FIELD OF THE INVENTION

The present invention relates to a solar tracking array. More specifically, the present invention relates to a solar tracking array which supports one or more photovoltaic panels and is capable of rotating the array about one or more axes using an actuator and drive assembly.

BACKGROUND OF THE INVENTION

Solar tracking devices to be used in conjunction with photovoltaic panels are well known in the art, with many types of configurations already available. So called static devices include a fixed structure supporting one or more photovoltaic panels in a fixed angled position relative to the sun. These devices are relatively simple to erect and maintain, but have disadvantages in terms of the low overall efficiency of the supported photovoltaic panels. This is because the face of the photovoltaic panel is not perpendicular to that of the rays from the sun for the majority of the daylight hours. Additionally, these types of devices are vulnerable to the elements and can be damaged by excessive gusts of wind, hail, rain and the like.

In order to overcome these disadvantages, various tracking devices have been designed which allow photovoltaic panels to be orientated along at least one axis. In this regard, and for future reference, the following inertial frame will be used to describe and define direction and orientation:

Z (Down)

For linear tracking devices, rotation is only possible about one of the above mentioned axis. More often than not, they are arranged along an axis running either from North to South (X axis) or East to West (Y axis). In the first instance, a roll about the X axis allows the photovoltaic panels to track the sun in its movement from East to West whereas in the second (less preferable) instance a pitch about the Y axis allows tracking of the sun from the horizon to its zenith. In either case, the overall efficiency of linear tracking devices is better than static devices as the angle of incidence is closer to the desired perpendicular angle.

One benefit of such linear tracking devices is that numerous panels can be supported along the rotating axis (X or Y as the case may be) and this has a substantial cost benefit. However; this linear system may not be optimally efficient as no provision is made for rotation about the Z axis (yaw), which would enable the device to rotate the photovoltaic panels in an East to West direction.

In terms of the prior; United States Patent No. 6,058,930 teaches of a ganged single axis solar tracker system, wherein multiple solar trackers are linked together with a linear motion linkage and operated by a single linear actuator, such as a screw jack, attached to a separate foundation located away from the solar tracker system. An advantage of such an array is that the costs of motor and drive system are shared by multiple tracker rows. However, an important disadvantage of this system is that both the linkage member and the drive has to withstand significant and often fluctuating wind loads on the entire tracker array, which necessitates the use of exceedingly expensive building materials and complicated drive systems to maintain a stable angle of incidence on the photovoltaic panel. Further, play in any of the linkages will tend to degrade performance of the entire system. As such, tight tolerances are needed for all the moving parts. Therefore, such systems become both less economic and efficient as the size of the tracker system increases and are often completely unsuitable for use in environments that experience strong and/or fluctuating wind gusts.

Chinese Patent Application No. CN102968127(A) discloses a linear driving device for a solar tracker comprising an outer tube and a sealing end cover arranged at the end portion of the outer tube; a screw arranged in the outer tube with one end of the screw being connected to a drive mechanism; a transmission nut in threaded match with the screw is arranged on the screw and a telescopic rod is arranged between the outer tube and the screw. One end of the telescopic rod is connected with the transmission nut, with the other end of the telescopic rod penetrating through the sealing end cover for connecting with a solar panel support member. It is to be noted that CN102968127(A) acknowledges the fact that corresponding structural design should be performed on the aspects of deflection, load resistance and protection for the device according to the using environment of the solar tracker. The disadvantage of providing further structural reinforcement is expected as telescopic rods' tensile strength are by its very nature inferior to that of a rigid solid member. Furthermore, it is a significant disadvantage that the construction of the solar track system which is to use the drive system is not standardized which increases manufacturing and installation costs.

Another commonly known alternative solution involves so-called dual-axis trackers. Such trackers have two degrees of freedom that act as axes of rotation. This allows for the tracker to rotate the photovoltaic panels about the Z axis (yaw) and about the Y axis (pitch) in relation to wherever the sun may be. It is obviously also possible that other combinations of axis can be used. This allows for an optimum angle of incidence between the face of the panels and the sun's rays resulting in the most efficient capturing of solar energy. It is, however, a disadvantage of such dual axis systems that the photovoltaic panels have to be spaced sufficiently far from each other in order to avoid one photovoltaic panel's shadow from falling on an adjacent photovoltaic panel. A further disadvantage is that such dual-axis devices require expensive machinery and, compared to single-axis devices, results in substantially higher maintenance and initial capital outlay costs. Increased overall efficiency of such dual-axis trackers therefore needs to be weighed up against the higher initial capital outlay and maintenance costs involved in installing such devices.

