Method for Aligning a Set of Solar Modules of a Solar Tracker

The invention relates to a method for aligning a set of solar modules of a solar tracker.

A solar tracker is comprised of several solar modules that form a set. Each solar module comprises an element for processing the solar radiation, such as a photovoltaic panel, a mirror, etc., mounted mobile on a base of the solar module in order to be able to track the movement of the sun. If the solar module is a one-axis solar module, the solar-tracking movement is azimuthal. If the solar module is a two-axis solar module, the solar-tracking movement is double, azimuthal and zenithal. Two adjacent solar modules of this set are connected to each other by means of connection and transmission of a solar-tracking movement. These means of connection and transmission are generally control bars that make it possible to connect and transmit a movement between two solar modules of a set that forms a solar tracker. On the other hand, the solar tracker comprises means of motorisation that make it possible to carry out the solar-tracking movement of all of the solar modules of the solar tracker. In a simple manner, the means of motorisation, that comprise an electric motor, are located at the centre of the set of solar modules of the solar tracker between two adjacent solar modules of this set. Note that the solar-tracking movement comprises, as indicated hereinabove, a movement referred to as azimuthal and/or a movement referred to as zenithal, according to the type of the solar tracker, one-axis or two-axis. In the case of a so-called two-axis solar tracker, each axis comprises a means of motorisation that can be independent of that of the other axis. Because of this, between two adjacent solar modules of the set of solar modules of the solar tracker, there is a first control bar for the azimuthal movement and a second control bar, generally parallel to the first control bar, for the zenithal movement.

In order to have an optimal production of energy from such a solar tracker comprised of a set of solar modules, the alignment of the elements for processing solar radiation of the solar modules of this set of solar modules is required. The elements for processing solar radiation make it possible to carry out said production of energy. It is therefore necessary to be able to align each one of the elements for processing solar radiation, therefore each one of the solar modules of the set of solar modules of the solar tracker precisely facing the sun in a simple and effective manner.

A purpose of the invention is to provide a method for aligning a set of solar modules of a solar tracker that makes it possible to align each one of the solar modules precisely facing the sun using solely the means of motorisation by axis and control bars that make it possible to transmit the movement to the various solar modules on this axis.

For this purpose, according to the invention, a method for aligning a set of solar modules of a solar tracker is provided comprising means of connection and of transmission of a solar-tracking movement of a solar module of the set of solar modules to a solar module adjacent of the set of solar modules, with the method comprising an iterative loop that comprises, for each on-going iteration, steps of:

a) disconnecting adjacent solar modules of an aligned subset of solar modules derived from a previous iteration;

b) defining which one of the previously disconnected adjacent solar modules will be the reference solar module for the on-going iteration;

c) orienting the aligned subset of solar modules in such a way that the solar modules of the aligned subset of solar modules are aligned with the reference solar module of the on-going iteration;

d) connecting the aligned subset of solar modules with the reference solar module for the on-going iteration so as to define an aligned subset of solar modules for the next iteration.

As such, carrying out the alignment via an iterative loop makes it possible, at each one of the iterations of the iterative loop, to adjust in a single effort the solar modules that form a subset previously aligned with one of the two solar modules of the set of solar modules of the solar tracker adjacent to this previously aligned subset, and this using control bars of each one of the axes of the solar tracker possibly associated with their means of motorisation.

Advantageously, but optionally, the method for aligning according to the invention has at least one of the following additional characteristics:

the method comprises a step of initialisation before any iteration of the iterative loop during which the aligned subset of solar modules comprises only one of the solar modules of the set of solar modules of the solar tracker;

the aligned subset of solar modules comprises means of motorisation of solar modules connected to at least one of the solar modules of the aligned subset of solar modules;

the step c) is carried out by the means of motorisation of solar modules;

during the step c), the orientation is carried out according to an offset in the alignment between the reference solar module for the on-going iteration and the solar module that belongs to the aligned subset of solar modules and adjacent to the reference solar module for the on-going iteration;

the method comprises a preliminary step of determining for each one of the solar modules of the set of solar modules of the solar tracker of an optimum position with respect to the Soleil, with the solar modules being connected together by the means of connection and of transmission; and

the offset in alignment is determined using the optimum position of the reference solar module for the on-going iteration and of the solar module adjacent that belongs to the aligned subset of solar modules.

