WO2009068704A1 - Tracking system for the collection of solar energy - Google Patents

Abstract

The invention relates to a solar tracking system intended for the generation of electric power using a module comprising photovoltaic panels, which has been specially designed for the optimised use of incident radiation. The system includes a mechanical structure for supporting and positioning the aforementioned module, which structure is supported by a concrete slab or base to which the lower end of a screw is also anchored. The other end of said screw is pivotally connected to a frame used to support the module. The position of the frame is adjusted by means of a motor which actuates the screw and is controlled from an electronic circuit included in the system. The circuit includes light sensors which provide the control circuit with information relating to the outside light level and which force the return of the supporting frame and the panel module to the initial position upon detection of a light level below a given threshold.

Description

 "FOLLOW-UP SYSTEM FOR SOLAR ENERGY COLLECTION"

DESCRIPTION

Object of the Invention

The present invention relates to a monitoring system for capturing solar energy, which provides essential novelty characteristics and notable advantages over the means known and used for the same purposes in the current state of the art.

More particularly, the solar tracking system proposed by the invention is integrated by a tracking structure associated with a modular set of photovoltaic panels for capturing solar energy for transformation into electrical energy, whose structure determines the optimal positioning of the panel module at each moment, together with an electronic circuit that is responsible for controlling the instantaneous positioning of the panel module and returning it to the initial starting point at the end of the day, that is, in the absence of daylight, so that it is operational from the moment it begins to dawn. Both the monitoring structure and the control electronics have been designed with simplicity and low maintenance criteria, which makes the system as a whole highly attractive both from the point of view of efficiency and from the point of view of manufacturing and installation costs.

The scope of the invention is obviously comprised within the industrial sector dedicated to the manufacture, assembly and installation of energy-related devices and devices. alternatives, and more especially with the production of electrical energy through photovoltaic panels.

Background and Summary of the Invention It is known by all in general the tendency for a certain number of years, to increase the use of the energies offered by natural and inexhaustible sources, such as the sun or wind. This fact is a consequence of the need to limit the consumption of fossil fuels such as coal or oil, which are increasingly scarce worldwide, together with greater respect for the environment in the face of such significant problems as global warming or others of a similar nature. .

Solar installations based on photovoltaic panels are increasingly numerous in a wide variety of geographical areas where a daily average of sun hours is received above a predetermined limit. These installations have the advantage that they are normally relatively easy to install, and they perform a direct transformation of the energy of the incident solar rays into electrical energy that can be used immediately, either in situ or for their injection of a nearby network for use in another remote location. Logically, photovoltaic solar installations always seek to achieve the best possible performance in terms of energy production per peak power unit of photovoltaic modules. In this sense, the use of solar trackers that allow a positioning of the solar panel modules with the greatest possible orthogonality with respect to the direction of the incident rays, has allowed to increase energy production by up to 50% compared to the mounted modules on fixed structures.

In this increase in energy production, the adaptation of the electronics used to control the positioning of the panels at all times has played a fundamental role. Thus, as usual, two different types of electronic solar tracking systems are currently known.

- Passive: it is based on programming the situation

(coordinates) of the tracking device, so that by means of a predefined program the follower is indicated the position to be taken at each moment of the day. The system requires the use of high precision position sensors. Passive systems are usually connected to a distribution network, so it is essential to carry a connection cable to the follower. The cost of electronics of this type of followers is high.

Active: uses light intensity sensors and an electrical and / or electronic circuit, with which orders are sent to the engine and the transmission organs so that they rotate to place the follower in the ideal position. Active systems can be autonomous or connected to a distribution network. When they are autonomous, they obtain the energy necessary for their operation from the panels themselves that are mounted on the tracker, or, in exceptional cases, from a solar module incorporated exclusively for this function. The cost of electronics incorporated by active systems is low. As will be understood, a main objective in solar trackers is to optimize profit or maximize performance by reducing costs to minimum values. From the point of view of electronics, cost reduction can be approached from several points of view:

Reducing the initial cost of the components; Reducing the energy consumption of the components during operation, and

Improving the efficiency of the follower, based on the exposure of the modules to the incident radiation for as long as possible, and with the greatest perpendicularity that can be achieved.

