Dynamic adjustment method for azimuth angle and elevation angle of photovoltaic double-shaft tracking support

Abstract

The invention discloses a method for dynamically adjusting an azimuth angle and an elevation angle of a photovoltaic double-shaft tracking bracket, belongs to the field of a control method of a photovoltaic panel bracket, and aims to improve the efficiency and the economical efficiency of a system. According to the scheme, the method comprises the following steps of S1, collecting time, longitude and latitude, photovoltaic panel postures and support installation parameters; s2, calculating the real-time position of the sun according to time and longitude and latitude; s3, performing anti-shadow calculation according to the tracking support installation parameters to obtain an anti-shadow correction value; and S4, adjusting the azimuth angle and the elevation angle of the bracket according to the real-time position of the sun and the anti-shadow correction value. According to the scheme, shadow shielding can be reduced, the positions of the photovoltaic panels can be adjusted in time through anti-shadow calculation of the photovoltaic panel installation parameters, mutual shielding between the front row of photovoltaic panels and the rear row of photovoltaic panels is avoided, and the power generation capacity of the whole system is further improved.

Description

Technical Field

[0001] The invention relates to a control method for a photovoltaic panel bracket. Background Art

[0002] With the development of solar energy technology, photovoltaic tracking systems have emerged to improve the energy conversion efficiency of solar panels. The construction of centralized photovoltaic power stations in China faces the problem of less and less available flat land, more and more complex terrain, and more and more expensive land prices. Especially as photovoltaic module technology becomes more and more mature and the possibility of reducing costs through technology becomes smaller and smaller, the value of reducing the cost per kilowatt-hour and increasing the project rate of return through tracking brackets has become increasingly prominent and has been unanimously recognized by the industry. Among the tracking brackets, the dual-axis tracking bracket technology is the most complex and is also the structural form that increases the highest power generation.

[0003] The Chinese patent with the patent publication number CN116795145B discloses a dual-axis tracking control method and system for a photovoltaic bracket, which is used to solve the problem that the existing tracking control method has high requirements and low efficiency. The method includes: the GNSS module in the controller host obtains the GPS signal to determine the current sun angle according to the GPS signal, and then determines the initial tracking control information of the photovoltaic bracket. Obtain meteorological information of the divided area range to determine the key meteorological parameters; determine the corresponding dynamic limit search range based on the photovoltaic structure affected by the key meteorological parameters, and obtain the tracking control adjustment information based on the dynamic limit search range, and adjust the initial tracking control information based on the tracking control adjustment information to obtain the target tracking control information; the controller receives the target tracking control information from the machine, controls the photovoltaic bracket to rotate the first shaft and the second shaft, and realizes the tracking of the photovoltaic bracket. This scheme does not fully take into account the technical characteristics of the dual-axis bracket, and there is still room for improvement in work efficiency.

[0004] Any discussion of the background technology throughout the specification does not mean that the background technology is necessarily the prior art known to technicians in the relevant field; any discussion of the prior art throughout the specification does not mean that the prior art is necessarily widely known. Summary of the invention

[0005] The present invention aims to provide a method for dynamically adjusting the azimuth and elevation angles of a photovoltaic dual-axis tracking bracket to improve the efficiency and economy of the system.

[0006] The method for dynamically adjusting the azimuth and elevation angles of the photovoltaic dual-axis tracking bracket in this scheme includes the following steps:

[0007] S1, collection time, longitude and latitude, photovoltaic panel posture and bracket installation parameters;

[0008] S2, calculate the real-time position of the sun according to time and longitude and latitude;

[0009] S3, performing anti-shadow calculation according to the installation parameters of the tracking bracket to obtain an anti-shadow correction value;

[0010] S4. Adjust the azimuth and elevation of the bracket according to the real-time position of the sun and the anti-shadow correction value.

[0011] This solution includes multiple brackets, and one calculation provides control functions for the posture adjustment of multiple brackets. This solution can reduce shadow occlusion. Through the anti-shadow calculation of the photovoltaic panel installation parameters, the position of the photovoltaic panel can be adjusted in time to avoid mutual occlusion between the front and rear rows of photovoltaic panels, further improving the power generation capacity of the overall system.

[0012] This solution integrates multiple sensor data and combines it with advanced control algorithms to achieve intelligent management and efficient operation of photovoltaic dual-axis tracking brackets. It not only improves power generation efficiency and enhances system stability and intelligence, but also improves operation and maintenance experience, bringing significant economic and social benefits.

