Method for controlling the orientation of a solar tracker based on cartographic models

Patent metadata

Field	Value
Publication number	US-11774539-B2
Application number	US-202117222742-A
Country	US
Kind code	B2
Filing date	Apr 5, 2021
Priority date	Jul 2, 2015
Publication date	Oct 3, 2023
Grant date	Oct 3, 2023

Abstract

A method for controlling the orientation of a single-axis solar tracker ( 1 ) orientable about an axis of rotation (A), said method repetitively completing successive control phases, where each control phase implements the following successive steps:
a) observing the cloud coverage above the solar tracker ( 1 ); b) comparing the observed cloud coverage with cloud coverage models stored in a database, each cloud coverage model being associated to an orientation setpoint value of the solar tracker; c) matching the observed cloud coverage with a cloud coverage model; d) servo-controlling the orientation of the solar tracker by applying the orientation setpoint value associated to said cloud coverage model retained during step c).

The present invention finds application in the field of solar trackers.

First claim

The invention claimed is:

1. A method for controlling an orientation of a solar tracker, the method comprising:
receiving an image of cloud coverage above the solar tracker;
determining an orientation setpoint value for the solar tracker based on the image of cloud coverage and cloud coverage models;
controlling the orientation of the solar tracker by applying the orientation setpoint value,
wherein the cloud coverage models include:
at least one zero-cloud coverage model corresponding to a direct inclination angle calculated based on a position of the Sun; and
at least two non-zero cloud coverage models corresponding to different optimized inclination angles.

2. The method according to claim 1 , wherein the orientation setpoint value is determined based on a composition of a cloud layer of the cloud coverage models.

3. The method according to claim 1 , wherein, for each of the cloud coverage models, the orientation setpoint value is determined based on a wear rate of mechanical members of the solar tracker.

4. The method according to claim 1 , wherein, for each of the cloud coverage models, the orientation setpoint value is determined based on an amount of energy to apply to the solar tracker to modify the orientation of the solar tracker.

5. The method according to claim 1 , wherein, for each of the cloud coverage models, the orientation setpoint value is determined based on a displacement speed of the solar tracker during a change in orientation of the solar tracker.

6. The method according to claim 1 , wherein an optimized inclination angle of the optimized inclination angles corresponds to an angle associated with a horizontal setting of the solar tracker.

7. The method according to claim 1 , wherein the cloud coverage models further include a fine cloud coverage model corresponding to an intermediate angle between the direct inclination angle and an angle corresponding to a horizontal setting of the solar tracker.

8. The method according to claim 1 , wherein the cloud coverage models further include an irregular cloud coverage model corresponding to the direct inclination angle.

9. The method according to claim 1 , further comprising translating the image of cloud coverage into a mapping of solar luminance according to different elevation angles (θi),
wherein determining the orientation setpoint value includes determining the orientation setpoint value based on a distribution of the solar luminance on the mapping and the distribution of the solar luminance in the cloud coverage models.

10. The method according to claim 9 , wherein the at least one zero-cloud coverage model corresponds to a cartographic model in which the solar luminance is at least equal to 80% of a maximum value of the solar luminance within an angular sector less than 30 degrees around the direct inclination angle, and
wherein the at least two non-zero cloud coverage models include a widespread cloud coverage model corresponding to a cartographic model in which the solar luminance is, within an angular sector greater than 150 degrees, a low value and a high value, wherein a difference between the low value and the high value is less than 50% of the high value, wherein the high value is less than 50% of the maximum value, and wherein the high value is associated with an elevation angle deviated by at least 20 degrees from the direct inclination angle.

11. The method according to claim 10 , wherein the at least two non-zero cloud coverage models include a fine cloud coverage model corresponding to an intermediate angle between the direct inclination angle and an angle corresponding to a horizontal setting of the solar tracker, and
wherein the fine cloud coverage model corresponds to a cartographic model in which the solar luminance is, within an angular sector greater than 150 degrees, a low value and a high value, wherein a difference between the low value and the high value which is lower than 50% of the high value, and wherein the high value is associated with an elevation angle located at less than 20 degrees from the direct inclination angle.

12. The method according to claim 10 , wherein the cloud coverage models further include an irregular cloud coverage model corresponding to the direct inclination angle, and
wherein the irregular cloud coverage model corresponds to a cartographic model in which the solar luminance is at least equal to 50% of the maximum value within an angular sector smaller than 30 degrees around the direct inclination angle, and in which the solar luminance is at least equal to 20% of the maximum value within an angular sector smaller than 30 degrees around another inclination angle.

13. The method according to claim 1 , wherein receiving the image of cloud coverage includes receiving a satellite image of the sky above the solar tracker.

14. The method according to claim 1 , wherein receiving the image of cloud coverage includes picking up a sky image of cloud coverage by an image pickup apparatus.

15. The method according to claim 14 , further comprising applying frequency weighting to the sky image of cloud coverage based on a frequency response of the image pickup apparatus and a useful frequency band of a solar collector.

16. The method according to claim 1 , further comprising:
determining that no cloud coverage model matches the image of cloud coverage; and
in response to determining that no cloud coverage model matches the image of cloud coverage, controlling the orientation of the solar tracker by applying the orientation setpoint value corresponding to a direct inclination angle.

17. A solar tracker comprising:
a fixed structure;
a platform supporting at least one solar collector, the platform being rotatably actuatable on the fixed structure by an actuation system;
an image pickup apparatus for receiving an image of the sky above the solar tracker;
a memory storing cloud coverage models; and
a controller coupled to the image pickup apparatus, the memory, and the actuation system, wherein the controller is configured to:
determine an orientation setpoint value for the platform based on the image and the cloud coverage models; and
control an orientation of the platform by applying the orientation setpoint value to the actuation system,

wherein the cloud coverage models include:
at least one zero-cloud coverage model corresponding to a direct inclination angle calculated based on a position of the Sun; and
at least two non-zero cloud coverage models corresponding to different optimized inclination angles.

18. The solar tracker according to claim 17 , wherein the image pickup apparatus is a hemispherical camera.

19. A method for controlling an orientation of a solar tracker, the method comprising:
receiving an image of cloud coverage above the solar tracker;
determining an orientation setpoint value for the solar tracker based on the image of cloud coverage, at least one zero-cloud coverage model corresponding to a direct inclination angle, at least one non-zero-cloud coverage model corresponding to an optimized inclination angle, and a displacement speed of the solar tracker during a change in orientation of the solar tracker; and
controlling the orientation of the solar tracker by applying the orientation setpoint value.

Assignees

• Nextracker Inc
• Nextracker Llc

Inventors

• Arliaud Jérôme
• Crucifix Adrien
• Blanc Philippe

Classifications

• G01S3/7861 Primary

  Solar tracking systems · CPC title

• F24S50/20

  for tracking · CPC title

• G05D3/105

  Solar tracker · CPC title

• H02S20/10

  Supporting structures directly fixed to the ground (H02S20/30 takes precedence) · CPC title

• H02S20/32

  specially adapted for solar tracking · CPC title