Solar Tracker with Blocking System

Abstract

The present invention relates to a solar tracker for capturing solar radiation comprising a support, a rotating shaft, and at least one solar panel. The solar tracker also comprises a tracking system capable of operating the rotating shaft for optimal placement of the solar panel and a blocking system connected to the rotating shaft. The tracking system comprises a control subsystem and an operating subsystem connected to a junction box with a microchip programmed to generate a signal sent by the control system and to send an unblocking command to the blocking system before allowing the operating system to move the rotating shaft. Once the solar panel has reached the optimal position, the blocking system is blocked again.

Claims

1. A solar tracker comprising: at least one support attached to a rotating shaft, wherein at least one solar panel is arranged; a tracking system equipped with a control subsystem and an operating subsystem of the rotating shaft, wherein said tracking system comprises at least one sensor for detecting the position of the rotating shaft, one motor for operating the rotating shaft, and one power source for said motor; and a blocking system connected to the rotating shaft comprising: at least one hydraulic piston connected to the rotating shaft and controlled by a solenoid valve, wherein the closing or opening of the solenoid valve keeps the movement of the hydraulic piston blocked or unblocked, respectively; and a junction box connected to the tracking system, to the motor, and to the blocking system.

2. The solar tracker according to claim 1, wherein the blocking system comprises two reciprocating hydraulic pistons, arranged in the form of a V, connected to a support at the lower portion thereof and to the rotating shaft at the upper portion thereof, such that the extension of said hydraulic pistons configures the angular blocking position of the rotating shaft.

3. The solar tracker according to claim 2, wherein the two reciprocating hydraulic pistons are connected to the rotating shaft through a rocker arm.

4. The solar tracker according to claim 2, wherein the hydraulic pistons are connected to one another by means of a hose communicating the oil chambers thereof, therefore allowing the passage of oil from one piston to another.

5. The solar tracker according to claim 4, wherein the hose is connected to the solenoid valve, such that it allows or retains the passage of oil from one piston to another.

6. The solar tracker according to claim 2, wherein the blocking system comprises a safety subsystem equipped with a pressure-limiting valve, configured for allowing the flow of oil between the hydraulic cylinders when pressure therein increases.

7. The solar tracker according to claim 1, wherein at least one hydraulic piston comprises a length when the blocking system is unblocked and the end moves away from the other end when the rotating shaft rotates.

8. The solar tracker according to claim 1, wherein the blocking system is unblocked by the junction box with the opening of the solenoid valve when the control subsystem of the tracking system emits a command for the motor to move in order to perform the correct positioning of the solar panels with the rotation of the rotating shaft.

9. The solar tracker according to claim 1, wherein the junction box comprises a microchip programmed with a time sequence.

10. The solar tracker according to claim 1, wherein the junction box comprises a diode rectifier bridge and, additionally, a filtering inductor and a filtering capacitor arranged at the output of said rectifier bridge.

11. The solar tracker according to claim 1, wherein the junction box comprises an auxiliary battery adapted to power the blocking system and, optionally, a charge controller adapted to receiving current from a solar panel, and to recharging or maintaining the charge of said auxiliary battery during the operation of the solar tracker.

12. The solar tracker according to claim 1, wherein at least one hydraulic piston comprises a variable length between ends.

13. The solar tracker according to claim 1, wherein the blocking system is fixed to the end supports at the end of at least one hydraulic piston and to the rotating shaft by means of a protrusion at the end of said hydraulic piston.

14. A method of blocking the solar tracker according claim 1, comprising blocking the signal from the junction box with the closing of the solenoid valve when the solar panel is in a given orientation and the motor is stopped.

15. The method according to claim 14, wherein the orientation of the solar panel is such that the plane formed by said solar panel is substantially perpendicular to the path of incidence of the solar rays thereon.

Description

DESCRIPTION OF THE DRAWINGS

[0018] The aforementioned and other features and advantages will be fully understood from the detailed description of the invention, as well as from the preferred embodiments referring to the attached figures which are described in the following paragraphs.

[0019] FIG. 1 shows an elevational view of a solar tracker in a first preferred embodiment of the invention.

[0020] FIG. 2 shows an elevational view of the tracking system of the solar tracker in a first preferred embodiment of the invention.

