All-terrain inverse tracking control algorithm of photovoltaic tracking support system

Abstract

The invention discloses an all-terrain inverse tracking control algorithm of a photovoltaic tracking support system, and belongs to the technical field of photovoltaic power generation. Comprising the following steps: S1, calculating a solar altitude theta and an azimuth angle alpha of a current point; s2, calculating an optimal angle beta opt under the condition of no shielding according to a solar energy radiation formula; and S3, adjusting the self inclination angle, and maximizing effective radiation under the condition of satisfying shadow avoidance. The method comprises the following steps: vectorization radiation optimization: converting astronomical data into space vector calculation, and uniformly processing terrain and shielding problems; a three-dimensional shadow model: fusing gradient height difference and azimuth off-axis correction; and non-uniform spacing adaptation: dynamic input is supported, and an actual engineering scene is adapted.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic power generation technology, in particular to a full-terrain inverse tracking control algorithm of a photovoltaic tracking support system, and is particularly suitable for photovoltaic power station scenes with slopes, off-axis and non-uniform row spacing. BACKGROUND

[0002] The existing photovoltaic tracking support inverse tracking algorithm has the following shortcomings:

[0003] Only applicable to horizontal terrain, unable to handle the case where slopes and off-axis exist simultaneously;

[0004] Requires array to be arranged at equal intervals, not suitable for actual engineering intervals;

[0005] Shadow calculation uses a two-dimensional simplified model, ignoring three-dimensional terrain features;

[0006] Does not consider the height difference shadow superposition effect caused by slopes. SUMMARY

[0007] The present application aims to solve the problem of the existing photovoltaic tracking support inverse tracking algorithm, and proposes a full-terrain inverse tracking control algorithm of a photovoltaic tracking support system, which can simultaneously adapt to slopes, off-axis and non-uniform spacing full-terrain inverse tracking control.

[0008] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0009] A full-terrain inverse tracking control algorithm of a photovoltaic tracking support system, comprising the following steps:

[0010] S1, calculating the solar elevation angle Θ and azimuth angle α of the current point;

[0011] S2, calculating the optimal angle β under no shadow according to the solar radiation formula opt ;

[0012] S3, adjusting the inclination angle to maximize the effective radiation under the condition of satisfying shadow avoidance.

[0013] Preferably, in step S1:

[0014] The latitude and longitude of the current point and the time are obtained through GPS;

[0015] The solar azimuth angle Θ and elevation angle α of the current point are obtained according to astronomical algorithms.

[0016] Preferably, in step S2:

[0017] The inclination of the device relative to the north-south axis is obtained by an electronic compass;

[0018] The radiation calculation formula of the solar panel under any orientation and inclination is as follows:

[0019] S moudle = S incident · cos α · sin β · cos Ψ + sin α · cos β.

[0020] Preferably, in step S3:

[0021] After the optimal angle of the solar panel under the current condition is calculated, the position of the front row shadow is calculated according to the distance from the front row, the panel width and the angle of the front row, so as to adjust itself to avoid the front row shadow.

[0022] Preferably, in step S3, the solar panel group string of the front row and the back row communicates through zigbee to obtain the current angle of the front row.

[0023] Preferably, in step S3, in the scene of slope, off-axis and non-uniform spacing, a dynamic shadow projection model needs to be established.

[0024] The method comprises the following steps:

[0025] S301, shadow boundary modeling;

[0026] In the size of the front row photovoltaic panel, the panel width W, the height H and the inclination angle β front .

[0027] The slope angle θ and the azimuth off-axis Ψ;

[0028] Shadow length formula

[0029]

[0030] S302, street avoidance angle calculation;

[0031] The effective radiation intensity on the inclined surface is determined by vector dot product

[0032] S moudle = S incident · (N · S);

[0033] Wherein, N is the normal vector of the photovoltaic panel, and S is the solar direction vector;

[0034] S303, inverse tracking target:

[0035] Adjust the inclination angle β rear of itself to maximize S moudle under the condition of meeting the shadow avoidance condition.

