Permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor

Abstract

The application discloses a permanent magnet biased three-degree-of-freedom magnetic suspension switched reluctance motor, torque stators of the motor are isolated from radial force stators and axial force stators, torque magnetic circuits for generating torque are isolated from bias magnetic circuits and suspension magnetic circuits for generating suspension force; since a pole arc angle of the radial force stator tooth is equal to a rotor period angle, the radial suspension magnetic circuit does not generate torque, and the axial suspension magnetic circuit does not overlap with the torque magnetic circuit, and does not generate torque; in addition, the torque magnetic circuit is a short magnetic circuit structure, and fault tolerance and reliability are high; the application integrates rotation and three-degree-of-freedom suspension functions, torque and three suspension forces are naturally decoupled in structure, and core loss is small; the three-pole magnetic bearing has simple structure, a power converter is mature and low in cost, and has good application prospect; bias magnetic flux is generated by permanent magnet excitation, and application occasions and working conditions have strong adaptability.

Description

Technical Field

[0001] This invention belongs to the field of magnetic levitation motors. Background Technology

[0002] Switched reluctance motors have a simple structure, with both the stator and rotor having salient poles. The stator has concentrated windings, while the rotor has no windings or permanent magnets. They offer excellent high-speed performance, strong fault tolerance, high temperature and grease resistance, and strong environmental adaptability, making them widely used in aerospace, electric vehicles, flywheel energy storage, textiles, oil, and mining. Magnetic levitation bearings offer advantages such as non-contact, frictionless operation, and ease of maintenance, effectively solving the bearing support problem in high-speed motors and finding wide application in the motor industry.

[0003] Traditional magnetic levitation switched reluctance motor systems, consisting of magnetic bearings and switched reluctance motors, require two separate controllers for independent control of the motor and magnetic bearings. This results in a large and costly drive system, hindering its widespread adoption in cost-sensitive civilian applications. Therefore, further reducing the system cost of magnetic levitation switched reluctance motors is a critical challenge that urgently needs to be addressed in this field. Summary of the Invention

[0004] Purpose of the invention: In order to solve the problems existing in the prior art, the present invention provides a permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor.

[0005] Technical Solution: This invention provides a permanent magnet biased three-degree-of-freedom magnetically levitated switched reluctance motor, comprising: a radial force stator, a torque stator, a non-magnetic support frame, a radial suspension coil, a torque coil, a permanent magnet, a stator annular magnetic yoke, a first axial force stator, a second axial force stator, a first axial suspension coil, a second axial suspension coil, a rotor, a rotor annular magnetic yoke, and a shaft; the number of permanent magnets, radial force stator teeth, non-magnetic support frame, and torque stator are the same; the stator annular magnetic yoke is cylindrical, and the first and second axial force stators have the same circular structure, with the two axial force stators respectively arranged opposite each other on two circular surfaces of the stator annular magnetic yoke. The centers of the two axial force stators have through holes for the shaft to pass through, and the inner diameter of the through holes is greater than the outer diameter of the shaft. The two axial force stators are... Type structure, The structure has annular teeth in the salient pole direction; the radial force stator is a salient pole structure, set in the stator annular magnetic yoke, located between two axial force stators, and the distance between the radial force stator and the two axial force stators is equal; the permanent magnet is square, closely set between the radial force stator and the stator annular magnetic yoke, and the center line of the permanent magnet coincides with the center line of the corresponding radial force stator tooth; the non-magnetic support frame is arc-shaped, set in the yoke between two adjacent teeth of the radial force stator, and the center line of the non-magnetic support frame coincides with the center line of the corresponding radial force stator yoke; the torque stator is set on the non-magnetic support frame, and the center of the torque stator coincides with the center line of the corresponding non-magnetic support frame; the rotor is set inside the radial force stator and sleeved on the rotor annular magnetic yoke, and the rotor annular magnetic yoke is sleeved on the shaft;

[0006] The radial force stator has three teeth, which are evenly distributed in space and spaced 120° apart. Radial suspension coils are wound on each tooth of the radial force stator, and the three suspension coils are connected in parallel to form three radial suspension windings. The polar arc angle of each tooth of the radial force stator is one rotor period angle.

[0007] The first axial suspension coil is wound on the annular teeth of the first axial force stator, and the second axial suspension coil is wound on the annular teeth of the second axial force stator. The two axial suspension coils are connected in series to form an axial suspension winding.

[0008] The torque coil is wound on the torque stator.

[0009] Furthermore, the rotor has a salient pole structure with 9 teeth, and the adjacent teeth are spaced 40° apart. The torque stator has a C-shaped structure, with the two teeth of a torque stator being spaced 40° apart, and the adjacent radial force stator teeth are spaced 40° apart from the torque stator teeth.

