Integrated flywheel uninterruptible power supply system

• US 6,657,320 B1
• Filed: 11/03/1999
• Issued: 12/02/2003
• Est. Priority Date: 11/03/1999
• Status: Expired due to Term

• Current Assignee: Piller USA, Inc. (Langley Holdings PLC)
• Original Assignee: Active Power Incorporated
• Inventors: Perkins, David E., Fuller, Robert L., Badger, David A., Andrews, James A., Lee, Randal A., Pitt, James R., Wehrlen, Dave J.
• Primary Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/433,528
• Time in Patent Office: 1,490 Days
• Field of Search: 307/47, 307/64-68, 361/695
• US Class Current: 307/64
• CPC Class Codes: H02J 9/066 characterised by the use of dynamo-electric machines H02J9/08 takes precedence
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids

Abstract

Integrated flywheel uninteruptible power supply (UPS) systems provide reliable back-up power protection in a single integrated housing unit. The integration of the two normally independent systems results in a synergism such that various components may be shared between the systems. For example, the flywheel unit and the UPS electronics unit may utilize a single cooling system that is less complex and requires less energy to operate than two independent cooling systems. Other shared components may include at least control circuitry, user and display interface circuitry, fusing, DC bus capacitors, and emergency shut-off circuitry.

Claims

1. An integrated uninterruptible power supply system that provides continuous power to a load, said system comprising:

a housing;

a flywheel energy storage unit that provides short term back-up energy to said load, said flywheel energy storage unit being mounted within said housing; and

an uninterruptible power supply (UPS) electronics unit that provides said continuous power to said load, said continuous power coming from said flywheel energy storage unit during a short term power outage of utility power and from said utility power after said short term power outage ends, said UPS electronics unit being mounted within said housing.

2. The uninterruptible power supply system of claim 1 further comprising a long term source of back-up power, said continuous power coming from said long term source of back-up power during a long term power outage of said utility power.

3. The uninterruptible power supply system of claim 2, wherein said long term source of back-up power is a GENSET.

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

a cooling system mounted within said housing that provides cooling to said flywheel energy storage unit and to said UPS electronics unit.

5. The uninterruptible power supply system of claim 4, wherein said cooling system comprises:

a forced air convection cooling system that draws cooling air across said flywheel energy storage unit and said UPS electronics unit.

6. The uninterruptible power supply system of claim 5, wherein said forced air convection cooling system draws said cooling across said flywheel energy storage unit prior to being drawn across said UPS electronics unit.

7. The uninterruptible power supply system of claim 5, wherein said forced air convection cooling system comprises a plurality of fans.

8. The uninterruptible power supply system of claim 7, wherein said forced air convection cooling system further comprises a plurality of dampers such that each fan has a damper that vents air drawn by said fan outside of said housing.

9. The uninterruptible power supply system of claim 8, wherein said plurality of dampers each comprise a flap that is OPENED or CLOSED depending on pressure differential between pressure inside of said housing and pressure outside of said housing.

10. The uninterruptible power supply system of claim 5, wherein said forced air convection cooling system includes a fan array having at least one redundant fan.

11. The uninterruptible power supply system of claim 1, wherein said flywheel energy storage unit and said UPS electronics unit share a common controller that controls said flywheel energy storage unit and said UPS electronics unit.

12. The uninterruptible power supply system of claim 11, wherein said controller unit is a programmable unit.

13. The uninterruptible power supply system of claim 1, further comprising:

a user interface panel that provides information on the operational status of said flywheel energy storage unit and said UPS electronics unit.

14. The uninterruptible power supply system of claim 1, further comprising emergency shut-down circuitry that shuts down said flywheel energy storage unit and said UPS electronics unit upon the detection of a unsafe condition.

15. The uninterruptible power supply system of claim 1, further comprising slotted bus plates coupled between said group consisting of said flywheel energy storage unit and utility power, and a DC bus in said system.

16. The uninterruptible power supply of claim 1, wherein said flywheel energy storage unit comprises circuitry that monitors power drawn by said load and, during LOW load conditions increases motor recharging current, and reduces motor charging current during HIGH load conditions.

17. The uninterruptible power supply system of claim 1, further comprising:

a bank of DC capacitors coupled in parallel to a DC bus, said DC bus being shared by said flywheel energy storage unit and said UPS electronics unit.

18. The uninterruptible power supply system of claim 17, further comprising a plurality of fusible links connected to said capacitors such that a failure of any one of said capacitors causes said fusible link to fuse OPEN, thereby isolating said failed capacitor.

