Computer-implemented method for optimizing the electricity production of a photovoltaic device and photovoltaic power plant thus optimized

Abstract

The present invention relates to a computer-implemented method for optimizing the electricity production of a photovoltaic power plant comprising a plurality of electricity production units, the method comprising the following steps: - Obtaining a mathematical model of the photovoltaic power plant, - Calculating, for a determined moment, by means of the mathematical model and the position of the sun at this determined moment, the electricity production of the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units, - Selecting, from this plurality of orientations, a determined orientation for each of the electricity production units which corresponds to a set of optimal positions for producing electricity by means of the photovoltaic power plant,and - Generate instructions for the control means to orient each of the electricity generating units towards their respective determined orientation. Abstract Figure: 6,

Description

Title of the invention: Computer-implemented method for optimizing the electricity production of a photovoltaic device and photovoltaic power plant thus optimized Field of the invention

[0001] The invention relates to a computer-implemented method for optimizing the electricity production of a photovoltaic power plant, the photovoltaic power plant comprising a plurality of electricity production units, the electricity production units each being designed to change their orientation relative to the sun, the electricity production units being connected to control means for controlling said orientation.

[0002] More specifically, the invention relates to a method for managing a photovoltaic power plant, such as an agrivoltaic power plant and such a power plant, in which the positioning of the photovoltaic panels can be controlled so as to optimize the general electricity production of the power plant during the day and during the year. According to one embodiment of the invention, the presence of shading on at least a portion of the photovoltaic panels can be taken into account to optimize said general electricity production of the power plant. State of the art

[0003] In the state of the art, it is known to use a backtracking system to optimize electricity production using photovoltaic panels. This backtracking system is designed for photovoltaic panels installed on land with regular slopes. This tracking system is not suitable for photovoltaic panels installed in a "wave" structure such as a canopy. According to the prior art, photovoltaic panels are, for example, fixed together on structures called "tables", a set of tables forming a photovoltaic power plant.

[0004] To optimize electricity production using photovoltaic panels, the panels are adjustable to be positioned in the direction of the sun. Typically, the panels are adjustable using a tracking system to follow the movement of the sun during the day and to adapt the orientation of the panels during the year.

[0005] Typically, the tables, on which the photovoltaic panels are mounted, are positioned in a first position, such as an essentially horizontal position. From said first position, the tables are oriented, using motors towards the sun to maximize their electricity production.

[0006] To optimize the electricity production of the tables placed closest to the sun, the tables must be rotated by an angle equal to the projected elevation of the sun. However, with such an orientation it is possible that the tables closest to the sun create shadows on the photovoltaic panels of the adjacent tables, leading to a drop in electricity production.

[0007] To avoid such a drop in electricity production, according to the prior art, the tables preferably follow the movement imposed by the backtracking consisting of orienting the tables as much as possible facing the sun without casting shadows on each other.

[0008] A first drawback of the known solutions of the prior art lies in the fact that the backtracking system as an input parameter only takes into account the avoidance of the formation of shadows on the solar panels. However, avoiding shadows does not necessarily make it possible to maximize the production of electricity with the entire installation.

[0009] Furthermore, the backtracking system does not take into account either the specific connection of the cells which together form a photovoltaic panel or the effect of a shadow on a part of said cells for the production of electricity from the panel. This means that the backtracking also does not take into account the partial shadow on a part of the photovoltaic panels of a power plant and the effect of this shadow on the overall production of electricity of said power plant.

[0010] Another disadvantage, according to the prior art, lies in the fact that point shadows, which can be created during the day, are also not taken into account during backtracking. These point shadows result, for example, from the presence of an object close to the power plant, such as a pole or a tree. Point shadows can also be formed by construction elements of the power plant itself, such as cables or poles forming part of the supporting structure of the power plant or other elements forming part of the supporting structure of the power plant or the environment close to the power plant. Preferably, the effect of such point shadows on the overall electricity production of a photovoltaic power plant should be controlled.

[0011] Therefore, in view of the above, it appears necessary to propose a solution allowing the optimized management of a photovoltaic power plant, such as an agrivoltaic power plant, in which the positioning of the tables can be controlled so as to optimize the overall electricity production of such a power plant during the day and the year. Subject of the invention

[0012] The subject matter of the present invention relates to a computer-implemented method for optimizing electricity production by means of a photovoltaic power plant, the photovoltaic power plant comprising a plurality of electricity production units, the electricity production units each being adapted to modify their orientation relative to the sun in order to optimize their electricity production at any time, the electricity production units being connected to control means for controlling said orientation, the method comprising the following steps:

[0013] - Obtain a mathematical model of the photovoltaic power station including the positions of the various electricity production units, the mutual distances between these units, the irradiance and position of the sun relative to the photovoltaic power plant,

[0014] - Calculate, for a given moment, using the mathematical model and the position of the sun at that determined moment, the electricity production of the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units, taking into account for each of the electricity production units their instantaneous orientation and their corresponding instantaneous electricity production,

[0015] - Select, from this plurality of orientations, a determined orientation for each of the electricity production units which corresponds to a set of optimal positions, and

[0016] - Generate instructions for the control means to orient each of the electricity production units towards their respective determined orientation.