Given the disadvantages outlined above, there clearly exists a present need for solar arrays capable of both increased efficiency and over static devices and increased mechanical simplicity and durability when compared to existing linear and duel-axis tracking devices.

OBJECTS OF THE INVENTION

It is accordingly an object of the present invention to provide a solar tracking array for supporting and orientating one or more solar photovoltaic panels.

It is a further object of the present invention that the solar tracking array should use fewer parts and rely on simpler mechanisms than existing linear and duel-axis tracking designs, while being more efficient than static devices.

Finally, it is an object of the present invention to provide for a solar tracking array which includes features for protecting the solar photovoltaic panels from inclement weather and other dangers as necessary. SUMMARY OF THE INVENTION

According to the present invention, there is provided a solar tracking array, including:

- at least one photovoltaic panel support frame attached to an elongate member;

- at least one vertical support shaft for pivotally supporting the elongate member;

- the elongate member being supported by the support shaft substantially parallel to the ground;

- the elongate member being rotated along its long axis by a rotating means;

- the rotating means consisting of an actuator attached to the elongate member and a drive assembly attached both to the actuator and the vertical support shaft;

- the drive assembly pivotally attached to the vertical support shaft such that the drive assembly can pivot about an axis substantially parallel to the axis of rotation of the elongate member;

- a portion of the actuator being moved along the long axis of the drive assembly; and

- the drive assembly pivoting as the actuator moves along its long axis to provide a constant distance between the actuator and the portion of the drive assembly to which the actuator is attached.

In an embodiment of the invention, the actuator may be attached to a terminal end of the elongate member.

In a further embodiment of the invention, there is provided for the drive assembly to be a screw drive. In a preferred embodiment of the invention, there is provided for the screw drive to be selected from any one of the group consisting of an acme screw drive, a ball screw drive and a roller screw drive. In a yet further embodiment of the invention, there is provided for the elongate member to be selected from any one of the group consisting of a square tube, round tube, bar, and spaced parallel round bars.

In an embodiment of the invention, there is provided for the solar tracking array to include a further pivoting means for pivoting the photovoltaic panel support frame along a second axis. In a preferred embodiment, the further pivoting means pivots substantially about the Y (pitch) axis.

In a further embodiment of the invention, the pivoting means includes a secondary drive assembly. In a preferred embodiment, the secondary drive assembly is attached to the elongate member. In a yet further embodiment, the drive assembly is connected to a secondary actuator attached to the photovoltaic panel support frame.

In a yet further embodiment of the invention, there is provided for the drive assembly to be a screw drive. In a preferred embodiment of the invention, there is provided for the screw drive to be selected from any one of the group consisting of an acme screw drive, a ball screw drive and a roller screw drive. In a further preferred embodiment of the invention, the secondary drive assembly engages the secondary actuator via a nut attached to the screw drive. In a further preferred embodiment, the secondary actuator is further connected to a plurality of photovoltaic panel support frames including further pivoting means, such that in operation the action of a single secondary drive assembly to move the secondary actuator pivots a plurality of photovoltaic panel support frames about their Y axes.

In one embodiment of the invention, the drive assembly may include an electrical motor. In another embodiment of the invention, the rotating means is adjustable to a desired rate of rotation. In a yet further embodiment of the invention, the rate of rotation is synchronized to track the sun East to West. In a preferred embodiment of the invention, the rate of rotation is computed by a processor. In a yet further embodiment of the invention, the solar tracking array includes a means to ascertain a geographic location of the device on earth. The means to ascertain a geographic location can be via GPS. In an alternative embodiment, a longitude and/or latitude co-ordinate can be entered directly into the device by a user according to the device's geographical location.

In an embodiment of the invention, the solar tracking array includes an electronic control circuit in communication with the rotating means. In a further embodiment of the invention, the rate of rotation is determined by the electronic control circuit in which astronomic calculations of the exact position of the sun are based on the current time and date and depending on the geographical position of the device.

In an embodiment of the invention, the solar tracking array includes an electronic control circuit in communication with the pivoting means. In a further embodiment of the invention, the rate of pivoting is determined by the electronic control circuit in which astronomic calculations of the exact position of the sun are based on the current time and date and depending on the geographical position of the device.

