Battery-less uninterruptable sequel power supply

• US 5,811,960 A
• Filed: 10/02/1996
• Issued: 09/22/1998
• Est. Priority Date: 10/02/1996
• Status: Expired due to Fees

• Current Assignee: United Power Corp. (Danaher Corporation)
• Original Assignee: United Power Corp. (Danaher Corporation)
• Inventors: Van Sickle, Robert J., Roberts, Darren T.
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US08/720,617
• Time in Patent Office: 720 Days
• Field of Search: 307/64, 307/67, 322/4, 322/32
• US Class Current: 322/4
• CPC Class Codes: H02J 9/066 characterised by the use of dynamo-electric machines H02J9/08 takes precedence

Abstract

A battery-less uninterruptable sequel power supply that converts mechanical rotation generated by a local power source to electrical power in the event of commercial line power distortion or failure is provided. The uninterruptable sequel power supply uses a voltage and frequency-tolerant rectifier-inverter combination that converts the decaying output of a de-accelerating synchronous alternating current machine to a stable alternating current voltage for driving a critical load. In the arrangement of the invention, there is no need to maintain rotary velocity of the synchronous alternating current machine during the transitory period between fault detection and connection of a prime mover.

Claims

1. A supplemental power supply comprising:

a synchronous alternating current machine connected to a moveable member, said synchronous alternating current machine being provided in a circuit that is connected to and running parallel with an alternating current line that extends, during a normal operating condition to a main power source, such that said synchronous alternating current machine;

(1) regulates power supplied from said main power source to a terminal for connection of a critical load; and

(2) maintains kinetic energy in said movable member,

and wherein during a power interrupt condition said alternating current line is disconnected from said main power source and said synchronous alternating current machine serves to generate a decaying alternating current voltage from said kinetic energy;

a rectifier for converting said decaying alternating current voltage to a direct current voltage; and

an inverter for converting said direct current voltage to a stable alternating current voltage for supply to said terminal.

2. The supplemental power supply of claim 1, further comprising:

a system controller, said system controller maintaining a stable frequency by controlling a frequency difference between said stable alternating current voltage and a voltage from said main power source and by maintaining said frequency within a predetermined tolerance in the absence of power from said main power source.

3. The supplemental power supply of claim 1, wherein said movable member comprises a flywheel.

4. The supplemental power supply of claim 1, further comprising:

a motor connected to said synchronous alternating current machine for providing startup energy to said synchronous alternating current machine prior to connection of said synchronous alternating current machine to said main power source.

5. The supplemental power supply of claim 3, further comprising:

a motor, said motor providing startup energy to said synchronous alternating current machine and said flywheel prior to connection of said synchronous alternating current machine to said main power source.

6. The supplemental power supply of claim 2, wherein said movable member comprises a flywheel;

said power supply further comprising a motor connected to said flywheel and said synchronous alternating current machine, wherein said system controller further controls a startup sequence where said motor provides kinetic energy to said flywheel and said synchronous alternating current machine.

7. The supplemental power supply of claim 2, further comprising:

a prime mover connected to said synchronous alternating current machine, said prime mover driving said synchronous alternating current machine to provide a stable alternating current voltage to said rectifier.

8. The supplemental power supply of claim 1, wherein said rectifier is frequency and voltage tolerant.

9. The supplemental power supply of claim 7, further comprising:

a clutch disposed between said prime mover and said synchronous alternating current machine, said clutch providing power to said synchronous alternating current machine from said prime mover.

10. The supplemental power supply of claim 1, wherein said synchronous alternating current machine regulates said power by filtering to substantially remove voltage transients.

11. The supplemental power supply of claim 1, wherein said circuit is inductively coupled to said alternating current line.

12. An uninterruptable power supply comprising:

a prime mover;

a clutch connected to said prime mover;

an input interrupt switch;

a synchronous alternating current machine connected to a moveable member, said synchronous alternating current machine being provided in a circuit that is connected to and running parallel with an alternating current line that extends, during a normal operating condition, to a main power source, via said input interrupt switch, such that said synchronous alternating current machine;

(1) regulates power supplied from said main power source to a terminal for connection of a critical load; and

(2) maintains kinetic energy in said movable member,

and wherein during a power interrupt condition said input interrupt switch is opened to disconnect said main power source from said alternating current line, whereby said synchronous alternating current machine generates a first stable alternating current voltage when mechanically driven by said prime mover via said clutch, and generates a decaying alternating current voltage and frequency when said clutch is disengaged;

a rectifier electrically connected to said synchronous alternating current machine, said rectifier for converting said first stable alternating current voltage and said decaying alternating current voltage and frequency to a direct current voltage;

an inverter for converting said direct current voltage to a second stable alternating current voltage for supply to said terminal; and

a system controller for sensing presence of a power interrupt condition and automatically reconfiguring said uninterruptable power supply by transferring a power generation function to the prime mover in a coordinated sequence.

13. The apparatus in claim 12, further comprising:

a bypass for disconnecting said synchronous alternating current machine from said rectifier and for electrically connecting said synchronous alternating current machine to said critical load.