Other characteristics and advantages of the invention will appear in the description hereinafter of a preferred embodiment of the invention in the annexed drawings:

FIG. 1 diagrammatically shows a solar tracker comprising a set of six solar modules interconnected together by control bars and intended to be aligned with the method for aligning according to the invention;

FIGS. 2 to 6 are diagrammatical views that show successive iterations of an iterative loop of the method for aligning according to the invention applied to the alignment of the solar modules of the solar tracker of FIG. 1.

In the rest of the description, the method for aligning a subset of solar modules of a solar tracker shall be described in detail in relation with a solar tracker 1 comprising a set of six solar modules 10, 20, 30, 40, 50, 60, such as shown in FIG. 1. Two adjacent solar modules of the solar tracker 1 are connected by a set of control bars. The solar module 10 is connected with the solar module 20 by a set of control bars 12. The solar module 20 is connected to the solar module 30 by a set of control bars 23. Likewise, the solar module 40 is connected to the solar module 50 by a set of control bars 45. The solar module 50 is however connected to the solar module 60 using a set of control bars 56. The solar module 30 is connected to the solar module 40 using a set of control bars 37, 74. Means of motorisation 70 of the solar tracker 1 are here located between the solar modules 30 and 40, with the set of control bars 37 connecting the means of motorisation 70 to the solar module 30 while the set of control bars 74 connects the means of motorisation 70 with the solar module 40. Note that here a single axis is represented by the set of control bars 12, 23, 37, 74, 45, 56 and are motorised by the means of motorisation 70. In the framework of a solar tracker with two axes, this set of control bars/means of motorisation is doubled, in such a way as to have a control bars/means of motorisation set for each one of the axes. Recall that, in the framework of a solar tracker with two axes, the first so-called azimuthal axis is controlled by a first control bars/means of motorisation set as described hereinabove, and the second so-called zenithal axis is controlled by a second control bars/means of motorisation set that is identical to that described hereinabove. In what shall follow, although described for a single control bars/means of motorisation set, this can be transposed to two control bars/means of motorisation sets by carrying out the steps concerning this set of control bars/means of motorisation concomitant to the two sets. By extension, this applies mutatis mutandis to a multi-axis tracker.

During the construction of the solar tracker 1, the various solar modules 10 to 60 are mounted in a position and a random alignment with respect to one another.

In a first stage, during a preliminary step, the method for aligning according to the invention will determine the optimum position with respect to the sun of each one of the solar modules of the set of solar modules of the solar tracker 1. This preliminary step is carried out while the solar modules 10, 20, 30, 40, 50, 60 of the solar tracker 1 are connected two by two by the various control bars 12, 23, 37, 74, 45, 56, regardless of the relative position of the solar modules 10, 20, 30, 40, 50, 60 at that moment. For this, several methods exist in order to carry out this preliminary step.

A first method consists in that the means of motorisation 70 are actuated in such a way that the first solar module here among the six solar modules 10, 20, 30, 40, 50, 60 of the solar tracker 1 is oriented optimally with respect to the sun. For this purpose, the means of motorisation 70 are accelerated or decelerated according to the case. At this moment, its azimuthal and zenithal positions in the framework of a two-axis solar tracker are taken and associated with a time of the taking, therefore with a corresponding position of the sun. Then, iteratively, the preceding operations are repeated for each one of the five other solar modules of the solar tracker. Since the various readings were taken at different times, they are recalculated at a common fixed time using the knowledge of the course, and therefore of the position, of the sun for the various reading times. At the end of this preliminary step, we have all of the azimuthal and zenithal positions of each one of the six solar modules 10, 20, 30, 40, 50, 60 of the solar tracker 1, representing for each one its optimum orientation with regards to the sun, for a common fixed time. Using all of the data on the azimuthal and zenithal positions obtained during this step of detecting the optimum position of each one of the solar modules with respect to the sun, it is possible to calculate the offset of the orientation or of the alignment between two adjacent solar modules of the set of solar modules 10, 20, 30, 40, 50, 60 of the solar tracker 1.

A second method consists in using a compensation device (not shown) located within each one of the solar modules of the solar tracker, a compensation device through which the control bar orients the solar module considered. This compensation device, which is actuated either manually or automatically, makes it possible to introduce an offset between the control bar that actuates the solar module and the effective orientation of the latter. This offset is taken for each one of the solar modules of the solar tracker. Using all of the data on the offsets obtained during this step of detecting the optimum position of each one of the solar modules with respect to the sun, it is possible to calculate the offset in the orientation or in the alignment between two adjacent solar modules of the set of solar modules 10, 20, 30, 40, 50, 60 of the solar tracker 1.