[0017] According to one embodiment of the invention, the mathematical model comprises parameters defining the area of ​​the installation of the photovoltaic power plant, such as latitude, longitude, altitude, orientation, albedo of the ground.

[0018] According to one embodiment of the invention, the step of calculating for the determined moment, by means of the mathematical model and the position of the sun at this determined moment, the electricity production of the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units comprises:

[0019] a) Calculate, for a first orientation of the plurality of electricity production units, a first instantaneous production of electricity from the photovoltaic power plant,

[0020] b) Modifying the orientation of at least a first electricity production unit of said plurality of electricity production units to obtain a modified orientation of the plurality of electricity production units,

[0021] c) Calculating for the modified orientation of the plurality of electricity production units a modified instantaneous production of electricity of the photovoltaic power plant, and

[0022] d) Repeat steps b) and c) to thereby obtain the instantaneous production of electricity from the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units.

[0023] According to one embodiment of the invention, the method further comprises:

[0024] - Quantify, using the mathematical model, the presence of at least one shadow created by at least one electricity generating unit on another electricity generating unit at the given time, to identify a shaded electricity generating unit,

[0025] - Reduce, using the mathematical model, the estimated electricity production of said shaded electricity production unit, and

[0026] - Calculate, for this determined moment, by means of the mathematical model and the reduced estimated electricity production for the shaded electricity production unit, the electricity production of the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units and

[0027] - Select, from this plurality of orientations, a determined orientation for each of the electricity production units which corresponds to an optimal position for producing electricity by means of the photovoltaic power plant at the determined time taking into account the reduced estimated electricity production for said shaded electricity production unit.

[0028] According to one embodiment of the invention, the mathematical model comprises parameters defining structural elements of the photovoltaic power plant and / or parameters defining objects in the vicinity of the photovoltaic power plant, the method further comprising:

[0029] - Quantify, using the mathematical model, the presence of at least one shadow created by a structural element of the photovoltaic power plant and / or an object near the photovoltaic power plant on an electricity production unit at the given time, to identify a shaded electricity production unit,

[0030] - Reduce, using the mathematical model, the estimated electricity production of said shaded electricity production module, and

[0031] - Calculate, for this determined moment, by means of the mathematical model and the reduced estimated electricity production for the shaded electricity production unit, the electricity production of the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units, and

[0032] - Select, from this plurality of orientations, a determined orientation for each of the electricity production units which corresponds to a set of optimal positions for producing electricity by means of the photovoltaic power plant at the determined time taking into account the reduced estimated electricity production for said shaded electricity production unit.

[0033] According to one embodiment of the invention, the estimated electricity production for the shaded electricity production unit is reduced in accordance with a mathematical function previously established using the electrical characteristics of said shaded module and its electrical connection.

[0034] According to a second aspect, the invention relates to a photovoltaic power plant for the production of electricity comprising:

[0035] - A plurality of electricity production units, the production units electricity units each being designed to change their orientation relative to the sun in order to optimize their electricity production at any time, the electricity production units being connected to control means for controlling said orientation,

[0036] - computing means adapted to host a mathematical model for the photovoltaic power plant comprising the positions of the various electricity production units, the mutual distances between these units, the irradiance and the position of the sun relative to the photovoltaic power plant, and adapted to calculate for a given moment, by means of the mathematical model and the actual position of the sun, the electricity production of the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units, taking into account, for each of the electricity production units, their instantaneous orientation and their corresponding instantaneous electricity production, the calculation means being further adapted to the selection, from said plurality of orientations, of a given orientation for each of the electricity production units which corresponds to an optimal position for producing electricity by means of the photovoltaic power plant at the given moment,and the generation of instructions for the control means, and,

[0037] - control means connected to the calculation means and adapted to receive instructions from said calculating means and to orient each of the electricity production units towards their respective determined orientation.

[0038] According to one embodiment of the invention, the photovoltaic power plant comprises at least one electricity production unit with a first module connected in parallel with at least one adjacent second module, the first and second modules comprising electricity-producing cells, the electricity production unit being provided with shunt diodes allowing the creation of a path for the electric current between an input and an output of the electricity production unit.

[0039] According to a third aspect, the invention relates to a computer program product comprising instructions which, when the program is executed by a computer, cause the latter to implement the method mentioned above.