14. The uninterruptable power supply of claim 12, wherein said synchronous alternating current machine regulates said power by filtering to substantially remove voltage transients.

15. The uninterruptable power supply of claim 12, wherein said circuit is inductively coupled to said alternating current line.

16. An uninterruptable power supply comprising:

a bridging generator electrically connected to said main power source and for generating a decaying direct current voltage when disconnected from said main power source;

a backup generator for providing a stable direct current voltage subsequent to the detection of an unacceptable main power condition;

an inverter for converting said decaying direct current voltage and said stable direct current voltage to a first stable alternating current voltage and frequency; and

a system controller for sensing the presence of a power interrupt condition, controlling a start-up sequence of said backup generator, and automatically reconfiguring said uninterruptable power supply by transferring power generation to the bridging generator and then to the backup generator in a coordinated sequence,

wherein said bridging generator comprises a first synchronous alternating current machine connected to a moveable member, said first synchronous alternating current machine being provided in a circuit that is connected to and running in parallel with an alternating current line that extends, during a normal operating condition, to a main power source, such that said first synchronous alternating current machine;

(1) regulates power supplied from said main power source to a terminal for connection of a critical load; and

(2) maintains kinetic energy in said member,

and wherein during a power interrupt condition said main power source is disconnected from said alternating current line and said first synchronous alternating current machine serves to generate a decaying alternating current voltage and frequency from said kinetic energy.

17. The uninterruptable power supply of claim 16, wherein said bridging generator further comprises a first rectifier for converting said decaying alternating current voltage and frequency to said decaying direct current voltage.

18. The uninterruptable power supply of claim 17, wherein said backup generator comprises:

a prime mover;

a second synchronous alternating current machine for generating a second stable alternating current voltage and frequency when mechanically driven by said prime mover; and

a second rectifier electrically connected to said second synchronous alternating current machine for converting said second stable alternating current voltage and frequency to said stable direct current voltage.

19. The uninteruptable power supply of claim 17, wherein said bridging generator further comprises a motor;

and wherein said movable member comprises a flywheel coupled to said motor, said motor providing kinetic energy to said synchronous alternating current machine and said flywheel prior to connection of said synchronous alternating current machine to said main power source.

20. The uninterruptable power supply of claim 17, further comprising a first switch;

a first inductor, wherein said first switch and said first inductor are serially connected in said alternating current line and electrically couple said main power source to said first synchronous alternating current machine;

a second inductor connecting said first inductor and said rectifier; and

a second switch connecting said terminal to said second inductor, wherein said main power source is inductively connected to said critical load by said first inductor and said second inductor when said first switch and said second switch are closed.

21. The uninterruptable power supply of claim 18, wherein said prime mover uses a pressure start.

22. The uninterruptable power supply of claim 16, further comprising

a first diode for electrically connecting said bridging generator to said inverter;

and

a second diode for electrically connecting said backup generator to said inverter.

23. The uninterruptable power supply of claim 16, wherein said first synchronous alternating current machine regulates said power by filtering to substantially remove voltage transients.

24. The uninterruptable power supply of claim 16, wherein said circuit is inductively coupled to said alternating current line.

25. A method for sustaining a stable alternating current voltage and frequency upon the occurrence of a power interrupt condition, comprising the steps of:

connecting, during a normal operating condition, a synchronous alternating current machine with a main power source by way of a circuit connected to and running parallel with an alternating current line extending to said main power source, such that said synchronous alternating current machine;

(1) maintains kinetic energy in a moveable member; and

(2) regulates power supplied by said main power source to a critical load,

generating a coincident inverter control signal with a voltage from the main power source during said normal operating condition;

detecting a presence of insufficient voltage from the main power source;

measuring a duration of the insufficient voltage;

disconnecting said synchronous alternating current machine from said main power source when said duration of the insufficient voltage exceeds a defined time indicating a power interrupt condition;

generating a free running inverter control signal coherent with said coincident inverter control signal when the main power source is disconnected;

converting said kinetic energy to a decaying alternating current voltage and frequency with said synchronous alternating current machine when the main power source is disconnected;

rectifying said decaying alternating current voltage and frequency to provide a direct current voltage;

inverting said direct current voltage to provide said stable alternating current voltage and frequency; and

applying said stable alternating current voltage and frequency to said critical load.

26. The method in claim 25, further comprising the steps of:

initiating a prime mover subsequent to the detection of insufficient voltage;

stabilizing said prime mover; and

transferring power from said prime mover to said synchronous alternating current machine for maintenance of said stable alternating current voltage.

27. The method in claim 25, further comprising the steps of:

initiating a prime mover subsequent to the detection of insufficient voltage;

transferring power from said prime mover to a second synchronous alternating current machine;

generating an intermediate alternating current voltage and frequency with said second synchronous alternating current machine;

converting a said intermediate alternating current voltage and frequency to a stable direct current with a second rectifier; and

applying said stable direct current voltage to said inverter to generate said stable alternating current voltage and frequency.

28. The method of claim 25, wherein said regulation comprises filtering to substantially remove voltage transients.

29. The method of claim 25, wherein said circuit is inductively coupled to said alternating current line.