UPS systems having multiple operation modes and methods of operating same

• US 20070216228A1
• Filed: 03/17/2006
• Published: 09/20/2007
• Est. Priority Date: 03/17/2006
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Lee, Kevin, Johnson, Robert, Ohman, Ove, Jonsson, Rune, Taimela, Pasi, Paulakonis, Joseph
• Granted Patent: US 7,508,094 B2
• Time in Patent Office: Days
• US Class Current: 307/64
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y04S 20/20 End-user application control systems

Abstract

A power supply system includes an AC input configured to be coupled to an AC source, an AC output configured to be coupled to a load, a UPS having an input coupled to the AC input and an output coupled to the AC output and a bypass circuit coupled between the AC input and the AC output and configured to open and close a bypass path therebetween. The system further includes a controller configured to control the UPS and the bypass circuit such that the UPS operates as an online UPS for a first input voltage magnitude condition at the AC input and as a standby UPS for a second input voltage magnitude condition at the AC input. A multi-mode converter may be coupled to a DC link of the UPS and configured to be selectively coupled to a battery and the AC input to respectively support battery conversion and current control at the AC input in respective first and second modes of operation of the UPS.

Claims

1. A power supply system comprising:

an AC input configured to be coupled to an AC source;

an AC output configured to be coupled to a load;

a UPS having an input coupled to the AC input and an output coupled to the AC output;

a bypass circuit coupled between the AC input and the AC output and configured to open and close a bypass path therebetween; and

a controller configured to control the UPS and the bypass circuit such that the UPS operates as an online UPS for a first input voltage magnitude condition at the AC input and as a standby UPS for a second input voltage magnitude condition at the AC input.

2. The system of claim 1, wherein the first voltage magnitude condition comprises an input voltage at the AC input having a magnitude greater than a predetermined threshold, and wherein the second input voltage magnitude condition comprises the input voltage at the AC input having a magnitude less than the predetermined threshold.

3. The system of claim 1, wherein the controller is configured to operate the UPS as a line current conditioner when the UPS is operating as a standby UPS.

4. The system of claim 1, wherein the UPS comprises a rectifier having an input coupled to the AC input, an inverter having an output coupled to the AC output, and a DC link coupling an output of the rectifier to an input of the inverter.

5. The system of claim 4, wherein the UPS further comprises a battery coupled to the DC link, and wherein the controller is configured to cause the inverter to provide current to charge the battery when the UPS is operating as a standby UPS.

6. The system of claim 5, wherein the UPS further comprises a converter coupling the battery to the DC link and wherein the controller is operatively associated with the converter and configured to operate the converter to control current at the input of the UPS when the UPS is operating as an online UPS.

7. The system of claim 4, wherein the controller is configured to cause the inverter to regulate an AC voltage at the AC output when the UPS is operating as an online UPS.

8. The UPS of claim 4, wherein the rectifier comprises a diode bridge.

9. A UPS comprising:

an AC input;

an AC output;

a diode bridge rectifier having an input coupled to the AC input;

an inverter having an output coupled to the AC output;

a DC link coupling an output of the rectifier to an input of the inverter;

a multi-mode converter coupled to the DC link and configured to be selectively coupled to a battery and the AC input to respectively support battery conversion and current control at the AC input in respective first and second modes of operation of the UPS.

10. The UPS of claim 9, wherein the multi-mode converter is configured to conduct current at the AC input during selected periods of an AC voltage waveform at the AC input.

11. The UPS of claim 10, wherein the selected periods comprise periods during which diodes of the diode bridge that couple the AC input to the DC link are reverse-biased.

12. The UPS of claim 10, wherein the selected periods comprise beginning and ending portions of half-cycles of the AC voltage waveform.

13. The UPS of claim 9, wherein the multi-mode converter comprises:

a half-leg circuit comprising first and second transistors coupled in series between first and second busses of the DC link;

an inductor coupled to a center tap of the half-leg circuit and configured to be coupled to the AC input; and

a controller configured to control the first and second transistors.

14. The UPS of claim 13, wherein the controller is configured to operate respective ones of the first and second switches in respective positive and negative half cycles of the input voltage at the AC input when the inductor is coupled to the AC input.

15. The UPS of claim 13, wherein the controller is configured to complementarily operate the first and second transistors during each of negative and positive half cycles of the input voltage at the AC input when the inductor is coupled to the AC input.

16. The UPS of claim 13, wherein the controller is an open loop or closed loop controller.

17. The UPS of claim 13, wherein the multi-mode converter further comprises a switch configured to selectively couple the inductor to the AC input and the battery, and wherein the controller is configured to control the switch.

18. A method of operating a power supply system including an AC input configured to be coupled to an AC source, an AC output configured to be coupled to a load, a UPS having an input coupled to the AC input and an output coupled to the AC output, and a bypass circuit coupled between the AC input and the AC output and configured to open and close a bypass path therebetween, the method comprising:

controlling the UPS and the bypass circuit such that the UPS operates as an online UPS for a first input voltage magnitude condition at the AC input and as a standby UPS for a second input voltage magnitude condition at the AC input.

19. The method of claim 18, wherein the first voltage magnitude condition comprises an input voltage at the AC input having a magnitude greater than a predetermined threshold, and wherein the second input voltage magnitude condition comprises the input voltage at the AC input having a magnitude less than the predetermined threshold.

20. The method of claim 18, further comprising operating the UPS as a line current conditioner when the UPS is operating as a standby UPS.

21. The method of claim 18, wherein the UPS comprises a rectifier having an input coupled to the AC input, an inverter having an output coupled to the AC output, a DC link coupling an output of the rectifier to an input of the inverter, and a battery coupled to the DC link, and wherein the method further comprises operating the inverter to provide current to charge the battery when the UPS is operating as a standby UPS.

22. The method of claim 21, wherein the UPS further comprises a battery converter coupling the battery to the DC link and wherein the method further comprises operating the battery converter to control current at the input of the UPS when the UPS is operating as an online UPS.

23. A method of operating a UPS including an AC input, an AC output, a diode bridge rectifier having an input coupled to the AC input, an inverter having an output coupled to the AC output, a DC link coupled to an output of the rectifier and a battery coupled to the DC link, the method comprising:

providing a converter coupled to the DC link;

coupling the converter to a battery and operating the converter to provide battery conversion in a first mode of operation of the UPS; and

coupling the converter to the AC input and operating the converter to control current at the AC input in a second mode of operation of the UPS.

24. The method of claim 23, wherein operating the converter to control current at the AC input in a second mode of operation of the UPS comprises conducting current at the AC input during selected periods of an AC voltage waveform at the AC input.

25. The method of claim 24, wherein the selected periods comprise periods during which diodes of the diode bridge that couple the AC input to the DC link are reverse-biased.

26. The method of claim 24, wherein the selected periods comprise beginning and ending portions of half-cycles of the AC voltage waveform.

27. The method of claim 23, wherein the converter comprises a half-leg circuit comprising first and second transistors coupled in series between first and second busses of the DC link and an inductor coupled to a center tap of the half-leg circuit and configured to be coupled to the AC input, and wherein operating the converter to control current at the AC input in a second mode of operation of the UPS comprises controlling the first and second transistors.

28. The method of claim 27, wherein operating the converter to control current at the AC input in a second mode of operation of the UPS comprises operating respective ones of the first and second switches in respective positive and negative half cycles of the input voltage at the AC input.

29. The method of claim 27, wherein operating the converter to control current at the AC input in a second mode of operation of the UPS comprises complementarily operating the first and second transistors during each of negative and positive half cycles of the input voltage at the AC input.