[0040] According to a fourth aspect, the invention relates to a computer-readable recording medium comprising instructions which, when executed by a computer, cause the computer to carry out the above-mentioned method. Brief description of the drawings

[0041] The aim, object and characteristics of the invention will appear more clearly on reading the following description given with reference to the figures in which:

[0042] [Fig-1] shows an example of a part of a photovoltaic power plant positioned above an agricultural plot, according to an embodiment of the invention;

[0043] [Fig.2] schematically shows tables of a photovoltaic power station in a first position, essentially horizontal, according to the prior art;

[0044] [Fig.3] schematically shows the tables according to [Fig.2] in a second position, oriented towards the sun, according to the prior art;

[0045] [Fig.4] shows a two-dimensional geometry model of the shading of a table on an adjacent table, according to one embodiment of the invention;

[0046] [Fig.5] shows graphically an experimental validation of the irradiation model overall effective, according to one embodiment of the invention;

[0047] [Fig.6] shows the example of nine photovoltaic panels connected in series on a table, according to one embodiment of the invention;

[0048] [Fig.7] shows the wiring of the cells of the half-modules of a panel photovoltaic, according to one embodiment of the invention;

[0049] [Fig. 8] shows the effective fraction for producing electricity of the solar radiation incident on a table as a function of the shaded linear fraction thereof, according to an embodiment of the invention. Detailed description of the invention

[0050] The detailed description below is intended to set out the invention in a sufficiently clear and complete manner, in particular with the aid of examples, but should in no case be regarded as limiting the scope of the protection to the particular embodiments and examples presented below.

[0051] In the following description, the term "set of optimal positions" is used. The term "set of optimal positions" refers to the set of orientations of the electricity production units for which the calculated electricity production is the highest among all the sets of orientations tested. The "tested" orientations are the set of orientations identified and for which a performance calculation has been carried out.

[0052] [Fig.l] shows an example of a part of a photovoltaic power plant 100 positioned above an agricultural plot. The photovoltaic power plant 100 comprises tables 10 on which photovoltaic panels 30 are fixed. The tables 10 are hung on a set of cables stretched above the agricultural plot 20. The set of cables comprises upper cables 51 and lower cables 52, mutually connected using turnbuckles 53. The upper cables 51 and the lower cables 52 are, at their respective ends, fixed near the upper ends of the posts 40. The posts 40 supporting these cables 51 and 52 have, for example, a height of approximately 8 m and are spaced, for example, approximately 27 m apart, allowing the passage of most agricultural machinery. At their upper ends, the posts 40 are connected using the crosspieces 4L

[0053] The photovoltaic power plant 100 according to [Fig.l] is an example of an “agrivoltaic” power plant. Such a photovoltaic power plant is defined as an electricity production installation using the radiative energy of the sun, the photovoltaic panels of which are located on an agricultural plot where they make it possible to maintain or sustainably develop agricultural production.

[0054] In the example of [Fig.l], the photovoltaic panels 30 are fixed on the tables 10 in series of nine panels 30 per table 10.

[0055] One of the predominant factors for the efficiency of a photovoltaic power plant 100 according to [Fig.l] is the optimization of the sharing of light, both necessary for the growth of the plants present on the agricultural plot 20 and for the production of electricity using the photovoltaic panels 30. To ensure this sharing while maximizing energy production, the photovoltaic panels 30 are typically oriented and mounted on motors allowing their rotation from East to West around a North-South axis. Thanks to this orientation and this mounting, the photovoltaic panels 30 can optimally follow the movement of the sun during the day and during the days of the year. The tables 10 are fixed on the upper cables 51 using fasteners allowing the rotation of the tables 10 relative to the cables 51. Said fasteners comprise motors adapted to receive instructions concerning the best orientation of the tables.The opposite fixings of each table 10 form an axis of rotation for the table 10 considered.

[0056] The attachments of the tables 10 to the cables 51 comprise, for example, cradles (not shown in [Fig.l]). Said cradles are adapted to be, on one side, attached to the cables 51 and, on the other side, to provide seats for receiving the opposite ends of the tables 10.

[0057] In the photovoltaic industry and in the context of the present description, the use of actuators to correctly position the panels 30 relative to the position of the sun is called solar “tracking”.

[0058] To allow mounting, as described above, the posts 40 are typically positioned in an East-West manner to thereby allow the cables 51, 52 to extend in a substantially East-West direction and to orient the tables 10 with their respective axes of rotation in the North-South direction.

[0059] Figures 2 and 3 show, schematically, the backtracking concept according to the prior art. In this example, the sun is placed to the left of the images and has a projected elevation in the image plane of 20°.

[0060] According to [Fig.2], the tables 10 are positioned essentially horizontally, in a first position. From the first position as shown in [Fig.2], the tables 10 are oriented, using the motors (not shown in Figures 2 and 3) towards the sun to maximize their electricity production.

[0061] To optimize the electricity production of the table shown on the left of [Fig.3], the tables 10 must be rotated by an angle of 20°, thanks to the projected elevation of the sun in this example. On the other hand, with such an orientation the photovoltaic panels of the adjacent tables 10 shade each other, causing a drop in electricity production. The presence of shadows is shown in [Fig.3] using the shaded surfaces.

[0062] To avoid such a drop in production, according to the prior art, the tables 10 preferably follow the backtracking behavior of orienting themselves as much as possible towards the sun without casting shadows on each other.

