Method and system for controling a luminaire

• US 20070043541A1
• Filed: 06/30/2006
• Published: 02/22/2007
• Est. Priority Date: 06/30/2005
• Status: Active Grant

• Current Assignee: LED Roadway Lighting Ltd.
• Original Assignee: Streelight Intelleigence, Inc.
• Inventors: Anderson, James, Cho, Yong, Cleland, Donald, Kurz, Gerald, Jacklin, Gregory, McCarthy, Colleen, Sharma, Pratibha, Kubek, Laurence, Wong, Carol
• Granted Patent: US 7,734,356 B2
• Time in Patent Office: Days
• US Class Current: 702/188
• CPC Class Codes: H05B 41/3922 and measurement of the incident light
• CPC Class Codes: H05B 41/40 discontinuously
• CPC Class Codes: H05B 47/16 by timing means
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

Methods and corresponding systems for controlling a light fixture include a memory for storing data and software. A multi-tap capacitor has a plurality of tap capacitors integrated into a capacitor housing. A plurality of switches are each coupled to one of the plurality of tap capacitors for selectively coupling the tap capacitors together to produce a variable multi-tap capacitance. A processor is coupled to the memory and the switches to facilitate: detecting a trigger for changing a lumen level output by the light fixture; determining a new lumen level in response to the trigger; determining a capacitance value that corresponds to the new lumen level; and configuring the plurality of switches to produce the multi-tap capacitance that corresponds to the new lumen level. The processor can record data in the memory that represents times of lumen changes and switch settings, which data correlates to power consumption.

Claims

1. A system for controlling a light fixture comprising:

memory for storing data and software;

a multi-tap capacitor having a plurality of tap capacitors integrated into a capacitor housing;

a plurality of switches, wherein each switch is coupled to one of the plurality of tap capacitors for selectively coupling the tap capacitors together to produce a multi-tap capacitance;

a processor coupled to the memory and the switches, wherein the processor, the switches, and the memory are cooperatively operable to facilitate;

detecting a trigger for changing a lumen level output by the light fixture;

determining a new lumen level in response to the trigger;

determining a capacitance value that corresponds to the new lumen level; and

configuring the plurality of switches to produce the multi-tap capacitance that corresponds to the new lumen level.

2. The system for controlling a light fixture according to claim 1 wherein the multi-tap capacitor comprises a base capacitor integrated into the capacitor housing, wherein the base capacitor has first and second terminals connected, respectively, to a first and a second connector lug, wherein each of the plurality of tap capacitors has a first tap capacitor terminal and a second tap capacitor terminal, wherein the first terminal of the base capacitor and each of the first tap capacitor terminals is connected, respectively, to a corresponding connector pin in a multi-pin connector, and wherein the second tap capacitor terminals are connected to the second terminal and the second connector lug, wherein the multi-tap capacitance is measured between the first and second connector lugs, and can be configured to be equal to the base capacitor value plus values of one or more selected tap capacitors connected in parallel with the base capacitor by the plurality of switches.

3. The system for controlling a light fixture according to claim 2 wherein the multi-tap capacitor has (t) number of tap capacitors, and wherein the t tap capacitors have a capacitance value

$\left(C_X\right)$

 

⁢

where ⁢

 

⁢

C x = C tap_tot ⁡

( 2 t - x ) 2 t - 1

for x equal 1 to t, where C<sub>tap—

tot</sub> has a the value equal to the difference between the base capacitor and a capacitance value for operating the light fixture at maximum brightness.

4. The system for controlling a light fixture according to claim 2 wherein the base capacitor has a capacitance value selected to operate the light fixture in a dimmest mode.

5. The system for controlling a light fixture according to claim 3 wherein the multi-tap capacitor has a maximum multi-tap capacitance substantially equal to the base capacitance connected in parallel with the n number of tap capacitors, and wherein the maximum multi-tap capacitance is selected to operate the light fixture in a brightest mode.

6. The system for controlling a light fixture according to claim 1 wherein the multi-tap capacitor is configured and adapted to replace a capacitor in a fixed brightness light fixture.

7. The system for controlling a light fixture according to claim 2 wherein the processor, the switches, and the memory are cooperatively operable to facilitate configuring the switches to connect selected pins in the multi-pin connector to produce the multi-tap capacitance that corresponds to the new lumen level.

8. The system for controlling a light fixture according to claim 1 wherein the processor, the switches, and the memory are cooperatively operable to facilitate the detecting the trigger for changing the lumen level comprises the processor, the switches, and the memory being cooperatively operable to facilitate detecting a time of day for changing the lumen level.

9. The system for controlling a light fixture according to claim 1 wherein the processor, the switches, and the memory are cooperatively operable to facilitate the detecting the trigger for changing the lumen level comprises the processor, the switches, and the memory being cooperatively operable to facilitate detecting a change in activity level.

10. The system for controlling a light fixture according to claim 1 comprising a data receiver coupled to the processor, and wherein the processor, the data receiver, and the memory are cooperatively operable to facilitate the detecting the trigger for changing the lumen level comprises the processor, the switches, the data receiver, and the memory being cooperatively operable to facilitate detecting a lumen level instruction received by the receiver.

11. The system for controlling a light fixture according to claim 9 wherein the data receiver is a wireless transceiver.

12. The system for controlling a light fixture according to claim 9 wherein the data receiver is a receiver for receiving data transmitted over power distribution wires.

13. The system for controlling a light fixture according to claim 9 wherein the data receiver is a transceiver.

14. The system for controlling a light fixture according to claim 1 wherein the processor, the switches, and the memory are cooperatively operable to facilitate determining the new lumen level in response to the trigger comprises the processor, the switches, and the memory being cooperatively operable to facilitate recalling from the memory a lumen level associated with the trigger.