[0010] Furthermore, the torque coils are wound on each tooth of the torque stator, and the torque coils on two teeth of the torque stator are connected in series to form a torque coil string. The three torque coil strings are connected in series to form a single-phase winding.

[0011] Furthermore, a unipolar drive method is used to drive the single-phase winding.

[0012] Furthermore, the rotor has a salient pole structure and 14 rotor teeth, which are evenly distributed in space, with a 25.7° interval between adjacent teeth; the torque stator has an E-type structure, with each torque stator having 3 teeth, the middle tooth being a common tooth and the remaining two teeth being torque teeth, and the width of the common tooth being greater than the width of the torque teeth, with a 30° difference between the common tooth and the torque teeth; the adjacent radial force stator is 60° away from the torque stator.

[0013] Furthermore, the torque coils are wound on each torque tooth of the torque stator, and two torque coils that are spatially 180° apart are connected in series as torque windings, resulting in a total of three torque windings, which are the A, B and C phase torque windings, respectively.

[0014] Furthermore, a unipolar drive method is used to drive the three-phase torque winding.

[0015] Furthermore, a bipolar drive method is used to drive the radial suspension winding and the axial suspension winding.

[0016] Furthermore, the permanent magnet is magnetized radially, and the magnetization directions of the permanent magnet are the same.

[0017] Beneficial effects:

[0018] (1) The present invention has the simplest structure, small size, low power consumption, and the drive circuit only requires 3 DC power amplifiers or 1 three-phase power inverter, which significantly reduces the cost of magnetic bearings;

[0019] (2) The present invention has rotation, axial suspension and two radial suspension capabilities, high integration, short axial length, high critical speed and high power density;

[0020] (3) The torque control magnetic circuit and the suspension control excitation are isolated from each other and have no coupling. The torque and suspension force are naturally decoupled in structure.

[0021] (4) All torque magnetic circuits are short magnetic circuit structures, which have good fault tolerance and low core loss;

[0022] (5) The bias flux excitation adopts permanent magnet excitation. When the permanent magnet generates the bias flux required for levitation force, it has small volume and weight, high power density, and large levitation force / levitation current ratio, which is beneficial to reduce levitation power consumption. Attached Figure Description

[0023] Figure 1 This is a three-dimensional structural schematic diagram of Example 1 of the present invention.

[0024] Figure 2 This is a schematic diagram of the magnetic flux generated by the single-phase winding current in Embodiment 1 of the present invention when the rotor is in the aligned position.

[0025] Figure 3 This is a schematic diagram of the magnetic flux generated by the single-phase winding current in Embodiment 1 of the present invention when the rotor is in an misaligned position.

[0026] Figure 4 This is a schematic diagram of the bias magnetic flux and horizontal radial suspension control magnetic flux generated by the permanent magnet and radial suspension winding current in Embodiment 1 of the present invention.

[0027] Figure 5This is a schematic diagram of the bias magnetic flux generated by the permanent magnet and the radial suspension winding current, and the vertical diameter suspension control magnetic flux, according to Embodiment 1 of the present invention.

[0028] Figure 6 This is a schematic diagram of the bias flux and axial suspension control flux generated by the permanent magnet and the axial suspension winding current in Embodiment 1 of the present invention.

[0029] Figure 7 This is a three-dimensional structural schematic diagram of Example 2 of the present invention.

[0030] Figure 8 This is a schematic diagram of the magnetic flux generated by the A-phase winding current in Embodiment 2 of the present invention when the rotor is in the aligned position.

[0031] Figure 9 This is a schematic diagram of the magnetic flux generated by the A-phase winding current in Embodiment 2 of the present invention when the rotor is in an misaligned position.

[0032] Figure 10 This is a schematic diagram of the bias magnetic flux and horizontal radial suspension control magnetic flux generated by the permanent magnet and radial suspension winding current in Embodiment 2 of the present invention.

[0033] Figure 11 This is a schematic diagram of the bias magnetic flux generated by the permanent magnet and the radial suspension winding current, and the vertical diameter suspension control magnetic flux, according to Embodiment 2 of the present invention.