[0063] Given the above observations, a first consideration is that Figures 2 and 3 clearly show that the backtracking is calculated relatively easily for tables 10 all located at the same altitude. On the other hand, the situation is more complex with tables 10 mounted on cables 51, 52 according to the example of [Fig.l].

[0064] Referring to [Fig.l], of the six tables 10 hung between each pair of consecutive posts 40, the two tables 10 closest to the posts will be at the highest altitudes and those located in the center of the cables 51, 52 at the lowest altitudes.

[0065] The differences in height of the six tables 10 located along the cables 51, 52 mean that the creation of the shaded surfaces of the tables 10 on neighboring tables 10 is different for the tables 10 depending on their position in a row of tables 10 and also depending on the time of day and / or the time of year and depending on the tracking angle taken by said tables 10.

[0066] A second consideration is the fact that the backtracking system according to the prior art only takes into account the adjustment of the photovoltaic power plant 100 with the avoidance of shadows as the only input parameter. However, this does not automatically lead to the maximization of the electricity production of the power plant. photovoltaic 100. Furthermore, such an adjustment does not take into account the presence of point shadows on a table 10. Such point shadows may be linked to the presence of a tall object, such as a tree for example next to one of the tables 10. Such an object could create a shadow on one or more tables, for example, during part of the day.

[0067] It should also be noted that, in the structure of the photovoltaic power plant 100 according to [Fig.l], the tables 10 are fixed in a structure comprising elements, such as posts 40, crosspieces 41, cradles and cables 51, 52. This type of construction creates the risk of having point shadows caused by constituent elements of the photovoltaic power plant 100 itself. In addition, it should be noted that the risk of having point shadows caused by constituent elements of the power plant itself is much greater for an agrivoltaic power plant of the type according to [Fig.l] than in standard photovoltaic power plants, with panels directly fixed to the ground.

[0068] The aim of the invention is to propose a method for managing a photovoltaic power plant, such as an agrivoltaic power plant and such a power plant, in which the positioning of the tables 10 can be controlled so as to optimize the general electricity production for the entire installation.

[0069] Firstly, the invention relates to a computer-implemented method for optimizing the electricity production of a photovoltaic power plant 100 in which the photovoltaic power plant 100 comprises a plurality of electricity production units, such as photovoltaic panels 30. Said electricity production units are each designed to modify their orientation relative to the sun in order to optimize their electricity production at any time. To allow an operator to control said orientation, the electricity production units are connected to control means.

[0070] The method according to the invention comprises several steps.

[0071] To begin, it is necessary to obtain a mathematical model of the photovoltaic power plant 100 comprising the positions of the different electricity production units 30, the mutual distances between these units 30, the irradiance and the position of the sun relative to the photovoltaic power plant 100.

[0072] Then, one must calculate, for a determined moment, by means of the mathematical model and the position of the sun at this determined moment, the electricity production of the photovoltaic power station 100 for a plurality of orientations for each of said plurality of electricity production units 30. For these calculations, the user must take into account for each of the electricity production units 30 their instantaneous orientation and their corresponding instantaneous electricity production.

[0073] In a following step, one must select, from this plurality of orientations, a determined orientation for each of the electricity production units 30 which corresponds to a set of optimal positions for producing electricity by means of the photovoltaic power station 100.

[0074] Using the preceding steps, the method according to the invention makes it possible to generate instructions so that the control means orient each of the electricity production units towards their respective determined orientations.

[0075] The technical effect of the method according to the invention is that at any time, the instantaneous production for all possible positions of the photovoltaic panels 30 and all relative positions of the photovoltaic panels 30 is known, so that the user knows the ideal orientation of all the photovoltaic panels 30 to maximize the electricity production of the entire photovoltaic power plant 100.

[0076] One of the advantages of the invention lies in the fact that the presence of one or more photovoltaic panels 30 partially in the shade can be accepted, provided that the total electricity production of the photovoltaic power plant 100 is maximized.

[0077] As indicated above, the mathematical model of the photovoltaic power plant 100 according to the invention comprises the positions of the different electricity production units 30. According to one embodiment of the invention, the mathematical model comprises parameters defining the area of ​​the installation of the photovoltaic power plant 100, such as latitude, longitude, altitude, orientation, albedo of the ground.

[0078] It should be noted that for modeling three types of inputs are used.

[0079] The first type of input concerns shadows. These inputs include parameters concerning: - tables (dimensions, dynamic spatial coordinates), - other objects casting shadows (their dimensions, their static spatial coordinates), - the position of the sun (elevation, azimuth) and - tracking angles.

[0080] These inputs are processed using mathematical functions to obtain the shaded fraction of the photovoltaic tables 30.

[0081] The second type of inputs concerns light. These inputs include parameters concerning:

[0082] - the site (latitude, longitude, altitude, orientation, albedo, IAM),

[0083] - horizontal irradiation data (GHI, BHI, DHI),

[0084] - the tracking angles, and

[0085] - the distance Earth - Sun.

