Power supply apparatus and methods with power-factor correcting bypass mode

• US 6,906,933 B2
• Filed: 11/01/2002
• Issued: 06/14/2005
• Est. Priority Date: 11/01/2002
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Powerware Corporation (Eaton Corporation PLC.)
• Inventors: Taimela, Pasi S.
• Primary Examiner(s): Patel, Rajnikant B.
• Application Number:
  US10/286,027
• Publication Number:
  US 20040085785A1
• Time in Patent Office: 956 Days
• Field of Search: 363/37, 363/34, 363/124, 363/131, 363/127, 363/132, 363/98, 323/205, 323/207, 307/105, 307 43- 46
• US Class Current: 363/37
• CPC Class Codes: H02J 3/32 using batteries with converting means
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 1/4258 using a single converter stage both for correction of AC input power factor and generation of a regulated and galvanically isolated DC output voltage H02M1/4241 takes precedence
• CPC Class Codes: H03F 2200/351 Pulse width modulation being used in an amplifying circuit
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A power supply apparatus, such as an uninterruptible power supply, includes an AC input configured to be coupled to an AC power source and an AC output. The apparatus also includes an AC/DC converter circuit, e.g., a boost rectifier circuit, with an input coupled to the AC input. The apparatus further includes a DC/AC converter circuit, e.g., an inverter circuit, configured to be coupled between an output of the AC/DC converter circuit and the AC output. A bypass circuit is operative to establish a coupling between the AC input to the AC output in a first (e.g., bypassed) state and to interrupt the coupling in a second (e.g., “on line”) state. The AC/DC converter circuit is operative to control current at the AC input when the bypass circuit is in the first state. For example, the AC/DC converter circuit may be operative to control current at the AC input to correct a power factor at the AC input port when bypassed, such that the AC/DC converter circuit may act as a line conditioner in the bypassed state.

Claims

1. A power supply apparatus, comprising:

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

an AC output;

an AC/DC converter circuit having an input coupled to the AC input;

a DC/AC converter circuit coupled between an output of the AC/DC converter circuit and the AC output; and

a bypass circuit operative to establish a coupling between the AC input and the AC output in a first state and to interrupt the coupling in a second state,

wherein the AC/DC converter circuit is operative to control current at the AC input when the bypass circuit is in the first state.

2. An apparatus according to claim 1, wherein the AC/DC converter circuit is operative to correct a power factor at the AC input when the bypass circuit is in the first state.

3. An apparatus according to claim 1, wherein the DC/AC converter circuit is operative to produce an AC output voltage at the AC output when the bypass circuit is in the second state.

4. An apparatus according to claim 3, wherein the AC/DC converter circuit is operative to correct a power factor at the AC input when the bypass circuit is in the second state.

5. An apparatus according to claim 1, wherein the AC output comprises a first AC output and further comprising a second AC output coupled to the AC input when the bypass circuit is each of the first and second states.

6. An apparatus according to claim 3, further comprising means for coupling and decoupling the output of the DC/AC converter circuit to and from the AC output.

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

a switching circuit;

a current reference signal generating circuit operative to generate a current reference signal responsive to a voltage at the AC input; and

a current control circuit operative to control the switching circuit responsive to the current reference signal and to a current at the AC input.

8. An apparatus according to claim 7, further comprising a current sensor operative to sense the current at the AC input, and wherein the current control circuit is operative to control the switching circuit responsive to the sensed current.

9. An apparatus according to claim 1, further comprising a current sensor operative to sense a current at the AC input, and wherein the AC/DC converter circuit is operative to control a power factor at the AC input responsive to the sensed current at the AC input.

10. An apparatus according to claim 9, wherein the current sensor comprises:

a first current sensor operative to sense a current passing through the bypass circuit; and

a second current sensor operative to sense a current passing through the AC/AC converter circuit.

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

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

13. An apparatus according to claim 1, wherein the DC/AC converter circuit is coupled to the output of the AC/DC converter circuit by a DC bus, wherein the AC/DC converter circuit is operative to produce a DC output voltage on the DC bus from the AC power source, and further comprising an auxiliary DC power source operative to power the DC bus.

26. A method according to claim 1, comprising controlling the AC/DC converter circuit responsive to a current at the AC input while the AC input is directly coupled to the AC output.

14. A power supply apparatus, comprising:

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

an AC output; and

an AC/AC converter circuit including a rectifier circuit coupled to the AC input, wherein the rectifier circuit is operative to control a power factor at the AC input when the AC input is directly coupled to the AC output.

15. A power supply apparatus according to claim 14, further comprising a bypass circuit operative to establish a coupling between the AC input and the AC output in a first state, and to break the coupling between the AC input and the AC output in a second state.

16. An apparatus according to claim 15, wherein the AC/AC converter circuit is operative to produce an AC output voltage at the AC output when the bypass circuit is in the second state.

17. An apparatus according to claim 16, wherein the rectifier circuit is operative to control a power factor at the AC input when the bypass circuit is in the second state.

18. An apparatus according to claim 14, wherein the AC output comprises a first AC output that is selectively connectable to the AC input and further comprising a second AC output connectable to the AC input.

19. An apparatus according to claim 14, wherein the rectifier circuit comprises:

a switching circuit;

a current reference signal generating circuit operative to generate a current reference signal responsive to a voltage at the AC input; and

a current control circuit operative to control the switching circuit responsive to the current reference signal and to a current at the AC input.

20. An apparatus according to claim 19, further comprising a current sensor operative to sense the current at the AC input, and wherein the current control circuit is operative to control the switching circuit responsive to the sensed current.

21. An apparatus according to claim 14, further comprising a current sensor operative to sense a current at the AC input, and wherein the rectifier is operative to control the power factor at the AC input responsive to the sensed current at the AC input.

22. An apparatus according to claim 14, wherein the rectifier circuit comprises a boost rectifier circuit and wherein the AC/AC converter circuit further comprises an inverter circuit coupled to an output of the rectifier circuit.

23. An apparatus according to claim 14, wherein the rectifier circuit is operative to produce a DC output voltage on a DC bus from the AC power source, and further comprising an auxiliary DC power source operative to power the DC bus.

24. A method of operating an AC power supply comprising an AC/AC converter circuit configured to be coupled between an AC input and an AC output and operative to generate an AC voltage at the AC output from an AC power source at the AC input, the AC/AC converter circuit including an AC/DC converter circuit coupled to the AC input, the method comprising:

directly coupling the AC input to the AC output while controlling a power factor at the AC input using the AC/DC converter circuit.

25. A method according to claim 24, wherein the AC/DC converter circuit comprises a rectifier circuit.