[0036] Preferably, in step S303:

[0037] D spacing is the actual panel spacing; the avoidance constraint condition

[0038]

[0039] Compared with the prior art, the present application provides a full-terrain inverse tracking control algorithm of a photovoltaic tracking support system, which has the following beneficial effects.

[0040] 1、The vectorization radiation optimization of the present application: astronomical data is converted into spatial vector calculation to uniformly process terrain and shielding problems; three-dimensional shadow model: fusion of slope height difference and azimuth axis correction; non-uniform spacing adaptation: support dynamic input, adapt to actual engineering scene.

[0041] Other advantages, objects, and features of the present application will be apparent to those skilled in the art from the following specification, and will be apparent from the practice of the present application. Such advantages, objects, and features will be apparent to those skilled in the art from the following specification, and will be apparent from the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The flowchart of the present application.

[0043] Figure 2 The schematic diagram of solar radiation.

[0044] Figure 3 The schematic diagram of unit vectors S and N. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments.

[0046] Referring to Figure 1 A full-terrain inverse tracking control algorithm of a photovoltaic tracking support system, comprising the following steps:

[0047] S1, calculating the solar elevation angle Θ and the azimuth angle α of the current point;

[0048] S2, calculating the optimal angle β under no shielding according to the solar radiation formula opt ;

[0049] S3, adjusting the inclination angle to maximize the effective radiation under the condition of satisfying the shadow avoidance.

[0050] In step S1:

[0051] The latitude and longitude of the current point and the time are obtained through GPS;

[0052] The solar azimuth angle Θ and the elevation angle α of the current point are obtained according to the astronomical algorithm.

[0053] This type of algorithm is relatively mature in the astronomical field, and there are many methods; for example, the Wang operator calculation method can be used.

[0054] The Wang operator was developed by Wang Bingzhong based on Bourges's method. He modified some of the day coefficients and changed the starting year from 1969 to 1985, making it closer to the true value. The calculated solar declination angle is in radians.

[0055] The formula is as follows, which is the same as the Bourges operator. The unit of solar declination angle is radians.

[0056] δ=0.3723+23.2567sin(ωt)+0.1149sin(2ωt)-0.1712sin(3ωt)

[0057] -0.7580cos(ωt)+0.3656cos(2ωt)+0.02010cos(3ωt)

[0058] The implementation code of Wang operator is as follows:

[0059] Double Wang(cDateTime date)

[0060] {

[0061] Int n=getDaysOfYear(date);

[0062] Int year = date.year;

[0063] Int temp=0.25*(year-1985);

[0064] Double n0=79.6764+0.2422*(year-1985)-temp;

[0065] Double t=n-1-n0; / / equivalent day number

[0066] Double w=2*M_PI / 365.2422; / / reference radian coefficient

[0067] Doubledellta=0.3723+23.2567*sin(w*t)+0.1149*sin(2*w*t)-0.1712*si n(3*w*t)-0.7580*cos(w*t)+0.3656*cos(2*w*t)+0.0201*cos(3*w*t);

[0068] return delta / 180.0*M_PI; / / radians

[0069] }

[0070] The solar power incident on a photovoltaic module depends not only on the power contained in the sunlight but also on the angle between the module and the sunlight. When the module surface is perpendicular to the sunlight, the power density absorbed by the surface is equal to the power density of the sunlight (in other words, the power density is at its maximum when the module surface is perpendicular to the sunlight). However, as the angle between the sun and a fixed surface changes, the power density received by the fixed module will be less than the power density of the incident sunlight.

[0071] The amount of solar radiation incident on the surface of a tilted module is the vertical component of the incident solar radiation.

[0072] like Figure 2 As shown, the solar radiation on the horizontal plane (S horizontal ) or solar radiation perpendicular to the direction of sunlight (S incident ), to calculate the solar radiation incident on the slope (S module ).

