Power factor correction control methods and apparatus

• US 20050219872A1
• Filed: 03/14/2005
• Published: 10/06/2005
• Est. Priority Date: 03/15/2004
• Status: Active Grant

• Current Assignee: Signify North America Corporation (Signify N.V.)
• Original Assignee: Color Kinetics Incorporated (Signify N.V.)
• Inventors: Lys, Ihor A.
• Granted Patent: US 7,358,706 B2
• Time in Patent Office: Days
• US Class Current: 363/21.40
• CPC Class Codes: H02M 1/0012 Control circuits using digital or numerical techniques in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873
• CPC Class Codes: H02M 1/0019 the disturbance parameters being load current fluctuations
• CPC Class Codes: H02M 1/008 Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 1/425 using a single converter stage both for correction of AC input power factor and generation of a high frequency AC output voltage
• CPC Class Codes: H02M 1/4291 by using a Buck converter to switch the input current
• CPC Class Codes: H02M 3/155 using semiconductor devices only
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/157 with digital control
• CPC Class Codes: H02M 3/33561 having more than one ouput with independent control
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/24 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/305 Frequency-control circuits
• CPC Class Codes: H05B 45/355 Power factor correction [PFC]; Reactive power compensation
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 45/385 using flyback topology
• 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

Power factor correction control methods and apparatus based on knowing in advance some information relating to anticipated load conditions (e.g., a desired power to be provided to a load). Based on “feeding-forward” known information about anticipated load conditions, power factor correction control loop response is significantly improved, particularly in situations in which the load power traverses a wide range in a short time period (e.g., load full off to load full on, or vice versa). As a result of improved control loop stability, smaller circuit components may be employed based on more predictable expectations for signal values, thereby reducing the cost and/or size of the implemented circuits. In one example, a processor controls both a feed-forward power factor correction apparatus and a feed-forward power driver for an LED-based light source to provide an efficient source of radiation using significantly streamlined circuits having fewer components and smaller space requirements.

Claims

1. A power factor correction apparatus, comprising:

at least one first switch; and

at least one switch controller to control the at least one first switch based at least on a predetermined desired power to be provided to a load coupled to the power factor correction apparatus.

2. The apparatus of claim 1, wherein the at least one switch controller is configured to process:

a first signal representing an AC line voltage to which the power factor correction apparatus is coupled;

a second signal representing an actual AC current drawn by the power factor correction apparatus;

a third signal representing a DC voltage output by the power factor correction apparatus; and

a fourth signal representing the predetermined desired power to be provided to the load,

so as to generate a first switch control signal to control the at least one first switch.

3. The apparatus of claim 2, wherein the at least one switch controller includes a voltage feedback loop configured to determine a fifth signal representing an effective conductance for the power factor correction apparatus, based on the first signal, the third signal, and the fourth signal.

4. The apparatus of claim 3, wherein the voltage feedback loop is configured to determine a total anticipated power signal based on the third signal and the fourth signal.

5. The apparatus of claim 4, wherein the voltage feedback loop is configured to compare the third signal to a reference voltage to generate a voltage error signal, condition the voltage error signal via a low pass filter, and determine the total anticipated power signal based on the conditioned voltage error signal and the fourth signal.

6. The apparatus of claim 5, wherein the voltage feedback loop is configured to calculate the fifth signal representing the effective conductance based on the first signal and the total anticipated power signal.

7. The apparatus of claim 6, wherein the at least one switch controller is configured to multiply the fifth signal and the first signal to generate a sixth signal representing a desired AC current to be drawn by the apparatus.

8. The apparatus of claim 7, wherein the at least one switch controller further comprises a current feedback loop configured to generate the first switch control signal based on the sixth signal and the second signal.

9. The apparatus of claim I, in combination with at least one power control apparatus disposed between the power factor correction apparatus and the load, the at least one power control apparatus comprising at least one second switch, wherein the at least one switch controller is further configured to control both the at least one first switch and the at least one second switch based at least on the predetermined desired power to be provided to the load.

10. The combination of claim 9, further comprising the load.

11. The combination of claim 10, wherein the load includes at least one LED.

12. The combination of claim 10, wherein the load includes at least one motor or actuator.

13. The combination of claim 10, wherein the load includes at least one heating element.

14. The combination of claim 9, wherein the at least one switch controller is configured to control the at least one second switch without receiving any feedback information relating to the load.

15. The combination of claim 9, wherein the at least one switch controller is configured to control the at least one second switch without regulating either a load voltage or a load current.

16. The combination of claim 9, wherein the at least one switch controller is configured to control at least one of a frequency and a duty cycle of multiple switching operations of the at least one second switch so as to provide a controllably variable power to the load.

17. The combination of claim 9, wherein the at least one switch controller is configured to receive at least one control signal representing the predetermined desired power to be provided to the load, wherein the at least one switch controller is further configured to control both the at least one first switch and the at least one second switch based at least on the at least one control signal.

18. The combination of claim 17, wherein the at least one switch controller is configured as an addressable device so as to facilitate control of the combination via a network.

19. The combination of claim 18, wherein the at least one control signal representing the predetermined desired power to be provided to the load is formatted using a DMX protocol.

20. The combination of claim 19, further including the load, wherein the load includes at least one LED.

21. A power factor correction method, comprising an act of:

A) controlling a current drawn from an AC power source based at least on a predetermined desired power to be provided to a load from the AC power source, so as to improve a power factor associated with the provision of actual power to the load.