[0034] Explanation of reference numerals in the attached figures: 1. Radial force stator; 2. Torque stator; 3. Non-magnetic support frame; 4. Radial suspension coil; 5. Torque coil; 6. Permanent magnet; 7. Stator annular magnetic yoke; 8. First axial force stator; 9. Second axial force stator; 10. First axial suspension coil; 11. Second axial suspension coil; 12. Rotor; 13. Rotor annular magnetic yoke; 14. Shaft; 15. Magnetic flux generated by single-phase winding current when the rotor is in the aligned position; 16. Magnetic flux generated by single-phase winding current when the rotor is in the misaligned position; 17. Bias flux generated by permanent magnet; 18. Horizontal radial suspension control flux generated by radial suspension winding current; 19. Vertical radial suspension control flux generated by radial suspension winding current; 20. Axial suspension control flux generated by axial suspension winding current. Detailed Implementation

[0035] The technical solution of a permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor topology of the present invention will be described in detail below with reference to the accompanying drawings:

[0036] like Figure 1The diagram shown is a three-dimensional structural schematic of Embodiment 1 of the present invention, wherein 1 is a radial force stator, 2 is a torque stator, 3 is a non-magnetic support frame, 4 is a radial suspension coil, 5 is a torque coil, 6 is a permanent magnet, 7 is a stator annular magnetic yoke, 8 is an axial force stator I (i.e., the first axial force stator), 9 is an axial force stator II (i.e., the second axial force stator), 10 is an axial suspension coil I (i.e., the first axial suspension coil), 11 is an axial suspension coil II (i.e., the second axial suspension coil), 12 is a rotor, 13 is a rotor annular magnetic yoke, 14 is a rotating shaft, and X, Y, and Z are the three coordinate axes of a rectangular coordinate system.

[0037] The three-degree-of-freedom magnetically levitated switched reluctance motor includes a radial force stator, a torque stator, a non-magnetic support frame, a torque coil, a radial suspension coil, a permanent magnet, a stator annular magnetic yoke, an axial force stator I, an axial force stator II, an axial suspension coil I, an axial suspension coil II, a rotor, a rotor annular magnetic yoke, and a shaft.

[0038] Both the axial force stator I and the axial force stator II are Type structure, the The convex pole direction of the structure forms an annular tooth, the... The structure has one through hole, the centerline of which coincides with the centerline of the annular tooth; the inner diameter of the through hole is larger than the outer diameter of the rotating shaft; the rotating shaft passes through the axial stator I and axial stator II and is arranged within the through hole; the stator annular magnetic yoke is cylindrical, the first axial force stator and the second axial force stator have the same structure, both being circular, and the two axial force stators are respectively arranged opposite each other on the two circular surfaces of the stator annular magnetic yoke; the radial force stator is arranged inside the stator annular magnetic yoke between the axial force stator I and the axial force stator II, and the distance between the axial force stator I and the radial force stator is equal to the distance between the axial force stator I and the radial force stator II. The spacing between stator II and the radial force stator is equal; the salient pole annular teeth of both the axial force stator I and the axial force stator II point towards the radial force stator; the radial force stator has a salient pole structure with 3 teeth, and the 3 teeth of the radial force stator are evenly distributed in space, with a 120° interval between the teeth; the non-magnetic support frame is arc-shaped, and in this embodiment there are 3 non-magnetic support frames, which are set in the yoke between two adjacent teeth of the radial force stator; in this embodiment there are 3 torque stators, which are set on the non-magnetic support frames; the center of the torque stator coincides with the centerline of the corresponding non-magnetic support frame and the centerline of the yoke of the radial force stator.

[0039] Each tooth of the radial force stator is wound with one radial suspension coil, for a total of three. The three radial suspension coils are connected in parallel to form three radial suspension windings.

[0040] The rotor is arranged within the radial force stator and the torque stator, and the rotor is fitted on the rotor annular magnetic yoke, which is fitted on the rotating shaft.

[0041] The rotor has a salient pole structure with 9 teeth, which are evenly distributed and spaced 40° apart. The torque stator consists of 3 C-shaped structures, each with a salient pole structure and 2 teeth. The teeth in each C-shaped structure are spaced 40° apart. Adjacent radial force stators are spaced 40° apart from the torque stator.

[0042] The permanent magnets are rectangular in structure, and there are a total of 3.

[0043] The C-type torque stator has one torque coil wound on each tooth. The torque coils on two teeth of each torque stator are connected in series to form a torque coil string, for a total of three. The three torque coil strings are connected in series to form a single-phase winding of the motor, which ultimately constitutes the torque winding of a single-phase 9 / 9 pole BSRM.

[0044] An axial suspension coil I is wound on the annular teeth in axial force stator I, and an axial suspension coil II is wound on the annular teeth in axial force stator II. The axial suspension coil I and the axial suspension coil II are connected in series to form an axial suspension winding.