[0021] FIG. 3 shows an elevational view of the blocking system of the solar tracker according to a first preferred embodiment of the invention.

[0022] FIG. 4 shows a perspective view of the mechanical attachment of the hydraulic piston with the rotating shaft in a first preferred embodiment of the invention.

[0023] FIG. 5 shows a second preferred embodiment of the blocking system of the invention.

REFERENCE NUMBERS USED IN THE DRAWINGS

[0024]

TABLE-US-00001 (1) Solar tracker  (1a) Support  (1b) Rotating shaft  (1c) Solar panel  (1d) End support  (1e) Socket joint (2) Tracking system  (2a) Control subsystem  (2b) Operating subsystem (3) Blocking system (4) Rocker arm (5) Motor (6a, 6b, 6c) Cables (7) Junction box (8) Hydraulic piston (8a, 8b) Ends of the hydraulic piston (9) Solenoid valve (10)  Hose (11)  Flat bar (12)  Protrusion

DETAILED DESCRIPTION OF THE INVENTION

[0025] A detailed description of the invention in reference to the different preferred embodiments thereof based on FIGS. 1-5 herein is set forth below. Said description is provided for purpose of illustrating, though not limiting the claimed invention.

[0026] As described in the preceding sections, the invention preferably relates to a photovoltaic solar tracker (1) configured for capturing solar radiation by means of orienting said solar tracker (1) towards the position of the sun. As shown in FIG. 1, the solar tracker (1) is supported on a preferably metallic structure comprising one or more supports (1a, 1d) that are fixed (for example, driven into, supported on, or cemented in the ground) and a longitudinal rotating shaft (1b) substantially perpendicular to the supports (1a). Likewise, one or more solar panels (1c) are fixed on said structure such that since the rotating shaft (1b) and the solar panel (1c) are attached to one another, when the rotating shaft (1b) rotates, the solar panel (1c) rotates as well. In the embodiment of FIGS. 1-5, the rotating shaft (1b) is preferably attached to the support (1a) by means of a ball and socket joint (1e) which can be observed in FIGS. 3 and 4. In a preferred embodiment of the solar tracker (1) of the invention, it further comprises a tracking system (2) for tracking the sun which is capable of operating the rotating shaft (1b) and the solar panel (1c) to make them rotate, being oriented towards the sun, in a programmed manner.

[0027] An embodiment of the tracking system (2) of the solar tracker (1) can be observed in FIG. 2 in greater detail. The tracking system (2) mainly comprises a control subsystem (2a) and an operating subsystem (2b).

[0028] The control subsystem (2a) comprises at least one position sensor configured for measuring the position of the rotating shaft (1b) and/or of the solar panel (1c). In turn, the operating subsystem (2b) comprises a motor (5) configured for operating means for moving the rotating shaft (1b) and/or the solar panel (1c). The control subsystem (2a) and/or the operating subsystem (2b) preferably comprise a power source connected to the motor (5), for example by means of cables (6a, 6c). The sensors and the power source are not depicted in the figures.

[0029] The purpose of the position sensors is to detect whether the solar panel (1c) is in the optimal position with respect to the sun, preferably in a programmed manner, using optical detection means (for example, cameras, although these means are not essential in the invention) connected to a solar position tracking algorithm. Therefore, when the sensors detect that the solar panel (1c) is not in the correct position, the control subsystem (2a) commands the motor (5) to act so as to move the rotating shaft (1b) and the solar panels (1c) to the correct position, corresponding to the one that produces the greatest solar energy capture, i.e., the position in which the surface of the solar panel (1c) is perpendicular to the sun rays.

[0030] The solar tracker (1) of the invention is mainly characterized by comprising a blocking system (3) connected to the rotating shaft (1b), such that the orientation of the solar tracker (1) is blocked when the solar panels (1c) are located in optimal position with respect to the sun and the rotating shaft (1b) is in standby. Therefore, the solar tracker (1) is blocked after each movement sequence of the solar panel (1c) until its optimal position, such that the solar tracker (1) does not experience instability effects due to harsh weather or vibrations due to effects of the wind. Furthermore, this increases the efficiency of the solar tracker (1), since maximum solar energy is harnessed at all times.

