FR3077463A1 - AGRIVOLTAIC SYSTEM AND METHOD FOR CULTIVATION OF PLANTS - Google Patents

Abstract

Agrivoltaic system, comprising a carrier structure (20) and at least one row, extending along an axis (Yi), photovoltaic sensors (10) held on top of crops (C) by the supporting structure, at least a part these sensors being movable along an axis (X) substantially perpendicular to the axis (Yi) of the row.

Description

AGRIVOLTAIC SYSTEM AND METHOD FOR GROWING PLANTS

The present invention relates to agrivoltaic systems and methods of growing plants using such systems.

By "agrivoltaic system" means a system allowing the production of electricity thanks to photovoltaic sensors arranged at least part of the time above crops.

Many agrivoltaic systems have already been proposed.

The publication WO 2013/117722 A1 describes a method of simultaneous use of solar energy for agricultural cultivation and the production of electricity using parallel rows of collectors arranged above the crops. These rows are oriented in a direction which forms with the east-west axis an angle between 10 ° and 80 °. The purpose of this arrangement is to standardize the lighting received on the ground within a daily or seasonal window.

The publication US 2010/0263660 A1 describes a system and a method the objective of which is to position rows of mobile photovoltaic sensors in rotation above crops.

Publication CH 706132 A2 describes a system making it possible to have photovoltaic sensors stationary above crops.

Application WO 2015/145351 A1 describes a process for shading controllable crops produced by photovoltaic sensors disposed above the crops, these sensors being movable in rotation about their longitudinal axis. The orientation of the panels can be controlled so as to optimize a desired agricultural result using local measures while minimizing the loss of electrical production compared to a reference without combination with crops.

In these existing systems, if it is desired to reduce the shade of the crops, the sensors are oriented parallel to the sun's rays, which consequently greatly reduces the electricity production. In addition, the panel orientation system may have certain technical limitations that prevent the panels from tilting at angles close to the vertical, which means that certain crop areas are necessarily shaded around midday.

There is therefore a need to further improve the agrivoltaic systems and the methods of growing plants using such systems.

The invention meets this need thanks to an agrivoltaic system comprising a support structure and at least one row, extending along an axis, of photovoltaic sensors maintained above crops by the support structure, at least a part of these sensors. being mobile, especially in translation, along an axis substantially perpendicular to the axis of the row.

By "substantially perpendicular" is meant perpendicular to + / 30 °, better at +/- 20 °, even better at +/- 10 °, preferably at +/- 5 ° or less.

The axis of a row of row i is hereinafter designated Yi.

The possibility of being able to position where desired the shadow of the sensors makes it possible to completely shade or brighten a crop, where the simple rotation of a sensor in the prior art only made it possible to vary the size of the shadow and therefore did not allow to shade a plant if the drop shadow was next to it or to completely deprive it of shade if the drop shadow was on it.

The invention makes it possible to make the illumination of the cultures very homogeneous at the daily time step, which can be an objective, for certain cultures or certain periods of the culture cycle.

Conversely, the invention makes it easy to make the illumination of cultures heterogeneous, which has a number of advantages.

First, it moderates the growth of undesirable plants, thanks to the possibility of shade and sunshine specifically the uncultivated areas in order to impede the development of these undesirable plants. This can for example consist of shading these areas most of the time in order to reduce the supply of solar energy to these undesirable plants and to sun them during the hottest periods of the day in order to destroy them by thermal stress. The need for chemical or manual weeding is reduced.

The invention also makes it possible to preserve the water resource, by specifically shading the areas between useful crops in order to minimize evaporation at ground level.

Finally, the invention can allow better production of electrical energy thanks to the possibility, if desired, of not providing any direct shade to the crops without the sensors being parallel to the rays of the sun. In this case, the sensors can for example be arranged so that their shadows remain between the rows of useful plants or, again, the sensors can be grouped, for example arranged in a vertical structure playing a windbreak role to cultures.

By "collector" is meant a solar collector producing electricity by photovoltaic conversion of light. A sensor comprises one or more photovoltaic cells arranged on a support, generally planar and of elongated shape. The sensors are sometimes also called "photovoltaic panels". The sensors are kept at a non-zero distance from the ground by the support structure, in particular at a height of between 3 and 5 m.

The material of the support of the cells of a sensor can be translucent, so as to diffuse the light which crosses the sensor between the cells, and to screen it. We can thus reduce the blackout effect of the sensors, while preserving plants from the direct impact of sunlight.

The sensors are preferably movable horizontally over at least part of their path, or in the event of a slope of the ground are movable with the same slope. To this end, the supporting structure may include rails, in particular horizontal rails, on which carriages carrying the sensors can move.

It may be advantageous to ensure that the sensors are movable vertically over at least part of their path. For example, the sensors move horizontally or parallel to the slope of the ground along the X axis to the end of a path, in particular horizontal, then optionally engage in a vertical path which allows for example to group them at ground level to protect them, or better to form a vertical structure playing a windbreak role.

