CN-115330822-B - Control method and device of photovoltaic tracking bracket and photovoltaic tracking system

Abstract

The invention discloses a control method and device of a photovoltaic tracking bracket and a photovoltaic tracking system, wherein a current clear sky index is determined based on the current total solar radiation intensity and the current clear sky radiation intensity, cloudy weather is determined to appear when the current clear sky index is smaller than a preset index value, all cloud images acquired in a first preset time period at the current moment and before the current moment are acquired, a solar radiation intensity influence area containing a solar position is extracted, future cloud coverage is predicted based on the change trend of historical cloud coverage in the solar radiation intensity influence area, the cloud change trend in the solar radiation intensity influence area is obtained, further, a future clear sky index corresponding to the future cloud coverage is determined, and the optimal tracking angle of the photovoltaic tracking bracket is determined based on the size of the future clear sky index. According to the invention, the cloud change trend in the solar radiation intensity influence area is considered when the optimal tracking angle is determined, so that the condition that the photovoltaic tracking bracket continuously rotates due to complex and changeable weather is effectively avoided.

Inventors

• ZHANG YOU
• WENG JIE

Assignees

• 阳光电源（上海）有限公司

Dates

Publication Date

20260505

Application Date

20220822

Claims (17)

1. 1. A control method of a photovoltaic tracking stand, characterized by being applied to a controller of a photovoltaic tracking system, the control method comprising: Determining a current clear sky index based on the current total solar radiation intensity and the current clear sky radiation intensity incident to the horizontal plane; when the current clear sky index is smaller than a preset index value, acquiring all cloud images acquired at the current moment and in a first preset time period before the current moment; extracting a solar radiation intensity influence area containing the sun position from each cloud image; determining a historical cloud coverage rate within the first preset time period before the current moment based on each solar radiation intensity influence area; Predicting future cloud coverage of a second preset time period after the current moment based on the change trend of each historical cloud coverage; according to the association relation between the cloud coverage rate and the clear sky index, determining a future clear sky index corresponding to the future cloud coverage rate; And determining an optimal tracking angle of the photovoltaic tracking bracket based on the magnitude of the future clear sky index.
2. 2. The control method according to claim 1, wherein the extracting a solar radiation intensity influence region including a solar position from each of the cloud images includes: cutting the edge distortion position of each cloud image by adopting an image processing library to obtain a target cloud image; determining the sun position on the target cloud image; and taking the sun position as a central point, and extracting a region with a distance from the central point being within a preset distance range as the solar radiation intensity influence region.
3. 3. The control method of claim 2, wherein the determining the sun position on the target cloud image comprises: Obtaining the geographic position of the current sun, wherein the geographic position comprises a zenith angle and an azimuth angle; And determining the sun position on the target cloud image according to the zenith angle and the azimuth angle.
4. 4. The control method according to claim 1, wherein said determining a historical cloud coverage rate for the first preset time period before the current time based on each of the solar radiation intensity influence areas includes: extracting cloud image features from each solar radiation intensity influence area by using a convolutional neural network, and determining a cloud coverage area in the solar radiation intensity influence areas based on the cloud image features; the historical cloud coverage of the corresponding cloud image is determined based on each of the cloud coverage areas and the corresponding solar radiation intensity impact region.
5. 5. The control method according to claim 1, wherein determining a future clear sky index corresponding to the future cloud coverage according to the correlation between the cloud coverage and the clear sky index comprises: Acquiring the total radiation intensity of all the historic sun and the radiation intensity of the historic clear sky in the first preset time period before the current moment; Determining each historical clear sky index in the first preset time period before the current moment based on each historical solar total radiation intensity and each historical clear sky radiation intensity to obtain a historical clear sky index sequence; Performing linear fitting on the historical clear sky index sequence and the historical cloud coverage rate sequence to obtain an association relationship between the cloud coverage rate and the clear sky index, wherein the historical cloud coverage rate sequence comprises the historical cloud coverage rates in the first preset time period before the current moment; And determining the future clear sky index corresponding to the future cloud coverage according to the correlation between the cloud coverage and the clear sky index.
6. 6. The control method according to claim 1, wherein the determining an optimal tracking angle of a photovoltaic tracking bracket based on the future clear sky index comprises: Judging whether the future clear sky index is smaller than the preset index value or not; If yes, comparing the magnitude relation between the current clear sky index and the future clear sky index; If the current clear sky index is not smaller than the future clear sky index, inputting the current solar radiation intensity corresponding to the current clear sky index into an inclined plane radiation amount calculation model to obtain current radiation values corresponding to each inclination angle of the inclined plane radiation amount calculation model; and determining an inclination angle corresponding to the maximum current irradiation value in the current irradiation values as the optimal tracking angle of the photovoltaic tracking bracket.
7. 7. The control method according to claim 6, characterized by further comprising: If the current clear sky index is smaller than the future clear sky index, obtaining the predicted solar radiation intensity of the second preset time period after the current moment based on the future clear sky index and a clear sky model at the corresponding moment; Inputting the predicted solar radiation intensity into the inclined plane radiation amount calculation model to obtain predicted radiation values corresponding to each inclination angle of the inclined plane radiation amount calculation model; And determining an inclination angle corresponding to the maximum predicted irradiation value in the predicted irradiation values as the optimal tracking angle of the photovoltaic tracking bracket.
8. 8. The control method according to claim 6, characterized by further comprising: And if the future clear sky index is not smaller than the preset index value, determining the optimal tracking angle of the photovoltaic tracking bracket by adopting an astronomical algorithm.
