Power factor corrected rectification

• US 5,502,630 A
• Filed: 07/19/1994
• Issued: 03/26/1996
• Est. Priority Date: 07/19/1994
• Status: Expired due to Fees

• Current Assignee: Transistor Devices Incorporated (Astrodyne Holding Corp.)
• Original Assignee: Transistor Devices Incorporated (Astrodyne Holding Corp.)
• Inventors: Rokhvarg, Alexander
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): BERHANE, ADOLF D
• Application Number:
  US08/277,500
• Time in Patent Office: 616 Days
• Field of Search: 363/67, 363/68, 363/69, 363/84, 363/87, 363/89, 363/44, 323/207, 323/220, 323/222
• US Class Current: 363/84
• CPC Class Codes: H02M 1/4208 Arrangements for improving power factor of AC input
• 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 is adapted to be connected to single or multiple phase power lines providing alternating current, for delivering power to a load. The supply has an energy storage device for storing and then delivering electrical energy to the load. An inductive system is adapted to be coupled to the power lines for inductively storing and discharging energy. A switching system is coupled to the inductive system for switching a flow of bidirectional current through the inductive system to alternately (a) store energy in the inductive system from the power lines and (b) convey energy from the inductive system and the power main to the energy storage device. Also included is a controller coupled to the switching system for operating it at a repetition rate exceeding that of half cycles of the power lines. The supply also includes a unidirectional conducting system having a pair of unidirectional conducting paths coupled between the inductive system and the energy storage device for steering bidirectional current from the inductive system to provide a unipolar potential at the energy storage device. The preferred embodiment shapes the line current waveform from the power lines into a sinusoid that is in phase with the voltage of the power lines to improve the power factor and reduce harmonic distortion. The preferred supply can produce a D.C. output that is regulated to be independent of line or load variations.

Claims

1. A power supply adapted to be connected to a power main providing alternating current, for delivering power to a load, comprising:

energy output means for conveying electrical energy to said load;

inductive means adapted to be coupled to said power main for inductively storing and discharging energy;

a unidirectional means having a pair of unidirectional conducting paths coupled between said inductive means and said energy output means for steering bidirectional current from said inductive means to provide a unipolar potential at said energy output means;

switching means coupled to said inductive means (a) for branching away from said pair of unidirectional conducting paths, and (b) for switching a flow of bidirectional current through said inductive means to alternately (i) store energy from said power main in said inductive means, and (ii) convey energy from said inductive means and said power main to said energy output means; and

control means coupled to said switching means for operating it at a repetition rate exceeding that of half cycles of said power main, said switching means having a duty cycle that is varied by said control means in a direction tending to keep current from said power main in phase with voltage on said power main.

2. A power supply according to claim 1 wherein said energy output means is operable to store energy and to deliver stored energy to said load.

3. A power supply according to claim 2 wherein said switching means is operable to switch currents without interrupting current flow from said power main, so that the power factor of the power supply is not degraded by current interruption.

4. A power supply according to claim 1 wherein said energy output means having a terminal at a voltage differing from the average voltage at said power main by an approximately constant amount.

5. A power supply according to claim 4 wherein said switching means is operable to switch currents without interrupting current flow from said power main, so that interference is not caused by current interruption.

6. A power supply according to claim 2 wherein said switching means is operable with said inductive means to boost voltage with respect to said power main.

7. A power supply according to claim 6 wherein said switching means is operable to boost two voltages of opposite polarities, each through different ones of said unidirectional conducting paths.

8. A power supply according to claim 7 wherein said two voltages of opposite polarities are constructively applied serially across said energy output means.

9. A power supply according to claim 6 wherein said switching means, by opening, is operable to serially direct current from said power main to said energy output means and to cause a discharge of energy in said inductive means.

10. A power supply according to claim 9 wherein said switching means is operable to switch currents without interrupting current flow from said power main, so that interference is not caused by current interruption at said power main.

11. A power supply according to claim 2 wherein said unidirectional means is operable to conduct current through said unidirectional conducting paths separately to different terminals of said energy output means.

12. A power supply according to claim 11 wherein said unidirectional conducting paths each conduct substantially for different half waves of said power main.

13. A power supply according to claim 2 wherein said energy output means has a pair of output terminals and wherein said unidirectional means comprises:

a pair of unidirectional conducting devices each connected from a different corresponding one of said output terminals to said inductive means.

14. A power supply according to claim 13 wherein said energy output means comprises:

a pair of capacitive devices serially connected together at a common terminal, said switching means being connected between said common terminal and said inductive means.