[0013] Furthermore, the collected data includes natural environment data. A variety of sensors can be integrated to monitor environmental changes in real time, and make targeted responses in a timely manner to ensure the stable operation of the system.

[0014] Furthermore, the Solar Position Algorithm astronomical algorithm is used to calculate the sun's position. The high-precision SPA (Solar Position Algorithm) astronomical algorithm published by the National Renewable Energy Laboratory (NREL) of the United States has higher accuracy.

[0015] Furthermore, the time data is collected from the real-time clock RTC chip, which can accurately obtain time information and adopt a regular time synchronization mechanism based on GPS to eliminate time accumulation errors.

[0016] Furthermore, the installation parameters include the east-west spacing of the brackets, the north-south spacing of the brackets, and the size of the components installed on the brackets. It is possible to accurately calculate whether the front row brackets will cast shadows on the rear row bracket components.

[0017] Furthermore, in S3, the row spacing is calculated first, and then the anti-shadow calculation is performed. The difference between the anti-shadow calculation of the dual-axis and the flat single-axis is that the "front and back" row spacing is variable, and different yaw angles have different row spacings. The row spacing needs to be determined first, and then a more accurate anti-shadow calculation result can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the operation flow of the motor in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below through specific embodiments:

[0020] 1. Hardware Structure

[0021] In a photovoltaic field, multiple dual-axis photovoltaic brackets and photovoltaic panels are installed. As shown in the figure, dozens of photovoltaic brackets form a sub-array. Each sub-array is equipped with a communication controller (Net Control Unit, also referred to as NCU below), and a tracking controller (Tracker Control Unit, also referred to as TCU below) is installed on the column of each bracket. The sub-array system uses Modbus RTU / MODBUS TCP protocol to connect to the SCADA monitoring system, which can realize remote control, statistical information display, individual information query, parameter setting, wind speed record query and other functions in heavy snow and other severe weather conditions.

[0022] NCU is installed on the meteorological pole, which is deployed close to the box-type transformer. LORA antenna realizes internal wireless communication, provides RS485 and electrical Ethernet ports externally, and supports optical fiber access. NCU is responsible for collecting meteorological sensor information, collecting and managing information within the subarray, and external communication.

[0023] The sensor configuration in the NCU includes: standard GPS, wind speed sensor, irradiation sensor, rain sensor, and snow depth sensor. The wind speed sensor uses a wind cup made of high-strength aluminum alloy, which is light in weight, has a small starting torque, and low inertia. It can truly reflect wind speed information and is used to determine whether it is necessary to enter the protection mode. GPS data can obtain the current geographic location information (longitude and latitude). Irradiation sensor data can measure the current solar radiation intensity and is used to evaluate the power generation efficiency of photovoltaic panels. Rainfall sensor data can detect rainfall and is used to trigger commands to clean photovoltaic panels or enter protection mode. The snow depth sensor can detect the depth of snow accumulation and is used to determine whether it is necessary to start the snow removal program or adjust the posture of the photovoltaic panels.

[0024] TCU can receive the time, longitude and latitude information from NCU, drive the dual-axis tracking bracket to chase the light, and receive instructions from NCU in extremely bad weather to perform operations such as wind shelter and snow removal. TCU uses wireless communication to exchange information with NCU and regularly upload operating data and fault alarm information.

[0025] Each TCU includes 1 controller host, 1 six-axis tilt sensor, and 2 sets of limit switches. Each set of TCUs configured with dual-axis tracking brackets is independently driven, and can use existing software and hardware to achieve the personalized tracking capability of a single bracket. The controller host and limit switches are installed on the column, and the six-axis tilt sensor is installed on the main beam.

[0026] The dual-axis adjustment can adopt existing technologies, such as the following main components:

[0027] Basic platform: The base used to support the entire tracking system.

[0028] The first rotating mechanism is arranged on the basic platform, including a first rotating shaft driven by a motor and a first rotating arm connected thereto, and is used to drive the photovoltaic panel to rotate in the east-west direction (azimuth direction) to track the rising and setting of the sun.

[0029] The second rotating mechanism is arranged at one end of the first rotating arm, including a second rotating shaft driven by a motor and a second rotating arm connected thereto, and is used to drive the photovoltaic panel to rotate in the north-south direction (zenith angle direction) to adapt to the vertical height changes of the sun in different seasons.