The supporting structure can be fixed, and in this case the sensors can move at a constant height above the crops, in particular a height chosen to allow the passage of an agricultural machine. As a variant, the support structure is made so as to be able to raise or lower, for example comprising uprights mounted on jacks. In this case, the sensors can be brought closer to the ground at night, for example, to help conserve heat from the ground.

Preferably, the sensors are orientable around the axis of the row to which they belong, preferably in the east-west direction, the longitudinal axis being oriented north-south. Thus, the sensors can be moved in such a variant both in rotation and in translation.

For example, sensors are rotatably mounted around the same geometric axis of rotation to form a row of sensors. The supporting structure comprises for example horizontal parallel rails extending in the direction of the axis X and the axis of rotation of the sensors of a row extends along the axis Yi, which is preferably perpendicular to the X axis. Each sensor is for example in the form of a panel carried by a support shaft of axis Yi resting at its ends on carriages sliding on the aforementioned rails. The sensor can have an elongated shape along the axis Yi of the row which integrates it. As a variant, the sensor has an elongated shape with a longitudinal axis perpendicular to the axis Yi of the row which incorporates it.

Each sensor can be centered on the Yi axis. Alternatively, the sensors can be paired and positioned on either side of the Yi axis.

Preferably, the number of sensors per row is greater than or equal to 3, better still greater than or equal to 5.

The number of rows is preferably greater than or equal to 3.

Two contiguous sensors can be placed side by side or spaced apart.

Preferably, the cultures comprise rows of plants and the axes of the rows are either substantially parallel or substantially perpendicular to said rows of sensors.

The same electric motor can be used to move several sensors along the X axis simultaneously. For example, this motor drives a rack which moves along one of the aforementioned rails the carriages carrying the sensor support shafts. At least one rod can transmit the drive movement of the carriages from one rail to the other, so that the same motor can ensure the synchronous movement of at least two carriages traveling on parallel rails and carrying the same support shaft. The sensors can also be driven using at least one cable and preferably a disengageable coupling device connecting this cable to the sensors.

Preferably, the sensors are arranged in parallel rows, as mentioned above. The system is preferably made so as to be able to take at least one configuration where the ratio between the width of the sensors and the center distance of the rows is between 20 and 40%.

The path of the sensors being effected at least in part along the aforementioned axis X, the system preferably comprises a computer for automatically determining the position to be given to the sensors along this axis as a function of the sunshine requirement of the crops affected by the shadow of the sensors. Preferably, the computer controls both the displacement of the sensors along the X axis and the angle of rotation of the sensors, according to one or more control laws which can depend on many parameters, such as the temperature for example.

The agrivoltaic system according to the invention can thus include a temperature sensor informing the calculator of the local temperature at the crop level.

The calculator can be arranged to determine the positioning of the sensors according to a history of sunshine and / or rainfall and / or the state of development of crops.

The computer can be local, in which case the positioning of the sensors can be determined autonomously by the computer.

The computer can also, as a variant, be at least partially relocated to a remote control center, communicating with the local system, for example by internet or by radio.

The structure supporting the sensors can be advantageously used in order to deploy a net over the crops. This net can have multiple functions:

- Protect crops against hail and this in connection with a weather forecast,

- protect crops from animal attacks,

- carry out additional shading on the crops, the choice of adding the blackout power of the net being decided for example according to an identified need for lighting of the crop, a history of sunshine and / or a sunshine forecast,

- participate in the control of the nocturnal microclimate above the crop by acting on the heat and humidity exchange with the external environment, the deployment being carried out according to an identified hydric and / or thermal need of the crop, d '' a hydric and / or thermal and / or lighting history of the crop, a measurement of the hydric and / or thermal state of the crop or a weather forecast.

The deployment and control of this net can be done automatically or manually by computer, the electrical energy necessary for this operation can come from the sensors' own production or come from the network if the installation is connected to it.

This protection system can also be deployed in the event of hail alerts above crops. The sensors can then be positioned in a configuration of least exposure to hailstones, for example as vertically as possible.

Another subject of the invention is, according to another of its aspects, a method of cultivating plants, using an agrivoltaic system according to the invention, comprising at least one row of sensors extending along an axis Yi maintained above crops by a supporting structure, at least a part of these sensors being movable along an axis X substantially perpendicular to the axis Yi of the row, in particular a system as defined above, this method comprising moving sensors according to the position of the sun so as to comply with a predefined law for the evolution of the position of the shadow cast on the crops.

The crops preferably include rows of useful plants, these rows being advantageously oriented substantially perpendicular to the axis X.

The displacement along the X axis of the sensors can be a function of the angles β, Θ, and h where // is the azimuth of the sun, Θ the elevation of the sun and h the height of the sensors relative to the ground, in particular of the form x = hx being the relative displacement of the sensor relative to a median position along the axis X perpendicular to the axis Yi of the row.