15. A power supply according to claim 14 comprising:

balancing means for (a) storing balancing energy when one of said capacitive devices is being charged, and (b) subsequently charging the other one of said capacitive devices using said balancing energy.

16. A power supply according to claim 15 wherein said balancing means comprises:

a steering circuit having a pair of capacitors each coupled to said energy output means for transferring a charge associated with one of said capacitive devices to another one of said capacitive devices.

17. A power supply according to claim 2 wherein said inductive means has a pair of inductor terminals and wherein said unidirectional means comprises:

a pair of unidirectional conducting devices each connected from a different corresponding one of said inductor terminals to separate terminals on said energy output means.

18. A power supply according to claim 2 wherein said inductive means has an inductor with a pair of inductor terminals and wherein said unidirectional means comprises:

a pair of unidirectional conducting devices each connected from a common one of said inductor terminals to separate terminals on said energy output means.

19. A power supply according to claim 18 wherein said switching means comprises:

a switching device connected between said common one of said inductor terminals and said energy output means.

20. A power supply according to claim 17 wherein said inductive means comprises:

a pair of inductive devices each serially connected to a different corresponding one of said unidirectional conducting devices.

21. A power supply according to claim 17 wherein said switching means comprises:

a pair of switching devices each being connected to a different corresponding one of said unidirectional conducting devices.

22. A power supply according to claim 2 comprising:

a current absoluting means coupled to said power main for producing and applying to said control means a current signal signifying the absolute value of current from said power main.

23. A power supply according to claim 22 comprising:

a voltage absoluting means coupled to said power main for producing and applying to said control means a voltage signal signifying the absolute value of voltage at said power main.

24. A power supply according to claim 12 comprising:

a pair of start-up diodes each connected from said power main to separate terminals on said energy output means.

25. A power supply according to claim 1 wherein said power main has multiple phases, said inductive means having a plurality of inductive devices, at least one for each of said multiple phases, said switching means having a plurality of switching devices, at least one for each of said multiple phases, each of said switching devices being coupled to a different corresponding one of said inductive devices for switching therethrough a flow of bidirectional current to alternately (a) store energy in said inductive means from an associated one of said multiple phases of said power main, and (b) convey energy from said inductive means and said associated one of said multiple phases of said power main to said energy output means.

26. A power supply according to claim 25 wherein said unidirectional means has a plurality of pairs of unidirectional conducting paths, each pair being coupled between a different affiliated one of said inductive devices and said energy output means for steering thereto bidirectional current from said inductive means to provide a unipolar potential at said energy output means.

27. A power supply according to claim 26 wherein said control means comprises a plurality of controllers, one for each of said multiple phases of said power main, each of said controllers being coupled to a different related one of said switching devices for operating it at a repetition rate exceeding that of half cycles of said power main, said supply comprising:

output sensing means coupled to each of said controllers and to said energy output means for commonly providing to each of said controllers a common signal signifying the voltage across said energy output means.

28. A power supply according to claim 27 wherein each of said switching devices has a duty cycle that is varied by said control means in a direction tending to keep current from each of said multiple phases of said power main in phase with voltage on said power main.

29. A power supply according to claim 28 comprising:

a plurality of current magnitude sensors separately coupled to different ones of said multiple phases of said power main to provide a plurality of current magnitude signals signifying currents from said power main, all but a predetermined one of said current magnitude sensors being separately connected to all but a pre-established one of said controllers, said predetermined one of said current magnitude sensors being connected to all but said pre-established one of said controllers, all but said pre-established one of said controllers being regulated as a function of the difference between said current magnitude signals at the controller.

30. A power supply according to claim 29 comprising:

a plurality of a current absoluting means, one for each of said multiple phases, each of said current absoluting means being coupled to a different one of said multiple phases of said power main for producing and applying to a correlated one of said controllers a current signal signifying the absolute value of current from said power main.

31. A power supply according to claim 25 wherein said energy output means has a virtual terminal, each of said switching devices being connected from said virtual terminal to a different one of said inductive devices, each of said switching devices having a duty cycle that is varied by said control means in a direction tending to minimize net current into said virtual terminal.

32. A power supply according to claim 27 comprising:

a plurality of a current absoluting means, one for each of said multiple phases, each of said current absoluting means being coupled to a different one of said multiple phases of said power main for producing and applying to a correlated one of said controllers a current signal signifying the absolute value of current from said power main.

33. A power supply according to claim 32 comprising:

a plurality of voltage absoluting means, one for each of said multiple phases, each of said voltage absoluting means being coupled to a different one of said multiple phases said power main for producing and applying to said correlated one of said controllers a voltage signal signifying the absolute value of voltage from one of said multiple phases of said power main.

