ACTIVE MAGNETIC BEARING ASSEMBLY USING PERMANENT MAGNET BIASED HOMOPOLAR AND RELUCTANCE CENTERING EFFECTS

• US 20030141773A1
• Filed: 01/30/2002
• Published: 07/31/2003
• Est. Priority Date: 01/30/2002
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Abel, Stephen G.
• Granted Patent: US 6,603,230 B1
• Time in Patent Office: Days
• US Class Current: 310/90.5
• CPC Class Codes: F16C 32/0444 Details of devices to control the actuation of the electromagnets
• CPC Class Codes: F16C 32/0489 with active support of five degrees of freedom, e.g. two radial magnetic bearings combined with an axial bearing
• CPC Class Codes: H02K 7/09 with magnetic bearings

Abstract

An active magnetic bearing assembly includes at least two rotors and two stator assemblies each having two pole faces. The pole faces of the stator assemblies are axially offset from the pole faces of their associated rotors. Thus, axial control of a shaft that is rotationally mounted using the active magnetic bearing assembly is provided by a reluctance centering force.

Claims

1. An active magnetic bearing assembly for rotationally mounting a shaft in a non-contact manner, the bearing assembly comprising:

a first bearing rotor having at least a first pole face and a second pole face;

a first stator assembly spaced radially outwardly of the first bearing rotor and having at least a first pole face and a second pole face that are axially offset from the first bearing rotor first pole face and second pole face, respectively, by a first predetermined distance in a first direction;

a second bearing rotor having at least a first pole face and a second pole face; and

a second stator assembly spaced radially outwardly of the second bearing rotor and having at least a first pole face and a second pole face that are axially offset from the second bearing rotor first pole face and second pole face, respectively, by a second predetermined distance and in a second predetermined direction that is opposite the first predetermined direction.

2. The magnetic bearing assembly of claim 1, wherein:

the first bearing rotor is coupled to the shaft at a first predetermined position on the shaft; and

the second bearing rotor is coupled to the shaft at a second predetermined position on the shaft.

3. The magnetic bearing assembly of claim 1, wherein the first and second stator assemblies each comprise:

a first stator body having at least one first coil wound pole extending radially inwardly therefrom, each first coil wound pole having a first pole face;

a second stator body having at least one second coil wound pole extending radially inwardly therefrom, each second coil wound pole positioned parallel to one of the first coil wound poles, and each having a second pole face; and

an axially polarized permanent magnet interposed between, and coupling together, the first and the second stator bodies.

4. The magnetic bearing assembly of claim 3, wherein the axially polarized permanent magnet in each bearing stator assembly supplies a permanent magnet force bias to its associated bearing rotor.

5. The magnetic bearing assembly of claim 3, wherein the first and second stator bodies each include eight substantially evenly spaced coil wound poles.

8. The magnetic bearing assembly of claim 1, wherein the first bearing rotor and first bearing stator, and the second bearing rotor and second bearing stator are each configured as homopolar magnetic bearings.

9. The magnetic bearing assembly of claim 1, further comprising:

a first axially polarized permanent magnet coupled to one of the first and second stator assemblies; and

a second axially polarized permanent magnet coupled to the shaft proximate the first axially polarized permanent magnet,

wherein the first and second axially polarized permanent magnets are oriented to repel one another.

6. The magnetic bearing assembly of clam 5, wherein selected adjacent coil wound poles on each of the first stator bodies are wound together with selected adjacent coil wound poles on their respective second stator bodies to form a single electromagnetic actuator.

7. The magnetic bearing assembly of claim 6, wherein the total number of electromagnetic actuators is four per stator assembly.

10. An energy storage flywheel assembly, comprising:

a shaft;

a flywheel coupled to the shaft; and

an active magnetic bearing assembly for rotationally mounting the shaft in a non-contact manner, the magnetic bearing assembly comprising;

a first bearing rotor coupled to the shaft on a first side of the flywheel and having at least a first pole face and a second pole face;

a first stator assembly spaced radially outwardly of the first bearing rotor and having at least a first pole face and a second pole face that are axially offset from the first bearing rotor first pole face and second pole face, respectively, by a first predetermined distance in a first direction;

a second bearing rotor coupled to the shaft on a second side of the flywheel, opposite the first side, and having at least a first pole face and a second pole face; and

a second stator assembly spaced radially outwardly of the second bearing rotor and having at least a first pole face and a second pole face that are axially offset from the second bearing rotor first pole face and second pole face, respectively, by a second predetermined distance and in a second predetermined direction that is opposite the first predetermined direction.

11. The energy storage flywheel of claim 10, wherein:

the first bearing rotor is coupled to the shaft at a first predetermined position on the shaft; and

the second bearing rotor is coupled to the shaft at a second predetermined position on the shaft.

12. The energy storage flywheel of claim 10, wherein the first and second stator assemblies each comprise:

a first stator body having at least one first coil wound pole extending radially inwardly therefrom, each first coil wound pole having a first pole face;

a second stator body having at least one second coil wound pole extending radially inwardly therefrom, each second coil wound pole positioned parallel to one of the first coil wound poles, and each having a second pole face; and

an axially polarized permanent magnet interposed between, and coupling together, the first and the second stator bodies.