In a further embodiment, the control circuit includes a sensing means enabling it to accurately determine the position and orientation/s of one or more photovoltaic panel support frames. In a preferred embodiment, these sensing means include a two axis gyro and accelerometer sensor.

The device includes a power supply unit. The power supply unity may be linked to supported photovoltaic panels. In a further embodiment, the power supply unit includes at least one battery to store electrical power. In an embodiment of the invention, the device includes a communications means. In a further embodiment, the communication means links the device to a network. In a further embodiment, the communication means allows for an operator to remotely control the device from a remote location. In yet a further embodiment, the communication means is used to transmit data to a network and/or remote system.

In an embodiment of the invention, the device includes a weather warning system. In a further embodiment of the invention, the weather warning system includes one or more of the following: wind measuring instruments (anemometer), atmospheric pressure instruments (barometer), temperature measuring instruments (thermometer) and/or humidity measuring instruments (hygrometer). In yet a further embodiment of the invention, the weather warning system is located at a remote location. In another embodiment, the weather warning system is in communication with the device via a communication means.

In an embodiment of the invention, in the event that a predetermined weather danger threshold is met by the weather warning system, an override feature provides for the solar tracking function to be overridden. In a further embodiment, the override feature causes supported panels to be rotated into a predetermined safe mode position.

In a yet further embodiment, the override feature includes a restraining means for preventing further movement of the rotating means. In a preferred embodiment of the invention, the safe mode position includes rotating the attached photovoltaic panels so as to harbour most sensitive and/or fragile parts of supported panels from a danger. In particular, in the event of a wind threat, attached panels are positions so as to create the smallest surface area in relation to the direction of the wind and/or winds gusts. Further, in the event of a threat of hail, attached panels are inverted so as to face towards the ground. Yet further, in the event of a threat of excessive snow, the attached panels are orientated so as to lie substantially perpendicular to the ground. In an embodiment of the invention at least two vertical supports support the device. In a preferred embodiment, a first vertical support engages with the rotating means and an at least second vertical support rotatably receives and supports a portion of the elongate member.

In a further embodiment of the invention, the engagement means consists of a reversibly-securable attachment means allowing free rotation of the elongate member along its long axis. In a preferred embodiment, this attachment means consists of a bearing assembly. In a further embodiment, this bearing assembly is in the form of a cradle whose lower bearing surface is attached to the terminal end of the vertical support.

In an embodiment of the invention, the elongate member includes one or more components in order to facilitate the attachment and removal of the elongate member to the vertical supports. In a preferred embodiment, this component is in the form of reversibly attachable sleeves located at the terminal ends of each vertical support.

In a yet further embodiment of the invention, there is provided for a plurality of solar tracking arrays to be in electronic communication with one another.

In an embodiment of the invention, there is provided for a plurality of solar tracking arrays to be mechanically connected to each other.

In a second aspect of the invention, there is provided use of a solar tracking array, substantially as herein described for supporting and orientating one or more photovoltaic panels. These and other objects, features and advantages of the invention will become apparent to those skilled in the art in the following detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, by way of example only, with reference to the accompanying figures in which:

Figure 1 is a perspective view of the solar tracking array of the invention with multiple photovoltaic panels attached to the elongate member;

Figure 2 is a side on view of the solar tracking array with a photovoltaic panel in the horizontal position; Figure 3 is a side on view showing the rotating means with a photovoltaic panel in the horizontal position;

Figure 4 is a side on view showing the rotating means with a photovoltaic panel rotated at an angle;

Figure 5 is a perspective view of the solar tracking array with both a rotating means and a pivoting means;

Figure 6 is a side on view of the solar tracking array with both a rotating means and a pivoting means with the photovoltaic panels in the horizontal position;

Figure 7 is a side on view of the solar tracking array with both a rotating means and a pivoting means with the photovoltaic panels in a pivoted position;

Figure 8 is a magnified and side on view of the pivoting means with the photovoltaic panels in a horizontal position; and Figure 9 is a magnified and side on view of the pivoting means with the photovoltaic panels in a pivoted position.

The presently disclosed subject matter will now be described more fully hereinafter with reference to the accompanying examples, in which representative embodiments are shown. The presently disclosed subject matter can, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the embodiments to those skilled in the art.

DETAILED DESCRIPTION OF THE DRAWINGS

The invention is not limited to the precise details as described herein and it will be appreciated by those skilled in the art that various embodiments are possible without departing from the scope of the invention.

