Sun sensor assembly and related method of using

• US 20080128586A1
• Filed: 10/12/2007
• Published: 06/05/2008
• Est. Priority Date: 10/13/2006
• Status: Abandoned Application

• Current Assignee: Soliant Energy, Inc. (Emcore Corporation)
• Original Assignee: Soliant Energy, Inc. (Emcore Corporation)
• Inventors: Gallant, Benjamin McLaughlin, Irwin, Philip C., Johnson, Richard L., Hines, Braden E.
• Application Number:
  US11/974,407
• Publication Number:
  US 20080128586A1
• Time in Patent Office: Days
• US Class Current: 250/203.4
• CPC Class Codes: G01S 3/7861 Solar tracking systems

Abstract

The present invention includes a sun sensor assembly having an aperture that defines an area that is less than the area of the photo-detecting surface of a corresponding first photo-detector. According to another aspect, the present invention also includes a solar concentrator includes at least two sun sensor assemblies mounted on the concentrator in a manner to help the solar concentrator track the sun. According to another aspect, the present invention also includes a method of processing electrical signals from two or more photo-detectors. According to yet another aspect, the present invention includes a sun tracking system that includes a solar panel that includes a solar concentrator and control system.

Claims

1. A sun sensor assembly comprising:

a) a first photo-detector and a second photo-detector, wherein each photo-detector has a photo-detecting surface,

b) a base having a first surface, wherein the first surface of the base comprises a first aperture and a second aperture, wherein the first aperture defines an area that is less than the area of the photo-detecting surface of the first photo-detector and the second aperture defines an area that is less than the area of the photo-detecting surface of the second photo-detector, and wherein the first photo-detector is positioned in a manner such that the first aperture overlies the photo-detecting surface of the first photo-detector in a manner so as to expose a portion of the photo-detecting surface to incident sun-light and the second photo-detector is positioned in a manner such that the second aperture overlies the photo-detecting surface of the second photo-detector in a manner so as to expose a portion of the photo-detecting surface to incident sun-light; and

c) a light blocking member positioned on the first surface of the base in a manner that allows an illumination source to differentially illuminate the first and second photo-detectors as a function of the angle between the illumination source and a normal vector of the photo-detecting surfaces.

2. The sun sensor assembly of claim 1, wherein the first aperture defines an area that is within the boundaries of the photo-detecting surface of the first photo-detector and the second aperture defines an area that is within the boundaries of the photo-detecting surface of the second photo-detector.

3. The sun sensor assembly of claim 1, wherein the light blocking member comprises a first and second ledge, wherein the first ledge is positioned on the light blocking member in a manner such that the first ledge shades a portion of the first photo-detector when the first photo-detector is pointed directly at the sun, and wherein the second ledge is positioned on the light blocking member in a manner such that the second ledge shades a portion of the second photo-detector when the second photo-detector is pointed directly at the sun, wherein the amount of shade cast by the first and second ledges is substantially equal when the first and second photo-detectors are pointed directly at the sun.

4. The sun sensor assembly of claim 3, wherein the light blocking member is a first light blocking member, and further comprising second and third light blocking members, wherein the second light blocking member is positioned on the base in a manner to reduce the field of view of the first photo-detector and the third light blocking member is positioned on the base in a manner to reduce the field of view of the second photo-detector.

5. The sun sensor assembly of claim 4, wherein the second light blocking member further comprises a ledge that is positioned on second light blocking member in a manner that reduces the field of view of the first photo-detector and wherein the third light blocking member further comprises a ledge that is positioned on third light blocking member in a manner that reduces the field of view of the second photo-detector.

6. The sun sensor assembly of claim 5, wherein the base and first, second, and third light blocking members form a unitary structure.

7. The sun sensor assembly of claim 4, wherein the combined field of view of the first and second photo-detectors is +/−

20 degrees.

8. The sun sensor assembly of claim 4, wherein the combined field of view of the first and second photo-detectors is +/−

15 degrees.

9. The sun sensor assembly of claim 4, wherein the combined field of view of the first and second photo-detectors is +/−

10 degrees.

10. The sun sensor assembly of claim 1, further comprising at least one additional photo-detector positioned on the base in a manner such that the at least one additional photo-detector has a field of view of at least +/−

45 degrees.

11. The sun sensor assembly of claim 1, further comprising four additional photo-detectors positioned on the sun sensor assembly in a manner such that each additional photo-detector has a field of view of at least +/−

45 degrees and such that the sun sensor assembly has a field of view of 360 degrees.

12. The sun sensor assembly of claim 1, wherein the base and light blocking member form a unitary structure.

13. A solar concentrator comprising at least two sun sensor assemblies mounted on the concentrator in a manner to help the solar concentrator track the sun, wherein the at least two sun sensor assemblies each comprise:

a) a first photo-detector and a second photo-detector, wherein each photo-detector has a photo-detecting surface,

b) a base having a first surface, wherein the first surface of the base comprises a first aperture and a second aperture, and wherein the first photo-detector is positioned in a manner such that the first aperture overlies the photo-detecting surface of the first photo-detector in a manner so as to expose a portion of the photo-detecting surface to incident sun-light and the second photo-detector is positioned in a manner such that the second aperture overlies the photo-detecting surface of the second photo-detector in a manner so as to expose a portion of the photo-detecting surface to incident sun-light; and

c) a light blocking member positioned on the first surface of the base in a manner that allows an illumination source to differentially illuminate the first and second photo-detectors as a function of the angle between the illumination source and a normal vector of the photo-detecting surfaces.

14. The solar concentrator of claim 13, wherein the at least two sun sensor assemblies are positioned orthogonally to each other.

15. The solar concentrator of claim 13, wherein each of the at least two sun sensor assemblies further comprise at least one additional photo-detector positioned on the base in a manner such that the at least one additional photo-detector has a field of view of at least +/−

45 degrees.

16. The solar concentrator of claim 13, further comprising two additional sun sensor assemblies mounted on the concentrator in a manner to help the solar concentrator track the sun, wherein each additional sun sensor assembly comprises:

a) a base; and

b) at least one photo-detector positioned on the base in a manner such that the photo-detector has a field of view of at least +/−

45 degrees.

17. A method of processing electrical signals from two or more photo-detectors comprising:

a) providing two or more photo-detectors, wherein each photo-detector generates an electrical signal indicative of the amount of incident light upon the photo-detector;

b) selecting one electrical signal from among the electrical signals generated by the two or more photo-detectors; and

c) conditioning the selected electrical signal in a manner so as to provide an unbiased electrical signal.

18. The method of claim 17, wherein two photo-detectors are pointed in the same direction with respect to the sun.

19. The method of claim 17, further comprising the steps of:

a) sending the conditioned signal to a microprocessor; and

b) causing the microprocessor to use the conditioned signal to control articulation of one or more solar concentrators.

20. A sun tracking system comprising:

a) a solar panel comprising;

i) a solar concentrator positioned on the solar panel in a manner sufficient to track the sun along an axis; and

ii) a sun sensor assembly positioned on the solar concentrator in a manner sufficient to track the sun along an axis, wherein the sun sensor assembly comprises at least two photo-detectors, wherein each photo-detector generates an electrical signal indicative of the amount of incident light upon each respective photo-detector;

b) a control system in electrical communication with the solar panel such that the control system can receive and send electrical signals in a manner to help the at least one solar concentrator track the sun, wherein the control system includes program instructions comprising;

i) selecting one electrical signal from among the electrical signals generated by the at least two photo-detectors; and

ii) conditioning the selected electrical signal in a manner so as to provide an unbiased electrical signal.