Uninterruptible power supplies having cooled components

• US 5,801,937 A
• Filed: 10/16/1996
• Issued: 09/01/1998
• Est. Priority Date: 10/16/1996
• Status: Expired due to Fees

• Current Assignee: American Superconductor Corporation
• Original Assignee: American Superconductor Corporation
• Inventors: Gold, Calman, Gran, Richard J.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Han, Y. J.
• Application Number:
  US08/732,029
• Time in Patent Office: 685 Days
• Field of Search: 363/34, 363/37, 363/40, 363/95, 363/97, 363/141, 307/46, 307/48, 307/64, 307/66, 307/85, 307/86, 307/87, 252/67, 252/68
• US Class Current: 363/141
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 7/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y04S 20/20 End-user application control systems

Abstract

Methods and apparatus for uninterruptible power supply (UPS) systems are provided. The UPS systems are configured to provide the advantages of an in-line device, and operate in a quasi-standby mode. The UPS includes a rectifier unit and inverter arranged to nominally deliver a portion (e.g. up to about 20%) of the primary AC power supply to a critical load through an output transformer. The rectifier unit preferably includes internal energy storage capabilities, such as a capacitor and inductor. The remaining portion of the AC power supply is nominally supplied directly to the critical load and is controlled by a transfer switch and the output transformer. When a fault is detected in the main AC power supply, the transfer switch switches to a faulted position and power is supplied from the rectifier inductor and capacitor or from a battery to the load through the inverter. Electronic switches such as MOSFETs are provided in the system to control the supply of power from the battery (or other energy storage device) to the inverter and to control the charging and discharging of the battery. The inverter and MOSFETs are designed to withstand transient overpower and overcurrent operation without deleterious consequences by liquid cooling the inverter or the inverter and the MOSFETs under predetermined conditions to temperatures between about 60 K and 270 K.

Claims

1. An uninterruptible power supply system, comprising:

a primary AC power supply;

an input transformer connected to the primarily AC power supply;

a transfer switch connected to the input transformer;

an output transformer connected to the transfer switch and connected to deliver a first portion of the primary AC power supply to a load under predetermined conditions;

rectification means connected to the input transformer;

an inverter connected to the rectification means and connected to deliver a second portion of the primary AC power supply to a load through the output transformer under predetermined conditions;

cooling means for maintaining the inverter within a predetermined temperature range;

at least one electronic switch connected to the inverter; and

energy storage means connected to the at least one electronic switch and connected to deliver power to the inverter under predetermined conditions.

2. The uninterruptible power supply system of claim 1, wherein the at least one electronic switch is configured to control the discharging of the energy storage means to the inverter under predetermined conditions.

3. The uninterruptible power supply system of claim 2, wherein the cooling means is configured to cool the at least one electronic switch and the inverter.

4. The uninterruptible power supply system of claim 3, wherein the rectification means includes internal energy storage means.

5. The uninterruptible power supply system of claim 4, wherein the internal energy storage means includes at least one capacitor.

6. The uninterruptible power supply system of claim 3, wherein the rectification means further includes at least one inductor.

7. The uninterruptible power supply system of claim 5 or 6, wherein the at least one electronic switch is at least one MOSFET, at least one IGBT or at least one FREDFET.

8. The uninterruptible power supply system of claim 7, wherein the inverter is a 300 kW inverter.

9. The uninterruptible power supply system of claim 5 or 6, wherein the energy storage means is a battery.

10. The uninterruptible power supply system of claim 5 or 6, wherein the transfer switch is a solid state transfer switch.

11. The uninterruptible power supply system of claim 10, wherein the solid state transfer switch is an IGBT switch.

12. The uninterruptible power supply system of claim 1, wherein the cooling means includes immersing the inverter in a cooling liquid.

13. The uninterruptible power supply system of claim 12, wherein the cooling liquid is nitrogen.

14. The uninterruptible power supply system of claim 13, wherein the liquid nitrogen maintains the inverter at a temperature of about 77 K.

15. The uninterruptible power supply system of claim 1, wherein the cooling means includes a cooling liquid that maintains the inverter at a temperature between 60 K to 270 K.

16. The uninterruptible power supply system of claim 15, wherein the cryogenic liquid is chemically inert.

17. The uninterruptible power supply system of claim 15, wherein the cryogenic liquid is nontoxic.

18. The uninterruptible power supply system of claim 15, wherein the cryogenic liquid is not hazardous to the environment.

19. The uninterruptible power supply system of claim 15, wherein the cryogenic liquid is a dielectric cryogenic liquid.

20. The uninterruptible power supply system of claim 15, wherein the cryogenic liquid is non-flammable.

21. The uninterruptible power supply system of claim 15, wherein the cryogenic liquid is non-ozone deleting.

22. The uninterruptible power supply system of claim 15, wherein the cryogenic liquid is a chlorine-free fluorocarbon or a mixture of chlorine-free fluorocarbons.

