Uninterruptible power supply with direction of DC electrical energy depending on predetermined ratio

• US 5,978,236 A
• Filed: 01/30/1998
• Issued: 11/02/1999
• Est. Priority Date: 01/31/1997
• Status: Expired due to Fees

• Current Assignee: Silverline Power Conversion LLC
• Original Assignee: Silverline Power Conversion LLC
• Inventors: Faberman, Ira S., Mills, Floyd
• Primary Examiner(s): BERHANE, ADOLF D
• Application Number:
  US09/016,170
• Time in Patent Office: 641 Days
• Field of Search: 363/17, 363/24, 363/37, 363/41, 363/55, 363/131, 363/132, 363/133, 307/64, 307/66
• US Class Current: 363/37
• CPC Class Codes: H02J 9/061 for DC powered loads
• CPC Class Codes: H02J 9/067 using multi-primary transformers, e.g. transformer having one primary for each AC energy source and a secondary for the loads
• CPC Class Codes: H02M 3/33584 Bidirectional converters

Abstract

An uninterruptible power supply is disclosed in which the backup energy source is connected to the power supply of the protected computer by means of a bi-directional power converter. This converter operates without sensing circuitry, relays, or switches, operating continuously when a load is present in either charging or discharging the backup energy source. This uninterruptible power supply can be placed within the available space of a functioning standard computer power supply enclosure, and may be configured so that it may be replaced during normal computer operation (i.e. it is "hot swappable"). Methods are described to interface the uninterruptible power supply to the computer, providing mutual control and communication. The device may be also used to power devices requiring external DC power, which are commonly found in association with computer operations.

Claims

1. An uninterruptible power supply for a source of DC power comprising:

(a) a restorable source of stored energy wherein the energy may be released and restored in DC electrical form; and

(b) a bi-directional converter including a transformer device having a turns ratio, and a plurality of switch devices that change between open and closed states to couple the stored energy source to the DC power source, wherein the power converter continuously operates, directing energy either toward the source of DC power from the source of stored energy or toward the source of stored energy from the source of DC power, wherein the direction of electrical energy flow depends upon the deviation of the ratio of the potential of the source of DC power and the potential of the source of stored energy from a predetermined ratio that is related to said turns ratio, and in which the direction of DC electrical energy is independent of said states of said switch devices.

2. The uninterruptible power supply of claim 1 wherein the restorable source of stored energy is a rechargeable battery.

3. The uninterruptible power supply of claim 1 wherein the source of DC power is the source of rectified DC voltage at the input of a switching power supply.

4. The uninterruptible power supply of claim 1 wherein the energy directed between the source of DC power and the source of stored energy is in the form of electrical current, wherein the magnitude of current directed toward the source of DC power from the source of stored energy or toward the source of stored energy from the source of DC power is controllable.

5. The uninterruptible power supply of claim 4 wherein the magnitude of current is controlled through means of pulse width modulation.

6. The uninterruptible power supply of claim 4 wherein the magnitude of current is controlled through duty cycle modulation at substantially constant frequency of substantially constant pulse widths.

7. The uninterruptible power supply of claim 4 wherein the magnitude of current is controlled through frequency modulation of substantially constant pulse widths.

8. The uninterruptible power supply of claim 1 wherein the restorable source of stored energy may be disconnected from the bi-directional power converter without interrupting the proper operation of devices that draw power from the source of DC power.

9. The uninterruptible power supply of claim 1 wherein the bi-directional power converter may be disconnected from the source of DC power without interrupting the proper operation of devices which draw power from the source of DC power.

10. The uninterruptible power supply of claim 9 wherein when the bi-directional power converter is disconnected from the DC power source, the bi-directional power converter contains less than 75% of the stored energy of the DC power source.

11. The uninterruptible power supply of claim 1, wherein the energy directed between the source of DC power and the source of stored energy is in the form of electrical current, wherein the magnitude of electrical current made available in either direction is greater than or equal to the inverse of the predetermined ratio of the potential of the source of DC power and the potential of the source of stored energy used in determining current direction.

12. The uninterruptible power supply of claim 11, wherein the magnitude of electrical current that can flow in the direction of the source of stored energy is greater than 10 amperes.

13. The uninterruptible power supply of claim 1, wherein the source of stored energy is maintained in parallel with a second source of stored energy.

14. The uninterruptible power supply of claim 13, wherein the second source of stored energy is connected through a unidirectional current device.

15. The uninterruptible power supply of claim 13, wherein the second source of stored energy is restorable.

16. The uninterruptible power supply of claim 1, wherein the source of DC power is a computer power supply located in a computer.

17. The uninterruptible power supply of claim 16, wherein the uninterruptible power supply is contained within the enclosure of the computer power supply.