[0073] Positioning the module at an angle to the incident light will reduce the module's power output.

[0074] With S module , S horizontal and S incident The relevant formula is:

[0075] S horizontal =S incident sinα;

[0076] S module =S incident sin(α+β).

[0077] in

[0078] α is the elevation angle;

[0079] β is the tilt angle measured from the horizontal.

[0080] According to these equations, the relationship between Smodule and Shoriz can be determined as:

[0081]

[0082] In step S2:

[0083] Get the device's current tilt relative to the north-south axis from the electronic compass.

[0084] The radiation formula for a solar panel at any orientation and tilt is as follows:

[0085] S moudle = S incident cos α sin β cos Ψ + sin α cos β.

[0086] α is the solar elevation angle, Θ is the solar azimuth angle.

[0087] β is the tilt angle of the assembly. For an assembly placed horizontally on the ground β = 0°. For an assembly placed vertically β = 90°.

[0088] Ψ is the azimuth angle of the assembly's orientation. Most assemblies are placed facing the equator.

[0089] Assemblies in the southern hemisphere are placed facing north, Ψ = 0; assemblies in the northern hemisphere are placed facing south, Ψ = 180.

[0090] S moudle and S incident represent the light intensity impinging on the assembly and the light intensity of the incoming sunlight, respectively, in W / m 2 S incident here only considers the direct radiation portion of the sunlight.

[0091] For an assembly placed perpendicular to the incoming sunlight, the tilt angle is equal to the solar zenith angle (90 - α = β), and the azimuth angle is equal to the solar azimuth angle (Ψ = Θ).

[0092] As the number of tilt and orientation angles becomes more complex, to simplify the calculations, the solar azimuth and elevation directions are converted to vectors. The convenience of using vectors is that the light intensity on a tilted surface is simply the dot product between the incoming light ray and the normal to the assembly.

[0093] As Figure 3 shown; light impinging on a tilted surface at an angle spreads over a larger area; the reduced intensity is the dot product of the unit vectors S and N.

[0094] S moudle = S incident cos(γ) = S incident S · N.

[0095] where S moudle and S incident are as defined previously, S is the unit vector pointing in the direction of the sun, N is the unit vector in the direction of the normal to the assembly surface, and γ is the angle between the two vectors.

[0096] Because the solar panel photovoltaic panel is single-axis operation, the motion range of the solar panel is a circular arc, and a large number of data operations are adopted in the MCU to obtain the angle of the solar panel to obtain the maximum radiation under the current condition, that is, the optimal angle.

[0097] In step S3:

[0098] Inverse tracking is a geometric problem. After calculating the optimal angle of the solar panel under the current condition, the position of the front row shadow is calculated according to the distance from the front row, the panel width, and the front row angle, so as to adjust itself to avoid the front row shadow.

[0099] The distance and the panel width need to be manually input, and the distance before and after is input at the same time. The panel width is generally consistent throughout the project;

[0100] The solar panel group string in the front row and the back row communicates through zigbee to obtain the current angle of the front row.

[0101] Inverse tracking essentially solves the geometric occlusion problem in three-dimensional space.

[0102] In step S3, a dynamic shadow projection model needs to be established under the conditions of slope, axis deviation, and non-uniform spacing; including the following steps.

[0103] S301, shadow boundary modeling.

[0104] In the size of the front row photovoltaic panel, the panel width W, the height H, and the inclination angle β front ;

[0105] Slope angle θ, azimuth angle axis deviation Ψ;

[0106] Shadow length formula

[0107]

[0108] S302, street avoidance angle calculation.

[0109] The effective radiation intensity on the inclined surface is determined by vector dot product

[0110] S moudle =S incident ·(N·S);

[0111] Wherein, N is the normal vector of the photovoltaic panel, and S is the solar direction vector.

[0112] S303, inverse tracking target.

[0113] Adjust the inclination angle β rear of itself to maximize S moudle under the condition of satisfying shadow avoidance.