Taking into consideration the foregoing comments, the present invention has proposed as its main objective the fact of developing and providing a substantially improved solar tracking system with respect to the currently known systems, based on a combined action of simple and economic design of both the electronics incorporated into the system as well as the structure of each module supporting the photovoltaic panels and monitoring the solar path. This objective has been fully achieved by means of the monitoring system that will be described in the following, whose main characteristics are included in the characterizing part of claim 1, and in the associated sub-claims dependent on the principal.

In essence, the system of the invention includes a control electronics belonging to the group that has been defined as "active" in the foregoing. The circuit includes brightness sensors that cause the drive of the follower motor to return the panel module to the starting position when the lack of light is detected (adjustable value), that is, when night comes, instead of when the first morning sun rays are detected as basically occurs in known followers, whereby the follower of the invention provides an increased use of solar energy. The circuit includes an electric power generator preferably consisting of a photovoltaic module, an energy accumulator preferably consisting of one or more accumulator batteries, an electronic circuit responsible for controlling the various functions, one or more light sensors connected directly to the electronic circuit for sending to the latter the informative signals of the level of luminosity, one or more position sensors also connected to the electronic circuit and indicative that the tilting of the module of photovoltaic panels has made its complete route during its return to the starting point, and a motor managed directly from the electronic circuit and whose rotation in both directions of rotation allows the panel assembly to be progressively moved at any time to the desired position.

For its part, the structure provided for the follower of the present invention has been conceived, as has been said, with extremely simplified characteristics, which makes it extraordinarily effective, at advantageous manufacturing costs with respect to conventional structures, and with post-installation maintenance needs substantially reduced compared to existing ones. In essence, each of the modules of the panels of the installation has a frame with orthogonal design obtained from various profiles that extend longitudinally, and in whose respective rails house the edges of the different panels, photovoltaic. This set is in solidarity with a support frame that generally takes the form of double

"H", this frame being supported by two vertical support groups by means of articulated joints that determine an axis of rotation or tilting in both directions with respect to said axis. A pushing element, preferably materialized by means of a spindle, a hydraulic jack, or other similar device, is attached to one of the branches of the frame, in a predetermined position, independently on either side of the tilting axis, so that The spindle extension or retraction of the spindle determines the positional variation of the panel module to one side or the other, thereby ensuring adequate monitoring of the sun along its path. This solar tracking action, together with the inclination that has been provided to the module of photovoltaic panels due to the difference in heights of the support groups, guarantee the reception of solar radiation with a desired degree of orthogonality for optimized performance of the set The inclination of the frame that supports the set of photovoltaic panels is adjusted according to the geographical latitude of the installation site.

As will be understood, with a construction like the one just described briefly in the above, excellent and optimized results are guaranteed in terms of the transformation of the incident solar energy into electrical energy, being only necessary that the set of panels is moved only around an axis of rotation determined by both support groups.

Brief Description of the Drawings These and other features and advantages of the The invention will become more clearly apparent from the following detailed description of a preferred embodiment thereof, given by way of illustration only and in no case limited, taken together with the accompanying drawings, in which :

Figure 1 shows a schematic general view of the electronic means used for the control of the system of the invention;

Figure 2 illustrates a schematic perspective view of an exemplary embodiment of a complete module of those provided by the system of the invention;

Figure 3 represents a schematic view, in perspective from below, of the determining support groups of the rotation axis and the double "H" frame, together with a larger D detail of any one of the articulated joints between said frame and each of the aforementioned support groups, and

Figure 4 is a schematic illustration of different limit and intermediate tilting positions of the photovoltaic panel module, together with the representation of the spindle oscillation range acting on the frame depending on each position.