Regardless of the method used to carry out the preliminary step of the method for aligning according to the invention, there are several methods that make it possible to determine if a solar module is located in an optimum position with regards to the sun.

The first method is purely manual and consists in detecting the best position of each one of the solar modules of a set of solar modules of a solar tracker thanks to a visual control on an element for processing the solar radiation that is part of the solar module considered.

A second method that can be used consists in detecting the best position of each solar module thanks to a device for detecting an aiming fault applied on the element for processing solar radiation of the solar module considered. Through this means, the value of the optimum positioning is directly given by the device for detecting faults.

A third method consists in using solar sensors positioned on or in the vicinity of the element for processing the solar radiation or by using the element for processing the solar radiation itself as a sensor. This method is similar to the first purely manual method described hereinabove. The optimum position with respect to the sun of the solar module is given when a maximum of power is measured at the output of the sensor or sensors associated with the element for processing solar radiation considered. This method can be semi-automatic by coupling a system for controlling the means of motorisation 70 to the sensor or sensors used for detecting the position.

Once the preliminary step has been carried out, the method for aligning according to the invention begins an iterative loop which will make it possible to simply and reliably align the solar modules 10, 20, 30, 40, 50, 60 of the set of solar modules of the solar tracker 1. In order to initialise this iterative loop, the method for aligning according to the invention comprises a step of initialisation wherein an aligned subset of solar modules is created and comprises one of the solar modules 10, 20, 30, 40, 50, 60 of the set of solar modules of the solar tracker 1 to be aligned. In order to use the means of motorisation 70 in order to carry out the various steps of alignment of the method for aligning according to the invention, the aligned subset of solar modules further comprises the means of motorisation 70. In these conditions, the solar module selected to initialise the aligned subset of solar modules is then adjacent to the means of motorisation 70.

Once the aligned subset of solar modules has been initialised as indicated hereinabove, the first step of the iterative loop relates to the disconnection of the aligned subset of solar modules from the solar modules adjacent to this subset by removal of the control bars that connect said solar modules adjacent to the aligned subset of solar modules. When the aligned subset of solar modules comprises only the solar module 40 and the means of motorisation 70, i.e. during the first iteration of the iterative loop of the method for aligning according to the invention, the control bars 45 and 37 are removed in order to disconnect the solar modules adjacent to this aligned subset of solar modules which are solar modules 50 and 30.

Once this step of connecting has been carried out, in a second step of the iterative loop of the method for aligning according to the invention, one of the solar modules adjacent to the aligned subset of solar modules considered during the step of the iterative loop and previously disconnected is defined as a reference solar module for the on-going iteration of the iteration loop of the method for aligning according to the invention. For example, for the first iteration, the choice concerns the solar module 50 or the solar module 30. Purely for the purposes of illustration, the solar module 50 is chosen as the reference solar module for the on-going iteration of the iterative loop of the method for aligning according to the invention. At this time the solar tracker 1 is in a state such as shown in FIG. 2.

Then, a third step of the iterative loop of the method for aligning according to the invention is carried out. This third step consists in orienting the aligned subset of solar modules in such a way that the solar modules of the aligned subset of solar modules are aligned with the reference solar module for the on-going iteration. This orientation can be carried out either using the means of motorisation 70 (if the latter have been included in the aligned subset of solar modules considered for the on-going iteration of the iterative loop of the method for aligning according to the invention), or manually by manually implementing the control bars that connect the solar modules of the aligned subset of solar modules considered for the on-going iteration of the iterative loop of the method for aligning according to the invention. In the framework of the first iteration that shows this step, here, the means of motorisation 70 are implemented in such a way as to change the orientation of the solar module 40 using the control bars 74 in such a way that the latter is aligned on the orientation of the reference solar module, here the solar module 50. For this, the previously defined offset is determined using optimum positions taken from the solar module 40 and from the solar module 50. The difference between the optimal positions of these solar modules makes it possible to carry out the required movements using means of motorisation 70 of the solar module 40 so that the latter come into alignment of the solar module 50 serving as a reference solar module.

