AC power supply apparatus with economy mode and methods of operation thereof

• US 6,295,215 B1
• Filed: 04/06/2000
• Issued: 09/25/2001
• Est. Priority Date: 04/06/2000
• Status: Expired due to Term

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Powerware Corporation (Eaton Corporation PLC.)
• Inventors: Zhang, Hong, Ohman, Ove, Faria, Des, Grudzinski, Piotr, Akbari, Edward
• Primary Examiner(s): BERHANE, ADOLF D
• Application Number:
  US09/545,201
• Time in Patent Office: 537 Days
• Field of Search: 363/34, 363/37, 363/124, 363/131, 363/132
• US Class Current: 363/37
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 5/22 using discharge tubes with control electrode or semiconductor devices with control electrode
• CPC Class Codes: H02M 5/257 using semiconductor devices only
• CPC Class Codes: H02M 5/458 using semiconductor devices only
• CPC Class Codes: H03F 2200/351 Pulse width modulation being used in an amplifying circuit

Abstract

A power supply apparatus includes an AC input port, an output port, and a bypass circuit that couples the AC input port to the output port. An AC/DC converter circuit, e.g., a rectifier circuit, produces a DC voltage from an AC input voltage at the AC input port. A DC/AC converter circuit, e.g., a current mode controlled inverter, controls current transfer between the output port and the AC/DC converter circuit responsive to a control input such that respective first and second component currents of a current delivered to a load coupled to the output port pass via respective ones of the bypass circuit and the DC/AC converter circuit. The DC/AC converter circuit may be operated such that current passing through the bypass circuit is constrained to be substantially in phase with the AC input voltage. The power supply apparatus may have another mode of operation in which the DC/AC converter circuit exclusively provides power to the output port, and may include an auxiliary DC power supply circuit that provides a DC voltage to the DC/AC converter circuit. Related power supply methods are also discussed.

Claims

1. A power supply apparatus, comprising:

an AC input port;

an output port;

a bypass circuit coupling the AC input port to the output port;

an AC/DC converter circuit, coupled to the AC input port, that produces a DC voltage from an AC input voltage at the AC input port; and

a DC/AC converter circuit, coupled to the AC/DC converter circuit, that controls current transfer between the output port and the AC/DC converter circuit responsive to a control input such that respective first and second component currents of a current delivered to a load coupled to the output port pass via respective ones of the bypass circuit and the DC/AC converter circuit.

2. An apparatus according to claim 1, wherein the DC/AC converter determines a desired current for the second component current and transfers current between the output port and the AC/DC converter circuit based on the determined desired current.

3. An apparatus according to claim 2, wherein the DC/AC converter circuit determines the desired current responsive to a current delivered to the load.

4. An apparatus according to claim 3, wherein the DC/AC converter circuit determines the desired current responsive to an output voltage at the output port and to an output current passing between the output port and the load.

5. An apparatus according to claim 3, wherein the DC/AC converter circuit determines the desired current responsive to the AC input voltage at the AC input port, to an output voltage at the output port and to an output current passing between the output port and the load.

6. An apparatus according to claim 1, wherein the first component current comprises a component of current substantially in phase with the AC input voltage.

7. An apparatus according to claim 6, wherein the second component current comprises at least one of a component of the current delivered to the load having a frequency other than a fundamental frequency of the AC input voltage and a component of the current delivered to the load out of phase with the AC input voltage.

8. An apparatus according to claim 1, wherein the DC/AC converter circuit constrains current passing through the bypass circuit to be substantially in phase with the AC input voltage.

9. An apparatus according to claim 2, wherein the DC/AC converter circuit comprises:

a switching circuit that selectively couples and decouples the output port to and from the AC/DC converter circuit responsive to a control signal; and

a controller that generates the control signal responsive to the determined desired current and to a current passing between the output port and the switching circuit.

10. An apparatus according to claim 2, wherein the DC/AC converter circuit comprises a current mode controlled inverter that variably passes current between the output port and the AC/DC converter circuit responsive to the determined desired current.

11. An apparatus according to claim 2, wherein the DC/AC converter circuit comprises as a tracking line filter.

12. An apparatus according to claim 1, wherein the AC/DC converter circuit comprises a rectifier circuit.

13. An apparatus according to claim 1, wherein the AC/DC converter circuit comprises:

a rectifier circuit, coupled to the AC input port, that produces a rectified DC voltage at a rectifier circuit output from the AC input voltage at the AC input port; and

a booster circuit, coupled to the rectifier circuit output, that produces a regulated DC voltage from the rectified DC voltage.