Description of a Preferred Embodiment

As mentioned above, the detailed description of the preferred embodiment of the invention will be carried out in the following with the help of the attached drawings, through which the same are used numerical references to designate the same or similar parts. Thus, attending first the representation of Figure 1, you can see This figure schematizes a set of blocks that implement a preferred embodiment of the control electronics incorporating the system of the invention. According to said representation, a block indicated with the numerical reference 1 representative of an electric power generator and preferably consisting of a photovoltaic module provided for that purpose, intended to generate the electricity necessary for the supply of the various consumption organs of the set. This generator is electrically connected to a block 3, indicative of the electronic control circuit, and through the latter, to a block 2 indicative of an accumulator group of electrical energy, such as one or more accumulator batteries. The assembly includes a block 4 representative of one or more brightness sensors, a block 5 indicative of an end position sensor or switch, and a block 6 indicative of an electric motor capable of rotating both ways of rotation and moving the follower to the right position at every moment.

Based on a circuit design such as the one depicted in the scheme of Figure 1, it follows that its operation is as follows:

During the hours of the day when there is sufficient incidence of solar radiation so that the generator 1 can produce energy, energy is supplied from said generator to meet the consumption needs associated with the electronic circuit 3, and to charge the accumulator group 2. When the intensity of the light falls below a predetermined threshold value, the electronic circuit 3 captures this situation through the sensor 4, at which time the circuit 3 switches the power supply so that it is now the accumulator group 2 that is responsible for supply the electrical energy demanded by the electronic circuit 3 and the associated mobile organs. From that moment and depending on the new situation detected by the circuit 3, said circuit determines the start-up of the motor 6 in the corresponding direction to bring the follower to the starting position, the sensor 5 being responsible for informing to electronic circuit 3 that the return path has been completed.

It will be appreciated that the control electronics incorporated by the system of the invention are simple and of course very reliable. The components can be chosen from a wide range with the characteristics and tolerances required by the different designs. The light sensor 4 may consist, for example, of photosensitive resistors, solar cells, LED-type photodiodes, or others. For its part, the electronic circuit 3 manages the various components associated therewith and that have just been described, namely, the charge of the accumulator group 2, the information coming from the light sensor 4, the change of state of the position sensor 5 when it is operated by the collapsible solar tracker module when it performs the return movement, or the motor 6 power supply when it is appropriate to move the solar tracker module.

As will be understood, the system could be powered from the power grid with the mere provision of the mandatory power supply. However, the described embodiment is preferred by virtue of its greater simplicity, especially in cases of installations involving multiple solar trackers, all of which need wiring for their respective power, with the consequent increase in costs and complexity. As for the position sensor group 5, any of those currently available on the market and having adequate reliability for the purposes for which it is intended can be used, being both the type of a mechanical switch and the type of an optical sensor . The driving element of the movement, that is to say, the motor 6, may also be constituted by any DC motor as long as it has adequate characteristics for the realization of the turning movement that is needed for the correct operation of the assembly.

Once the different components that make up the system control electronics and the characteristics that define them are described, the description of the mechanical structural part of a monitoring module for solar energy collection of the type that integrates the system will now be carried out. system of the invention. For this, reference will be made to Figure 2 and following of the attached drawings, in which the different parts of the assembly are shown together with the characteristics that identify each of them.

Thus, referring first to Figure 2 of the drawings, a general view of a preferred embodiment of the system of the invention can be seen, embodied in a tracking module for solar energy collection, according to a schematic view, in perspective from above, of said module. The assembly is erected from a lower slab 7 for fixing to the ground, from which two vertical support groups in general are raised, a front one consisting of legs 8 anchored in said lower slab 7 and converging at the highest point, and a rear one consisting of legs 9 also anchored in said slab 7 and which also converge at the highest point. The definition of the terms "front" and "rear" should understood according to the position in which an external observer sees the aforementioned Figure, without this being interpreted in any limiting sense.