Once this step of orientation has been carried out, a fourth step of the iterative loop of the method for aligning according to the invention consists in connecting the reference solar module of the on-going iteration to the aligned subset of solar modules that was just oriented during the preceding step. For this, the control bars between the reference solar module and the solar module that is adjacent to it of the aligned subset of the previously oriented solar modules are put back into place in such a way as to obtain a new aligned subset of solar modules which will be used during a following iteration if there still remain any solar modules of the set of solar modules of the solar tracker 1 with respect to which the new aligned subset of solar modules has not been aligned. In the framework of the first iteration now being described, at the end of the fourth iteration of the iterative loop of the method for aligning according to the invention, the solar tracker 1 is in a configuration wherein the new aligned subset of solar modules comprises, in addition to the means of motorisation 70, the solar module 40 and the solar module 50 perfectly aligned with respect to one another and connected to one another.

Starting from here, if the new aligned set of solar modules is not equal, in the number of solar modules, to the set of solar modules that forms the tracker 1, a new iteration of the iterative loop of the method for aligning according to the invention is carried out, and this until the set of solar modules of the tracker 1 has been integrated into the aligned subset of solar modules.

In order to illustrate the example of the solar tracker of FIGS. 1 to 6, for the second iteration of the iterative loop of the method for aligning according to the invention, the aligned subset of solar modules considered for the first step of this iterative loop is the subset comprised of means of motorisation 70 and of the two solar modules 40 and 50. This aligned subset of solar modules is then disconnected from the adjacent solar modules of the set of solar modules of the solar tracker 1, i.e., here, of the solar module 60 and of the solar module 30. Note that as the solar module 30 was not chosen during the preceding loop as the reference solar module, the latter remained disconnected from the new aligned subset of solar modules coming from the first iteration of the iterative loop of the method for aligning according to the invention. Again, the choice of the reference solar module for this second iteration of the iterative loop of the method for aligning according to the invention is carried out between the solar module 60 and the solar module 30. Here, purely for the purposes of illustration, the solar module 60 is defined as the reference solar module for this second iteration. Then, the solar modules 40 and 50 that form the aligned subset of solar modules for this second iteration is set into movement by the means of motorisation 70 through the control bars 74 and 45 in such a way as to align the solar module 50 with respect to the solar module 60 by using the offset in alignment between the two solar modules 50 and 60, an alignment offset determined using the previously taken optimum positions for these two solar modules 50 and 60. The solar tracker 1 is in a state shown in FIG. 3A. Once the step of orientation of this second iteration carried out, the control bar 56 is set back into place in such a way as to connect the solar module 50 with the solar module 60 whereon it is aligned and as such integrate the solar module 60 into a new aligned subset of solar modules which will be used for a possible third iteration of the iterative loop of the method for aligning according to the invention. The solar module 40 had been aligned with the solar module 50 during the first iteration, consequently the latter, at the end of the second iteration, is then also aligned with the solar module 60.

The aligned subset of solar modules coming from this second iteration therefore comprises three solar modules in the example for the purposes of illustration used which does not correspond to the six solar modules of the set of solar modules of the solar tracker 1. Consequently, a third iteration of the iterative loop is carried out. The results of this third iteration are shown in FIG. 4. In this situation, the aligned subset of solar modules considered for this third iteration has only one adjacent solar module which is the solar module 30. Indeed, the solar module 60 does not comprise any adjacent solar modules outside of the aligned subset of solar modules of which it is a part due to the fact that the solar module 60 is located at an end of the set of solar modules of the solar tracker 1. Consequently, the solar module 30 is chosen as the reference solar module for this third iteration, with the connection bar 37 remaining removed in order to leave this solar module 30 disconnected from the means of motorisation 70. This is shown in FIG. 3B. Again, using the means of motorisation 70, the aligned subset of solar modules for this third iteration is oriented in such a way that the solar module 60 is aligned with the solar module 30 by using the offset in alignment determined using previously calculated optimum positions of the solar module 30 and of the solar module 60. Consequently, the solar modules 40 and 50 are then also aligned with the solar module 30. Once this orientation has been carried out, the solar module 30 is reconnected using the control bar 37 to the means of motorisation 70 and therefore to the solar module 40. Consequently, the solar module 30 is then integrated to a new aligned subset of solar modules comprising the solar modules 30, 40, 50 and 60 as well as the means of motorisation 70.

