Method and apparatus for providing uninterruptible power

• US 7,939,968 B2
• Filed: 08/31/2004
• Issued: 05/10/2011
• Est. Priority Date: 08/31/2004
• Status: Active Grant

• Current Assignee: Schneider Electric IT Corporation (Schneider Electric SE)
• Original Assignee: American Power Conversion Corporation (Schneider Electric SE)
• Inventors: Pedersen, Michael, Hjort, Thomas Enné
• Primary Examiner(s): Fureman; Jared J
• Assistant Examiner(s): Amrany; Adi
• Application Number:
  US10/930,734
• Publication Number:
  US 20060043793A1
• Time in Patent Office: 2,443 Days
• Field of Search: 307/46, 307/64, 307/65, 307/66
• US Class Current: 307/66
• CPC Class Codes: H02J 9/062 for AC powered loads

Abstract

Methods and apparatus for providing uninterruptible power are provided by aspects of the invention. One aspect is more particularly directed to an uninterruptible power supply for providing power to a load. The uninterruptible power supply includes a first input to receive input power from an input power source, an output to provide output power, a bypass input to receive bypass power from a bypass power source, wherein the bypass input is selectively coupled to the output to provide output power from the bypass power source, an input power circuit coupled to the first input and having a DC output that provides DC power having a first DC voltage level, a back-up power source coupled to the input power circuit to provide DC power at the DC output in a back-up mode of operation, and an inverter circuit having an output coupled to the DC output of the input power circuit and having an output coupled to the output of the uninterruptible power supply to provide the output power derived from at least one of the input power source and the back-up power source. The uninterruptible power supply is constructed and arranged in a bypass mode of operation to control the inverter circuit to convert AC power from the bypass power source at the output of the inverter circuit to DC power at the input of the inverter circuit.

Claims

1. An uninterruptible power supply for providing power to a load, the uninterruptible power supply comprising:

a first input to receive input power from an input power source;

an output to provide output power;

a bypass input to receive bypass power from a bypass power source, wherein the bypass input is selectively coupled to the output to provide output power from the bypass power source;

an input power circuit coupled to the first input, configured to receive power from the input power source, and having a DC output that provides DC power having a first DC voltage level;

a back-up power source coupled to the input power circuit to provide DC power having a second DC voltage level in a back-up mode of operation;

an inverter circuit having an input coupled to the DC output of the input power circuit and an output coupled to the output of the uninterruptible power supply and configured to provide the output power derived selectively from the input power source and the back-up power source; and

a bypass switch coupled between the bypass input and the output of the inverter circuit and controlled to operate in a closed position in a bypass mode of operation to power the load from the bypass power source through the bypass switch in the bypass mode of operation; and

wherein the uninterruptible power supply is constructed and arranged in the bypass mode of operation to control the inverter circuit to convert AC power from the bypass power source at the output of the inverter circuit to DC power at the input of the inverter circuit;

further comprising a battery charger coupled to the input of the inverter circuit to receive DC power and provide power to charge the back-up power source in the bypass mode of operation; and

a power supply separate from the battery charger and coupled to the input of the inverter circuit to receive operating DC power from the inverter and constructed and arranged to provide DC power to components of the uninterruptible power supply in the bypass mode of operation.

2. The uninterruptible power supply of claim 1, wherein the back-up power source includes at least one battery.

3. The uninterruptible power supply of claim 2, wherein the first input and the bypass input are configured to be coupled to a common source of power.

4. The uninterruptible power supply of claim 3, wherein the first input is configured to receive AC power.

5. The uninterruptible power supply of claim 4, wherein the input power circuit includes a power factor correction circuit.

6. The uninterruptible power supply of claim 1, wherein the first input is configured to receive AC power.

7. The uninterruptible power supply of claim 1, wherein the input power circuit includes a power factor correction circuit.

8. An uninterruptible power supply for providing power to a load, the uninterruptible power supply comprising:

a first input to receive input power from a first power source;

an output to provide output power;

a bypass input to receive bypass power, wherein the bypass input is selectively coupled to the output to provide output power from the bypass power;

an input power circuit, configured to receive power through the first input from the input power source, coupled to the first input and having a DC output that provides DC power having a first DC voltage level;

a back-up power source coupled to the input power circuit to provide DC power having a second DC voltage level in a back-up mode of operation;

an inverter circuit having an input coupled to the DC output of the input power circuit and an output coupled to the output of the uninterruptible power supply and configured to provide the output power derived selectively from the input power and power from the back-up power source;

a bypass switch coupled between the bypass input and the output of the inverter circuit and controlled to operate in a closed position in a bypass mode of operation to provide bypass power to the load in the bypass mode of operation through the bypass switch;

means for controlling the inverter circuit in the bypass mode of operation to convert AC power from the bypass power source at the output of the inverter circuit to DC power at the input of the inverter circuit;

means for charging the back-up power source in the bypass mode of operation; and

a power supply, separate from the means for charging, coupled to the input of the inverter circuit to receive operating DC power from the inverter and configured to provide DC power to components of the uninterruptible power supply in the bypass mode of operation.

9. The uninterruptible power supply of claim 8, wherein the back-up power source includes at least one battery.

10. The uninterruptible power supply of claim 9, wherein the means for controlling the inverter circuit include means for controlling power factor at the output of the inverter circuit in bypass mode of operation.

11. The uninterruptible power supply of claim 10, wherein the first input is configured to receive AC power.

12. The uninterruptible power supply of claim 8, wherein the first input is configured to receive AC power.

13. The uninterruptible power supply of claim 8, wherein the first input and the bypass input are configured to be coupled to a common source of power.

14. A method for providing uninterrupted power from a power supply having a first input, a bypass input and an output from which power is provided, a bypass switch coupled between the bypass input and the output, the power supply further including a back-up power source and an inverter that converts DC power to AC power for use at the output of the power supply, the method comprising:

operating the power supply in a first mode of operation with power at the output being supplied from the inverter and derived from power at the first input;

operating in a back-up mode of operation with power at the output being supplied from the inverter and derived from power from the back-up power source;

operating in a bypass mode with the bypass switch closed and with AC power at the output being supplied from power at the bypass input through the bypass switch bypassing the inverter; and

in the bypass mode, operating the inverter to provide DC power at an input of the inverter from AC power at an output of the inverter;

wherein the back-up power source is coupled to the input of the inverter, and wherein the method further comprises charging the back-up power source using a charging circuit in the bypass mode;

wherein the back-up power source includes a battery and wherein charging the back-up power source includes using DC power at the input of the inverter to charge the battery; and

wherein the power supply further includes a power supply unit, separate from the charging circuit, coupled to the input of the inverter, and wherein the method further comprises powering the power supply unit from the DC power from at the input of the inverter in bypass mode.

15. The method of claim 14, further comprising controlling current into the output of the inverter in the bypass mode to be substantially in phase with voltage at the output of the inverter.

16. The method of claim 15, further comprising sensing a voltage at the input of the inverter in bypass mode and controlling the inverter to maintain the voltage at the input of the inverter at a predetermined value.

17. The method of claim 16, further comprising receiving AC power at the first input in the first mode of operation.

18. The method of claim 14, further comprising operating in a back-up mode of operation with power at the output being derived from power from the back-up power source.

19. The method of claim 14, further comprising receiving AC power at the first input in the first mode of operation.