Claims
- 1. A flywheel system comprising:
a flywheel mass supported by electromagnetic bearings said flywheel mass being rotatably coupled to a motor-generator for bi-directionally exchanging mechanical energy with said motor-generator; and, a backup generator rotatably coupled to said flywheel mass for unidirectionally converting mechanical energy from said flywheel mass into electrical power for providing backup electrical power to said electromagnetic bearings.
- 2. The flywheel system of claim 1 wherein said motor-generator is a variable speed synchronous reluctance machine and said backup generator is a variable speed permanent magnet machine.
- 3. The flywheel system of claim 2 wherein a unidirectional AC-to-DC electric power converter electrically interconnects said backup generator to a first DC bus.
- 4. The flywheel system of claim 3 wherein a bi-directional DC-to-DC electric power converter electrically interconnects said first DC bus to a second DC bus.
- 5. The flywheel system of claim 4 wherein said electromagnetic bearings are electrically connected to said second DC bus.
- 6. The flywheel system of claim 5 wherein a bi-directional AC-to-DC electric power converter interconnects said motor-generator and said second DC bus.
- 7. The flywheel system of claim 6 wherein said first DC bus exchanges electric power bi-directionally with an electrical network.
- 8. A flywheel system comprising:
a flywheel mass attached to a flywheel shaft wherein the flywheel mass and shaft share a common axis of rotation; at least one electromagnetic bearing having an electromagnet adjacent to a ferromagnetic portion of the shaft; and, a backup generator for providing electrical power to at least one electromagnetic bearing said generator having an electrical stator adjacent to a permanent magnet portion of the shaft.
- 9. The flywheel system of claim 8 wherein the ferromagnetic portion of the shaft includes a plurality of magnetic steel laminates.
- 10. The flywheel system of claim 9 wherein the permanent magnet portion of the shaft includes a permanent magnet embedded in the shaft.
- 11. The flywheel system of claim 10 including a motor-generator rotatably coupled to the flywheel.
- 12. The flywheel system of claim 11 wherein the motor-generator is a variable speed synchronous reluctance machine.
- 13. The flywheel system of claim 12 wherein a unidirectional AC-to-DC electric power converter electrically interconnects said backup generator to a first DC bus.
- 14. The flywheel system of claim 13 wherein a bi-directional DC-to-DC electric power converter electrically interconnects said first DC bus to a second DC bus.
- 15. The flywheel system of claim 14 wherein at least one of said electromagnetic bearings is electrically connected to the second DC bus.
- 16. The flywheel system of claim 15 wherein a bi-directional AC-to-DC electric power converter interconnects said motor-generator and said second DC bus.
- 17. The flywheel system of claim 16 wherein the first DC bus exchanges electric power with an electric network.
- 18. A method of safely stopping a flywheel during a power outage comprising the steps of;
providing a flywheel having a backup AC generator formed by an electrical stator adjacent to a permanent magnet portion of said flywheel; electrically connecting a unidirectional AC-to-DC electric power converter to said electrical stator; and, providing a DC bus for electrically interconnecting the DC output of said AC to DC electric power converter and electric loads critical to safe flywheel shutdown.
- 19. The method of claim 18 above wherein at least one electromagnetic bearing is a load critical to safe flywheel shutdown.
- 20. The method of claim 19 above wherein the electromagnetic bearing includes a fixed electromagnet adjacent to a ferromagnetic portion of the shaft said portion formed from ferromagnetic laminates having electrical insulation interposed between them.
Parent Case Info
[0001] This application claims priority from Provisional Application 60/476,226 filed Jun. 6, 2003.
Provisional Applications (1)
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Number |
Date |
Country |
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60476226 |
Jun 2003 |
US |