22. The method of claim 21, wherein the act A) comprises an act of:

A1) processing;

a first signal representing an AC line voltage associated with the AC power source;

a second signal representing the current drawn from the AC power source;

a third signal representing a DC voltage applied at least in part across the load; and

a fourth signal representing the predetermined desired power to be provided to the load,

so as to generate a first control signal to control the current drawn from the AC power source.

23. The method of claim 22, wherein the act A1) comprises an act of:

determining a fifth signal representing an effective conductance, based on the first signal, the third signal, and the fourth signal.

24. The method of claim 23, wherein the act of determining a fifth signal comprises an act of:

determining a total anticipated power signal based on the third signal and the fourth signal.

25. The method of claim 24, wherein the act of determining a total anticipated power signal comprises acts of:

comparing the third signal to a reference voltage to generate a voltage error signal;

conditioning the voltage error signal via a low pass filter; and

determining the total anticipated power signal based on the conditioned voltage error signal and the fourth signal.

26. The method of claim 25, wherein the act of determining the fifth signal comprises an act of:

calculating the fifth signal representing the effective conductance based on the first signal and the total anticipated power signal.

27. The method of claim 26, wherein the act Al) further comprises an act of:

multiplying the fifth signal and the first signal to generate a sixth signal representing a desired AC current to be drawn from the AC power source.

28. The method of claim 27, wherein the act Al) further comprises an act of:

generating the first control signal based on the sixth signal and the second signal.

29. The method of claim 21, wherein the first control signal controls at least one first switch to control the current drawn from the AC power source, and wherein the method further comprises an act of:

B) controlling both the at least one first switch and at least one second switch configured to provide the actual power to the load, based at least on the predetermined desired power to be provided to the load.

30. The method of claim 29, wherein the act B) comprises an act of:

controlling the at least one second switch without receiving any feedback information relating to the load.

31. The method of claim 29, wherein the act B) comprises an act of:

controlling the at least one second switch without regulating either a load voltage or a load current.

32. The method of claim 29, wherein the act B) comprises an act of:

controlling at least one of a frequency and a duty cycle of multiple switching operations of the at least one second switch so as to provide a controllably variable power to the load.

33. The method of claim 29, further comprising an act of:

C) receiving via a network at least one addressed control signal representing the predetermined desired power to be provided to the load.

34. The method of claim 33, wherein the at least one addressed control signal is formatted using a DMX protocol.

35. An apparatus, comprising:

at least one power factor correction switch;

at least one power control switch; and

at least one switch controller to control both the at least one power factor correction switch and the at least one power control switch based at least on a predetermined desired power to be provided to a load coupled to the apparatus.

36. The apparatus of claim 35, further comprising the load.

37. The apparatus of claim 36, wherein the load includes at least one LED.

38. The apparatus of claim 36, wherein the load includes at least one motor or actuator.

39. The apparatus of claim 36, wherein the load includes at least one heating element.

40. The apparatus of claim 35, wherein the at least one switch controller is configured to process:

a first signal representing an AC line voltage to which the apparatus is coupled;

a second signal representing an actual AC current drawn by the apparatus;

a third signal representing a DC voltage applied at least in part across the at least one power control switch; and

a fourth signal representing the predetermined desired power to be provided to the load,

so as to generate a power factor correction control signal to control the at least one power factor correction switch.

41. The apparatus of claim 40, wherein the at least one switch controller is configured to control the at least one power control switch without receiving any feedback information relating to the load.

42. The apparatus of claim 40, wherein the at least one switch controller is configured to control the at least one power control switch without regulating either a load voltage or a load current.

43. The apparatus of claim 40, wherein the at least one switch controller is configured to control at least one of a frequency and a duty cycle of multiple switching operations of the at least one power control switch so as to provide a controllably variable power to the load.

44. The apparatus of claim 35, wherein the at least one switch controller is configured as an addressable device so as to facilitate control of the apparatus via a network.

45. The apparatus of claim 44, wherein at least one control signal, received by the apparatus and representing the predetermined desired power to be provided to the load, is formatted using a DMX protocol.

46. The apparatus of claim 45, further including the load, wherein the load includes at least one LED.

47. The apparatus of claim 35, wherein the at least one power control switch includes at least a first power control switch and a second power control switch, wherein the load includes at least a first load associated with the first power control switch and a second load associated with the second power control switch, and wherein the at least one switch controller is configured to control the at least one power factor correction switch, the first power control switch, and the second power control switch, based on respective predetermined desired powers to be provided to at least the first load and the second load.

48. The apparatus of claim 47, further comprising the first load and the second load, wherein:

the first load comprises at least one first LED configured to generate first radiation having a first spectrum; and

the second load comprises at least one second LED configured to generate second radiation having a second spectrum different from the first spectrum.

49. The apparatus of claim 48, wherein the at least one switch controller is configured to independently control the first power control switch and the second power control switch so as to controllably vary a first intensity of the first radiation and a second intensity of the second radiation, based on the respective predetermined desired powers to be provided to the at least one first LED and the at least one second LED.

50. The apparatus of claim 49, wherein the at least one switch controller is configured as an addressable device so as to facilitate control of the apparatus via a network.

51. The apparatus of claim 50, wherein at least one control signal, received by the apparatus and representing the respective predetermined desired powers to be provided to the at least one first LED and the at least one second LED, is formatted using a DMX protocol.