Piloting, in particular in X, that is to say along the X axis, sensors can be carried out so as to reduce the supply of solar energy between the rows and hamper the development of undesirable plants between the rows. This control, in particular in X, of the sensors can still be carried out so as to maintain the direct illumination by the sun between the rows when the sun is high and thus generate a thermal stress opposing the development of undesirable plants between the rows . The piloting, in particular in X, of the sensors can still be carried out so as to shade the zones between the rows in order to minimize evaporation at ground level.

The sensors can be controlled automatically from at least data representative of local crop environment conditions, in particular crop temperature, soil hygrometry and / or rainfall. The law for controlling the positioning of the sensors can in particular be based on the stress level of the culture. The stress model evaluates this criterion for example according to a history of sunshine and / or temperature of the crop, as well as a measurement of the leaf temperature of the crop. The input and output parameters that can be used by this stress model are not limited to the parameters mentioned above.

The positioning of the sensors can be modified according to a control law seeking to obtain a qualitative and / or quantitative maximum. For example, in the case of vegetable crops, the positioning of the sensors can be carried out according to a control algorithm of the positioning of the sensors aimed at avoiding excessive heating of the leaves. The presence of the sensors can thus be used to adequately intercept light in order to optimize photosynthesis and obtain a production yield higher than what it would be in the total absence of shade. In the case of vine growing, the positioning of the occulting elements can be chosen according to the degree of sugar sought in the grape, and ultimately the quality of the wine obtained.

The sensors can be grouped together to minimize the shade cast on the crops. Such a grouping can take place for example in spring when the shade must be reduced to the minimum. The sensors can be grouped together by giving the rows of sensors the closest possible X positions in an end of travel zone.

When the sensors are movable along a horizontal then vertical path in an end-of-travel area, the method can include the step of grouping the sensors in this end-of-travel area to form a vertical structure opposing the wind.

When the sensors are rotatable, in particular around their longitudinal axis, the method can include the step of orienting the sensors substantially vertically or obliquely, in particular within 45 ° from the vertical, when they are grouped together.

Still when the sensors are rotatable, especially around their longitudinal axis, the method can include the step of moving the sensors both along the X axis and in rotation in order to comply with a predefined law for crop shading .

This shift can allow crops to be placed in microclimatic conditions that are more favorable for obtaining a desired agricultural result while seeking to achieve an optimum that minimizes the production of electrical energy compared to a reference without combination with cultures.

Preferably, as indicated above, the positioning of the sensors is automatically controlled by computer using at least data representative of local conditions of the environment of the crops, in particular the temperature of the air and / or of the crops, the sunshine. cumulative and / or instantaneous, relative air humidity, soil hygrometry, and / or rainfall.

The invention makes the best use of the presence of solar collectors to allow crops to benefit from variable sunshine according to their need for light and / or heat and / or to act on water stress.

The translation and orientation of the sensors can be controlled so as to automatically avoid, during a heat wave, that the plants are not subjected to excessive heating. Conversely, in spring, the translation and the orientation can be controlled so as to automatically maximize the warming of the ground, including at night by reflecting infrared emitted from the ground, in order to promote germination.

The orientation of the collectors and their position according to Tax X can be controlled to channel the rainwater flowing on the collectors towards the crops or between crops, in particular to avoid the impact of water drops on the leaves and fruits

The invention can make it possible to improve agricultural production compared to a crop in full sun, or a reference yield, and if necessary to produce more electrical energy than with sensors whose translation or orientation n '' cannot be changed using actuators.

The positioning of the sensors can be modified according to a control law seeking to obtain a qualitative and / or quantitative maximum. For example, in the case of vegetable crops, the positioning of the sensors can be carried out according to a control algorithm aimed at avoiding excessive heating of the leaves. The presence of the sensors can thus be used to adequately intercept light in order to optimize photosynthesis and obtain a production yield higher than what it would be in the total absence of shade. In the case of vine growing, the positioning of the sensors can be chosen according to the degree of sugar sought in the grape, and ultimately the quality of the wine obtained.

The positioning of the sensors can be controlled as a function of a quantity of target light energy to be reached, this quantity of target light energy being in particular dependent on the need for the crops, the deficit or the surplus of energy of the previous day or from previous days, and / or weather forecasts.

Preferably, the positioning (along the X axis and in rotation) of the sensors is modified as a function of meteorological data and in particular i) at least one history of sunshine of the crops and a history of heat received by the crops , and / or a pluviometry history and ii) a target set for the current day, a quantity of sunshine, heat and / or pluviometry to be received by the plant as well as temperature limits not to exceed. This history can be carried out locally, thanks to the local detection of temperature, sunshine, rainfall and / or soil humidity. For example, if the sunshine of the previous days is considered to meet the light and / or heat needs of the crops over a given period, the sensors can be positioned at any time so as to meet the objectives of the day, by favoring electrical production. If, on the other hand, the sunshine of the previous days is considered as insufficiently meeting the light and / or heat needs of the crops, then the sensors are positioned so as to favor the need for sunshine of the crops. In this case, the positioning of the sensors may not correspond to the optimization of electrical production depending on the position of the sun.