14. An apparatus according to claim 13, further comprising a neutral regulator circuit coupled to the AC/DC converter circuit.

15. An apparatus according to claim 13, further comprising a DC filter circuit coupled to the AC/DC converter circuit.

16. A power supply apparatus, comprising:

an AC input port;

first and second voltage busses;

an output port;

an AC/DC converter circuit, coupled to the AC output port and to the first and second voltage busses, that produces a DC voltage across the first and second voltage busses from an AC input voltage at the AC input port;

a first switching circuit that selectively couples the AC input port and the output port responsive to a first control input;

a second switching circuit that selectively couples the output port and the first and second voltage busses responsive to a second control input; and

a control circuit that generates the first and second control inputs such that, in a first mode of operation, the first switching circuit decouples the AC input port from the output port while the second switching circuit supplies power to the output port and such that, in a second mode of operation, the first switching circuit couples the AC input port to the output port and supplies a first component of a power at the output port while the second switching circuit supplies a second component of the power at the output port.

17. An apparatus according to claim 16, wherein the control circuit determines a current that supports a power demand at the output port and generates the second control input based on the determined current.

18. An apparatus according to claim 17, wherein the control circuit determines the current that supports the power demand at the output port responsive to a current delivered to the load.

19. An apparatus according to claim 18, wherein the control circuit determines the current that supports the power demand at the output port responsive to an output voltage at the output port and to an output current passing between the output port and the load.

20. An apparatus according to claim 18, wherein the control circuit determines the current that supports the power demand at the output port responsive to the AC input voltage at the AC input port, to an output voltage at the output port and to an output current passing between the output port and the load.

21. An apparatus according to claim 16, wherein the control circuit, in the second mode of operation, generates the second control input such that the current passing through the first switching circuit is substantially in phase with the AC input voltage.

22. An apparatus according to claim 16, wherein the control circuit, in the second mode of operation, generates the second control input such that the second switching circuit carries a current that is at least one of a current having a frequency other than the frequency of the AC input voltage and a current out of phase with the AC input voltage.

23. An apparatus according to claim 16, wherein the control circuit operates the second switching circuit as a current mode controlled inverter.

24. An apparatus according to claim 16, further comprising an auxiliary DC power supply circuit that produces a DC voltage across the first and second voltage busses.

25. An uninterruptible power supply apparatus, comprising:

an AC input port;

an AC output port;

a bypass circuit that couples and decouples the AC input port to and from the AC output port responsive to a first control input; and

a series train AC/AC conversion circuit, coupled to the AC input port and to the AC output port, that transfers power between the AC input port and the AC output port such that, in a first mode of operation, the series train AC/AC conversion circuit transfers a first component of power from the AC input port to the AC output port while the bypass circuit transfers a second component of power from the AC input port to the AC output port and such that, in a second mode of operation, the series train AC/AC conversion circuit transfers power from the AC input port to the AC output port while the bypass circuit decouples the AC input port from the AC output port.

26. An apparatus according to claim 25, wherein the series train AC/AC conversion circuit, in the first mode of operation, causes the bypass circuit to predominantly transfer real power from the AC input port to the AC output port.

27. An apparatus according to claim 25, wherein the series train AC/AC conversion circuit comprises:

an AC/DC converter circuit, coupled to the AC input port, that produces a DC voltage from an AC voltage at the AC input port; and

a DC/AC converter circuit, coupled to the AC/DC converter circuit, that controls current transfer between the AC/DC converter circuit and the AC output port.

28. An apparatus according to claim 27, wherein the DC/AC converter circuit controls current transfer between the AC/DC converter circuit and the AC output port responsive to a current passing between the AC output port and a load coupled to the AC output port.

29. An apparatus according to claim 25, wherein the series train AC/AC conversion circuit further comprising a DC input port and is operative to produce an AC voltage at the AC output port from a DC power source coupled to the DC input port.