As previously mentioned and clearly visible in the drawing, the legs 9 of the rear support group converge at a point that is higher than the convergence point of the legs 8 of the front support group. This difference in heights determines a predetermined degree of inclination that will be adjusted based on the geographical latitude of the place where the system is to be installed, logically adapted to the height of the sun on the horizon, and in such a way that a high degree of perpendicularity of solar radiation. As mentioned, the upper points of convergence of both support groups constitute the tilting points for a double "H" shaped frame, formed by two parallel stringers 10 and separated from each other by a predetermined distance, and two crossbars 11 extended between said stringers. This frame supports a frame 12 of orthogonal configuration with longitudinal profiles, leaving spaces in which to house the different panels (not shown) by inserting the edges of the latter along the rails of said profiles, thereby guaranteeing a effective clamping against the pressure that circulating winds can exert at the installation site, with maximum anchor strength, and also with the use of a minimum number of screws or other fixing means. The assembly includes an element capable of extension and retraction, preferably a spindle 13 that driven through a suitable means, for example the motor 6 already described in relation to Figure 1 of the drawings, can cause the displacement of its corresponding rod in the sense wanted. The spindle 13 has the lower end interlocked in the concrete slab 7 itself by means of a pivotal joint, while the upper end has it pivotally connected to a crosspiece 11 of the double "H" shaped frame, on one side, and to a certain distance, from the axis of rotation determined by the two opposite convergence points of the legs 8, 9 of both support groups.

Figure 3 is a schematic view, in perspective from below and on a larger scale, of the assembly of Figure 2, provided only for the purposes of a clearer representation of the elements that support the set of photovoltaic panels (not shown), together with a detail of one of the elements that provide the swing link between the support frame and one of the support groups. In addition, it is possible to see the provision of a "U" piece indicated by reference number 14, in solidarity with the bottom face of one 11 of the double-frame crossings "H", and intended to constitute the point of attachment with the spindle rod (not shown in this Figure). On the other hand, the detail D makes it possible to appreciate how at one of the convergence points, for example the convergence point of the legs 9 of the rear support group, a part 15 is disposed advantageously attached to both legs 9 mentioned, and having an upper configuration also in the form of "U" to allow the respective stringer 11 to be tilted, linked to the sides of the "U" by means of a bolt 16 or a similar bolt that offers sufficient strength to resist with guarantee the efforts to which it will be subjected during the whole operating life. It will be understood that the arrangement is exactly the same in relation to the other support group, that is, that corresponding to the joint between the legs 8 of the front group. As can be seen from the description that has been made in the foregoing, the frame of the double assembly "H" and the structural frame 12 that it supports, can be folded towards one or the other side of the imaginary axis of rotation created by the pieces 15 "U" associated to the ends of each of the front and rear support groups, keeping the inclination provided by the height difference between both support groups. This tilting is determined, as has been said by the action of the spindle 13, and can be clearly seen in Figure 4. The graphic representation shows the extreme positions that the module M for supporting the panels, inclined to one and the other, can adopt. tilting shaft side, together with a completely horizontal intermediate position. The spindle 13 is represented in the three positions corresponding to those of the module M, being able to appreciate its oscillation by virtue of the arc travel C made by the upper end of the spindle rod in its pivotal connection with the part 14. This arc C has as a radius the distance between the position of the connecting piece 14 between the spindle rod and the crossbar 11 of the double "H" frame, which is equivalent to a projection on the concrete base or slab delimited by points "A" and ^W B ", separated by a distance equal to said radius, and at whose intermediate point the lower end of the spindle 13 is pivotably anchored. In this way, a distance of oscillation of the spindle to both sides is determined sufficiently short to guarantee that the transmission of stresses through the spindle towards the anchor point in the lower slab 7, is carried out close to a vertical line, originating transverse components of reduced magnitude and therefore with minimal repercussions on the structure. According to a preferred embodiment of the invention, the pivoting of the module M with respect to the horizontal one provided by the operation of the spindle 13, is of the order of 140 °, that is, 70 ° on each side of the intermediate horizontal position that shown in Figure 4. However, this angle can be varied depending on each specific need and in order to adapt the assembly to the requirements of each embodiment.

It is not considered necessary to make the content of this description more extensive so that a person skilled in the art can understand its scope and the advantages derived therefrom, as well as carry out its practical realization.

