Forced air stator ventilation system and stator ventilation method for superconducting synchronous machine

1. A synchronous machine comprising:

a rotor coupled to a rotor cooling system, wherein the rotor comprises a cylindrical rotor surface having longitudinal slots and conductive windings arranged in the slots;

a stator around the rotor and separated from the rotor by an annular gap defined by the rotor and an inner surface of the stator, wherein the stator includes at least one stator cooling passage, wherein the cooling passage is open to the annular gap to allow cooling fluid to flow between the gap and passage, and

a stator ventilation system in fluid communication with the at least one stator cooling passage, and said ventilation system including a cooling fluid driving device arranged at an outer periphery of the stator, wherein said cooling fluid driving device further comprises a mechanically moving cooling gas displacement device.

2. A synchronous machine as in claim 1 wherein said ventilation system further comprises a heat exchanger and the rotor is turbine driven.

3. A synchronous machine as in claim 1 wherein said rotor comprises a superconducting coil, said rotor cooling system provides cryogenic cooling fluid to said coil and the rotor is turbine driven.

4. A synchronous machine as in claim 1 which is an electromagnetic generator and the rotor is turbine driven.

5. A synchronous machine as in claim 1 which is a motor.

6. A synchronous machine as in claim 1 wherein said ventilation system is a forward flow ventilation system.

7. A synchronous machine as in claim 1 wherein said ventilation system is a reverse flow system.

8. A synchronous machine as in claim 1 wherein said ventilation system is a closed-loop system in which cooling gas circulates through the stator and a heat exchanger in a flow path of the gas.

9. A synchronous machine as in claim 1 wherein said ventilation system is an open-loop system in which cooling gas passes through the stator and the air gap, and exhausts to an environment outside of the machine.

10. A synchronous machine as in claim 1 further comprising a fan controller for regulating a speed of the fluid driving device.

11. A synchronous machine comprising:

a rotor coupled to a rotor cooling system, wherein the rotor comprises a cylindrical rotor surface having longitudinal slots and conductive windings arranged in the slots;

a stator around the rotor and separated from the rotor by an annular gap defined by the rotor and an inner surface of the stator, wherein the stator includes at least one stator cooling passage, wherein the cooling passage is open to the annular gap to allow cooling fluid to flow between the gap and passage, and

a stator ventilation system in fluid communication with the at least one stator cooling passage, and said ventilation system including a cooling fluid driving device arranged around an outer periphery of the stator,

wherein the cooling fluid driving device is at least one stator mounted fan.

12. A synchronous machine as in claim 11 wherein the at least one stator mounted fan is mounted on an outer periphery of annular ducts of the stator.

13. A synchronous machine comprising:

a rotor coupled to a rotor cooling system;

a stator around the rotor and separated from the rotor by an annular gap between the rotor and an inner surface of the stator, wherein the stator includes at least one stator cooling passage, and

a stator ventilation system in fluid communication with the at least one stator cooling passage, and said ventilation system including a cooling fluid driving device arranged around an outer periphery of the stator,

wherein the cooling fluid driving device is at least one stator mounted fan, and

wherein the at least one stator mounted fan is mounted radially outward of an end turn of a stator winding.

14. A superconducting electromagnetic machine comprising:

a rotor having a cryogenically cooled superconducting rotor coil winding, wherein the rotor comprises a cylindrical rotor surface having longitudinal slots and conductive windings arranged in the slots;

a stator coaxial with said rotor and having stator coils magnetically coupled with said superconducting rotor coil winding, said stator coils arranged around said rotor, and said stator having cooling passages extending from an inner periphery of the stator to an outer periphery of the stator, said inner periphery separated from the rotor by an annular air gap, wherein the cooling passages are open to the annular gap to allow cooling fluid to flow between the gap and passage;

said rotor coupled to a cryogenic cooling system;

a stator ventilation system providing cooling gas to said cooling passages of the stator, and said stator ventilation system further comprises at least one fan mounted around the stator.

15. A superconducting electromagnetic machine as in claim 14 further comprising a fan controller regulating a fan speed of the at least one fan.

16. A superconducting electromagnetic machine as in claims 15 wherein said fan controller receives a stator temperature signal, and the fan speed is regulated based on the stator temperature signal.

17. A superconducting electromagnetic machine as in claim 14 which is an electromagnetic generator.

18. A synchronous machine as in claim 14 which is a motor.

19. A superconducting electromagnetic machine as in claim 14 wherein said ventilation system is a forward flow ventilation system.

20. A superconducting electromagnetic machine as in claim 14 wherein said ventilation system is a reverse flow ventilation system.

21. A superconducting electromagnetic machine as in claim 14 wherein said ventilation system is a closed-loop system in which cooling gas circulates through the stator and a heat exchanger in a flow path of the gas.

22. A superconducting electromagnetic machine as in claim 14 wherein said ventilation system is an open loop system.