Bearingless flywheel systems, winding and control schemes, and sensorless control

Patent metadata

Field	Value
Publication number	US-9515531-B2
Application number	US-201213723598-A
Country	US
Kind code	B2
Filing date	Dec 21, 2012
Priority date	Dec 23, 2011
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

Flywheel systems are disclosed that provide increased energy density and operational effectiveness. A first bearingless motor and a second bearingless motor may be configured to simultaneously suspend the central rotor in a radial direction and to rotate the central rotor. However, certain implementations may have one motor or more than two motors, depending on the design. A plurality of the flywheel systems may be collectively controlled to perform community energy storage with higher storage capacities than individual flywheel systems.

First claim

The invention claimed is:

1. An apparatus, comprising:
a central rotor configured as a flywheel to store energy, said central rotor extending vertically and rotating about a vertical axis;
a magnetic bearing located above the central rotor to levitate the rotor along the vertical axis;
a first bearingless motor located above the central rotor; and
a second bearingless motor located below the central rotor; wherein
the first bearingless motor and the second bearingless motor are configured to simultaneously suspend the central rotor in a radial direction relative to the vertical axis and to rotate the central rotor about the vertical axis;
an active or a passive axial magnetic bearing configured to provide axial control of the central rotor; and
wherein the active or passive magnetic bearing has a magnet bias configured to lift a portion or all of a weight of the central rotor near a nominal gap without current.

2. The apparatus of claim 1 , wherein a combination of a mass, a radius, and a speed of the central rotor are sufficient to operate the apparatus as a generator continuously for greater than fifteen minutes.

3. The apparatus of claim 1 , wherein the central rotor has a cylindrical shape.

4. The apparatus of claim 1 , wherein the first bearingless motor and the second bearingless motor are configured to suspend the central rotor in a non-vertical direction.

5. The apparatus of claim 1 , wherein the first bearingless motor and the second bearingless motor comprise bearingless motor/generators.

6. The apparatus of claim 1 , wherein at least one of the first bearingless motor and the second bearingless motor comprises a rotor outside of a stator.

7. The apparatus of claim 1 , further comprising:
a vacuum housing in which the central rotor spins, thereby eliminating power losses due to air drag.

8. The apparatus of claim 1 , wherein the bearingless motors and axial magnetic bearings are configured to utilize power electronics to interface with the power grid or external power bus.

9. An apparatus, comprising:
a central rotor configured as a flywheel to store energy, said central rotor extending vertically and rotating about a vertical axis;
a magnetic bearing located above the central rotor to levitate the rotor along the vertical axis;
a first bearingless motor located above the central rotor; and
a second bearingless motor located below the central rotor; wherein
the first bearingless motor and the second bearingless motor are configured to simultaneously suspend the central rotor in a radial direction relative to the vertical axis and to rotate the central rotor about the vertical axis;
an active or a passive axial magnetic bearing configured to provide axial control of the central rotor; and
wherein the active or passive magnetic bearing comprises:
a mounting ring configured to hold parts of the active or passive axial magnetic bearing;
a magnetic inner pole and a magnetic outer pole;
a magnet ring; and
a coil positioned between the inner pole and the outer pole.

10. An apparatus, comprising:
a central rotor configured as a flywheel to store energy, said central rotor extending vertically and rotating about a vertical axis;
a magnetic bearing located above the central rotor to levitate the rotor along the vertical axis;
a first bearingless motor located above the central rotor; and
a second bearingless motor located below the central rotor; wherein
the first bearingless motor and the second bearingless motor are configured to simultaneously suspend the central rotor in a radial direction relative to the vertical axis and to rotate the central rotor about the vertical axis;
a mechanical touchdown bearing system configured to support the central rotor when a levitation system is not powered, and/or during a failure of the levitation system;
where in the mechanical touchdown bearing system comprises:
one or more bearings configured to support axial and radial loads;
one or more touchdown surfaces configured to provide an interface between the central rotor and the one or more bearings; and
one or more spring/damper mounting structures configured to limit a force and displacement of the central rotor when operating on the mechanical touchdown bearing system.

11. The apparatus of claim 10 , wherein a combination of a mass, a radius, and a speed of the central rotor are sufficient to operate the apparatus as a generator continuously for greater than fifteen minutes.

12. The apparatus of claim 10 , wherein the central rotor has a cylindrical shape.

13. The apparatus of claim 10 , wherein the first bearingless motor and the second bearingless motor are configured to suspend the central rotor in a non-vertical direction.

14. The apparatus of claim 10 , wherein the first bearingless motor and the second bearingless motor comprise bearingless motor/generators.

15. The apparatus of claim 10 , wherein at least one of the first bearingless motor and the second bearingless motor comprises a rotor outside of a stator.

16. The apparatus of claim 10 , further comprising:
a vacuum housing in which the central rotor spins, thereby eliminating power losses due to air drag.

17. The apparatus of claim 10 , wherein the bearingless motors and axial magnetic bearings are configured to utilize power electronics to interface with the power grid or external power bus.

18. An apparatus, comprising;
a central rotor configured as a flywheel to store energy, said central rotor extending vertically and rotating about a vertical axis;
a magnetic bearing located above the central rotor to levitate the rotor along the vertical axis;
a first bearingless motor located above the central rotor; and
a second bearingless motor located below the central rotor; wherein
the first bearingless motor and the second bearingless motor are configured to simultaneously suspend the central rotor in a radial direction relative to the vertical axis and to rotate the central rotor about the vertical axis;
wherein operation of the apparatus is controlled by a control system;
wherein the control system comprises:
a supervisory controller configured to control overall operation of the apparatus and to interface with local and remote users;
one or more motor current controllers configured to provide commands to motor power electronics;
one or more magnetic bearing controllers configured to provide commands to magnetic bearing power electronics; and
a DC bus, force, torque, and speed controller configured to regulate a local power bus and to provide commands to the one or more motor current controller and the one or more magnetic bearing controllers.

19. The apparatus of claim 18 , wherein a combination of a mass, a radius, and a speed of the central rotor are sufficient to operate the apparatus as a generator continuously for greater than fifteen minutes.

20. The apparatus of claim 18 , wherein the first bearingless motor and the second bearingless motor are configured to suspend the central rotor in a non-vertical direction.

Assignees

• Nasa
• The Us Administrator Of Nat Aeronautics And Space Administration

Inventors

• Jansen Ralph H
• Trase Larry M
• Dever Timothy P
• Kascak Peter E
• Kraft Thomas G

Classifications

• H02K7/09 Primary

  with magnetic bearings · CPC title

• H02K7/025

  for power storage · CPC title

• F16C32/0497

  generating torque and radial force · CPC title

• Y02E60/16

  Mechanical energy storage, e.g. flywheels or pressurised fluids · CPC title

• H02K5/16

  Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields (magnetic bearings H02K7/09) · CPC title