[0086] These inputs are processed using mathematical functions to obtain the direct, diffuse and reflected irradiances on the inclined plane of the tracking modules (BTI, DTI, RTI).

[0087] The third type of input concerns electricity production. These inputs include parameters concerning: - the results concerning the above-mentioned shadows (Shaded Fraction), - the results concerning light (BTI, DTI, RTI), and - the electrical wiring of the photovoltaic power station 100.

[0088] These inputs are processed using mathematical functions to obtain the simulated instantaneous electricity production.

[0089] In an optimization phase, said results concerning the instantaneous electricity production, simulated together with possible backtracking parameters (this means the set of possible values ​​for which the optimal combination is sought) are used to obtain optimal backtracking parameters and the percentage of expected electricity production gain together with an indication of the distribution of the expected gains as a function of the parameters.

[0090] To identify the optimal orientation of all the photovoltaic panels 30 iterative calculations can be employed, in which the step of calculating for the determined moment, by means of the mathematical model and the position of the sun at this determined moment, the electricity production of the photovoltaic power plant 100 for a plurality of orientations for each of said plurality of electricity production units comprises:

[0091] a) Calculate, for a first orientation of the plurality of electricity production units, a first instantaneous production of electricity from the photovoltaic power station 100,

[0092] b) Modifying the orientation of at least a first electricity production unit 30 of said plurality of electricity production units to obtain a modified orientation of the plurality of electricity production units,

[0093] c) Calculating for the modified orientation of the plurality of electricity production units a modified instantaneous production of electricity of the photovoltaic power station 100, and

[0094] d) Repeat steps b) and c) to thereby obtain the instantaneous production of electricity from the photovoltaic power plant 100 for a plurality of orientations for each of said plurality of electricity production units.

[0095] According to one embodiment of the invention, a two-dimensional geometric model is used to quantify the shaded fraction of each table 10 of a photovoltaic power plant, such as an agrivoltaic power plant as a function of time, linked to the presence of neighboring tables 10. In a second step, this model is coupled with a part with the actual altitude data of each table and on the other hand with the angular decomposition models of solar radiation to produce, as a function of time, an estimate of the effective global tilted irradiation received by each table. In English, the term Global Tilted Irradiance, or GTI is used to refer to said effective global irradiation received by each table.

[0096] A two-dimensional geometry model of the shading of a table on an adjacent table has been developed and is shown with reference to [Fig.4]. In this model, the tables, represented by lines of length a, separated by a distance b, a height Ah and inclined at angles [31 and [32 with respect to the horizontal are illuminated by a sun whose elevation projected in the plane orthogonal to the tables is denoted y.

[0097] In [Fig.4] we call: - y(t) the projection of the solar elevation in the plane orthogonal to the tables in o. 9 - [31 (t) and |32(t) the angles of the tables relative to the horizontal in ° (0° to horizontal, 90° vertical); - at the height of the tables in m; - b the inter-table distance in m; and - Ah the difference in height between the rotation axes of the tables in m.

[0098] The quantity y depends on the elevation e and the azimuth a of the sun as well as on the angular shift of the plane orthogonal to the modules co by the formula:

[0099] [Math.l] tan e tan y = ---:--—-

[0100] The elevation and solar azimuth data needed to calculate the quantity y come from the PVLIB2 package used with the Python language. According to this model, the shaded distance d^ on a table is written:

[0101] [Math.2] | i* 4__ —____________ _

[0102] It is finally possible to relate this distance to the length of the table and limit the result between 0 and 100% to obtain a shaded fraction of the tables by the formula:

[0103] [Math.3] Al U = £00 * 0, msn „ 1 J |

[0104] The two-dimensional approximation results in a linear and not a surface shaded fraction.

[0105] The outputs of this model are curves representing the shaded fraction of tables as a function of time. The presence or absence of shade depends essentially on the relative heights of the tables 10. When a neighboring table 10 is at an altitude at least equal to that of the measured table 10, it can cast a shadow on it.

[0106] Concerning the presence of point shading for a photovoltaic power plant, such as an agrivoltaic power plant, it is noted that the presence of this type of shading depends on the environmental factors of a power plant, such as the presence of tall objects such as trees, etc.

[0107] From the shading model presented above, the terrain data and the inter-table shading it is possible to generate an efficient GTI model.

[0108] According to the invention, the calculation for identifying the optimal orientations for photovoltaic panels 30 taking into account the possible presence of shadows comprises the following steps:

[0109] - Quantify, using the mathematical model, the presence of at least one shadow created by at least one electricity production unit 30 on another electricity production unit 30 at the determined time, to identify a shaded electricity production unit 30,

[0110] - Reduce, using the mathematical model, the estimated electricity production of said shaded electricity production unit 30, and

[0111] - Calculate, for this determined moment, by means of the mathematical model and the reduced estimated electricity production for the shaded electricity production unit 30, the electricity production of the photovoltaic power plant 100 for a plurality of orientations for each of said plurality of electricity production units and

[0112] - Select, from this plurality of orientations, a specific orientation for each of the electricity production units 30 which corresponds to an optimal position for producing electricity by means of the photovoltaic power plant 100 at the determined time taking into account the reduced estimated electricity production for said shaded electricity production unit 30.

