Arc maintenance device for high density discharge lamps including an adaptive wave form monitor

• US 20050258765A1
• Filed: 03/15/2002
• Published: 11/24/2005
• Est. Priority Date: 03/15/2001
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Bodine Company Incorporated
• Inventors: Crenshaw, David B, Rodriguez, Reginald J.
• Granted Patent: US 7,091,676 B2
• Time in Patent Office: Days
• US Class Current: 315/86
• CPC Class Codes: H05B 41/2885 Static converters especially adapted therefor; Control thereof H05B41/2882 takes precedence
• CPC Class Codes: H05B 41/2923 against abnormal power supply conditions
• CPC Class Codes: H05B 41/2928 for protecting the lamp against abnormal operating conditions
• CPC Class Codes: H05B 41/38 Controlling the intensity of light
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A supplemental arc maintenance electrical supply for a high density discharge (HID) lamp (L) for applying a high frequency supplemental arc voltage to maintain the arc during a period of unstable or intermittent AC supply in addition to or in lieu of the voltage or current being supplied to the lamp by the HID ballast (12). AC supply instability is identified in less time than the unstable or intermittent power will cause the lamp to arc to extingish and energize a supplemental arc maintenance electrical supply to maintain the arc of the lamp during the period of instability or interruption, so long as its internal, rechargeable battery is operational. The monitoring system (18) also recognizes the re-establishment of a stable (as by being a persistently repeating cycle but not necessarily a sinusoidal AC supply) repeating electrical power supply which is also of sufficient energy level to maintain operation of the HID lamp.

Claims

1. Apparatus for supplying a supplemental power to the arc of a gas lamp powered by a inverter ballast responsive to instability of a main power supply comprising:

a rechargeable battery;

a battery charger;

a high frequency inverter ballast for supplying power directly to the gas lamp, selectively connectable to the lamp upon a signal indicating instability of the mains power supply to the lamp;

an isolation filter interposed between the lamp inverter ballast and the lamp whereby said high frequency inverter ballast is connected to the lamp intermediate the isolation filter and the lamp;

a monitor circuit for monitoring the waveform of the mains power supply to the lamp inverter ballast, the monitor circuit detecting and storing a plurality of successive data points representing the waveform and detecting and storing a plurality of successive data points of the next successive waveform, means for comparing successive corresponding data points of the waveform and the next successive waveforms and initiating the operation of the high frequency inverter ballast to supply power to the lamp upon the identification of a predetermined number of consecutive data points of the next successive waveform which deviate by more than a predetermined value from the corresponding stored data points of the waveform.

2. The apparatus according to claim 1 wherein the monitor circuit includes a sync pulse generator to initiate the detecting and storing of data points of the waveform and successive waveform at an established time standard with respect to the waveform.

3. The apparatus according to claim 2 wherein the monitor circuit includes an input scaler and rectifier to generate a rectified voltage replica of the mains power supply waveform and the stored data points are generated from the replica waveform and the next successive waveform.

4. The apparatus according to claim 3 wherein the monitor circuit includes a filter for converting the voltage replica of successive waveforms to a DC equivalent.

5. The apparatus according to claim 4 wherein the monitor circuit includes a logic circuit driven by the filtered DC voltage, said logic circuit providing an output when the level of the filtered DC voltage exceeds a preset level.

6. The apparatus according to claim 1 wherein the monitor circuit includes means for storing as a target waveform, the last successive waveform compared to a prior waveform having fewer than the preset number of consecutive data points deviating from the predetermined value.

7. The apparatus according to claim 6 wherein the monitor circuit includes means for counting the number of the last successive waveform compared to a prior waveform having fewer than the preset number of consecutive data points deviating from the predetermined value.

8. The apparatus according to claim 7 wherein the means for counting provides an output signal upon reaching a preset value of the counted number.

9. The apparatus according to claim 8 wherein the output signal of the counting means signals the high frequency inverter ballast to be disconnected from the lamp.

25. The method of monitoring according to claim 4 wherein the method of monitoring includes a filtering the converted voltage replica of successive waveforms to a DC equivalent.

26. The method of monitoring according to claim 5 wherein the method of monitoring includes generating a logic signal from the filtered DC voltage, said logic signal providing an output when the level of the filtered DC voltage exceeds a preset level.

10. A monitor circuit for monitoring the waveform of an electrical input signal, the monitor circuit detecting and storing a plurality of successive data points representing the waveform and detecting and storing a plurality of successive data points of the next successive waveform, means for comparing successive corresponding data points of the successive waveform to the prior waveform and providing an output signal upon the identification of a predetermined number of consecutive data points of the next successive waveform which deviate by more than a predetermined value from the corresponding stored data points of the prior waveform.

11. The apparatus according to claim 10 wherein the monitor circuit includes a sync pulse generator to initiate the detecting and storing of data points of the waveform and successive waveform at an established time standard with respect to the waveform.

12. The apparatus according to claim 11 wherein the monitor circuit includes an input scaler and rectifier to generate a rectified voltage replica of the mains power supply waveform and the stored data points are generated from the replica waveform and the next successive waveform.

13. The apparatus according to claim 12 wherein the monitor circuit includes a filter for converting the voltage replica of successive waveforms to a DC equivalent.

14. The apparatus according to claim 13 wherein the monitor circuit includes a logic circuit driven by the filtered DC voltage, said logic circuit providing an output when the level of the filtered DC voltage exceeds a preset level.