13. The energy storage flywheel of claim 12, wherein the axially polarized permanent magnet in each bearing stator assembly supplies a permanent magnet force bias to its associated bearing rotor.

14. The energy storage flywheel of claim 12, wherein the first and second stator bodies each include eight substantially evenly spaced coil wound poles.

17. The energy storage flywheel of claim 10, wherein the first bearing rotor and first bearing stator, and the second bearing rotor and second bearing stator are each configured as homopolar magnetic bearings.

18. The energy storage flywheel of claim 10, further comprising:

a motor/generator operably coupled to the shaft.

19. The energy storage flywheel of claim 10, further comprising:

a first axially polarized permanent magnet coupled to one of the first and second stator assemblies; and

a second axially polarized permanent magnet coupled to one of the first and second sides of the flywheel, proximate the first axially polarized permanent magnet,

wherein the first and second axially polarized permanent magnets are oriented to repel one another.

15. The energy storage flywheel of clam 14, wherein selected adjacent coil wound poles on each of the first stator bodies are wound together with selected adjacent coil wound poles on their respective second stator bodies to form a single electromagnetic actuator.

16. The energy storage flywheel of claim 15, wherein the total number of electromagnetic actuators is four per stator assembly.

20. An apparatus for imparting rotational motion to a shaft, comprising:

a shaft;

a rotational motion imparting device coupled to the shaft; and

an active magnetic bearing assembly for rotationally mounting the shaft in a non-contact manner, the magnetic bearing assembly comprising;

a first bearing rotor coupled to the shaft on a first side of the flywheel and having at least a first pole face and a second pole face;

a first stator assembly spaced radially outwardly of the first bearing rotor and having at least a first pole face and a second pole face that are axially offset from the first bearing rotor first pole face and second pole face, respectively, by a first predetermined distance in a first direction;

a second bearing rotor coupled to the shaft on a second side of the flywheel, opposite the first side, and having at least a first pole face and a second pole face; and

a second stator assembly spaced radially outwardly of the second bearing rotor and having at least a first pole face and a second pole face that are axially offset from the second bearing rotor first pole face and second pole face, respectively, by a second predetermined distance and in a second predetermined direction that is opposite the first predetermined direction.

21. The apparatus of claim 20, wherein:

the first bearing rotor is coupled to the shaft at a first predetermined position on the shaft; and

the second bearing rotor is coupled to the shaft at a second predetermined position on the shaft.

22. The apparatus of claim 20, wherein the first and second stator assemblies each comprise:

a first stator body having at least one first coil wound pole extending radially inwardly therefrom, each first coil wound pole having a first pole face;

a second stator body having at least one second coil wound pole extending radially inwardly therefrom, each second coil wound pole positioned parallel to one of the first coil wound poles, and each having a second pole face; and

an axially polarized permanent magnet interposed between, and coupling together, the first and the second stator bodies.

23. The apparatus of claim 22, wherein the axially polarized permanent magnet in each bearing stator assembly supplies a permanent magnet force bias to its associated bearing rotor.

24. The apparatus of claim 22, wherein the first and second stator bodies each include eight substantially evenly spaced coil wound poles.

27. The apparatus of claim 20, wherein the first bearing rotor and first bearing stator, and the second bearing rotor and second bearing stator are each configured as homopolar magnetic bearings.

28. The apparatus of claim 20, wherein the rotational force imparting device comprises a motor.

29. The apparatus of claim 20, wherein the rotational force imparting device comprises a turbine wheel.

30. The magnetic bearing assembly of claim 20, further comprising:

a first axially polarized permanent magnet coupled to one of the first and second stator assemblies; and

a second axially polarized permanent magnet coupled to the shaft proximate the first axially polarized permanent magnet,

wherein the first and second axially polarized permanent magnets are oriented to repel one another.

25. The apparatus of clam 24, wherein selected adjacent coil wound poles on each of the first stator bodies are wound together with selected adjacent coil wound poles on their respective second stator bodies to form a single electromagnetic actuator.

26. The apparatus of claim 25, wherein the total number of electromagnetic actuators is four per stator assembly.

31. A satellite, comprising:

a housing;

at least one component having a shaft, the component positioned within the housing; and

an active magnetic bearing assembly for rotationally mounting the shaft in a non-contact manner, the bearing assembly comprising;

a first bearing rotor having at least a first pole face and a second pole face,

a first stator assembly spaced radially outwardly of the first bearing rotor and having at least a first pole face and a second pole face that are axially offset from the first bearing rotor first pole face and second pole face, respectively, by a first predetermined distance in a first direction,

a second bearing rotor having at least a first pole face and a second pole face, and

a second stator assembly spaced radially outwardly of the second bearing rotor and having at least a first pole face and a second pole face that are axially offset from the second bearing rotor first pole face and second pole face, respectively, by a second predetermined distance and in a second predetermined direction that is opposite the first predetermined direction.