[0045] The permanent magnets are radially magnetized, and the magnetization directions of the three permanent magnets are the same. The pole arc angle of each tooth of the radial force stator is one rotor cycle angle, i.e., 40°. When current is applied to the torque coils on two teeth of each torque stator, the magnetic flux generated on the two teeth has opposite polarities, thus forming a series magnetic circuit between the two teeth. When current is applied to the three radial suspension coils, a bipolar magnetic flux will be generated. By changing the magnitude and direction of the current flowing in the suspension winding, a horizontal radial suspension force and a vertical radial suspension force are generated. The positive horizontal direction is defined as the zero-degree spatial angle position, and the spatial angle is positive when changing in the counterclockwise direction. When the magnetic flux generated on the two teeth of the radial force stator at spatial angles of 210° and 330° is opposite in polarity, a horizontal radial levitation force is generated. When the magnetic flux generated on the two teeth of the radial force stator at spatial angles of 210° and 330° is the same in polarity and opposite in polarity to the magnetic flux generated on the levitation tooth of the radial force stator at spatial angle of 90°, a vertical radial levitation force is generated. When current is applied to the axial levitation winding, a bipolar magnetic flux will be generated. The magnetic flux generated on the annular tooth of the axial force stator I is opposite in polarity to the magnetic flux generated on the annular tooth of the axial force stator II.

[0046] The single-phase winding adopts the unipolar drive method of the traditional switched reluctance motor; the radial suspension winding and the axial suspension winding adopt the bipolar drive method, and the suspension winding is constantly energized to generate horizontal suspension force, vertical suspension force and axial suspension force respectively.

[0047] like Figure 2 , Figure 3The figures shown are schematic diagrams of the magnetic flux generated by the single-phase winding current in Embodiment 1 of the present invention when the rotor is in an aligned position and an misaligned position. 15 represents the magnetic flux generated by the single-phase winding current when the rotor is in an aligned position, and 16 represents the magnetic flux generated by the single-phase winding current when the rotor is in a misaligned position. The X-axis is defined as being in the horizontal direction, the Y-axis as being in the vertical direction, and the Z-axis as being in the axial direction.

[0048] When the center line of the rotor teeth coincides with the center line of the torque stator teeth, the magnetic circuit reluctance is at its minimum. When the center lines of two adjacent rotor teeth coincide with the center lines of the torque stator teeth, the magnetic circuit reluctance is at its maximum.

[0049] When a current of i is applied to the single-phase winding, three bipolar magnetic fluxes are generated. Each bipolar magnetic flux is distributed in an N-S pattern on two teeth of each torque stator. Each magnetic flux loop consists of: one torque stator tooth, radial air gap, rotor tooth and rotor yoke (or rotor tooth), radial air gap, another torque stator tooth, torque stator yoke, and then closing at the same torque stator tooth. This magnetic flux is a short magnetic circuit distribution. Using the unipolar drive method of a traditional switched reluctance motor, the torque winding conduction generates a rotating magnetic field, which interacts with the constant magnetic field of the permanent magnet to achieve the rotational operation of the motor.

[0050] like Figure 4 , Figure 5 , Figure 6 The diagrams shown are schematic diagrams of the bias flux and horizontal radial suspension control flux generated by the permanent magnet and radial suspension winding current in Embodiment 1 of the present invention, respectively; the bias flux and vertical diameter suspension control flux generated by the permanent magnet and radial suspension winding current in Embodiment 1 of the present invention, respectively; and the bias flux and axial suspension control flux generated by the permanent magnet and axial suspension winding current in Embodiment 1 of the present invention. 17 represents the bias flux generated by the permanent magnet, 18 represents the horizontal radial suspension control flux generated by the radial suspension winding current, 19 represents the vertical diameter suspension control flux generated by the radial suspension winding current, and 20 represents the axial suspension control flux generated by the axial suspension winding current.

[0051] The three permanent magnets are radially magnetized, and all permanent magnets are magnetized in the same direction. The bias magnetic flux generated by the permanent magnets passes through the radial force stator yoke, radial force stator teeth, radial air gap, rotor teeth, rotor yoke, and rotor annular magnetic yoke. Then it splits into two: one path passes through the axial air gap, axial stator I annular teeth, axial stator I yoke, stator annular magnetic yoke, and then to the permanent magnet radial closed loop; the other path passes through the axial air gap, axial stator II annular teeth, axial stator II yoke, stator annular magnetic yoke, and then to the permanent magnet radial to form another closed loop.