In addition to the geographical position, the orientation, the inclination, the height, the inter-row spacing of the installations, the computer control of the sensors is preferably carried out according to a control law specific to each cultivated plant variety.

Among the parameters that can enter into the selection of the control law from a library of pre-established control laws, and / or in the adaptation of a control law to the pursuit of a predefined agricultural result, may appear the cultivated variety, as well as quantitative or qualitative criteria, such as the search for maximum agricultural production, a desired maturity date or a particular quality of the cultivated plant.

The sensors can be positioned in the evening or during the night so as to reflect the thermal radiation from the ground as much as possible or at least to the ground, during the night, in order to regulate the temperature of the ground (heating or cooling). The positioning of the sensors for the night can be controlled, for example, according to the observed or expected atmosphere-ground temperature gradient, and according to the objective pursued (cooling or heating the ground). For example, if there is a need to cool the soil and the atmosphere-soil gradient is negative (the soil is warmer than the air), the sensors can be oriented perpendicular to the soil and positioned in line with the crops or grouped . Before each modification of the positioning of the sensors, it can be determined whether the consumption of electrical energy for this modification is necessary with regard to the expected benefit for the crops.

The cultivation process advantageously comprises the measurement of the temperature at the crop level and the positioning of the sensors is controlled at least as a function of the temperature measured.

The axis of the rows of sensors can be aligned with the North-South or East-West direction or alternatively make an angle with it.

The positioning of the sensors advantageously depends on the state of development of the crops. Thus, during the winter, the positioning can be controlled so as to warm the soil at the end of the winter period, in order to promote germination.

The positioning of the sensors is preferably controlled so as to maintain the cultures within a predefined minimum and / or maximum temperature range. Thus, during periods of heat, the positioning of the sensors can correspond to maximum shade production in crops.

The positioning of the sensors can be controlled as a function of a quantity of target light energy to be reached, this quantity of target light energy being in particular dependent on the need for the crops, the deficit or the surplus of energy of the previous day or from previous days, and / or weather forecasts.

The computer control of the sensors is preferably carried out according to a control law specific to each cultivated plant variety.

The computer control of the sensors is preferably carried out according to the geographic position and the dimensional characteristics of the system, in particular its geographic position, its orientation, its height, the spacing between rows of sensors.

The displacement along the X axis of the rows of sensors can be carried out according to an individual control; this allows you to control the position of each row independently of the others. As a variant, the displacement of the rows of sensors is carried out in a global manner or in groups of rows of sensors. The travel along the X axis of a sensor ranges, for example, from -2 m to +2 m. When the cultures are arranged in suitably oriented parallel rows, an overall displacement of the sensors along the X axis is possible.

The subject of the invention is also, independently or in combination with the above, a process for cultivating plants in rows using a concealment system, in particular agrivoltaic, comprising occultation elements, preferably photovoltaic collectors, movable relative to a supporting structure, in which the occulting elements are displaced as a function of the position of the sun so as to reduce the supply of solar energy between the rows and hinder the development of undesirable plants between the rows .

The shadow of the occulting elements, in particular the sensors, if the latter remained stationary, would move on the ground over time. The displacement of the occulting elements, in particular of the sensors, is chosen so as to compensate for this movement of the shadow and to ensure that the shadow is static or its displacement slowed down for a certain duration, for example more than 15 min. , better more than 30 min, even better more than an hour, even two hours or three hours. Thus, on the one hand, the shade by remaining static or moving on the ground more slowly than it would if the sensors were stationary, slows the development of the plants located between the rows. On the other hand, since the unshaded areas remain static or move on the ground more slowly than they would if the sensors were stationary, the crops found there benefit from a longer period of sunshine.

The subject of the invention is also, independently or in combination with the above, a process for cultivating plants in rows using a concealment system, in particular agrivoltaic, comprising occultation elements, in particular sensors photovoltaic, movable relative to a supporting structure, in which the concealing elements, in particular the sensors, are moved as a function of the position of the sun so as to maintain direct illumination by the sun between the rows when the sun is high and thus generating thermal stress opposing the development of undesirable plants between the rows.

Here, the displacement of the occulting elements, in particular of the sensors, is also chosen so as to compensate for the natural movement of the shadow and to ensure that the shadow is static or its displacement slowed down for a certain duration, for example by more than 15 min, better more than 30 min, even better more than an hour, even two hours or three hours. Thus, by making the shadow static or by making its evolution on the ground slower than if the occulting elements, in particular the sensors, were stationary, it is prevented from reaching the undesirable plants and your creates the thermal stress sought. This process is, for example, implemented during the period +/- 2 hours from the zenith, and preferably in summer, or when the temperature of the air is greater than or equal to 28 ° C.