[0030] Photovoltaic panel support frame: connected to one end of the second rotating arm, used to fix the photovoltaic panel to ensure that the photovoltaic panel can change its direction following the movements of the first rotating mechanism and the second rotating mechanism.

[0031] 2. Tracking Control Algorithm

[0032] The control principle is to use the closed-loop control of the sun position combined with the six-axis tilt sensor (external), and it also has the anti-shadow tracking function. The control system calculates the current sun position, that is, the altitude angle and azimuth angle, based on the astronomical algorithm. The control system detects the tilt sensor signal and obtains the current angle of the tracking bracket. The control system drives the motor to run and drives the tracking bracket to the position facing the current sun, so as to track the sun at any time. The motor is operated as follows: Figure 1 The process shown runs:

[0033] 1. Calculation of sun position:

[0034] Using the high-precision SPA (Solar Position Algorithm) astronomical algorithm published by the National Renewable Energy Laboratory (NREL) of the United States, the sun's position can be accurately calculated based on time, longitude and latitude information, with an accuracy of up to 0.0003°.

[0035] The bracket controller is equipped with a real-time clock RTC (Rea1-time c1ock) chip, which can accurately obtain time information and adopt a regular time synchronization mechanism based on GPS to eliminate time accumulation errors and solve the problem of clock loss during power outages.

[0036] 2. Tracking angle calculation:

[0037] According to the sun's position (altitude angle, azimuth angle), the target rotation angle of the component can be calculated to ensure that the solar radiation on the east-west normal line is at a 90° angle to the component.

[0038] 3. Anti-shadow calculation:

[0039] Based on the tracking bracket installation parameters (such as east-west spacing, north-south spacing, and the size of the components installed on the bracket), it is possible to accurately calculate whether the front bracket will cast a shadow on the rear bracket components, thereby switching to anti-shadow mode for tracking.

[0040] The difference between the dual-axis anti-shadow calculation and the flat single-axis is that the "front and back" row spacing is variable, and different yaw angles have different row spacing.

[0041] First, we need to solve the problem of calculating the variable row spacing. Under different solar azimuths, the shadows produced by the dual-axis brackets are generated between different brackets:

[0042] 1) The solar azimuth is -90° (due east), and the shadow of the middle bracket is produced on the west bracket;

[0043] 2) The solar azimuth is -60°, and the shadow of the middle bracket is still produced on the west bracket;

[0044] 3) The solar azimuth is -45°, and the shadow of the middle bracket is produced on the north bracket;

[0045] 4) The solar azimuth is -30°, and the shadow of the middle bracket is still produced on the north bracket;

[0046] 5) When the solar azimuth is 0°, the shadow of the middle bracket is still produced on the northern bracket;

[0047] The change in the distance between the front and rear rows is related to the east-west distance and the solar azimuth of the on-site installation. Through geometric calculation, the accurate real-time distance in the direction of the sun's normal can be obtained. The calculation steps are as follows:

[0048] 1) Determine the direction of sunlight. Assume that the direction of sunlight is a unit vector S, and its coordinates in three-dimensional space can be determined by the solar azimuth and zenith:

[0049] S=(cos(Azimuth)·sin(Zenith),sin(Azimuth)·sin(Zenith),cos(Zenith))

[0050] 2) Calculate the normal direction of the photovoltaic panel. Assuming that the normal direction of the photovoltaic panel is a unit vector N, its coordinates in three-dimensional space can be determined by the yaw angle Yaw and the pitch angle Pitch:

[0051] N=(sin(Pitch)·sin(Yaw),sin(Pitch)·cos(Yaw),cos(Pitch))

[0052] 3) Calculate the angle between sunlight and the normal direction of the photovoltaic panel. The angle θ can be obtained by vector dot product operation:

[0053] cos(θ)=N·S

[0054] 4) Calculate the spacing in the direction of the sun's normal. To obtain the spacing of the photovoltaic panels in the direction of the sun's normal, it is necessary to project the east-west spacing dx and the north-south spacing dy onto the sun's normal. First, construct a plane rectangular coordinate system determined by the normal direction of the photovoltaic panels, and then project dx and dy onto this coordinate system:

[0055] D norm 2 =(d x ·cos(θ x )) 2 +(d y ·cos(θ y )) 2

[0056] Among them, θx and θy are the angles between the normal direction of the photovoltaic panel and the east-west direction and the north-south direction respectively. These angles can be determined by the yaw angle and pitch angle of the photovoltaic panel.