9. 9. A control device for a photovoltaic tracking stand, characterized by being applied to a controller of a photovoltaic tracking system, the control device comprising: the current clear sky index determining unit is used for determining a current clear sky index based on the current total solar radiation intensity and the current clear sky radiation intensity which are incident on the horizontal plane; The cloud image acquisition unit is used for acquiring all cloud images acquired at the current moment and in a first preset time period before the current moment when the current clear sky index is smaller than a preset index value; a region extraction unit for extracting a solar radiation intensity influence region containing a solar position from each of the cloud images; A history cloud coverage rate determining unit configured to determine a history cloud coverage rate in the first preset period of time before the current time based on each of the solar radiation intensity influence areas; a future cloud coverage determination unit, configured to predict a future cloud coverage of a second preset time period after the current time based on a change trend of each of the historical cloud coverage; the future clear sky index determining unit is used for determining a future clear sky index corresponding to the future cloud coverage according to the association relation between the cloud coverage and the clear sky index; and the tracking angle determining unit is used for determining the optimal tracking angle of the photovoltaic tracking bracket based on the size of the future clear sky index.
10. 10. The control apparatus according to claim 9, wherein the region extraction unit includes: the clipping subunit is used for clipping the edge distortion position of each cloud image by adopting an image processing library to obtain a target cloud image; a sun position determining subunit for determining the sun position on the target cloud image; And the region extraction subunit is used for taking the sun position as a central point and extracting a region with a distance from the central point being within a preset distance range as the solar radiation intensity influence region.
11. 11. The control device according to claim 10, wherein the sun position determining subunit is specifically configured to: Obtaining the geographic position of the current sun, wherein the geographic position comprises a zenith angle and an azimuth angle; And determining the sun position on the target cloud image according to the zenith angle and the azimuth angle.
12. 12. The control apparatus according to claim 9, wherein the history cloud coverage determination unit includes: A cloud coverage area determination subunit, configured to extract cloud image features from each of the solar radiation intensity influence areas by using a convolutional neural network, and determine a cloud coverage area in the solar radiation intensity influence areas based on the cloud image features; And a historical cloud coverage rate determination subunit configured to determine the historical cloud coverage rate of the corresponding cloud image based on each cloud coverage area and the corresponding solar radiation intensity influence area.
13. 13. The control device according to claim 9, wherein the future clear sky index determination unit includes: The radiation intensity obtaining subunit is used for obtaining all the historical solar total radiation intensity and the historical clear sky radiation intensity in the first preset time period before the current moment; A clear sky index sequence determining subunit, configured to determine each historical clear sky index in the first preset time period before the current time based on each historical solar total radiation intensity and each historical clear sky radiation intensity, so as to obtain a historical clear sky index sequence; The fitting subunit is used for performing linear fitting on the historical clear sky index sequence and the historical cloud coverage rate sequence to obtain an association relation between the cloud coverage rate and the clear sky index, wherein the historical cloud coverage rate sequence comprises the historical cloud coverage rates in the first preset time period before the current moment; a future clear sky index determining subunit, configured to determine, according to a correlation between the cloud coverage and a clear sky index, the future clear sky index corresponding to the future cloud coverage.
14. 14. The control apparatus according to claim 9, wherein the tracking angle determination unit includes: the judging subunit is used for judging whether the future clear sky index is smaller than the preset index value; the comparing subunit is used for comparing the magnitude relation between the current clear sky index and the future clear sky index under the condition that the judging subunit judges that the current clear sky index is positive; A current irradiation value determining subunit, configured to input, if the current clear sky index is not less than the future clear sky index, a current solar radiation intensity corresponding to the current clear sky index into an inclined plane radiation amount calculation model, so as to obtain current irradiation values corresponding to each inclination angle of the inclined plane radiation amount calculation model; And the first tracking angle determination subunit is used for determining the inclination angle corresponding to the maximum current irradiation value in the current irradiation values as the optimal tracking angle of the photovoltaic tracking bracket.
15. 15. The control device according to claim 14, wherein the tracking angle determination unit further includes: A radiation intensity prediction subunit, configured to obtain, if the current clear air index is smaller than the future clear air index, a predicted solar radiation intensity of the second preset time period after the current time based on the future clear air index and a clear air model at a corresponding time; A predicted irradiation value determining subunit, configured to input the predicted solar radiation intensity into the inclined plane radiation amount calculation model, and obtain predicted irradiation values corresponding to each inclination angle of the inclined plane radiation amount calculation model; And the second tracking angle determination subunit is used for determining the inclination angle corresponding to the maximum predicted irradiation value in each predicted irradiation value as the optimal tracking angle of the photovoltaic tracking bracket.
16. 16. The control device according to claim 14, wherein the tracking angle determination unit further includes: And the third tracking angle determining subunit is used for determining the optimal tracking angle of the photovoltaic tracking bracket by adopting an astronomical algorithm under the condition that the judging subunit judges no.
17. 17. The photovoltaic tracking system is characterized by comprising a photovoltaic module, a photovoltaic tracker, a photovoltaic inverter and a controller, wherein the controller comprises the control device of the photovoltaic tracking bracket according to any one of claims 9-16; The controller is respectively in communication connection with the photovoltaic tracker and the photovoltaic inverter, the photovoltaic tracker is connected with at least one photovoltaic module through a mechanical structure, and at least one photovoltaic module is connected to the direct current side of the photovoltaic inverter.