23. The uninterruptible power supply system of claim 22, wherein the number of carbons in the fluorocarbon or fluorocarbons is in the range of 2 to 5.

24. The uninterruptible power supply system of claim 22, wherein the fluorocarbon is completely halogenated.

25. The uninterruptible power supply system of claim 22, wherein the fluorocarbon is a fluoroalkane.

26. The uninterruptible power supply system of claim 25, wherein the fluorocarbon is heptafluoropropane.

27. The uninterruptible power supply system of claim 26, wherein the heptafluoropropane is 1,1,1,2,3,3,3-heptafluoropropane.

28. The uninterruptible power supply system of claim 26, wherein the heptafluoropropane is 1,1,1,2,2,3,3-heptafluoropropane.

29. The uninterruptible power supply system of claim 26, wherein the fluoroalkane is completely halogenated.

30. The uninterruptible power supply system of claim 29, wherein the fluoroalkane is octafluoropropane.

31. The uninterruptible power supply system of claim 29, wherein the fluoroalkane is decafluoro n-butane.

32. The uninterruptible power supply system of claim 29, wherein the fluoroalkane is decafluoro isobutane.

33. The uninterruptible power supply system of claim 29, wherein the fluoroalkane is a mixture of fluoroalkanes selected from the group consisting of octafluoropropane, decafluoro n-butane and decafluoro isobutane.

34. The uninterruptible power supply system of claim 29, wherein the fluoroalkane is dodecafluoropentane, isomers of dodecafluoropentane or mixtures thereof.

35. An power supply system, comprising:

a primary AC power supply;

an input transformer connected to the primary AC power supply;

a transfer switch connected to the input transformer;

an output transformer connected to the transfer switch and connected to deliver at a first portion of the primary AC power supply to a load;

rectification means connected to the input transformer, the rectification means including internal energy storage means;

an inverter including a plurality of semiconductor switches, the inverter connected to the rectification means and connected to deliver a second portion of the primary AC power supply to a load through the output transformer, the power provided by the inverter to the load characterized in that transients in the primary AC power supply do not affect the load;

cooling means for maintaining the inverter having the plurality of semiconductor switches at a predetermined temperature;

at least one electronic switch connected to the inverter; and

energy storage means connected to the at least one electronic switch and connected to deliver power to the inverter under predetermined conditions.

36. The power supply system of claim 35, wherein the transfer switch is a solid state transfer switch.

37. The power supply system of claim 36, wherein the solid state transfer switch is an IGBT switch.

38. The power supply system of claim 35, wherein the cooling means includes immersing the inverter in a cooling liquid.

39. The power supply system of claim 38, wherein the cooling liquid is nitrogen.

40. The power supply system of claim 39, wherein the liquid nitrogen maintains the inverter at a temperature of about 77 K.

41. The power supply system of claim 35, wherein the cooling means includes a cooling liquid that maintains the inverter at a temperature between 60 K and 270 K.

42. The power supply system of claim 41, wherein the cooling liquid is chemically inert.

43. The power supply system of claim 41, wherein the cooling liquid is nontoxic.

44. The power supply system of claim 41, wherein the cryogenic liquid is not hazardous to the environment.

45. The power supply system of claim 41, wherein the cooling liquid is a dielectric cryogenic liquid.

46. The power supply system of claim 41, wherein the cooling liquid is nonflammable.

47. The power supply system of claim 41, wherein the cooling liquid is non-ozone deleting.

48. The power supply system of claim 41, wherein the cooling liquid is a chlorine-free fluorocarbon or a mixture of chlorine-free fluorocarbons.

49. The power supply system of claim 48, wherein the number of carbons in the fluorocarbon or fluorocarbons is in the range of 2 to 5.

50. The power supply system of claim 48, wherein the fluorocarbon is completely halogenated.

51. The power supply system of claim 48, wherein the fluorocarbon is a fluoroalkane.

52. The power supply system of claim 51, wherein the fluorocarbon is heptafluoropropane.

53. The power supply system of claim 52, wherein the heptafluoropropane is 1,1,1,2,3,3,3-heptafluoropropane.

54. The power supply system of claim 52, wherein the heptafluoropropane is 1,1,1,2,2,3,3-heptafluoropropane.

55. The power supply system of claim 51, wherein the fluoroalkane is completely halogenated.

56. The power supply system of claim 55, wherein the fluoroalkane is octafluoropropane.

57. The power supply system of claim 55, wherein the fluoroalkane is decafluoro n-butane.

58. The power supply system of claim 55, wherein the fluoroalkane is decafluoro isobutane.

59. The power supply system of claim 55, wherein the fluoroalkane is a mixture of fluoroalkanes selected from the group consisting of octafluoropropane, decafluoro n-butane and decafluoro isobutane.

60. The uninterruptible power supply system of claim 55, wherein the fluoroalkane is dodecafluoropentane, isomers of dodecafluoropentane or mixtures thereof.

61. The uninterruptible power supply system of claim 35, wherein the plurality of semiconductor switches include MOSFETs or IGBTS.