[0052] A current of i is applied to each of the three radial suspension windings. u1 i v1 iw1 At this time, two radial bipolar magnetic fluxes will be generated. One magnetic flux passes through the 210° position tooth of the radial force stator, the radial air gap, the rotor tooth, the rotor yoke, the rotor tooth, the radial air gap, the 90° position tooth of the radial force stator, the yoke of the radial force stator, and finally back to the 210° position tooth of the radial force stator, forming a closed loop. The other magnetic flux passes through the 210° position tooth of the radial force stator, the radial air gap, the rotor tooth, the rotor yoke, the rotor tooth, the radial air gap, the 330° position tooth of the radial force stator, the yoke of the radial force stator, and finally back to the 210° position tooth of the radial force stator, forming a closed loop. When the magnetic fluxes generated on the two teeth of the radial force stator at spatial angles of 210° and 330° have opposite polarities, a horizontal radial levitation force is generated. The radial levitation winding is applied as follows... Figure 4 The current i shown u i v i w At this time, the air gap magnetic flux at the 210° position tooth of the radial force stator is enhanced, while the air gap magnetic flux at the 90° and 330° positions of the radial force stator is weakened, which will generate a horizontal (X-axis) positive levitation force; when the current i u1 i v1 i w1 When the direction changes, a horizontal (X-axis) negative levitation force will be generated, where the current applied to the radial force stator at the spatial angle of 330° is greater than the current applied to the radial force stator at the spatial angle of 90° and the radial force stator at the spatial angle of 210°.

[0053] A current of i is applied to each of the three radial suspension windings. u2 i v2 i w2 At this time, a radially bipolar symmetrical magnetic flux will be generated. One of the magnetic fluxes passes through the 210° position tooth of the radial force stator, the radial air gap, the rotor tooth, the rotor yoke, the rotor tooth, the radial air gap, the 90° position tooth of the radial force stator, the yoke of the radial force stator, and finally back to the 210° position tooth of the radial force stator, forming a closed loop. When the magnetic flux generated on the two teeth of the radial force stator at spatial angles of 210° and 330° has the same polarity and is opposite to the magnetic flux polarity on the levitation tooth of the radial force stator at spatial angle of 90°, a vertical radial levitation force is generated. The radial levitation winding is applied as follows Figure 5 The current i shown u2 i v2 i w2 At this time, the air gap magnetic flux under the teeth at the 210° and 330° positions of the radial force stator is enhanced, while the air gap magnetic flux under the teeth at the 90° position of the radial force stator is weakened, which will generate a vertical (Y-axis) positive levitation force; when the current i u2 i v2 i w2When the direction changes, a vertical (Y-axis) negative levitation force will be generated.

[0054] The axial suspension winding is applied with a current of i z At this time, a radially bipolar symmetrical magnetic flux will also be generated. Each magnetic flux passes through the annular teeth of axial force stator I, the yoke of axial force stator I, the stator annular magnetic yoke, the yoke of axial force stator II, the annular teeth of axial force stator II, the negative axial air gap, the rotor annular magnetic yoke, the positive axial air gap, and finally back to the annular teeth of axial force stator I, forming a closed loop. The axial suspension winding is applied as... Figure 6 The current i shown z When the magnetic flux in the negative axial direction of the air gap increases, and the magnetic flux in the positive axial direction of the air gap decreases, a levitation force will be generated in the negative axial (Z-axis) direction; when the current i z When the direction changes, a positive axial (Z-axis) levitation force will be generated.

[0055] Therefore, by adopting a bipolar drive method, the magnitude and direction of the three levitation forces can be controlled by reasonably controlling the magnitude and direction of the levitation winding current, thereby generating three levitation forces of arbitrary direction and magnitude, and thus achieving stable axial and two radial levitation operation of the rotor.

[0056] like Figure 7 The diagram shown is a three-dimensional structural schematic of Embodiment 2 of the present invention, wherein 1 is a radial force stator, 2 is a torque stator, 3 is a non-magnetic support frame, 4 is a radial suspension coil, 5 is a torque coil, 6 is a permanent magnet, 7 is a stator annular magnetic yoke, 8 is an axial force stator I, 9 is an axial force stator II, 10 is an axial suspension coil I, 11 is an axial suspension coil II, 12 is a rotor, 13 is a rotor annular magnetic yoke, 14 is a rotating shaft, and X, Y, and Z are the three coordinate axes of a rectangular coordinate system.

[0057] The three-degree-of-freedom magnetically levitated switched reluctance motor includes a radial force stator, a torque stator, a non-magnetic support frame, a torque coil, a radial suspension coil, a permanent magnet, a stator annular magnetic yoke, an axial force stator I, an axial force stator II, an axial suspension coil I, an axial suspension coil II, a rotor, a rotor annular magnetic yoke, and a shaft.

