9) is equal to the number of the rhombus-shaped open inner slots, and every two commutator segments (9) are connected through a carbon brush (10) and then connected to a three-phase AC power supply; an air gap (3) is provided between the rotor core (4) and the stator core (1); The commutator comprises a base (7) which is made of insulating material and on which a commutator cylinder is provided. The commutator segments (9) are distributed on the surface of the commutator cylinder. The commutator segments (9) are insulated from each other. The two ends of each carbon brush (10) are aligned with the outer sides of the two commutator segments (9) corresponding thereto. The chord length width is equal to the width of the two commutator segments (9) plus the insulation width between the two commutator segments (9). The 6N commutator segments (9) are divided into a U phase, a V phase, and a W phase. When the rotor rotates, the carbon brush (10) remains stationary, and the control winding sequentially enters and leaves the phase where the commutator segment (9) is located. The number of commutator segments (9) corresponding to the carbon brush (10) remains unchanged. Each commutator segment (9) is connected to a three-phase AC power supply via its corresponding carbon brush (10). The insulation width between the commutator segments (9) is equal to the width of the commutator segments (9); The arc of the stator suspension teeth A, B, and C is less than 80°, the arc of the offset teeth X, Y, and Z is less than 40°, and the arc of the stator suspension teeth is twice the arc of the offset teeth. The air gap bias flux density under the offset teeth is the saturation value. B s , the air gap bias flux density under the stator suspension tooth is B s / 2.

2. A distributed winding AC hybrid magnetic bearing according to claim 1, characterized in that: Assuming N=2, the rotor core (4) has 12 rhombus-shaped open inner slots evenly distributed along its circumference, and the control windings R1-R 12 For suspension control, the control windings R1 and R7, R2 and R8, R3 and R9, R4 and R 10 , R5 and R 11 , R6 and R 12 The four commutator segments (9) connected in series respectively, with the other end connected to the corresponding commutator segments (9) in the commutator, connecting the control windings R1, R2, R7, and R8 in the inner slot of the diamond opening as the U phase, connecting the control windings R3, R4, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, R26, R27, R28, R29, R30, R31, R32, R33, R34, R35, R36, R37, R38, R39, R40, R41, R42, R43, R44, R45, R46, R47, R48, R49, R50, R51, R52, R 10 The four commutator segments (9) are V phases, connected to the control windings R5, R6, R 11 , R 12 The four commutator segments (9) are W phase.

3. A distributed winding AC hybrid magnetic bearing according to claim 2, characterized in that: The diamond-shaped opening inner slot controls the winding R1-R 12 A three-phase inverter is used to provide control current. When a three-phase AC power supply is input, a magnetic flux distribution corresponding to the bias magnetic flux is generated.

4. A distributed winding AC hybrid magnetic bearing according to any one of claims 1 to 3, characterized in that: The stator iron core (1) and the rotor iron core (4) are made of a whole piece of magnetic conductive material, and the permanent magnet (2) is made of rare earth permanent magnet material.

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