Uninterruptible power supply systems using electrohydraulic energy storage

• US 9,488,193 B2
• Filed: 12/23/2013
• Issued: 11/08/2016
• Est. Priority Date: 12/23/2013
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Al-Atat, Hassan, Mahulkar, Vishal, Larish, Chad
• Primary Examiner(s): Cuevas, Pedro J
• Application Number:
  US14/138,660
• Publication Number:
  US 20150176607A1
• Time in Patent Office: 1,051 Days
• Field of Search: 290/1.R, 290/54, 604/13, 606/52, 307/68
• US Class Current: 1/1
• CPC Class Codes: F15B 1/022 used as an emergency power source, e.g. in case of pump failure
• CPC Class Codes: H02J 15/003 in the form of hydraulic energy
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02J 9/08 requiring starting of a prime-mover
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids
• CPC Class Codes: Y02P 80/10 Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
• CPC Class Codes: Y02P 90/50 Energy storage in industry with an added climate change mitigation effect

Abstract

A power supply system includes an inverter configured to be coupled to a load and an energy storage device, such as one or more capacitors, coupled to a DC input of the inverter. The power supply system further includes an electrohydraulic energy storage system configured to be coupled to the load and including a hydraulic accumulator, a generator, and a hydraulic motor mechanically coupling the generator and the hydraulic accumulator, along with a control circuit configured to control the electrohydraulic energy storage system responsive to a state of an AC power source coupled to the load.

Claims

1. A power supply system comprising:

an uninterruptible power supply (UPS) comprising an AC input configured to be coupled to an AC power source, an AC output, an inverter and an electrical energy storage device coupled to a DC input of the inverter, the UPS configured to selectively electrically couple the AC output to the AC power source and the electrical energy storage device responsive to a state of the AC power source;

an electrohydraulic energy storage system comprising a hydraulic accumulator, a generator coupled to the UPS, and a hydraulic motor mechanically coupling the generator and the hydraulic accumulator; and

a control circuit configured to control the electrohydraulic energy storage system responsive to the state of the AC power source.

2. The power supply system of claim 1, wherein the control circuit is configured to selectively provide power to the load from the energy storage device and the hydraulic accumulator responsive to the state of the AC power source.

3. The power supply system of claim 2, wherein the control circuit is configured to sequentially supply power to the load from the energy storage device and the hydraulic accumulator responsive to a failure of the AC power source.

4. The power supply system of claim 2, wherein the control circuit is configured to concurrently supply power to the load from the energy storage device and the hydraulic accumulator.

5. The power supply system of claim 1, wherein the energy storage device comprises a capacitor.

6. The power supply system of claim 1, wherein the electrohydraulic energy storage system is coupled to the DC input of the inverter.

7. The power supply system of claim 1, wherein the electrohydraulic energy storage system further comprises a reversible motor/pump subsystem configured to be powered by the AC power source and wherein the control circuit is configured to operate the motor/pump subsystem to charge the hydraulic accumulator.

8. The power supply system of claim 1, wherein the generator comprises a reversible motor/generator, wherein the hydraulic pump comprises a reversible motor/pump, and wherein the control circuit is configured operate the motor/generator and the motor/pump to charge the hydraulic accumulator.

9. The system of claim 1, wherein the UPS comprises an on-line UPS.

10. The system of claim 1, wherein the UPS comprises a standby UPS.

11. An apparatus comprising:

a generator configured to be coupled to a power input of an uninterruptible power supply (UPS) comprising an AC input configured to be coupled to an AC power source, an AC output, an inverter and an electrical energy storage device coupled to a DC input of the inverter, the UPS configured to selectively electrically couple the AC output to the AC power source and the electrical energy storage device responsive to a state of the AC power source;

a hydraulic motor configured to drive the generator;

a hydraulic accumulator;

a valve coupling the hydraulic accumulator to the hydraulic motor; and

a control circuit configured to control the valve.

12. The apparatus of claim 11, wherein the control circuit is configured to control the valve responsive to a state of the UPS.

13. The apparatus of claim 11, wherein the control circuit is configured to control the valve responsive to a state of the AC power source.

14. The apparatus of claim 11, further comprising a pump configured to charge the hydraulic accumulator.

15. The apparatus of claim 14, further comprising a motor coupled to the AC power source and configured to drive the pump.

16. The apparatus of claim 11:

wherein the hydraulic motor comprises a motor/pump;

wherein the generator comprises a motor/generator; and

wherein the control circuit is configured to operate the motor/pump as a pump and the motor/generator as a motor to charge the accumulator.

17. The power supply system of claim 11, wherein the generator is configured to be coupled to an AC input of the UPS.

18. The power supply system of claim 11, wherein the generator is configured to be coupled to a DC input of the UPS.

19. A method of operating a UPS comprising an AC input coupled to an AC power source, an AC output, an inverter and an electrical energy storage device coupled to a DC input of the inverter, the UPS configured to selectively electrically couple the AC output to the AC power source and the electrical energy storage device responsive to a state of the AC power source, the method comprising:

providing energy to the load from the AC power source via the UPS; and

providing energy to the load from a hydraulic accumulator via a generator coupled to the UPS.

20. The method of claim 19, wherein providing energy to the load from a hydraulic accumulator via a generator coupled to the UPS comprises selectively providing energy to the load from an energy storage device and the hydraulic accumulator via the UPS responsive to a state of the AC power source.

21. The method of claim 20, wherein selectively providing energy to the load from an energy storage device and a hydraulic accumulator via the UPS responsive to a state of the AC power source comprises providing energy to the load from the energy storage device via an inverter of the UPS.

22. The method of claim 21, wherein selectively providing energy to the load from an energy storage device and a hydraulic accumulator via the UPS responsive to a state of the AC power source comprises providing energy to the load from the hydraulic accumulator via the inverter.

23. The method of claim 20, wherein selectively providing energy to the load from an energy storage device and a hydraulic accumulator via the UPS responsive to a state of the AC power source comprises providing energy to the load from the energy storage device and the hydraulic accumulator responsive to a failure of the AC power source.