[0031] In a preferred embodiment of the invention, the solar tracker (1) comprises a junction box (7), connected to the blocking system (3) and to the tracking system (2) (preferably to both the control subsystem (2a) and the operating subsystem (2b)), likewise comprising a microchip (or equivalent programmable computing means) programmed with a time sequence. Said microchip is therefore configured so that the commands sent by the control subsystem (2a) to the motor (5) are synchronized or coordinated with the position checks of the position sensors. Likewise, the junction box (7) can send unblocking commands to the blocking system (3) so that the rotating shaft (1b) can rotate when the command from the control subsystem (2a) to the motor (5) is executed.

[0032] The junction box (7) is preferably connected to the tracking system (2), to the motor (5), and to the blocking system (3) by means of the corresponding cables (6a, 6b, and 6c). In the embodiment of FIG. 2, the junction box (7) is connected to the control subsystem (2a) by means of a first cable (6a), to the operating subsystem (2b) comprising the motor (5) by means of a second cable (6c), and to the blocking system (3) by means of a third cable (6b). The signals of the control subsystem (2a) therefore pass through the junction box (7) before reaching an intended element, being diverted to the motor (5) either immediately or a delay being generated in the initial signal, depending on the programming of said junction box (7).

[0033] Additionally, in the embodiment of FIGS. 1 and 3, the blocking system (3) is fixed to at least one end support (1d) of the solar tracker (1). However, in other preferred embodiments of the invention, the blocking system (3) can be fixed to any other of the supports (1a) (for example, it has been found that the supports (1a) next to the end support (1d) are also very energy efficient). Furthermore, the blocking system (3) is also connected to the rotating shaft (1b), since it is in charge of blocking or allowing the rotation of the rotating shaft (1b), and with it the solar panel (1c). At the same time, the blocking system (3) is connected to the junction box (7) by means of the cable (6b), wherein the junction box (7) is in charge of sending the blocking or unblocking signal to the blocking system (3) of the rotating shaft (1b).

[0034] FIG. 3 shows an embodiment of the blocking system (3), where it can be observed that the blocking system (3) comprises a hydraulic piston (8) with a solenoid valve (9), wherein the hydraulic piston (8) comprises ends (8a, 8b). The hydraulic piston (8) is thereby fixed to the support (1d) at one end (8a) of the hydraulic piston (8) and is connected to the rotating shaft (1b) at the other end (8b) of the hydraulic piston (8). Namely, the preferred attachment of the end (8b) of the hydraulic piston (8) to the rotating shaft (1b) is performed by means of a flange-type mechanical part attaching the end (8b) of the hydraulic piston (8) preferably with a protrusion (12) fixed to the rotating shaft (1b), as shown in the embodiment of FIGS. 3 and 4.

[0035] Additionally, it can also be observed in FIG. 3 that the solenoid valve (9) keeps the hydraulic piston (8) blocked and, with it, the rotating shaft (1b) when the solar panel (1c) is located in the optimal position with respect to the position of the sun. The hydraulic piston (8) therefore comprises a variable length (L) that can be extended or reduced as the rotating shaft (1b) rotates when the hydraulic piston (8) is unblocked. Likewise, after each movement of the rotating shaft (1b), the hydraulic piston (8) is preferably blocked again by the solenoid valve (9) with a fixed length (L′). After each movement, the solar tracker (1) is thereby blocked, i.e., protected against the aforementioned harsh weather.

[0036] Additionally, the solenoid valve (9) is connected to the hydraulic piston (8), such that when it receives the signal from the junction box (7), the solenoid valve (9) opens or closes, allowing the oil to flow through the hydraulic piston (8) and allowing the hydraulic piston (8) to be extended or reduced, varying the length (L) and allowing freedom of rotation of the rotating shaft (1b).

[0037] In a preferred embodiment of the invention, the junction box (7) additionally comprises a diode rectifier bridge, which ensures the maintenance of polarity in the blocking elements (for example, through the solenoid valve (9)), so that reverse currents can be controlled in the blocking system (3). The output of said rectifier bridge is preferably filtered by an inductor and a capacitor and, even more preferably, the entire circuit is protected by a resettable fuse, whose functionality can be programmed to reset after a period of time.