The subject of the invention is also, independently or in combination with the above, a process for cultivating plants in rows using a concealment system, in particular agrivoltaic, comprising occultation elements, in particular sensors photovoltaic, mobile relative to a supporting structure, in which the occulting elements, in particular the sensors, are moved as a function of the position of the sun so as to maintain the static shadow on the plants or to make it evolve on the ground more slowly than it would if the occulting elements were stationary, the said process being implemented in the spring before the flowering of the plants to acclimatize them to conditions of lower light, preferably shading them so that the duration d 'total shading is extended by at least 10%, better at least 20%, compared to stationary blackout elements. Alternatively, this process can be implemented in the same way to lengthen the maturation period of cultivated plants, especially fruits. As a variant, this process can be implemented in the same way to delay the maturity of the plants and consequently their placing on the market.

The subject of the invention is also, independently or in combination with the above, a method for cultivating plants in rows using a concealment system, in particular agrivoltaic, comprising concealment elements, in particular photovoltaic sensors. , movable relative to a supporting structure, in which the concealing elements, in particular the sensors, are moved as a function of the position of the sun so as to shade the areas between the rows in order to minimize evaporation at ground level.

Here, the displacement of the occulting elements, in particular of the sensors, is also chosen so as to compensate for the natural movement of the shadow and to ensure that the shadow is static or its displacement slowed down for a certain duration, for example by more than 15 min, better more than 30 min, even better more than an hour, even two hours or three hours. Thus, by making the shadow static or by making its evolution on the ground slower than if the occultation elements, in particular the sensors, were stationary, we maintain the shadow on the cultivated rows and we reduces evaporation. This process is, for example, carried out during the period +/- 2 hours compared to the zenith, and preferably in summer or when the air temperature is greater than or equal to 28 ° C.

The invention will be better understood on reading the detailed description which follows, of non-limiting examples of implementation thereof, as well as on examining the appended drawing, in which:

FIG. 1A schematically represents an example of an agrivoltaic system according to the invention,

FIGS. 1B and 1C are two elevation views of the system of FIG. 1A illustrating the movement of the sensors,

FIG. 2 schematically represents a system for controlling the positioning of the sensors according to the invention,

FIG. 3 schematically represents an example of evolution over time of the light energy received by the cultures and the sensors,

- Figures 4 to 7 illustrate examples of controlling the orientation of the sensors as a function of time,

FIG. 8 is an example of controlling the movement of the sensors along the X axis during the day,

- Figure 9 is a simplified representation of a crop stress model based on leaf temperature,

- Figure 10 shows a variant of the system according to the invention comprising a protective net,

FIGS. 11A to 11C schematically show in elevation a variant of the agrivoltaic system according to the invention, with different configurations of the sensors,

FIG. 12 is a perspective view of an alternative agrivoltaic system according to the invention,

FIGS. 12A to 12G represent details of the embodiment of the system of FIG. 12, and

- Figures 13A and 13B illustrate two alternative positioning of the sensors relative to the axis of their row.

FIG. 1 shows an agrivoltaic system according to the invention, comprising a plurality of solar collectors 10 movable in translation along an axis X.

The sensors 10 are arranged in rows, the latter being of respective axes Yi, i being the row of the row.

Preferably, all the sensors 10 of the same row i are mobile in rotation simultaneously around the axis Yi of the row, so as to be able to modify the angle formed by the plane of each sensor with the horizontal.

The sensors 10 are held by a supporting structure 20, making it possible to provide under the sensors 10 a height sufficient for the passage of agricultural machinery, in particular a height of between 3 and 5 m.

The supporting structure 20 comprises uprights 21 which support a primary frame 22 on which a secondary frame 23 is movable in translation in the horizontal plane along the axis X. This secondary frame 23 supports the sensors 10.

Each sensor 10 can be moved in translation along the axis X, and optionally in rotation about the corresponding axis Yi, using at least one actuator 30, shown diagrammatically in FIG. IB and IC.

The actuators 30 each comprise for example one or more electric motors, and are constituted for example by servomotors.

The cultures C are preferably arranged in rows and can be reached by the shade cast on the ground by the sensors 10. The cultures C can be of any type and for example be vegetable crops or vines.

FIGS. 1B and 1C show two positions of the sun corresponding to different times of the day. These two figures have illustrated a strategy for controlling the movement of the sensors in which the cultures C benefit from the maximum illumination in both situations thanks to the translation of the sensors 10 in the horizontal plane.

If we refer to FIG. 2, we see that the position to be given to the sensors 10 can be determined by a local computer 40 which is connected via any power interface adapted to the actuators 30.

The computer 40 preferably receives information from one or more local probes, for example a temperature probe 41 placed at the level of crops C and a hygrometry probe 42 placed in the soil at the level of crops C. Other sensors can be added, such as a rain gauge, anemometer, and / or a camera to visualize the state of development of the cultures, as well as one or more biosensors, if necessary.