[0113] According to the invention, it is possible for the mathematical model to comprise parameters defining structural elements of the photovoltaic power station 100 and / or parameters defining objects near the photovoltaic power plant 100. The method further comprises:

[0114] - Quantify, using the mathematical model, the presence of at least one shadow created by a structural element of the photovoltaic power plant 100 and / or an object near the photovoltaic power plant 100 on an electricity production unit 30 at the determined time, to identify a shaded electricity production unit 30,

[0115] - Reduce, using the mathematical model, the estimated electricity production of said 30 shaded electricity production module, and

[0116] - Calculate, for this determined moment, by means of the mathematical model and the reduced estimated electricity production for the shaded electricity production unit 30, the electricity production of the photovoltaic power plant 100 for a plurality of orientations for each of said plurality of electricity production units 30, and

[0117] - Select, from this plurality of orientations, a specific orientation for each of the electricity production units 30 which corresponds to an optimal position for producing electricity by means of the photovoltaic power plant 100 at the determined time taking into account the reduced estimated electricity production for said shaded electricity production unit 30.

[0118] [Fig.5] shows an experimental validation of the efficient GTI model. The electricity production of a part of the photovoltaic power plant 100 is illustrated by the black curve under the name "Production". The dotted line "Without shading" and dashed line "Model" curves respectively represent the output of the efficient GTI model assuming a perfectly clear sky without shading and with the shading calculated for the tables studied. These curves are multiplied by a constant so that their scale coincides with that of the electricity production.

[0119] As shown in [Fig.5], in the afternoon, the studied tables 10 are not shaded. The three curves coincide. During the day, the tables 10 are not shaded, the blue and red curves are identical and their variation does not faithfully reproduce that of the black production curve. This can be explained by a possibly not perfectly clear sky (around 12:00) as well as by a non-optimal treatment of the reflected radiation and a non-modeled rear-face GTI.

[0120] In the morning, tables 10 are shaded. The black production curve then moves significantly away from the blue “unshaded” curve. The objective of the modeling (red curve) is to reproduce as faithfully as possible the variations in production during shaded periods.

[0121] In the case presented in [Fig.5] we observe a good modeling of the shading effect. The same result was obtained for other tables 10 of the central photovoltaic 100, for other clear sky days in spring and summer. We can therefore conclude that the modeling makes it possible to understand, reproduce and predict table-table shading on the photovoltaic power plant.

[0122] In addition to the possibility, described above, of calculating and predicting in advance the presence of shadows on the solar panels, it is possible, according to the invention, to provide the solar installation with sensors making it possible to determine the presence of shadows on the basis of a measured reduction in electricity production, during use of the solar installation.

[0123] An important factor in modeling the electricity production of a photovoltaic power plant, such as an agrivoltaic power plant, is the way in which the different photovoltaic panels 30 are electrically connected. Indeed, when several photovoltaic panels 30 are connected in series, the same current flows through them. This common current is equal to the current flowing in the element in said series having the lowest current.

[0124] To explain the influence of the connection of the photovoltaic panels 30, reference is made to figures 6 and 7.

[0125] The way in which the photovoltaic panels 30 are wired and arranged relative to the shading is important for modeling their electricity production. [Fig.6] shows the example that a total of nine photovoltaic panels 30 are connected in series per table 10. The photovoltaic panels 30 are arranged vertically.

[0126] Each photovoltaic panel 30 is divided into two half-modules with a first module 31 which forms the upper part of the photovoltaic panel 30 and a second module 32 which forms the lower part of the photovoltaic panel 30. Each half-module 31, 32 is composed of 36 photovoltaic cells, for a total of 72 cells per panel 30.

[0127] [Fig.7] shows that half-module 31 and half-module 32 are wired electrically in parallel. Each third of the cells of a half-module 31 is wired in series with a corresponding third of the cells of a half-module 32. This type of connection implies that the current flowing in the photovoltaic panels 30 is equal to the sum of the current flowing in the cell with the lowest current of the half-module 31 and the cell with the lowest current of the half-module 32. In [Fig.7], the path of the current through photovoltaic cells is schematically indicated with the reference 70. The current 70 moves from an input 71 to an output 72.

[0128] If a table 10 has nine photovoltaic panels 30 wired in series, like the example shown in [Fig.6], this implies that the current flowing in the table 10 is equal to the module 30 which has the sum of the current flowing in the half-module 31 and the half-module 32 which has the lowest current in the table 10.

[0129] Referring to Figures 3 and 6, it is easy to imagine that the shading on the half-modules 31, 32 of the panels 30 of the same table 10 is not necessarily equally distributed. The half-modules 32, forming the lower part of the panels 30 are, in the examples of Figures 3 and 6, at least partially covered and the half-modules 31 of the same panels 30 are not covered.