19. The uninterruptible power supply system of claim 1, wherein said flywheel energy storage unit comprises:

a flywheel housing;

a rotor having distal and proximal ends mounted within said flywheel housing;

a pair of shaft bearings mounted in said flywheel housing such that one shaft bearing is mounted in proximity of said distal end of said rotor, and the other shaft bearing is mounted in proximity of said proximal end of said rotor; and

a pair of sleeved bearings, each of which is mounted to one end of said rotor.

20. The uninterruptible power supply system of claim 1, wherein said flywheel energy storage unit comprises:

a flywheel housing;

a rotor mounted in said housing; and

a single sensor system that senses both vibration and commutation of said rotor.

21. The uninterruptible power supply system of claim 1, wherein said flywheel energy storage unit comprises:

a flywheel housing;

a rotor mounted in said flywheel housing, said rotor having a shaft; and

a digitally adjustable position sensor mounted to one end of said shaft that senses the rotational position of said rotor.

22. The uninterruptible power supply system of claim 1, wherein said housing comprises:

a heavy gage steel base that said flywheel is mounted to;

a light gage frame mounted to said base that supports control electronics for said flywheel energy storage unit and said UPS electronics unit.

23. The uninterruptible power supply system of claim 22, wherein said base is installed on a concrete slab utilizing lightweight cleats that are mounted to one side of said housing.

24. The uninterruptible power supply system of claim 2, wherein said long term source of back-up power is a diesel generator having a startup circuit, said flywheel energy storage unit comprising:

a flywheel housing;

a rotor mounted within said flywheel housing; and

a DC output produced by a solid state switching circuit connected to said startup circuit of said diesel generator that provides continuous startup power to said startup circuit.

25. The uninterruptible power supply system of claim 1, wherein said UPS electronics unit comprises:

a plurality of static switches, each of which includes a pair of thyristors connected together in anti-parallel;

a monitoring circuit that monitors current being input to said UPS electronics unit; and

a control circuit that, based on the monitored current, only gates a forward biased one of said pair of said thyristors.

26. The uninterruptible power supply system of claim 1, wherein said UPS electronics unit comprises:

a sensor circuit that monitors an output of said UPS electronics unit and determines output current and output voltage;

circuitry that determines output power factor based on said monitored current and voltage; and

control circuitry that calculates inductive voltage of said UPS output and adjusts parameters of said UPS electronics unit such that input voltage into said UPS unit and output voltage out of said UPS electronics unit are closely matched.

27. The uninterruptible power supply system of claim 11, wherein said controller includes a digital signal processor (DSP) inserted in series with a data acquisition pipeline that provides input data to said controller, said data pipeline being produced at least by performing analog measurements that are converted to digital signals, said DSP providing filtering and error correction for offset and gain errors in said analog measurements.

28. The uninterruptible power supply system of claim 11, wherein said controller comprises:

a motherboard that includes processing circuitry that performs control functions for said flywheel energy storage unit and said UPS electronics unit and network circuitry that provides a network interface for remote access to said controller.

29. An integrated uninterruptible power supply system that provides continuous power to a load, said system comprising:

a housing;

a flywheel energy storage unit that provides short term back-up energy to said load, said flywheel energy storage unit being mounted within said housing;

a long term source of back-up power; and

an uninterruptible power supply (UPS) electronics unit that provides said continuous power to said load, said continuous power coming from at least one of said flywheel energy storage unit or said long term source of back-up power during an interruption in utility power and from said utility power after said interruption ends, said UPS electronics unit being mounted within said housing.

30. An integrated uninterruptible power supply system that provides continuous power to an external load, said system comprising:

a housing;

a flywheel energy storage unit that provides short term back-up energy to said load, said flywheel energy storage unit being mounted within said housing; and

an uninterruptible power supply (UPS) electronics unit that provides said continuous power to said load, said continuous power coming from one of the group consisting of said flywheel energy storage unit, utility power and a long term source of back-up power, said UPS electronics unit being mounted within said housing.

31. A stand alone integrated uninterruptible power supply system that provides continuous power to a load, said load being independent from said system, said system comprising:

a housing;

a flywheel energy storage unit that provides short term back-up energy to said load, said flywheel energy storage unit being mounted within said housing; and

an uninterruptible power supply (UPS) electronics unit that provides said continuous power to said load, said continuous power coming from one of the group consisting of said flywheel energy storage unit, utility power and a long term source of back-up power, said UPS electronics unit being mounted within said housing.