Flywheel power supply having axial magnetic bearing for frictionless rotation

• US 6,262,505 B1
• Filed: 03/26/1997
• Issued: 07/17/2001
• Est. Priority Date: 03/26/1997
• Status: Expired due to Term

• Current Assignee: Perfect Galaxy International Limited
• Original Assignee: Satcon Technology Corporation
• Inventors: Lansberry, Geoffrey B., Bushko, Dariusz A., Stanton, William E., Nichols, Stephen B., OʼRourke, James, Serdar, Luka, Nimblett, Francis E., Rao, Gita P., Amaral, Michael E., Hockney, Richard L.
• Primary Examiner(s): TAMAI, KARL I
• Application Number:
  US08/824,862
• Time in Patent Office: 1,574 Days
• Field of Search: 310/74, 310/90.5, 310/51, 745/72, 745/74, 74/54.6, 244/165, 244/166
• US Class Current: 310/90.5
• CPC Class Codes: F16C 2361/55 Flywheel systems
• CPC Class Codes: F16C 2380/28 Motor, generator coupled with a flywheel
• CPC Class Codes: F16C 32/0442 with devices affected by abnormal, undesired or non-standard conditions such as shock-load, power outage, start-up or touchdown
• CPC Class Codes: F16C 32/0457 Details of the power supply to the electromagnets
• CPC Class Codes: F16F 15/03 using magnetic or electromagnetic means F16F9/53, F16F15/005 take precedence
• CPC Class Codes: F16F 15/315 characterised by their supporting arrangement, e.g. mountings, cages, securing inertia member to shaft F16F15/31 takes precedence
• CPC Class Codes: H02K 7/025 for power storage
• CPC Class Codes: H02K 7/083 radially supporting the rotary shaft at both ends of the rotor H02K7/086, H02K7/09 take precedence
• CPC Class Codes: H02K 7/09 with magnetic bearings
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids
• CPC Class Codes: Y10T 74/2131 Damping by absorbing vibration force [via rubber, elastomeric material, etc.]

Abstract

A power supply device for providing uninterrupted power for a period of time is disclosed. The power supply device has a controller and a flywheel device. The flywheel device has a housing that contains a flywheel rotor and a motor/generator rotor. The flywheel rotor and the motor/generator rotor are mounted on a common shaft. An active axial magnetic bearing is located to support the shaft for frictionless rotation. The bearing provides support for the shaft, the flywheel rotor and motor/generator rotor. The axial magnetic bearing is attached to the housing and provides, in combination with the motor/generator rotor, a flux path and magnetic field to exert a magnetic force to lift the motor/generator rotor and the shaft on which it is mounted.

Claims

1. A power supply device for providing uninterrupted power for a period of time,

the power supply device comprising a controller and a flywheel device,

the flywheel device comprising a housing containing a flywheel rotor and a motor/generator comprising a motor/generator rotor,

the flywheel rotor and the motor/generator rotor being mounted on a common shaft,

an active axial magnetic bearing comprising a coil surrounding the shaft and being located adjacent to the motor/generator rotor for frictionless rotation,

the bearing providing support for the shaft, the flywheel rotor and motor/generator rotor,

the axial magnetic bearing being attached to the housing and providing, in combination with the motor/generator rotor, a flux path and magnetic field tending to lift the motor/generator rotor and the shaft on which it is mounted,

wherein a single flux path extends through the motor/generator rotor and axial magnetic bearing providing the magnetic field tending to lift the motor/generator rotor and the shaft on which it is mounted.

2. The power supply device of claim 1, wherein the housing contains a vacuum.

3. The power supply device of claim 1, wherein the motor/generator is located between the axial magnetic bearing and the flywheel rotor.

4. The power supply device of claim 1, wherein a passive radial magnetic bearing is located at one end of the shaft.

5. The power supply device of claim 4, wherein the passive radial magnetic bearing off-loads about 70% of the weight of the shaft and rotors mounted thereon.

6. The power supply device of claim 1, wherein a passive radial magnetic bearing is located at both ends of the shaft.

7. The power supply device of claim 6, wherein the passive radial magnetic bearings off-load about 70% of the weight of the shaft and rotors mounted thereon.

8. The power supply device of claim 1, wherein the passive radial magnetic bearing comprises an axially polarized permanent magnet.

9. The power supply device of claim 8, further comprising a radial touchdown bearing.

10. The power supply device of claim 9, wherein the radial touchdown bearing comprises a ring of a polyimide material.

11. The power supply device of claim 8, wherein the axially polarized permanent magnet provides additional axial support for the shaft and rotors mounted thereon.

12. The power supply device of claim 8, wherein the axially polarized permanent magnet provides axial support for about 70% or more of the weight of the shaft and rotors mounted thereon.

13. The power supply device of claim 1, wherein the flywheel rotor has a rim comprising glass or carbon fibers in an epoxy matrix.

14. The power supply device of claim 1, wherein the motor/generator is a permanent magnet brushless device.

15. The power supply device of claim 14, further comprising a rotating return flux path for the permanent magnet brushless device.

16. The power supply device of claim 14, wherein the motor/generator has a 4 pole configuration.

17. The power supply device of claim 14, wherein the motor/generator comprises neodymium boron iron magnets.

18. The power supply device of claim 1, wherein the motor/generator is located along the shaft between the axial magnetic bearing and the flywheel rotor and wherein a passive radial magnetic bearing is located at one end of the shaft.