[0038] In those embodiments in which the motor (5) has low power or insufficient capacity, the derivation box (7) may further comprise an auxiliary battery, adapted to power the blocking system (3). Even more preferably in these embodiments, the junction box (7) can be equipped with a charge controller, for example of the MPPT (“Maximum power point tracking”) or PWM (“Pulse width modulation”) type by means of which current is received from a solar panel (1c) and the battery is recharged or maintained.

[0039] In different embodiments according to the previous examples, it is also possible to isolate the control stage and the power stage comprised in the circuit of the junction box (7) with insulating elements or assemblies selected from any of those known in the state of the art.

[0040] Likewise, in another preferred embodiment of the invention according to FIG. 5, the blocking system (3) comprises two preferably reciprocating hydraulic pistons (8) (i.e., when the length of one increases, the length of the one decreases), and more preferably arranged in the form of a V, connected to a support (1a, 1d) at the lower portion thereof (for example, by means of a flat bar (11)) and to the rotating shaft (1b) at the upper portion thereof, for example being connected to said rotating shaft (1b) through a rocker arm (4) which allows transmitting the force of said hydraulic pistons (8) by angularly orienting the rotating shaft (1b) and blocking the position thereof under a given tilt angle.

[0041] In this same embodiment, the hydraulic pistons (8) are preferably connected by means of a hose (10) communicating the oil chambers thereof, therefore allowing the passage of oil from one piston (8) to another. The solenoid valve (9) is preferably arranged in this hose (10), and it will be in charge of allowing or retaining the passage of oil, such that when the valve (9) is closed (provided that electrical current does not reach it, for example if it is a normally closed valve (9)), the blocking system (3) will be in the blocked position, since the flow of oil from one hydraulic piston (8) to another is not allowed, therefore impeding the movement of the rods or ends (8b) inside the cylinders (8). Likewise, when the motor (5) of the solar tracker (1) starts to operate, the valve (9) opens, in turn opening the oil circuit between the hydraulic pistons (8).

[0042] In another preferred embodiment of the invention, the blocking system (3) has a safety subsystem in case the solenoid valve (9) fails and cannot open, or in case there is an electrical failure between the connection between the junction box (7) and the valve (9). Said safety subsystem preferably comprises a pressure-limiting valve, for example one that operates mechanically, the function of which is to allow the flow of oil between the hydraulic cylinders (8) when pressure therein increases, i.e., when the tracker (1) tries to move its position but the valve (9) has been closed for some reason.

[0043] Preferably, the operation of the solar tracker (1) in any of the embodiments herein described starts by reading the position sensors of the tracking system (2), which check the position of the tracker (1) every so often, wherein the sensors are preferably programmed with the check time desired by the operator. With each position check, if the sensors do not detect movement of the sun with respect to the position of the solar panel (1c), i.e., the solar panels (1c) are in the optimal position, the solar tracker (1) will be kept in standby and the hydraulic pistons (8) blocked. Conversely, if it is detected that the sun has moved, the position sensors send a signal to the control subsystem (2a) to start up movement of the rotating shaft (1b). The power source thereby sends a movement signal to the motor (5), which is also intercepted by the junction box (7). The junction box (7) thereby programs the movement signal of the motor (5) by means of the microchip (or equivalent computing means) and activates the opening of the solenoid valve (9), allowing the release of the hydraulic piston or pistons (8). After the unblocking of said hydraulic pistons (8), the movement signal ends and the junction box (7) commands the motor (5) to act in order to rotate the rotating shaft (1b). The rotating shaft (1b) can therefore rotate because the hydraulic pistons (8) are unblocked and can vary their length (L). The rotation of the rotating shaft (1b) therefore continues until the solar panel (1c) is oriented in its optimal position.

[0044] Finally, by means of position sensors the tracking system (2) determines that the solar panel (1c) is in the optimal position, and then the control subsystem (2a) cuts off power to the junction box (7) and the blocking system (3) is activated, i.e., the solenoid valve (9) closes, blocking the hydraulic pistons (8) with a fixed length (L′), preventing any type of movement of the rotating shaft (1b) and, therefore, of the solar tracker (1).