It is particularly advantageous, in general, to use a non-contact infrared sensor to measure the temperature of the crops. It is thus possible to use an infrared camera which points to the crops at different locations and makes it possible to calculate a spatially averaged temperature.

The computer 40 can also exchange data, for example via a wireless telephone network, with a remote server 50, which can for example inform the computer 40 of the upcoming weather.

The computer 40 can be produced from any microcomputer or computer equipment making it possible to control the positioning of the sensors 10 as a function of one or more control laws giving the positioning to be imposed on the sensors as a function of the place, the date, time and a number of other parameters related to C crops.

The computer 40 can thus include a calculation unit and a local memory in which the local measured data, for example temperature, hygrometry and rainfall, can be recorded, in order to know the history of the environmental conditions of the crops.

The computer memory can also include servo parameters which govern the positioning of the sensors according to the needs of the crops. These parameters can change over time and, depending on the season, for example, favor the sunshine or not of crops.

The control law or laws can be initially programmed in the computer 40, or as a variant be downloaded by the computer 40 from the remote server 50, or even be updated periodically by the remote server 50.

In an exemplary embodiment, the computer 40 has autonomous operation. Depending on the season, the sowing date and possibly other parameters entered by the farmer, he automatically and daily controls the positioning of the sensors 10 so as to satisfy the need for sunshine, temperature, humidity, rainfall of crops over a given period of time. In this case, the sensors 10 are, for example, positioned for a fraction of the day to let in as much light as possible, to the detriment of electrical production. Then, once the need for sunshine has been satisfied, the sensors are brought in by activating the actuators in a position aimed at maximizing electrical production.

If, however, the local temperature measured at the crop level is excessive, or higher than the set target, the positioning of the sensors can be changed to shelter the crops from the sun and avoid excessive heating.

The computer 40 can also determine the positioning to be given to the sensors to limit the development of undesirable plants in an area extending between the rows of crop C as explained above, by reducing the illumination in this area or by creating a thermal stress. .

In an alternative embodiment, the computer 40 receives instructions for controlling the sensors from the remote server 50, to which it can transmit, for example, local sunshine and temperature data, as well as data concerning the crops and their stage of development. . The server 50 transmits back to the computer information concerning the positioning to be given to the sensors, in real time or over a certain period to come.

When the sensors 10 are positioned to maximize the electric production, they can follow in real time the course of the sun from east to west.

FIG. 3 shows an example of the evolution of the light energy received over time, for the sensors and the crops. When the sensors follow the path of the sun, they receive about a third of the light energy. Cultures receive two thirds of it. It is possible to increase the amount of energy received by the crops by playing on the positioning of the sensors so as to reduce the occultation of the crops.

We can set in advance a target amount of energy for a day d depending on the light energy requirement of crops, the deficit or surplus of energy received the day before or the previous days, and weather forecasts allowing estimate the amount of energy expected for this day j.

If necessary, the model that sets the target quantity of energy is more elaborate and takes into account the price of electricity or its potential valuation on the markets.

In FIG. 3, the variation over time of the energy received is shown in dotted lines until the target quantity is reached. To do this, we increase the energy received by the crops by decreasing the Q ’received by the sensors in favor of less concealment of the crops.

FIG. 4 shows an example of evolution of the angle of the sensors over time. Dotted is the curve which corresponds to a classic tracking of the course of the sun.

To increase the light energy received by crops, we can leave the horizontal sensors between sunrise and tl, then after t2 until sunset. Between tl and t2, the orientation of the sensors is carried out so as to follow the course of the sun.

Leaving the horizontal panels does not minimize blackout but does not consume electricity to orient them.

In the variant illustrated in FIG. 5, between sunrise and tl, the positioning of the sensors is modified to allow the maximum light to pass to the crops, and likewise after t2 until sunset.

In FIG. 6, it can be seen that the sensors are piloted as in the example in FIG. 4. However, between t2 and t3 the tracking of the sun is restored to allow the crops to benefit from maximum occultation in order to protect these last of an excessive temperature. In this example, the temperature of the cultures is monitored, for example by means of an infrared camera. In this example, we have assumed that the temperature exceeds a limit value at time t3. The control system of the panel then triggers the transition to sun tracking mode from t3 to sunset.

An example of the evolution of the angular travel of the sensors at the end of the winter period is shown in FIG. 7.

We see in this figure that the sensors are positioned during day d-1 to minimize the occultation, by orienting them substantially parallel to the sun's rays over time.

If the weather forecast announces a cold period without sun on the day, the sensors can be kept horizontal during the day and at night so as to reflect the infrared from the ground to the crops as much as possible. On day d + 1, a piloting similar to that of day d-1 is carried out.