Description

Control method and device of photovoltaic tracking bracket and photovoltaic tracking system Technical Field The invention relates to the technical field of photovoltaic power generation, in particular to a control method and device of a photovoltaic tracking bracket and a photovoltaic tracking system. Background In a photovoltaic tracking system, in order to improve the power generation efficiency, a photovoltaic module is generally fixed on a photovoltaic tracking bracket. The photovoltaic tracking support can enable the orientation of the photovoltaic module to be adjusted according to illumination conditions so as to reduce the included angle between the photovoltaic module and direct sunlight, enable the photovoltaic module to obtain the maximum irradiation amount and improve the power generation efficiency. At present, the photovoltaic tracking system mainly adopts an astronomical algorithm to determine the tracking angle of the photovoltaic tracking bracket. The method is a sun tracking control method for calculating the sun ray angle based on astronomical information. However, the method does not consider the influence of weather, so that a large error exists in the determined tracking angle. In order to improve the accuracy of tracking angles, the problems are optimized by some existing tracking algorithms, and the current weather condition is synthesized when the tracking angle of the photovoltaic tracking bracket is determined. Although the accuracy of the tracking angle is improved to a certain extent by the optimized tracking algorithm, the weather is usually complex and changeable, sun tracking is carried out only by referring to the current weather, the tracking angle is caused to fluctuate frequently, the photovoltaic tracking bracket is caused to rotate continuously, the generated energy of the photovoltaic power station is lost, and the service life of the photovoltaic tracking bracket is influenced. Disclosure of Invention In view of the above, the invention discloses a control method and a device for a photovoltaic tracking bracket and a photovoltaic tracking system, so as to consider the weather change trend, mainly the state and the change trend of cloud around the sun when determining the optimal tracking angle, thereby effectively avoiding the condition that the photovoltaic tracking bracket continuously rotates due to complex and changeable weather, further improving the generating capacity of a photovoltaic power station and prolonging the service life of the photovoltaic tracking bracket. A control method of a photovoltaic tracking bracket, applied to a controller of a photovoltaic tracking system, the control method comprising: Determining a current clear sky index based on the current total solar radiation intensity and the current clear sky radiation intensity incident to the horizontal plane; when the current clear sky index is smaller than a preset index value, acquiring all cloud images acquired at the current moment and in a first preset time period before the current moment; extracting a solar radiation intensity influence area containing the sun position from each cloud image; determining a historical cloud coverage rate within the first preset time period before the current moment based on each solar radiation intensity influence area; Predicting future cloud coverage of a second preset time period after the current moment based on the change trend of each historical cloud coverage; according to the association relation between the cloud coverage rate and the clear sky index, determining a future clear sky index corresponding to the future cloud coverage rate; And determining an optimal tracking angle of the photovoltaic tracking bracket based on the magnitude of the future clear sky index. Optionally, the extracting a solar radiation intensity influence area including a solar position from each cloud image includes: cutting the edge distortion position of each cloud image by adopting an image processing library to obtain a target cloud image; determining the sun position on the target cloud image; and taking the sun position as a central point, and extracting a region with a distance from the central point being within a preset distance range as the solar radiation intensity influence region. Optionally, the determining the sun position on the target cloud image includes: Obtaining the geographic position of the current sun, wherein the geographic position comprises a zenith angle and an azimuth angle; And determining the sun position on the target cloud image according to the zenith angle and the azimuth angle. Optionally, the determining, based on each solar radiation intensity influence area, the historical cloud coverage rate within the first preset time period before the current moment includes: extracting cloud image features from each solar radiation intensity influence area by using a convolutional neural network, and determining a cloud coverage area in the sola