19. The power supply device of claim 18, wherein the passive radial magnetic bearing off-loads about 70% of the weight of the shaft and rotors mounted thereon.

20. A flywheel device comprising:

a housing containing a flywheel rotor and

a motor/generator comprising a motor/generator rotor,

the flywheel rotor and the motor/generator rotor being mounted on a common shaft,

an active axial magnetic bearing comprising a coil surrounding the shaft and being located adjacent to the motor/generator rotor for frictionless rotation, the bearing providing support for the shaft, the flywheel rotor and motor/generator rotor,

the axial magnetic bearing being connected to the housing and providing, in combination with the motor/generator rotor, a flux path and magnetic field tending to lift the motor/generator rotor and the shaft on which it is mounted,

wherein a single flux path extends through the motor/generator rotor and axial magnetic bearing providing the magnetic field tending to lift the motor/generator rotor and the shaft on which it is mounted.

21. The flywheel device of claim 20, wherein the housing contains a vacuum.

22. The flywheel device of claim 20, wherein the motor/generator is located between the axial magnetic bearing and the flywheel rotor.

23. The flywheel device of claim 20, wherein a passive radial magnetic bearing is located at one end of the shaft.

24. The flywheel device of claim 23, wherein the passive radial magnetic bearing off-loads about 70% of the weight of the shaft and rotors mounted thereon.

25. The flywheel device of claim 20, wherein a passive radial magnetic bearing is located at both ends of the shaft.

26. The flywheel device of claim 25, wherein the passive radial magnetic bearing off-loads about 70% of the weight of the shaft and rotors mounted thereon.

27. The flywheel device of claim 20, wherein the passive radial magnetic bearing comprises an axially polarized permanent magnet.

28. The flywheel device of claim 27, further comprising a radial touchdown bearing.

29. The flywheel device of claim 28, wherein the radial touchdown bearing is a ring comprising a polyimide material.

30. The flywheel device of claim 27, wherein the axially polarized permanent magnet provides additional axial support for the shaft and rotors mounted thereon.

31. The flywheel device of claim 27, wherein the axially polarized permanent magnet provides axial support for about 70% or more of the weight of the shaft and rotors mounted thereon.

32. The flywheel device of claim 20, wherein the flywheel rotor has a rim comprising glass or carbon fibers in an epoxy matrix.

33. The flywheel device of claim 20, wherein the motor/generator is a permanent magnet brushless device.

34. The flywheel device of claim 33, further comprising a rotating return flux path for the permanent magnet brushless device.

35. The flywheel device of claim 33, wherein the motor/generator has a 4 pole configuration.

36. The flywheel device of claim 33, wherein the motor/generator comprises neodymium boron iron magnets.

37. A backup power supply comprising a flywheel device according to claim 20.

38. The backup power supply of claim 37, comprising a plurality of flywheel devices connected in parallel.

39. A power supply device for providing uninterrupted power for a period of time, the power supply device comprising a controller and a flywheel device, the flywheel device comprising:

a housing containing a flywheel rotor and a motor/generator comprising a motor/generator rotor, the flywheel rotor and the motor/generator rotor being mounted on a common shaft, an active axial magnetic bearing being located to support the shaft for frictionless rotation, the bearing providing support for the shaft, the flywheel rotor and motor/generator rotor, the axial magnetic bearing being attached to the housing and providing, in combination with the motor/generator rotor, a flux path and magnetic field tending to lift the motor/generator rotor and the shaft on which it is mounted, wherein a single flux path extends through the motor/generator rotor and axial magnetic bearing providing the magnetic field tending to lift the motor/generator rotor and the shaft on which it is mounted,

the flywheel device further comprising a damping device positioned at one end of the shaft, the damping device comprising a plate member having a center bore and a sleeve positioned in the center bore and fitting around the shaft, the plate member having a chamber for containing a fluid, the chamber communicating with the center bore by means of a bore hole for fluid passage therebetween, the chamber containing a spring and a plug, the plug being located between the spring and the fluid to transfer a force from the spring to the fluid or the fluid to the spring.

40. A flywheel device comprising:

a housing containing a flywheel rotor and a motor/generator comprising a motor/generator rotor, the flywheel rotor and the motor/generator rotor being mounted on a common shaft, an active axial magnetic bearing being located to support the shaft for frictionless rotation, the bearing providing support for the shaft, the flywheel rotor and motor/generator rotor, the axial magnetic bearing being connected to the housing and providing, in combination with the motor/generator rotor, a flux path and magnetic field tending to lift the motor/generator rotor and the shaft on which it is mounted,

wherein the motor/generator is located between the axial magnetic bearing and the flywheel rotor,

wherein a single flux path extends through the motor/generator rotor and axial magnetic bearing providing the magnetic field tending to lift the motor/generator rotor and the shaft on which it is mounted,

the flywheel device further comprising a damping device positioned at one end of the shaft, the damping device comprising a plate member having a center bore and a sleeve positioned in the center bore and fitting around the shaft, the plate member having a chamber for containing a fluid, the chamber communicating with the center bore by means of a bore hole for fluid passage therebetween, the chamber containing a spring and a plug, the plug being located between the spring and the fluid to transfer a force from the spring to the fluid or the fluid to the spring.