The quantity of target energy for day d + 1 can be calculated from the quantity of light energy actually received by the cultures on day d and, possibly, the previous days. To determine the quantity of light actually received, a pyrheliometer or pyranometer can be used. Better, we calculate this energy from that received by the sensors, knowing their orientation and that of the sun and using a mathematical model which gives the average energy on the ground taking into account the occultation brought by the sensors.

FIG. 8 represents a theoretical example of controlling the value x of translation according to Tax X of the sensors 10 making it possible to freeze the position of the center of the shadow cast at ground level in the case where Longitudinal tax of the sensors 10 is parallel to Tax is West. The equation followed by this piloting is ^with h the height of the sensors relative to the ground, β Γ azimuth of the sun and Θ the elevation of the sun. The position on the ground can be chosen so as to permanently shade the crops or, on the contrary, to permanently illuminate them as illustrated in FIGS. 1B and 1C. The value of the abscissa x taken in practice will take into account the minimum and maximum translation constraints.

Figure 9 is a simplified representation of the level of crop stress based on leaf temperature. This curve shows that in order to meet a maximum stress criterion for the crop, the control system can seek to keep the leaf temperature within an interval between Tmin and Tmax by acting on the orientation of the sensors.

In a variant not illustrated, the sensors used are arranged so as to be orientable along two axes of rotation.

In FIG. 10, the possibility of using the supporting structure 20 has been illustrated to support a protection system 60 against bad weather, in particular hail, for example in the form of a net which is deployed between the uprights 21 of the structure 20. This deployment can be automated if necessary, using cables stretched between the uprights 21, permanently present. In this case, it is possible not to use the sensors 10 to protect the crops during the downpour, and to orient them for example so as to minimize the risk of them being damaged.

In FIG. 11A, an alternative embodiment of the invention has been shown where the rows of sensors 10 are driven along the axis X by at least one cable 140 thanks to a disengageable coupling device 141. This cable 140 is kept at a certain distance from the supporting structure 20 by means of pulleys 142 and can be set in motion by means of end winders 143. When a sensor 10 has to be moved, the coupling device is locked and the movement cable is passed to the sensor. Once the sensor has reached its destination, the locking device is released, and the cable can run without driving this sensor. The locking device comprises for example a jaw actuated by an electric motor.

Figure 1 IB illustrates a configuration of the agrivoltaic system where the rows of sensors 10 are grouped at one end of the system in order to produce the minimum shade on crops C.

The agrivoltaic system can be made in such a way that the rows of sensors 10 can move not only horizontally along the axis X but also vertically, in particular when arriving on one side of the support structure 20.

It is thus possible to drive the sensors 10 horizontally to one of the pulleys 142, then vertically as illustrated in FIG. 11C. The sensors 10 thus grouped, preferably at different heights as illustrated, can form a vertical structure protecting the cultures C from the wind.

FIG. 12 shows an implementation of the agrivoltaic system according to the invention where the rows of sensors 10 are maintained on the supporting structure 20 by means of carriages 151 inserted in rails 150, each in the form of a profile open towards the top, of the supporting structure 20. These carriages 151 may comprise wheels 70 rolling on the upper face of the rails 150 as illustrated in FIGS. 12F and 12G as well as wheels 70 rolling on their internal surface bordering the opening of the profile, and retaining each carriage 151 on the rail 150 in which it is engaged.

The carriages 151 carry shafts 152 for supporting the sensors 10, oriented perpendicular to the rails 150, which are oriented along the axis X.

The translational movement of the sensors 10 along the X axis can be ensured in various ways, and for example as illustrated by at least one motor 56 visible more particularly in FIG. 12C, which transmits a rotation to a plurality of toothed wheels 53 via one or more transmission shafts 52 which extend parallel to the longitudinal axes of the rows. These toothed wheels 53 each engage on a rack 71 secured to the rail 150, producing a translational movement along the corresponding rail 150, thanks to at least one carriage 54 engaged therein.

The rotational movement of the sensors 10 about their longitudinal axis, that is to say the rotational movement of the support shaft 152, is ensured for example as illustrated by a motor 57 visible more particularly in FIG. 12D, causing a plurality of wheel and worm gear transmissions 59 by means of a transmission shaft 58. Each of these transmissions transforms a rotational movement of the shaft 58 into a rotational movement of the shaft 152 which is coupled to it. Alternatively, other types of transmissions can be used.

Thus, the same motor 56 can drive synchronously with the shaft 52 at least two racks 71, and thus ensure the movement along the X axis of the associated sensors 10. The same motor 57 can in turn drive synchronous rotation at least two rows of associated sensors, thanks to the shaft 58.

The sensors of a row can be given various shapes and orientations.

FIG. 13A represents sensors 10 whose longitudinal axis is perpendicular to the axis Yi of the row which integrates them. FIG. 13B illustrates a preferred variant where the longitudinal axis of the sensors 10 is parallel to the axis Yi of their row.