[0058] Both the axial force stator I and the axial force stator II are Type structure, the The convex pole direction of the structure forms an annular tooth, the... The structure has one through hole, the centerline of which coincides with the centerline of the annular tooth; the inner diameter of the through hole is larger than the outer diameter of the rotating shaft; the rotating shaft passes through the axial stator I and axial stator II and is arranged within the through hole; the stator annular magnetic yoke is cylindrical, the first axial force stator and the second axial force stator have the same structure, both being circular, and the two axial force stators are respectively arranged opposite each other on the two circular surfaces of the stator annular magnetic yoke; the radial force stator is arranged inside the stator annular magnetic yoke between the axial force stator I and the axial force stator II, and the distance between the axial force stator I and the radial force stator is equal to the distance between the axial force stator I and the radial force stator II. The spacing between stator II and the radial force stator is equal; the salient pole annular teeth of both the axial force stator I and the axial force stator II point towards the radial force stator; the radial force stator has a salient pole structure with 3 teeth, and the 3 teeth of the radial force stator are evenly distributed in space, with a 120° interval between the teeth; the non-magnetic support frame is arc-shaped, and in this embodiment there are 3 non-magnetic support frames, which are set in the yoke between two adjacent teeth of the radial force stator; in this embodiment there are 3 torque stators, which are set on the non-magnetic support frames; the center of the torque stator coincides with the centerline of the corresponding non-magnetic support frame and the centerline of the yoke of the radial force stator.

[0059] Each tooth of the radial force stator is wound with one radial suspension coil, for a total of three. The three radial suspension coils are connected in parallel to form three radial suspension windings.

[0060] The rotor has a salient pole structure with 14 teeth, which are evenly distributed and spaced 360° / 14 (25.7°) apart. There are 3 torque stators with an E-type structure, which is also a salient pole structure with 3 teeth. The middle tooth is a common tooth, and the teeth on the left and right sides are torque teeth. The common tooth and the torque teeth in each torque stator are 30° apart. Adjacent radial force stators are 60° apart from the torque stators.

[0061] The permanent magnets are rectangular in structure, and there are a total of 3.

[0062] The stator annular magnetic yoke has an annular structure, and the rotor annular magnetic yoke has an annular structure.

[0063] The rotor is arranged within the radial force stator and the torque stator, and the rotor is fitted on the rotor annular magnetic yoke, which is fitted on the rotating shaft.

[0064] The torque stator of the E-type structure has one torque coil wound on each torque tooth, for a total of 6; two torque coils spatially separated by 180° are connected in series to form one torque winding, for a total of 3, which are the A, B and C phase torque windings in sequence.

[0065] An axial suspension coil I is wound on the annular teeth of the axial force stator I, and an axial suspension coil II is wound on the annular teeth of the axial force stator II. The axial suspension coil I and the axial suspension coil II are connected in series to form an axial suspension winding.

[0066] The polar arc angle of each tooth of the radial force stator is one rotor cycle angle, which is 360° / 14, or 25.7°. When current is applied to the torque coils on the two torque teeth of each E-type torque stator, the magnetic flux generated on the two torque teeth has opposite polarities and forms two series magnetic circuits through the common tooth. When current is applied to the three radial suspension coils, two bipolar magnetic fluxes will be generated. By changing the magnitude and direction of the current in the suspension winding, horizontal radial suspension force and vertical radial suspension force are generated. The positive horizontal direction is defined as the zero-degree spatial angle position. When changing in the counterclockwise direction, the spatial angle is positive, and the positive horizontal direction leads. A horizontal radial levitation force is generated when the magnetic flux polarities generated on the two teeth of the radial force stator at spatial angles of 210° and 330° are opposite in the vertical positive direction of 90°. A vertical radial levitation force is generated when the magnetic flux polarities generated on the two teeth of the radial force stator at spatial angles of 210° and 330° are the same and opposite to the magnetic flux polarities generated on the levitation teeth of the radial force stator at spatial angle of 90°. When current is applied to the axial levitation winding, a bipolar magnetic flux is generated. The magnetic flux polarity generated on the annular teeth of the axial force stator I is opposite to the magnetic flux polarity generated on the annular teeth of the axial force stator II.

[0067] The A, B, and C three-phase torque windings adopt the unipolar drive method of the traditional switched reluctance motor, and are turned on alternately to generate output torque; the radial suspension winding and axial suspension winding adopt the bipolar drive method, and the suspension winding is constantly energized to generate horizontal suspension force, vertical suspension force and axial suspension force respectively.

[0068] like Figure 8 , Figure 9 The figures shown are schematic diagrams of the magnetic flux generated by the A-phase winding current in Embodiment 2 of the present invention when the rotor is in an aligned position and an unaligned position. Figure 8 It is the magnetic flux generated by the A-phase winding current when the rotor is in the aligned position. Figure 9 It is the magnetic flux generated by the A-phase winding current when the rotor is in a misaligned position. The X-axis is defined as horizontal, the Y-axis as vertical, and the Z-axis as axial.