Notwithstanding the foregoing, and since the description made corresponds only to a preferred embodiment, it will be understood that within its essentiality multiple variations of detail may be introduced, also protected, which may affect features and details such as variations in shape. and size, construction materials, number of panels included in each module, or any other necessary for the adaptation of the installation to the different needs, easily imaginable by those skilled in the art, without entailing departing from the scope of protection of the invention defined only by the claim set forth below.

Claims

1. - Monitoring system for solar energy collection, in particular a system designed to carry out positional monitoring of the solar path that guarantees an incidence of solar radiation on photovoltaic solar panels generating electricity with the highest possible orthogonality, whose system It is implemented by a control electronics designed to automatically perform the instantaneous positioning of the pick-up elements, and by a mechanical support structure designed to resist the stresses derived from external agents present at the installation site, which is characterized by : the control electronics include a set of main components such as an electronic control circuit (3), an electric power generating device (1), an accumulator group (2), means (4) light sensors, means (5 ) position sensors, and materialized motor means by means of a engine (6) and intended to transmit movement to the corresponding organs of the system; The support structure is intended to support the module (12) of collector panels in the different operating positions of said module, and consists of two support groups, one front and one rear, of different heights, between which an axis is defined inclined to rotate and pivot in both directions, up to a predetermined limit angle, for the frame of the module (12) of collector panels supported by a double "H" frame that includes two main stringers (10), parallel and spaced from each other, and crossbars (11) extended between said stringers. 2. System according to claim 1, characterized in that the said electric power generating device (1) preferably consists of a solar module of specific design. 3. System according to claims 1 and 2, characterized in that the light sensors means (4) generate signals that inform the electronic control circuit (3) about the level of ambient luminosity, such that when said level of luminosity falls below a given threshold value, the electronic circuit (3) determines the return of the module (12) of panels to the initial starting position, by controlled operation of the motor (6), the sensor (5) being the person in charge of informing the electronic circuit (3) that the mentioned initial position has been reached. 4. - System according to claims 1 to 3 above, characterized in that the light sensor means (4) are chosen between photosensitive resistors, solar cells, LED-type photodiodes, or other conventional ones of a similar nature, and because the means ( 5) Position detectors consist essentially of an optical sensor or a switch device. 5. System according to claim 1, characterized in that each of the front and rear support groups of the mechanical structure is constituted by two or more respective legs (8, 9) that are anchored by their lower ends in a base or concrete slab (7), and that converge in an upward direction to join at the highest point where a respective piece (15) has been associated in solidarity with each support group, adopting a "U" shape, whereby each respective of the crossbars is held (11) of the support frame of the module of collector panels with the help of a respective bolt (16), and with the possibility of tilting in both directions of rotation. 6. System according to claim 1, characterized in that the tilting of the sensor panel module is determined by the action of a thrust element such as a spindle (13) which is pivotally interlocked at the lower end on the same base or slab (7) of concrete, and which at the top end has its rod pivotally linked to one (11) of the crossbars of the double "H" frame, through a "U" piece (14) integral with said crossbar , and located on either side of the tilting axis of the panel module, keeping a distance with said axis. 7. System according to claim 6, characterized in that the distance between the pivoting clamping part (14) of the upper end of the spindle (13) and the axis of rotation is such that the radius of the arc ( C) followed by said part (14) during the two-way tilting of the frame and the panel module supported by the latter, determines a projection delimited between the points (A and B) on the concrete slab (7), being the lower end of the spindle (13) anchored in the base (7) in an intermediate position between the mentioned limit points (A and B). 8. System according to claim 7, characterized in that in a preferred embodiment, the tilting angle of the double support frame "H" and the module (12) of sensor panels it supports, extends to an amplitude 70 ° on each side below the horizontal. 9. System according to the preceding claims, characterized in that the sensor panel module consists substantially of an orthogonal frame (12) with longitudinal profiles, whose profiles have rails> that allow the introduction of the edges of the sensor panels inside. , and facilitate the fastening of said panels with the use of a minimum amount of fasteners.