Of course, the invention is not limited to the examples which have just been described. For example, the sensors can slide in different planes, so that they can be grouped together by being superimposed. You can have only one sensor per row, if necessary.

In alternative embodiments of the invention, the sensors are replaced by non-photovoltaic screening elements. In other variants, the agrivoltaic system includes occultation elements made up of photovoltaic sensors, and non-photovoltaic occultation elements. For example, these are the same format as the sensors and have the same shading properties on crops. They can be used, for example, when the photovoltaic system is equipped with photovoltaic sensors or cells in several installments but it is desired to maximize the shading capacities of the system as soon as the supporting structure is installed.

The expression comprising a must be understood as being synonymous with comprising at least one, unless otherwise specified.

Claims (20)

1. Agrivoltaic system, comprising a support structure (20) and at least one row, extending along an axis (Yi), of photovoltaic sensors (10) held above crops (C) by the support structure, at least a part of these sensors being movable along an axis (X) substantially perpendicular to the axis (Yi) of the row. 2. System according to the preceding claim, the sensors (10) being movable horizontally over at least part of their path. 3. System according to one of claims 1 and 2, the sensors (10) being movable vertically over at least part of their path. 4. System according to any one of the preceding claims, the sensors (10) being orientable around the axis (Yi) of the corresponding row, preferably in the east-west direction. 5. System according to any one of the preceding claims, the sensors (10) being arranged in parallel rows, the system being preferably made so as to be able to take at least one configuration where the ratio between the width of the sensors and the center distance of rows is between 20 and 40%. 6. System according to any one of the preceding claims, the path of the sensors (10) being carried out at least partly along an axis (X), the system comprising a computer (40) for automatically determining the position to be given to the sensors. along this axis as a function of the sunshine requirement of the crops affected by the shadow cast by the collectors. 7. System according to any one of the preceding claims, each sensor (10) being elongated along a longitudinal axis parallel to the axis (Yi) of the row which integrates this sensor. 8. System according to any one of the preceding claims, the number of sensors (10) per row being greater than or equal to 3, better still greater than or equal to 5. 9. System according to any one of the preceding claims, the number of rows being greater than or equal to 3. 10. System according to any one of the preceding claims, the crops comprising rows of plants and the axes (Yi) of the rows being substantially parallel to said rows. 11. Method for producing electrical energy using an agrivoltaic system comprising at least one row of sensors extending along an axis (Yi), held above crops by a support structure (20), at at least part of these sensors being movable along an axis (X) substantially perpendicular to the axis (Yi) of the row, in particular a system as defined in any one of the preceding claims, this method comprising moving the sensors ( 10) as a function of the position of the sun so as to comply with a predefined law for the evolution of the position of the shadow cast on the crops (C), in particular exposing the surface on the ground under the sensors heterogeneously over time. 12. Method according to the preceding claim, the displacement of the sensors being a function of the angles β, Θ, and h where /? Is the azimuth of the sun, Θ the elevation of the sun and h the height of the sensors relative to the ground, in particular: x = hx being the relative displacement of the sensor relative to a median position along the axis (X) perpendicular to the axis (Yi) of the row. 13. Method according to one of claims 11 and 12, the cultures comprising rows of useful plants, the control of the sensors along the axis (X) perpendicular to the axis (Yi) of the row being carried out so as to reduce the supply of solar energy between rows and hinder the development of undesirable plants between rows. 14. Method according to any one of claims 11 to 13, the cultures comprising rows of useful plants, the control of the sensors along the axis (X) perpendicular to the axis (Yi) of the row being carried out so to maintain direct illumination by the sun between the rows when the sun is high and generate thermal stress opposing the development of undesirable plants between the rows. 15. Method according to any one of claims 11 to 14, the cultures comprising rows of useful plants, the control of the sensors along the axis (X) perpendicular to the axis (Yi) of the row being carried out so shade areas between rows (C) to minimize evaporation at ground level. 16. Method according to any one of claims 11 to 15, the control of the sensors (10) being carried out automatically from at least data representative of local conditions of environment of the cultures, in particular the temperature of the cultures, l 'soil hygrometry and / or rainfall. 17. Method according to any one of claims 11 to 16, the sensors (10) being grouped together to minimize the shade projected on the crops. 18. Method according to any one of claims 11 to 17, the sensors (10) being movable along a horizontal then vertical path in an end of stroke zone, the 5 process comprising the step of grouping the sensors in the end-of-travel area to form a vertical structure opposing the wind. 19. Method according to one of claims 11 to 18, the sensors (10) being rotatable, in particular around their longitudinal axis, the method comprising the step of orienting the sensors substantially vertically or obliquely with a 10 angle of less than 45 ° with the vertical when grouped. 20. A method according to any one of claims 11 to 19, the sensors (10) being rotatable, especially around the axis (Yi) of their row, the method comprising the step of moving the sensors to the times along the axis (X) and in rotation in order to respect a predefined law of crop shading.