[0114] D spacingActual panel spacing (support non-uniform value input); avoidance constraint condition

[0115]

[0116] In the control algorithm: first, the altitude angle and azimuth angle of the sun are calculated by the basic astronomical algorithm, and then the optimal angle of the sun under the condition of axis inclination is calculated by formula, and then the front row shadow is calculated by slope, spacing, panel width and front row angle, and then the angle is adjusted to avoid the shadow.

[0117] The overall process is as follows:

[0118] 1, real-time input: GPS position, time, slope / axis angle, front row parameter, spacing data;

[0119] 2, astronomical calculation: solve Θ and α by using Wang operator;

[0120] 3, radiation optimal angle: calculate the optimal inclination angle β without obstruction by vector model opt ;

[0121] 4, shadow avoidance: if β opt violates the avoidance constraint, the critical angle β rear is used;

[0122] In the present application, at least the following advantages are provided:

[0123] 1, vectorized radiation optimization: astronomical data is converted into spatial vector calculation, and terrain and obstruction problems are uniformly processed;

[0124] 2, three-dimensional shadow model: combining slope height difference and azimuth correction;

[0125] 3, non-uniform spacing adaptation: D spacing Support dynamic input, adapt to actual engineering scene.

[0126] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

[0127] Although the embodiments of the present application have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and modifications to the above-mentioned embodiments within the scope of the present application.

Claims

1. An all-terrain inverse tracking control algorithm for a photovoltaic tracking bracket system, characterized in that: The following steps are involved: S1, calculate the solar altitude angle Θ and azimuth angle α of the current point; S2. Calculate the optimal angle β without obstruction according to the solar radiation formula opt ; S3. Adjust its own inclination angle to maximize effective radiation while meeting the shadow avoidance conditions.

2. The all-terrain inverse tracking control algorithm for the photovoltaic tracking bracket system according to claim 1 is characterized in that: In step S1: Get the latitude, longitude and time of the current point through GPS; The solar azimuth angle Θ and altitude angle α of the current point are obtained according to the astronomical algorithm.

3. The all-terrain inverse tracking control algorithm for the photovoltaic tracking bracket system according to claim 1 is characterized in that: In step S2: Obtain the device's current tilt relative to the north-south axis using the electronic compass; The formula for calculating the radiation of a solar panel at any orientation and tilt is as follows: S moudle =S incident ·cosα·sinβ·cosΨ+sinα·cosβ。 4. The all-terrain inverse tracking control algorithm for the photovoltaic tracking bracket system according to claim 1 is characterized in that: In step S3: After calculating the optimal angle of the solar panel in the current situation, the position of the front row shadow is calculated based on the distance from the front row, the panel width, and the front row angle, so as to adjust itself to avoid the front row shadow.

5. The all-terrain inverse tracking control algorithm for the photovoltaic tracking bracket system according to claim 4 is characterized in that: In step S3, the front and rear rows of solar panel strings communicate with each other via Zigbee to obtain the current angle of the front row.

6. The all-terrain inverse tracking control algorithm for the photovoltaic tracking bracket system according to claim 1, characterized in that: In step S3, a dynamic shadow projection model needs to be established in the slope, off-axis and non-uniform spacing scenarios; The following steps are involved: S301, shadow boundary modeling; The dimensions of the front photovoltaic panels are: width W, height H, and inclination angle β front ; Slope angle θ, azimuth off-axis Ψ; Shadow length formula S302, calculation of street avoidance angle; The effective radiation intensity on the inclined surface is determined by the vector dot product S moudle =S incident ·(N·S); Where N is the normal vector of the photovoltaic panel, and S is the sun direction vector; S303, reverse tracking target: Adjust its own inclination angle β rear , maximize S while satisfying the shadow avoidance condition moudle .

7. The all-terrain inverse tracking control algorithm for the photovoltaic tracking bracket system according to claim 1, characterized in that: In step S303: D spacing is the actual plate spacing; avoidance constraint

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