[0069] The alignment position is defined as when the center line of the rotor tooth coincides with the center line of the torque tooth, at which point the magnetic reluctance is minimized; the misalignment position is defined as when the center lines of two adjacent rotor teeth coincide with the center line of the torque tooth, at which point the magnetic reluctance is maximized. Each torque tooth of the torque stator has one torque coil wound on it, for a total of six. Two torque coils spatially separated by 180° are connected in series to form one torque winding, for a total of three, namely the A, B, and C phase torque windings.

[0070] When the current applied to phase A winding is i a When current is applied to the B-phase and C-phase windings, a bipolar symmetrical magnetic flux is generated, with each flux distributed in an N-S pattern on each E-type stator torque tooth. Each flux loop consists of: a torque tooth in the torque stator, a radial air gap, rotor teeth and rotor yoke (or rotor teeth), a radial air gap, a common torque stator tooth, a torque stator yoke, and then back to the torque stator tooth for closure. This flux is a short-circuit magnetic flux. Similarly, when current is applied to the B-phase and C-phase windings, a bipolar symmetrical short-circuit magnetic flux is also generated. Using the unipolar drive method of a traditional switched reluctance motor, the A, B, and C phase torque windings are turned on alternately to generate output torque, thus enabling the motor to rotate.

[0071] like Figure 10 , Figure 11 The figures shown are schematic diagrams of the bias magnetic flux and horizontal radial suspension control magnetic flux generated by the permanent magnet and radial suspension winding current in Embodiment 2 of the present invention, respectively, and the bias magnetic flux and vertical radial suspension control magnetic flux generated by the permanent magnet and radial suspension winding current in Embodiment 2 of the present invention. The schematic diagrams of the bias magnetic flux and axial suspension control magnetic flux generated by the permanent magnet and axial suspension winding current in Embodiment 2 of the present invention are also shown. Figure 6 The magnetic fluxes shown are exactly the same. 17 is the bias flux generated by the permanent magnet, 18 is the horizontal radial suspension control flux generated by the radial suspension winding current, and 19 is the vertical radial suspension control flux generated by the radial suspension winding current.

[0072] The three permanent magnets are radially magnetized, and all permanent magnets are magnetized in the same direction. The bias magnetic flux generated by the permanent magnets passes through the radial force stator yoke, radial force stator teeth, radial air gap, rotor teeth, rotor yoke, and rotor annular magnetic yoke. Then it splits into two: one path passes through the axial air gap, axial stator I annular teeth, axial stator I yoke, stator annular magnetic yoke, and then into the permanent magnet radial closed loop; the other path passes through the axial air gap, axial stator II annular teeth, axial stator II yoke, stator annular magnetic yoke, and then into the permanent magnet radial to form another closed loop.

[0073] When current is applied to the radial levitation winding, two bipolar control fluxes are generated, which are related to... Figure 4 , Figure 5 The radial control flux path is the same; when current is applied to the axial levitation winding, a two-pole control flux is generated, which is the same as the radial control flux path. Figure 6The axial control flux paths are the same;

[0074] Therefore, the principle of levitation force generation in Example 2 is exactly the same as that in Example 1. When the three levitation windings adopt a bipolar drive mode, the magnitude and direction of the three levitation forces can be controlled by reasonably controlling the magnitude and direction of the current in the three levitation windings, thereby generating three levitation forces of arbitrary direction and magnitude, and thus achieving stable axial and two radial levitation operations of the rotor.

[0075] In both embodiments, since the pole arc angle of each tooth of the radial force stator is one rotor cycle angle, the magnetic reluctance of the magnetic circuit formed by the radial levitation winding and the permanent magnet within the radial force stator does not change with the rotor position. Therefore, neither the radial levitation winding nor the permanent magnet generates a kinematic electromotive force, nor does it generate torque. Thus, the present invention can achieve natural decoupling of torque and levitation force in its structure.

[0076] In summary, this invention integrates a switched reluctance motor with a three-degree-of-freedom magnetic levitation bearing to form a permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor with axial and radial levitation and rotational operation. The stator employs an isolated structure, isolating the torque magnetic circuit from the permanent magnet bias flux and the levitation magnetic circuit. Furthermore, since the pole arc angle of the radial force stator teeth is equal to one rotor cycle angle, neither the radial levitation current nor the permanent magnet generates torque. The axial levitation control magnetic circuit does not overlap with the torque magnetic circuit and also does not generate torque; therefore, the torque and the three levitation forces are naturally decoupled structurally. The torque magnetic circuits are all short-circuit structures, exhibiting good fault tolerance and low core loss. This invention boasts high structural and functional integration, which is beneficial for reducing motor size and improving critical torque and power density.