[0130] Indeed, when the shading is not equally distributed over the nine panels 30 of a table 10, the series connection of the panels 30 implies that the current circulating in the table 10 is limited by the panels 30 and in particular by the most shaded half-modules 32.

[0131] To optimize the production of electricity, if at least a sufficiently large part of the surface of said second half-module 32 is covered by a shadow, said second half-module 32 is independent of the first half-module 31 to allow the first half-module 31 to produce electricity without being slowed down by the current of the second half-module 32, covered by the shadow. This is why photovoltaic panels 30 equipped with two half-modules are sold commercially.

[0132] In [Fig.7], in addition to the half-modules seen previously, electrical shunts 60 also allow more optimal circulation of the current in the event of shading on a part of the module on the left or right part of the module 30. If shading is present on the left part of the module 30, then the leftmost electrical shunt 60 will become conductive and will allow the current coming from the right part not to be slowed down by the shaded cells of the left part of the module 30.

[0133] In the present invention, the specific capacity of the photovoltaic panels 30 to have one or more independent half-modules and the presence of electrical shunts 60 is used optimally in the presence of unavoidable shading on a part of the power plant for different reasons.

[0134] The current flowing in the photovoltaic panel 30, before the shunt is equal to the current flowing in the left part at least partially covered by a shadow and after the shunt the current is equal to the current flowing in the right part of the module 30, not covered by a shadow.

[0135] In the present invention, this parameter is used to calculate the optimal orientation of the photovoltaic panels 30. When the calculations show that one or more half-modules are in the shade, the electricity production using these half-modules will be much lower than that of the half-module not covered by a shade. The optimal orientation can then be calculated for the rest of the installation. In practice, it may very well be that in order to optimize all the electricity production of the photovoltaic power plant 100, it is necessary to accept that the production of a part of the photovoltaic panels or the production of one or more half-modules is very low because of the shading. In other words, the calculations can show that to optimize the production of the entire photovoltaic plant it is better to “sacrifice” the potential electricity production of a part of the photovoltaic panels 30 and / or the potential electricity production of one or more half-modules of the photovoltaic plant.

[0136] It can be seen that the type of wiring described above justifies the linear approximation described with reference to [Fig.4], above. The shaded linear fraction is called the ratio between the maximum shadow height on a table 10 and the height of the table 10. For example, in [Fig.6] it can be seen that the maximum height of the shadow, indicated by the shaded surface on the whole of the table 10 is approximately 25%.

[0137] Taking this into consideration, a model of the fraction of radiation useful for electrical generation received by the table 10 as a function of the latter's shaded linear fraction has been developed. This model is shown in [Fig. 8].

[0138] [Fig. 8] shows the effective fraction for producing electricity of the solar radiation incident on a table 10 as a function of the shaded linear fraction thereof. As long as the cells positioned at the bottom of the panels 30 are not entirely shaded, the effective fraction of the radiation decreases linearly with the shaded fraction. In the example of [Fig.7] and 8, each panel 30 is composed of 24 cells in its height. This means that the cells positioned at the bottom of the panels 30 are not entirely shaded if the linear fraction is less than the threshold value of 1 / 24 ~ 4% shading of the panel 30.

[0139] As shown in [Fig. 8], beyond the threshold value of 1 / 24 shading and up to the top of the lower half-module 32, as at least one cell of the half-module is entirely shaded, the entire lower half-module 32 is lost and the effective fraction of the radiation received by the table 10 is equal to that received by the upper half-module 31, i.e. 50%.

[0140] The same evolution described above for the lower half-module 32 occurs for the upper half-module 31, while the shading extends to the top of the panels 30 of the table 10.

[0141] With reference to the above, it should further be noted that according to the invention, one or more tables 10 may be placed in series and together form a "string". In order to optimize the electricity production of the entire photovoltaic power plant 100, it is possible that the calculations using the mathematical model show that the production of a string or part of the string must be sacrificed to optimize the total electricity production of the photovoltaic power plant 100. Upon reading the above, it is clear that according to the invention, an ideal orientation of the panels can be calculated to produce electricity at any time of the day and at any time of the year.

[0142] In addition to the description of the use of the invention to optimize the optimal production of electricity using the photovoltaic power plant 100, it is noted that the result of the calculations and the orientation of the photovoltaic panels 30 can, among other things, allow the user to obtain the following resulting control modes: Tracking schedules, Zero shadow tracking, Tracking optimized by half module, and Mixed tracking.

[0143] Furthermore, according to the invention described above, the use of the mathematical model allows, at the user's choice, to control the production of electricity.

[0144] The embodiments described above are given as examples only.