18. The uninterruptible power supply of claim 16, wherein the uninterruptible power supply detects inadequate cooling within the computer power supply within which it is contained, and causes an alert to be produced that is from the set comprising audible and visual alerts.

19. The uninterruptible power supply of claim 16, wherein the uninterruptible power supply is removable from computer power supply while the power supply is energized.

20. The uninterruptible power supply of claim 16, wherein the restorable source of stored energy is removable while the power supply is energized.

21. The uninterruptible power supply of claim 16, wherein the uninterruptible power supply is accessible from the outside of the computer.

22. The uninterruptible power supply of claim 16, wherein the restorable source of stored energy is accessible from the outside of the computer.

23. The uninterruptible power supply of claim 16, wherein the restorable source of stored energy is connected to the computer power supply by an electrically conductive cable of which at least some of the cable is external to the computer power supply, and which is distinct from that of the AC mains power cable.

24. The uninterruptible power supply of claim 1, wherein the source of DC power is the unfiltered output of a switching power supply.

25. The uninterruptible power supply of claim 24, wherein the energy directed towards the restorable source of stored energy is derived from the unfiltered output of a winding of the switching power supply transformer.

26. The uninterruptible power supply of claim 1, wherein a portion of the energy is diverted from the bi-directional power converter and is adapted for use by external electrical devices.

27. The uninterruptible power supply of claim 26, wherein the diversion of power is accomplished by using at least one winding on a transformer.

28. The uninterruptible power supply of claim 1, wherein a single electronic component is used concurrently as a fuse and as a resistor developing a voltage proportional to current flowing in the restorable source of stored energy.

29. The uninterruptible power supply of claim 28, wherein the proportional voltage developed across the electrical component is used in regulating the current restoring the energy to the restorable source.

30. The uninterruptible power supply of claim 28, wherein the proportional voltage developed across the electrical component is used in detecting the direction of current in the restorable source of stored energy.

31. The uninterruptible power supply of claim 28, wherein the proportional voltage developed across the electrical component is used in detecting whether the level of current flowing in the restorable source of stored energy is at least a predetermined level of current.

32. The uninterruptible power supply of claim 28, wherein the proportional voltage developed across the electrical component is used in modifying a predetermined value representing the approach of energy depletion of the restorable source of stored energy.

33. The uninterruptible power supply of claim 1, wherein a voltage proportional to current flowing in the restorable source of stored energy is developed across an electrical component and is used in modifying a predetermined value representing the approach of energy depletion of the restorable source of stored energy.

34. The uninterruptible power supply of claim 1, wherein operation is not initiated unless voltage is present at the source of DC power and a signal from the computer representing energization of the power equipment is present.

35. The uninterruptible power supply of claim 1, wherein operation is terminated when the signal representing energization of the power equipment is absent.

36. The uninterruptible power supply of claim 1, wherein communication from the uninterruptible power supply to the computer motherboard is mediated through a cable intended for connection with an internal peripheral.

37. The uninterruptible power supply of claim 1, wherein communication from the uninterruptible power supply to the computer motherboard is mediated by a connection in parallel with a mechanical switch used to initiate system shutdown.

38. The uninterruptible power supply of claim 1, wherein the power supply generates audio signals that are enunciated by a computer system speaker, and wherein the wires connecting to the speaker are in parallel with other wires connected to the speaker.

39. The uninterruptible power supply of claim 1 wherein each of said plurality switch devices continuously operates between said open and closed states.

40. A method of providing redundant power to a source of DC power, comprising the steps of:

(a) providing a source of restorable stored energy; and

(b) coupling the restorable stored energy source to the DC power source in a manner to direct energy either toward the source of DC power from the source of stored energy or toward the source of stored energy from the source of DC power using a plurality of switch devices that change between open and closed states, wherein the direction of electrical energy flow depends upon the deviation of the ratio of the potential of the source of DC power and the potential of the source of stored energy from a predetermined ratio and in which the direction of DC electrical energy is independent of said states of said switch devices.

41. An apparatus for providing redundant power to a source of DC power, comprising:

(a) means for providing a source of restorable stored energy; and

(b) means for coupling, which includes means for transforming having a turns ratio, the restorable stored energy source to the DC power source in a manner to direct energy either toward the source of DC power from the source of stored energy or toward the source of stored energy from the source of DC power, wherein the direction of electrical energy flow depends upon the deviation of the ratio of the potential of the source of DC power and the potential of the source of stored energy from a predetermined ratio that is related to said turns ratio.

42. The apparatus of claim 41, wherein, whenever the potential of the source of DC power is equal to the potential of the source of stored energy based on said turns ratio, no deviation exists.