30. An uninterruptible power supply apparatus, comprising:

an AC input port;

an AC output port;

a bypass circuit that couples and decouples the AC input port to and from the AC output port responsive to a first control input;

a rectifier circuit, coupled to the AC input port, that produces a DC voltage at a rectifier circuit output from an AC input voltage at the AC input port; and

an inverter circuit, coupled to the rectifier circuit output and to the AC output port, that transfers power between the rectifier circuit and the AC output port such that, in a first mode of operation, the inverter circuit transfers a first component of power to the AC output port while the bypass circuit transfers a second component of power to the AC output port and such that, in a second mode of operation, the inverter circuit transfers power to the AC output port while the bypass circuit decouples the AC input port from the AC output port.

31. An apparatus according to claim 30, wherein the inverter circuit, in the first mode of operation, causes the bypass circuit to predominantly transfer real power from the AC input port to the AC output port.

32. An apparatus according to claim 30, wherein the inverter circuit, in the first mode of operation, controls current transfer between the rectifier circuit and the AC output port responsive to a current passing between the AC output port and a load coupled to the AC output port.

33. An apparatus according to claim 30, wherein the inverter circuit comprises a current mode controlled inverter circuit that controls current transfer between the rectifier circuit and the AC output node responsive to a reference current.

34. An apparatus according to claim 33, wherein the inverter circuit comprises a control circuit that generates the reference current.

35. An apparatus according to claim 34, wherein the control circuit generates the reference current responsive to at least one of an AC output voltage at the AC output port, the AC input voltage, a current passing between the AC output port and a load coupled to the AC output port, a bypass current passing through the bypass circuit, and a current passing between the AC input port and an AC power source coupled to the AC input port.

36. An apparatus according to claim 30, further comprising an auxiliary DC power source coupled to the inverter circuit.

37. A method of producing AC power at a load, the method comprising:

coupling an AC power source to the load through a bypass path;

coupling the AC power source to an intermediate bus such that a DC voltage is generated at the intermediate bus; and

controlling current transfer between the intermediate bus and the load such that respective first and second component currents of a current delivered to the load pass via respective ones of the bypass path and the intermediate bus.

38. A method according to claim 37, wherein controlling current transfer between the intermediate bus and the load such that respective first and second component currents of a current delivered to the load pass via respective ones of the bypass path and the intermediate bus comprise controlling current transfer between the intermediate bus and the load such that predominantly real power is delivered to the load via the bypass path.

39. A method according to claim 38, wherein controlling current transfer between the intermediate bus and the load such that respective first and second component currents of a current delivered to the load pass via respective ones of the bypass path and the intermediate bus comprises controlling current transfer between the intermediate bus and the load such that predominantly non-real power components are delivered to the load via the intermediate bus.

40. A method according to claim 39, further comprising determining a current that supports a power demand at the output port, and wherein controlling current transfer between the intermediate bus and the load such that respective first and second component currents of a current delivered to the load pass via respective ones of the bypass path and the intermediate bus comprises controlling current transfer between the intermediate bus and the load based on the determined current.

41. A method according to claim 40, further comprising sensing a current delivered to the load, and wherein determining a current that supports a power demand at the output port comprises determining the current that supports the power demand at the output port responsive to the sensed current.

42. A method according to claim 40, further comprising sensing an output voltage at the load, and sensing an output current passing through the load, and wherein determining a current that supports a power demand at the output port comprises determining the current that supports the power demand responsive to the sensed output current and the sensed output voltage.

43. A method according to claim 40, further comprising sensing an AC input voltage produced by the AC power source, sensing an output voltage at the load, and sensing an output current passing through the load, and wherein determining a current that supports a power demand at the output port comprises determining the current that supports the power demand at the output port responsive to the sensed AC input voltage, the sensed output current and the sensed output voltage.

44. A method according to claim 37, wherein controlling current transfer between the intermediate bus and the load such that respective first and second component currents of a current delivered to the load pass via respective ones of the bypass path and the intermediate bus comprises controlling current transfer between the intermediate bus and the load such that current passing through the bypass path is substantially in phase with an AC input voltage produced by the AC power source.

45. A method according to claim 37, wherein controlling current transfer between the intermediate bus and the load such that respective first and second component currents of a current delivered to the load pass via respective ones of the bypass path and the intermediate bus comprises controlling current transfer between the intermediate bus and the load such that a current passing between the intermediate bus and the load has a frequency other than the frequency of an AC input voltage of the AC power source and/or is out of phase with the AC input voltage.