[0077] In addition, the bias flux of the present invention adopts permanent magnet excitation. When the bias flux required for the permanent magnet to generate levitation force is generated, it has small volume and weight, high power density, and large levitation force / levitation current ratio, which is beneficial to reducing levitation power consumption.

[0078] Those skilled in the art will readily conceive of other advantages and variations based on the above embodiments. Therefore, this invention is not limited to the specific examples described above, but is merely an example to illustrate one aspect of the invention in detail. Without departing from the spirit of this invention, all technical solutions obtained by those skilled in the art through various equivalent substitutions based on the above specific examples should be included within the scope of the claims of this invention and their equivalents.

Claims

1. A permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor, characterized in that, include: The system comprises a radial force stator, a torque stator, a non-magnetic support frame, a radial suspension coil, a torque coil, a permanent magnet, a stator annular magnetic yoke, a first axial force stator, a second axial force stator, a first axial suspension coil, a second axial suspension coil, a rotor, a rotor annular magnetic yoke, and a shaft. The number of permanent magnets, radial force stator teeth, non-magnetic support frame, and torque stator are the same. The stator annular magnetic yoke is cylindrical. The first and second axial force stators have identical circular structures. The two axial force stators are respectively positioned opposite each other on two circular surfaces of the stator annular magnetic yoke. Each axial force stator has a through hole at its center for the shaft to pass through, and the inner diameter of the through hole is greater than the outer diameter of the shaft. The two axial force stators are... Type structure, The structure has annular teeth in the salient pole direction; the radial force stator is a salient pole structure, set in the stator annular magnetic yoke, located between two axial force stators, and the distance between the radial force stator and the two axial force stators is equal; the permanent magnet is square, closely set between the radial force stator and the stator annular magnetic yoke, and the center line of the permanent magnet coincides with the center line of the corresponding radial force stator tooth; the non-magnetic support frame is arc-shaped, set in the yoke between two adjacent teeth of the radial force stator, and the center line of the non-magnetic support frame coincides with the center line of the corresponding radial force stator yoke; the torque stator is set on the non-magnetic support frame, and the center of the torque stator coincides with the center line of the corresponding non-magnetic support frame; the rotor is set inside the radial force stator and sleeved on the rotor annular magnetic yoke, and the rotor annular magnetic yoke is sleeved on the shaft; The radial force stator has three teeth, which are evenly distributed in space and spaced 120° apart. Radial suspension coils are wound on each tooth of the radial force stator, and the three suspension coils are connected in parallel to form three radial suspension windings. The polar arc angle of each tooth of the radial force stator is one rotor period angle. The first axial suspension coil is wound on the annular teeth of the first axial force stator, and the second axial suspension coil is wound on the annular teeth of the second axial force stator. The two axial suspension coils are connected in series to form an axial suspension winding. The torque coil is wound on the torque stator.

2. The permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor according to claim 1, characterized in that, The rotor has a salient pole structure with 9 teeth, and the adjacent teeth are 40° apart. The torque stator has a C-shaped structure, and the two teeth of a torque stator are 40° apart. The adjacent radial force stator teeth and torque stator teeth are 40° apart.

3. A permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor according to claim 2, characterized in that, The torque coil is wound on each tooth of the torque stator. The torque coils on two teeth of the torque stator are connected in series to form a torque coil string. The three torque coil strings are connected in series to form a single-phase winding.

4. A permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor according to claim 3, characterized in that, A single-phase winding is driven using a unipolar drive method.

5. A permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor according to claim 1, characterized in that, The rotor has a salient pole structure and 14 rotor teeth that are evenly distributed in space, with a 25.7° interval between adjacent teeth. The torque stator has an E-type structure, with each torque stator having 3 teeth. The middle tooth is a common tooth, and the remaining two teeth are torque teeth. The width of the common tooth is greater than the width of the torque teeth, and the common tooth is 30° away from the torque teeth. The adjacent radial force stator is 60° away from the torque stator.

6. A permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor according to claim 5, characterized in that, The torque coils are wound on each torque tooth of the torque stator. Two torque coils that are 180° apart in space are connected in series to form a torque winding, resulting in a total of three torque windings, which are the A, B and C phase torque windings, respectively.

7. A permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor according to claim 6, characterized in that, The three-phase torque winding is driven by a unipolar drive method.

8. A permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor according to claim 1, characterized in that, The radial suspension winding and the axial suspension winding are driven by a bipolar drive method.

9. A permanent magnet biased three-degree-of-freedom magnetic levitation switched reluctance motor according to claim 1, characterized in that, The permanent magnets are magnetized radially, and the magnetization directions of the permanent magnets are the same.

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