15. The apparatus according to claim 10 wherein the monitor circuit includes means for storing as a target waveform, the last successive waveform compared to a prior waveform having fewer than the preset number of consecutive data points deviating from the predetermined value.

16. The apparatus according to claim 15 wherein the monitor circuit includes means for counting the number of the last successive waveform compared to a prior waveform having fewer than the preset number of consecutive data points deviating from the predetermined value.

17. The apparatus according to claim 16 wherein the means for counting provides an output signal upon reaching a preset value of the counted number.

18. The apparatus according to claim 17 wherein the monitor circuit includes a sync pulse generator to initiate the detecting and storing of data points of the waveform and successive waveform at an established time standard with respect to the waveform.

19. The apparatus according to claim 18 wherein the monitor circuit includes an input scaler and rectifier to generate a rectified voltage replica of the mains power supply waveform and the stored data points are generated from the replica waveform and the next successive waveform.

20. The apparatus according to claim 19 wherein the monitor circuit includes a filter for converting the voltage replica of successive waveforms to a DC equivalent.

21. The apparatus according to claim 20 wherein the monitor circuit includes a logic circuit driven by the filtered DC voltage, said logic circuit providing an output when the level of the filtered DC voltage exceeds a preset level.

22. A method of monitoring a periodic waveform including the steps comprising:

establishing a reference point in the period of a periodic waveform;

storing a predetermined number of successive periodic data points at uniform intervals in the period of the waveform representing the level value of the waveform;

comparing successive corresponding data points of a prior waveform to a next succeeding waveforms and providing a signal upon identification of a predetermined number of consecutive data points of the succeeding waveform which deviate from the corresponding stored data points of the prior waveform by more than a predetermined amount.

23. The method of monitoring according to claim 22 wherein the method of monitoring includes initiating a sync pulse at a preselected point in a waveform to initiate the detecting and storing of data points of the prior waveform and successive waveform at a corresponding established time standard with respect to each waveform.

24. The method of monitoring according to claim 23 wherein the method of monitoring includes scaling and rectifying of the periodic waveform to generate a rectified voltage replica of the prior waveform and generating the stored data points from the replica prior waveform and the next successive waveform.

27. The method of monitoring according to claim 22 wherein the method of monitoring includes means for storing as a target waveform, the last successive waveform compared to a prior waveform having fewer than the preset number of consecutive data points deviating from the predetermined value.

28. The method of monitoring according to claim 27 wherein the method of monitoring includes means for counting the number of the last successive waveform compared to a prior waveform having fewer than the preset number of consecutive data points deviating from the predetermined value.

29. The method of monitoring according to claim 28 wherein the means for counting provides an output signal upon reaching a preset value of the counted number.

30. The method of monitoring according to claim 29 wherein the output signal of the counting means signals the high frequency inverter ballast to be disconnected from the lamp.

31. A method of monitoring the waveform of an electrical input signal comprising the steps of detecting and storing a plurality of successive data points representing the waveform and detecting and storing a plurality of successive data points of the next successive waveform, comparing successive corresponding individual data points of the successive waveform to the prior waveform to the prior waveform and providing an output signal upon the identification of a predetermined number of consecutive data points of the next successive waveform which deviate by more than a predetermined value from the corresponding stored data points of the prior waveform.

32. The method of monitoring according to claim 31 wherein the method of monitoring includes a sync pulse generator to initiate the detecting and storing of data points of the waveform and successive waveform at an established time standard with respect to the waveform.

33. The method of monitoring according to claim 32 wherein the method of monitoring includes an input scaler and rectifier to generate a rectified voltage replica of the mains power supply waveform and the stored data points are generated from the replica waveform and the next successive waveform.

34. The method of monitoring according to claim 33 wherein the method of monitoring includes a filter for converting the voltage replica of successive waveforms to a DC equivalent.

35. The method of monitoring according to claim 34 wherein the method of monitoring includes a logic circuit driven by the filtered DC voltage, said logic circuit providing an output when the level of the filtered DC voltage exceeds a preset level.

36. The method of monitoring according to claim 35 wherein the method of monitoring includes means for storing as a target waveform, the last successive waveform compared to a prior waveform having fewer than the preset number of consecutive data points deviating from the predetermined value.

37. The method of monitoring according to claim 36 wherein the method of monitoring includes means for counting the number of the last successive waveform compared to a prior waveform having fewer than the preset number of consecutive data points deviating from the predetermined value.

38. The method of monitoring according to claim 37 wherein the means for counting provides an output signal upon reaching a preset value of the counted number.

39. The method of monitoring according to claim 38 wherein the method of monitoring includes a sync pulse generator to initiate the detecting and storing of data points of the waveform and successive waveform at an established time standard with respect to the waveform.

40. The method of monitoring according to claim 39 wherein the method of monitoring includes an input scaler and rectifier to generate a rectified voltage replica of the mains power supply waveform and the stored data points are generated from the replica waveform and the next successive waveform.

41. The method of monitoring according to claim 40 wherein the method of monitoring includes a filter for converting the voltage replica of successive waveforms to a DC equivalent.

42. The method of monitoring according to claim 41 wherein the method of monitoring includes a logic circuit driven by the filtered DC voltage, said logic circuit providing an output when the level of the filtered DC voltage exceeds a preset level.