Claims

Claims

1. A computer-implemented method for optimizing the electricity production of a photovoltaic power plant, the photovoltaic power plant comprising a plurality of electricity production units, the electricity production units each being designed to change their orientation relative to the sun in order to optimize their electricity production at any time, the electricity production units being connected to control means for controlling said orientation, the method comprising the following steps: - Obtaining a mathematical model of the photovoltaic power plant comprising the positions of the different electricity production units, the mutual distances between these units, the irradiance and the position of the sun relative to the photovoltaic power plant, - Calculating, for a given moment, by means of the mathematical model and the position of the sun at this given moment,the electricity production of the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units, taking into account for each of the electricity production units their instantaneous orientation and their corresponding instantaneous electricity production, - Selecting, from this plurality of orientations, a determined orientation for each of the electricity production units which corresponds to a set of optimal positions for producing electricity by means of the photovoltaic power plant at the determined time, and - Generating instructions for the control means to orient each of the electricity production units towards their respective determined orientation.,

2. Method according to claim 1, in which the mathematical model comprises parameters defining the area of the installation of the photovoltaic power plant, such as latitude, longitude, altitude, orientation, albedo of the ground.

3. A method according to claim 1 or 2, wherein the step of calculating for the determined moment, by means of the mathematical model and the position of the sun at that determined moment, the electricity production of the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units comprises: a) Calculating, for a first orientation of the plurality of electricity production units, a first instantaneous production of electricity of the photovoltaic power plant, b) Modifying the orientation of at least a first electricity production unit of said plurality of electricity production units to obtain a modified orientation of the plurality of electricity production units, c) Calculating for the modified orientation of the plurality of electricity production units a modified instantaneous production of electricity of the photovoltaic power plant, and d) Repeating steps b) and c) to thereby obtain the instantaneous production of electricity of the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units.

4. A method according to claim 1, 2 or 3, wherein the method further comprises: - Quantifying, using the mathematical model, the presence of at least one shadow created by at least one electricity production unit on another electricity production unit at the determined time, to identify a shaded electricity production unit, - Reducing, using the mathematical model, the estimated electricity production of said shaded electricity production unit, and - Calculating, for this determined time, using the mathematical model and the reduced estimated electricity production for the shaded electricity production unit, the electricity production of the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units and - Selecting, from this plurality of orientations,a determined orientation for each of the electricity production units which corresponds to a set of optimal positions for producing electricity by means of the photovoltaic power plant at the determined time taking into account the reduced estimated electricity production for said shaded electricity production unit.,

5. Method according to any one of the preceding claims, wherein the mathematical model comprises parameters defining structural elements of the photovoltaic power plant and / or parameters defining objects in the vicinity of the photovoltaic power plant, the method further comprising: - Quantifying, using the mathematical model, the presence of at least one shadow created by a structural element of the photovoltaic power plant and / or an object in the vicinity of the photovoltaic power plant on an electricity production unit at the determined moment, to identify a shaded electricity production unit, - Reducing, using the mathematical model, the estimated electricity production of said shaded electricity production module, and - Calculating, for this determined moment, using the mathematical model and the reduced estimated electricity production for the shaded electricity production unit,the electricity production of the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units, and - Selecting, from this plurality of orientations, a determined orientation for each of the electricity production units which corresponds to an optimal position for producing electricity by means of the photovoltaic power plant at the determined time taking into account the reduced estimated electricity production for said shaded electricity production unit.,

6. A method according to claim 4 or 5, wherein the estimated electricity production for the shaded electricity production unit is reduced in accordance with a mathematical function previously established using the electrical characteristics of said shaded module and its electrical connection.

7. A photovoltaic power plant for the production of electricity comprising: - A plurality of electricity production units, the electricity production units each being designed to change their orientation relative to the sun in order to optimize their electricity production at any time, the electricity production units being connected to control means for controlling said orientation, - calculation means adapted to host a mathematical model for the photovoltaic power plant comprising the positions of the different electricity production units, the mutual distances between these units, the irradiance and the position of the sun relative to the photovoltaic power plant, and adapted to calculate for a given moment, by means of the mathematical model and the actual position of the sun, the electricity production of the photovoltaic power plant for a plurality of orientations for each of said plurality of electricity production units, taking into account, for each of the electricity production units, their instantaneous orientation and their corresponding instantaneous electricity production, the calculation means being further adapted to the selection, from said plurality of orientations,of a determined orientation for each of the electricity production units which corresponds to an optimal position for producing electricity by means of the photovoltaic power plant at the determined time, and to the generation of instructions for the control means, and - control means connected to the calculation means and adapted to receive instructions from said calculation means and to orient each of the electricity production units towards their respective determined orientation.,

8. A photovoltaic power plant according to claim 7, comprising at least one electricity production unit with a first module connected in parallel with at least one adjacent second module, and wherein the first and second modules comprise electricity-producing cells, the electricity production unit being provided with shunt diodes allowing the creation of a path for the electric current between an input and an output of the electricity production unit.

9. Computer program product comprising instructions which, when the program is executed by a computer, cause the latter to implement the method according to one of claims 1 QA

10. a o. A computer-readable recording medium comprising instructions which, when executed by a computer, cause the computer to carry out the method according to one of claims 1 to 6.

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