Again, the new aligned subset of solar modules comprises four solar modules, a number which is different from the one of six solar modules of the set of solar modules of the solar tracker 1. Consequently, a fifth iteration of the iterative loop is carried out in the same conditions as hereinabove. The reference module for this fifth iteration is the solar module 20 of which the control bars 23 connecting it to the solar module 30 are removed. Again, the solar module 30 is aligned with the solar module 20 using means of motorisation 70, which implies the identical orientation of the solar modules 40, 50 and 60 with respect to this solar module 20. The solar tracker 1 is in a state shown in FIG. 4. As hereinabove, in order to carry out this orientation, the offset in alignment between the solar module 20 and the solar module 30 is determined using optimum positions of these two solar modules 20 and 30 determined hereinabove. Once the orientation is done, the solar module 20 is reconnected to the solar module 30 by setting the control bars 23 back into place and a new aligned subset of solar modules is as such carried out by integrating the solar module 20 to the aligned subset of solar modules coming from the previous iteration.

At the end of this fifth iteration, the number of solar modules of the new aligned subset of solar modules is five, which does not correspond to the number of solar modules of the set of solar modules of the solar tracker 1 which is six. As such, a sixth iteration of the iterative loop is carried out in a manner similar to the preceding iterations. The reference solar module is the solar module 10 which is disconnected by withdrawal of the control bars 12 of the solar module 20. The orientation of the solar module 20 on the solar module 10 is based on an offset in the alignment determined using the optimum positions of the two solar modules 10 and 20 that were previously taken. Once the orientation has been carried out, the connection bars 12 are reinstalled, reconnecting the solar module 10 to the solar module 20 and creating a new aligned subset of solar modules comprising this time the six solar modules of the set of solar modules of the solar tracker 1, as shown in FIG. 6. The set of solar modules of the solar tracker 1 having been perfectly aligned with each other, the method for aligning according to the invention is terminated.

Note that, in what precedes, the order in which the various solar modules have been successively integrated is purely for the purposes of illustration and can be different. For example, still considering the initialisation of the aligned subset of solar modules with said solar module 40 and the means of motorisation 70, the order can be:

alignment with the solar module 50 then with the module 30 then with the solar module 60 then with the solar module solar module 20 then with the solar module 10;

alignment with the solar module 50, then the solar module 30 then the solar module 20 then the solar module 60 then the solar module 10;

alignment with the solar module 50 then the solar module 30 then the solar module 20 then the solar module 10 then the solar module 60;

alignment with the solar module 30 then the solar module 20 then the solar module 10 then the solar module 50 then the solar module 60;

alignment with the solar module 30 then the solar module 50 then the solar module 20 then the solar module 10 then the solar module 60;

alignment with the solar module 30 then the solar module 50 then the solar module 60 then the solar module 20 then the solar module 10;

alignment with the solar module 30 then the solar module 50 then the solar module 20 then the solar module 60 then the solar module 10;

alignment with the solar module 30 then with the solar module 20 then with the solar module 50 then with the solar module 60 then with the solar module 10; and

alignment with the solar module 30 then with the solar module 20 then with the solar module 50 then with the solar module 10 then with the solar module 60.

It is also possible to initialise the aligned subset of solar modules with the solar module 30 and the means of motorisation 70. From here, the order of the alignment and of the iteration of the iterative loop of the method for aligning according to the invention can be:

alignment with the solar module 20 then the solar module 10 then the solar module 40 then the solar module 50 then the solar module 60;

alignment with the solar module 20 then the solar module 40 then the solar module 10 then the solar module 50 then the solar module 60;

alignment with the solar module 20 then the solar module 40, then the solar module 50 then the solar module 10 then the solar module 60;

alignment with the solar module 20 then the solar module 40, then the solar module 50 then the solar module 60 then the solar module 10;

alignment with the solar module 40 then the solar module 20, then the solar module 10 then the solar module 50 then the solar module 60;

alignment with the solar module 40 then the solar module 20, then the solar module 50 then the solar module 10 then the solar module 60;

alignment with the solar module 40 then the solar module 20, then the solar module 50 then the solar module 60 then the solar module 10;

alignment with the solar module 40 then the solar module 50, then the solar module 60 then the solar module 20 then the solar module 10;

alignment with the solar module 40, then the solar module 50 then the solar module 20 then the solar module 10 then the solar module 60; and

alignment with the solar module 40, then the solar module 50 then the solar module 20 then the solar module 60 then the solar module 10.

Other orders are further possible and depend on the choice of the solar module for the initialisation of the aligned subset of solar module, a choice which itself can depend on the position of the means of motorisations 70 in all of the solar modules of the solar tracker 1.

Of course, it is possible to make to the invention many modifications without however leaving the scope of the latter.

Method for Aligning a Set of Solar Modules of a Solar Tracker

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