High-voltage flywheel energy storage system
A high-voltage flywheel energy storage system to prevent ionization, plasma formation, and electrical arc discharge and corresponding method are provided. The high-voltage flywheel energy storage system prevents ionization, plasma formation, and electrical arc discharge by isolating the motor windings and motor end windings from the partial vacuum environment existing in the flywheel housing.
1. A method for reducing ionization and plasma formation in a high-voltage flywheel energy storage system comprising:
providing a flywheel in a flywheel housing;
drawing a partial vacuum in the flywheel housing;
providing a motor/generator, the motor/generator having a rotor connected to the flywheel and a stator including, a motor winding;
preventing plasma formation in the motor winding by isolating the motor winding, from the partial vacuum in the flywheel housing,
wherein the motor/generator is retained in a motor/generator housing adjacent the flywheel housing,
wherein a fluid passageway extends between the flywheel housing and a portion of the motor/generator housing, and
wherein an interior pressure of a second portion of the motor/generator housing is ambient air pressure.
2. The method of claim 1 , wherein preventing plasma formation in the motor winding by isolating the motor winding includes encapsulating the motor winding in a non-electrically conductive material.
3. The method of claim 2 , wherein encapsulating the motor winding includes filling the interior of the stator with the material to displace air, gas, or vapor.
4. The method of claim 1 , further comprising operating the high-voltage flywheel energy storage system above approximately 300 volts.
5. The method of claim 4 , wherein operating the high-voltage flywheel energy storage system above approximately 300 volts includes operating below approximately 690 volts.
6. The method of claim 4 , further comprising operating the high-voltage flywheel energy storage system at approximately 440 volts.
7. The method of claim 4 , further comprising operating, the high-voltage flywheel energy storage system at approximately 460 volts.
8. The method of claim 4 , further comprising operating the high-voltage flywheel energy storage system at approximately 480 volts.
9. The method of claim 1 , wherein drawing a partial vacuum in the flywheel housing includes reducing the interior pressure of the flywheel housing to approximately 0.01 Torr.
10. The method of claim 1 , wherein drawing a partial vacuum in the flywheel housing includes reducing the interior pressure of the flywheel housing to below approximately 0.01 Torr.
11. The method of claim 1 , wherein drawing a partial vacuum in the flywheel housing includes reducing the interior pressure of the flywheel housing to approximately 1×10 −4 Torr.
12. The method of claim 1 , wherein drawing the partial vacuum in the flywheel housing reduces an interior pressure within a portion of the motor/generator housing.
13. The method of claim 12 , wherein the rotor resides in the portion of the motor/generator housing.
14. The method of claim 1 , wherein drawing the partial vacuum in the flywheel housing creates a partial vacuum in the portion of the motor/generator housing containing the rotor.
15. The method of claim 1 , further comprising a seal positioned between the flywheel housing and the motor/generator housing.
16. The method of claim 15 , wherein the seal is a non-contact seal, a magnetic liquid rotary seal, or a labyrinth seal.