15. The system for controlling a light fixture according to claim 1 comprising a lamp lumen sensor coupled to the processor for measuring a lumen level output of a lamp in the light fixture, wherein the processor, the switches, the lamp lumen sensor, and the memory are cooperatively operable to facilitate:

measuring a lamp lumen output of the lamp using the lamp lumen sensor;

comparing the lamp lumen output to a set point; and

reconfiguring the switches to produce an adjusted multi-tap capacitance for operating the lamp at a lamp lumen output closer to the set point.

16. A method for controlling a light fixture comprising:

configuring a multi-tap capacitor to produce a first capacitance for operating the light fixture at a first lumen level;

reconfiguring the multi-tap capacitor to produce a second capacitance for operating the light fixture at a second lumen level;

reading a lumen output of a lamp in the light fixture;

comparing the lumen output with the second lumen level to produce a lumen level error; and

reconfiguring the multi-tap capacitor to produce an adjusted second capacitance to reduce the lumen level error.

17. The method for controlling a light fixture according to claim 16 wherein the reconfiguring the multi-tap capacitor comprises:

providing a multi-tap capacitor having a plurality of tap capacitors integrated within a capacitor housing;

providing a plurality of switches, wherein each of the plurality of switches is connected to one of the tap capacitors; and

reconfiguring the switches to connect selected ones of the plurality of tap capacitors in parallel to provide the second capacitance.

18. The method for controlling a light fixture according to claim 16 wherein the reconfiguring the multi-tap capacitor comprises reconfiguring the multi-tap capacitor in response to detecting a lumen change trigger.

19. The method for controlling a light fixture according to claim 18 wherein the detecting a lumen change trigger comprises detecting a time of day having a scheduled lumen change.

20. The method for controlling a light fixture according to claim 18 wherein the detecting a lumen change trigger comprises detecting a change in activity level.

21. The method for controlling a light fixture according to claim 18 wherein the detecting a lumen change trigger comprises detecting a change in ambient light level.

22. The method for controlling a light fixture according to claim 18 wherein the detecting a lumen change trigger comprises receiving in a receiver an instruction to change a lumen level.

23. The method for controlling a light fixture according to claim 16 comprising logging, in response to reconfiguring of the multi-tap capacitor, data that indicates a prior configuration of the multi-tap capacitor and a time of operation of the light fixture in the prior configuration of the multi-tap capacitor.

24. The method for controlling a light fixture according to claim 18 wherein the logging data comprises logging data representing the adjusted second capacitance.

25. A method for specifying a multi-tap capacitor for use in a light fixture comprising:

determining a number of tap capacitors (t) in the multi-tap capacitor based upon a number of adjustment levels (a) of the lumen output of the light fixture;

determining a base capacitance value of a base capacitor in the multi-tap capacitor based upon a dimmest operation of the light fixture;

determining a maximum capacitance value of the multi-tap capacitor based upon a full brightness operation of the light fixture; and

determining a capacitance value (C_x) for each of t number of tap capacitors based upon the number of adjustment levels a, the base capacitance value, and the maximum capacitance value, wherein parallel circuit combinations of the base capacitor and selected ones of the t tap capacitors produce capacitance values for operating the light fixture at a levels of brightness.

26. The method for specifying a multi-tap capacitor according to claim 25 wherein the determining the base capacitance value for the dimmest operation of the light fixture comprises determining the base capacitor value for operating the light fixture at 50% of a power rating of the light fixture.

27. The method for specifying a multi-tap capacitor according to claim 25 wherein the determining the number of tap capacitors (t) based upon the number of adjustment levels (a) comprises determining the number of tap capacitors (t) based, at least in part, on the following formula:

t=log₂ a.

28. The method for specifying a multi-tap capacitor according to claim 25 wherein the determining the capacitance value (C_x) for each of t number of tap capacitors comprises determining a capacitance value (C_x) for each of t number of tap capacitors based, at least in part, on the following formula:

$C_x=\frac{C_{\mathrm{tap\_tot}}<br><br>\left(2^{t-x}\right)}{2^t-1}$

where x is from 1 to t, and C<sub>tap—

tot</sub> is equal to a difference between the maximum capacitance value and the base capacitance value.

29. A multi-tap capacitor comprising:

a capacitor housing defining a capacitor cavity;

a primary terminal and a common terminal, each fixed to the capacitor housing and having conductive portions inside the capacitor cavity and outside the capacitor cavity;

a base capacitor within the capacitor cavity, wherein the base capacitor has a first terminal connected to the primary terminal and a second terminal connected to the common terminal, wherein the base capacitor has a base capacitance value selected for operating a light fixture in a minimum brightness mode; and

(t) number of tap capacitors within the capacitor cavity, wherein each of the t tap capacitors has a first terminal connected to a corresponding connector pin, and wherein each tap capacitor has second terminal connected to the common terminal, and wherein each of the t tap capacitors can be connected in parallel to the base capacitor by a circuit coupled to the connector pins, and wherein all the t tap capacitors connected in parallel have a capacitance value C<sub>tap—

tot</sub>, and wherein C<sub>tap—

tot</sub> is equal to the difference between the base capacitance value and a maximum capacitance value selected for operating the light fixture in a maximum brightness mode.

30. The multi-tap capacitor according to claim 29 wherein the number t is based upon a number of adjustment levels (a) of the multi-tap capacitor.

31. The multi-tap capacitor according to claim 30 wherein the number t is based, at least in part, upon a the formula:

t=log₂ a.

32. The multi-tap capacitor according to claim 29 wherein a capacitance value (Cx) of each of the t tap capacitors is based, at least in part, upon the formula:

$C_x=\frac{C_{\mathrm{tap\_tot}}<br><br>\left(2^{t-x}\right)}{2^t-1}$

where x is from 1 to t.