34. A power supply according to claim 27 wherein said energy output means has a pair of output terminals and a common terminal, each of said switching devices being connected from said common terminal to a different one of a plurality of intermediate terminals, each of said inductive devices being connected from a different one of said intermediate terminals to a correlated one of said multiple phases of said power main, said unidirectional means including a plurality of pairs of unidirectional conducting devices, for each pair both of said unidirectional conducting devices being connected from (a) a common connection at a corresponding one of said intermediate terminals, to (b) a separate connection at different ones of the pair of output terminals of said energy output means.

35. A power supply according to claim 25 wherein said energy output means is operable to store energy and to deliver stored energy to said load.

36. A power supply according to claim 35 wherein said switching means is operable to switch currents without interrupting current flow from each of the multiple phases of said power main, so that the power factor of the power supply is not degraded by current interruption.

37. A power supply according to claim 36 wherein each of the switching devices has duty cycle that is varied by said control means in a direction tending to keep current from each of the multiple phases of said power main in phase with voltage of said power main.

38. A power supply according to claim 35 wherein each of said switching devices is operable with said inductive means to boost voltage with respect to said power main.

39. A power supply according to claim 38 wherein said unidirectional means has a plurality of pairs of unidirectional conducting paths, each pair being coupled between a different affiliated one of said inductive devices and said energy output means for steering thereto bidirectional current from said inductive means to provide a unipolar potential at said energy output means, each of said switching devices being operable through different pairs of said unidirectional conducting paths to boost two voltages of opposite polarities.

40. A power supply according to claim 35 wherein each of said switching devices, by opening, is operable to serially direct current from said power main to said energy output means and to cause a discharge of energy in said inductive means.

41. A power supply according to claim 39 wherein each of said unidirectional conducting paths in each pair conduct substantially for different half waves of one of the multiple phases of said power main.

42. A power supply according to claim 25 wherein said energy output means comprises:

a pair of capacitive devices serially connected together at a common terminal, each of said switching devices being connected between said common terminal and said inductive means.

43. A power supply according to claim 42 comprising:

balancing means for (a) storing balancing energy when one of said capacitors is being charged, and (b) subsequently charging the other one of said capacitors using said balancing energy.

44. A power supply adapted to be connected to a power main providing alternating current, for delivering power to a load, comprising:

a pair of capacitive devices serially connected across a pair of output terminals and connected together at a common terminal for storing and conveying electrical energy to said load;

inductive means adapted to be coupled to said power main for inductively storing and discharging energy;

a pair of unidirectional conducting devices each connected from a different corresponding one of said output terminals to said inductive means;

switching means coupled to said inductive means and being connected between said common terminal and said inductive means; and

control means coupled to said switching means for operating it at a repetition rate exceeding that of half cycles of said power main, said switching means having a duty cycle that is varied by said control means in a direction tending to keep current from said power main in phase with voltage on said power main.

45. A power supply according to claim 44 wherein said inductive means comprises:

an inductive device having an intermediate terminal, said unidirectional conducting devices each being connected from said intermediate terminal to a different one of said output terminals, said switching means being connected between said common terminal and said intermediate terminal.

46. A power supply adapted to be connected to a power main having multiple phases, for delivering power to a load, comprising:

a pair of capacitive devices being serially connected across a pair of output terminals and connected together at a common terminal for storing and conveying electrical energy to said load;

a plurality of inductive devices, one for each of said multiple phases of said power main, each of said inductive devices being adapted to be separately coupled to a corresponding one of said multiple phases of said power main for inductively storing and discharging energy;

a plurality of pairs of unidirectional conducting devices, one pair for each of said multiple phases of said power main, each of said unidirectional conducting devices of each pair being connected from a related one of said output terminals to an associated one of said inductive devices;

a plurality of switching devices, one for each of said multiple phases of said power main, each of said switching devices being coupled from said common terminal to an affiliated one of said inductive devices; and

control means coupled to each of said switching devices for operating them at a repetition rate exceeding that of half cycles of said power main, said switching means having a duty cycle that is varied by said control means in a direction tending to keep current from said power main in phase with voltage on said power main.

47. A power supply according to claim 46 wherein each of said inductive devices having an intermediate terminal, each of the unidirectional conducting devices of each pair being connected from a one of said output terminals to the intermediate terminal of one of said inductive devices, each of said switching devices being connected from said common terminal to the intermediate terminal of a different respective one of said inductive devices.