Granted Patent B2

US 10,575,375 · App. 16/401,847 · Granted Feb 25, 2020

Abstract

Claims (53)

1. A lighting system comprising:

a driver configured to provide a first drive signal and a second drive signal;

a light-emitting diode (LED) array coupled to the driver and configured to receive the first drive signal and the second drive signal;

a first sensor positioned to sense natural light in a room;

a second sensor positioned to sense light intensity for a zone of the room; and

an electronic controller, coupled to the driver, the first sensor, and the second sensor, including a memory and an electronic processor configured to

control the driver to provide the first drive signal to the LED array;

receive, from the first sensor, a first light intensity;

receive, from the second sensor, a second light intensity;

retrieve from the memory a task-to-sensor ratio for the second sensor;

determine an expected light intensity based on the first light intensity, the first drive signal, and the task to sensor ratio;

determine whether the second light intensity exceeds the expected light intensity; and

in response to determining that the second light intensity exceeds the expected light intensity,

determine an artificial light intensity based on first drive signal and the task-to-sensor ratio;

determine a total natural light intensity based on the second light intensity and the artificial light intensity;

determine a non-useful natural light intensity based on the total natural light intensity, the first light intensity, and the task-to-sensor ratio;

determine the second drive signal based on a desired light intensity for the zone, the total natural light intensity, the non-useful natural light intensity, and the artificial light intensity; and

control the driver to provide the second drive signal to the LED array.

2. The system of claim 1 , wherein determining whether the second light intensity exceeds the expected light intensity includes comparing a difference between the second light intensity and the expected light intensity to a difference threshold.

3. The system of claim 1 , wherein the task-to-sensor ratio is a ratio of an intensity of a generated artificial light for the zone to a sensed light intensity for the zone; the sensed light intensity having been sensed with no natural light present in the zone.

4. The system of claim 1 , wherein determining the artificial light intensity includes multiplying a light intensity value for the first drive signal by the task-to-sensor ratio.

5. The system of claim 1 , wherein determining the total natural light intensity includes subtracting the artificial light intensity from the second light intensity.

6. The system of claim 1 , wherein determining the non-useful natural light intensity includes multiplying the first light intensity by the task-to-sensor ratio, and subtracting the product from the total natural light intensity.

7. The system of claim 1 , wherein determining the second drive signal includes

subtracting the non-useful natural light intensity from the total natural light intensity to determine a first difference; and

subtracting the first difference and the artificial light intensity from the desired light intensity for the zone to determine a second difference.

8. A lighting system comprising:

a driver configured to provide a first drive signal and a second drive signal;

an LED array coupled to the driver and configured to receive the first drive signal and the second drive signal;

a sensor positioned to sense light intensity for a zone; and

an electronic controller, coupled to the driver and the sensor, including a memory and an electronic processor configured to

control the driver to provide the first drive signal to the LED array;

receive, from the sensor, a first light intensity;

retrieve from the memory a task-to-sensor ratio for the sensor;

receive a non-useful light intensity;

determine an artificial light intensity based on first drive signal and the task-to-sensor ratio;

determine the second drive signal based on a desired light intensity for the zone, the non-useful natural light intensity, and the artificial light intensity; and

control the driver to provide the second drive signal to the LED array.

9. The system of claim 8 , wherein determining the artificial light intensity includes multiplying a light intensity value for the first drive signal by the task-to-sensor ratio.

10. The system of claim 8 , wherein the task-to-sensor ratio is a ratio of an intensity of a generated artificial light for the zone to a sensed light intensity for the zone; the sensed light intensity having been sensed with no natural light present in the zone.

11. The system of claim 10 , wherein the non-useful natural light intensity is determined by

subtracting a sensed light intensity for the zone, taken at a representative time by the first sensor, from an expected light intensity for the sensor;

wherein the expected light intensity is determined by multiplying a second sensed light intensity for the zone, taken at the representative time by a second sensor at task level, by the task-to-sensor ratio, and

wherein the representative time is representative of the direct and reflected natural light that will be present throughout the day.

12. The system of claim 8 , wherein determining the second drive signal includes

subtracting the non-useful natural light intensity and the artificial light intensity from the desired light intensity for the zone to determine a difference.

13. The system of claim 8 , wherein the non-useful light intensity is retrieved from the memory.

14. The system of claim 8 , wherein the non-useful light intensity is based on the first light intensity received from the sensor.

15. The system of claim 14 , wherein the non-useful light intensity is further based on an algorithm.

16. The system of claim 15 , wherein the algorithm includes subtracting a value from the first light intensity.

17. The system of claim 16 , wherein the value is determined based on a dim level of the LED array.

18. The system of claim 16 , wherein the value is a predetermined value.

19. The system of claim 8 , wherein the non-useful light intensity is received from a second sensor.

Assignments (6)