[0057] After the effective row spacing calculation, the anti-shadow calculation problem is decoupled into geometric calculation on the plane. The calculation steps are as follows:

[0058] 1) Determine the projection of the photovoltaic panel under sunlight. Assume that the direction of sunlight is a unit vector S, whose coordinates in three-dimensional space can be determined by the solar azimuth and zenith.

[0059] 2) Calculate the normal direction N of the photovoltaic panel and find the angle θ between the photovoltaic panel and the direction of sunlight.

[0060] 3) Calculate the projection length of the photovoltaic panel. Use trigonometric functions to calculate the projection length Lproj of the photovoltaic panel on the ground:

[0061] Lproj = h·tan(θ)

[0062] Among them, h is the height of the photovoltaic panel from the ground, and θ is the angle between the normal direction of the photovoltaic panel and the direction of sunlight.

[0063] 4) Determine the projection direction. Determine the projection direction based on the solar azimuth and the yaw angle of the photovoltaic panel. The projection direction can be decomposed into east-west and north-south components.

[0064] 5) Calculate the projection components in the east-west and north-south directions. Since the photovoltaic panel can rotate in two directions, the projection length needs to be decomposed into east-west and north-south components:

[0065] Lproj,x=Lproj·cos(αx)

[0066] Lproj,y=Lproj·cos(αy)

[0067] Among them, αx and αy are the angles between the projection of the photovoltaic panel and the east-west and north-south directions respectively.

[0068] 6) Determine the shadow area. Use the projection components Lproj,x and Lproj,y, combined with the east-west spacing dx and the north-south spacing dy, to determine whether the shadow falls on the next row of photovoltaic panels.

[0069] If the projection length exceeds the east-west spacing or the north-south spacing, it means that the front row of photovoltaic panels will cast shadows on the rear row of photovoltaic panels.

[0070] 7) Calculate the size of the shadow area. If the projection does fall on the rear photovoltaic panels, the size of the shadow area can be further calculated. The size of the shadow area depends on the size of the photovoltaic panel, the projection length and its direction.

[0071] When the installation parameters include the east-west spacing of the bracket, the north-south spacing of the bracket, and the size of the components installed on the bracket, the projection component is combined with the east-west spacing and the north-south spacing to determine whether the shadow falls on the next row of photovoltaic panels. If the projection component is greater than the corresponding east-west spacing or north-south spacing, the front row of photovoltaic panels will cast a shadow on the rear row of photovoltaic panels. If the projection does fall on the rear row of photovoltaic panels, the size of the shadow area can be further calculated.

[0072] After the anti-shadow calculation is completed, when it is determined that a shadow is about to form, the direction of the photovoltaic panel is adjusted in advance to avoid shadow obstruction.

[0073] The above is only an embodiment of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the scheme of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for dynamically adjusting the azimuth and elevation angles of a photovoltaic dual-axis tracking bracket, characterized in that The following steps are involved: S1, collection time, longitude and latitude, photovoltaic panel posture and bracket installation parameters; S2, calculate the real-time position of the sun according to time and longitude and latitude; S3, performing anti-shadow calculation according to the installation parameters of the tracking bracket to obtain an anti-shadow correction value; S4. Adjust the azimuth and elevation of the bracket according to the real-time position of the sun and the anti-shadow correction value.

2. The method for dynamically adjusting the azimuth and elevation angles of a photovoltaic dual-axis tracking bracket according to claim 1, characterized in that: The collected data includes natural environment data.

3. The method for dynamically adjusting the azimuth and elevation angles of a photovoltaic dual-axis tracking bracket according to claim 2 is characterized in that: The Solar PositionAlgorithm astronomical algorithm is used to calculate the sun's position.

4. The method for dynamically adjusting the azimuth and elevation angles of a photovoltaic dual-axis tracking bracket according to claim 3 is characterized in that: The time data is collected from the real-time clock RTC chip.

5. The method for dynamically adjusting the azimuth and elevation angles of a photovoltaic dual-axis tracking bracket according to claim 4 is characterized in that: The installation parameters include the east-west spacing of the bracket, the north-south spacing of the bracket, and the size of the components installed on the bracket.

6. The method for dynamically adjusting the azimuth and elevation angles of a photovoltaic dual-axis tracking bracket according to claim 5, characterized in that: In S3, the row spacing calculation is performed first, and then the anti-shadow calculation is performed.

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