As seen in Figure 1 , a solar tracking array (10) is shown. In this figure, a plurality of photovoltaic panels (12) can be seen supported by the solar tracking array (10). Any number of photovoltaic panels (12) can be supported along a length of the solar tracking array (10) by photovoltaic panel support frames (14) attached to the elongate member (16). The number of photovoltaic support frames (14) that can be ably supported will depend on a number of factors, largely determined by the required torque needed to rotate and maintain the degree of rotation of the photovoltaic panels (12) at any given time.

In Figure 1 , the solar tracking array (10) has been arranged such that the elongate member (16) is aligned in a substantially North/South direction with an axis running along a length of the elongate member (16) being defined as the X axis. It is preferable for the X axis to be arranged such that it lies substantially horizontal with respect to the terrain. The elongate member (16) can be rotated about the X axis and, when rotated, all joined or supported structures rotate with the elongate member (16) to rotate from East to West and vice versa.

The solar tracking array (10) includes a rotating means (18) to, amongst other things, cause such rotation to occur and vertical support shafts (20). The facilitation of such rotation can be achieved in a number of ways including by way of bearings or other means, but is achieved in this embodiment by the use of ball bearing assemblies, with the bearing being capable of rotating even where sections of the elongate member are not in perfect alignment.

A cradle assembly (62) is located at the terminal ends of the vertical support shafts (20) to facilitate such rotating action.

In Figures 3, an example of a rotating means (18) is illustrated. The rotating means (18) consists of an actuator (22) attached to the elongate member (16) and a drive assembly (24). The actuator (22) includes a nut (26) capable of pivoting in order to align with the long axis of the drive assembly.

The drive assembly (24) is pivotally attached to the vertical support shaft (20), and includes a screw (28) to which the nut (26) is threaded. The drive assembly (24) rotates the screw (28), driving the nut (26) along the long axis of the drive assembly (24). As the nut (26) moves along the long axis of the drive assembly (24), the assembly pivots about the attachment point in order to maintain a constant distance between the actuator (22) and the portion of the drive assembly to which the actuator (22) is attached. In this embodiment, this point is where the nut (26) is currently attached to the screw (28). As seen in Figure 4, this overall rotation about the X axis, when the elongate member (16) is arranged in a North/South configuration, allows for an East to West tracking of the sun by the photovoltaic panel support frames (14) and any photovoltaic panels (12) attached thereto from the sun's rising position to setting position. Here, the rotating motion of the elongate member (16) is preferentially facilitated (as mentioned herein above) by a cradle assembly (62) attached to the terminal end of a vertical support shaft (20).

As shown in Figure 5, a further embodiment of the solar tracking array (38) includes a pivoting means (40). The pivoting means (40) allows the photovoltaic panel support frames (14) to pitch and in so doing track the sun from the horizon to its zenith and back to the horizon again.

As shown in Figure 5, a workable arrangement for the pivoting means (40) is shown. In this instance, a secondary drive assembly (42) is attached to the rotating means (18). The second drive assembly (42) is substantially similar to the drive assembly (28) which effects the rotation of the elongate member (16) and is connected to a lever (44) by means of an secondary actuator (46). Attached to a distal end of the lever (44) is a rigid rod (48). The rigid rod (48) mechanically connects the pivoting means (40) to a plurality of photovoltaic panel support frames (14).

Depending on the direction of rotation of the lever (44), the rigid rod (48) can pull an end of a mechanically connected photovoltaic panel support frame (14) toward from the pivoting means, causing the photovoltaic panel support frame (14) to pivot about independent Y axes. Such a pulling action can cause the photovoltaic panel support frame (14) to pivot from a substantially horizontal position (as seen in Figure 8) to an inclined angle (as seen in Figure 9). Conversely, if the direction of rotation of the second drive assembly (42) and lever (44) is reversed, the rigid rod (48) pushes a mechanically connected photovoltaic panel support frame (14) back toward a substantially horizontal position (as shown in Figure 8). Such arrangement also allows for the photovoltaic panel support frame (14) to pivot past the horizontal position such that the photovoltaic panel support frame (14) inclines towards the other direction (not shown).

It is possible that multiple photovoltaic panel support frames (14) can be connected to the rigid rod (48). In doing so, multiple photovoltaic panel support frames (14) can be pivoted simultaneously using only one pivoting means (40). In such instances the secondary actuator (46) or electrical motor (not shown) connected to the secondary drive assembly (42) will be dependent on the required torque and/or power required to maintain the photovoltaic panel support frames (14) at the desired inclination.

In an arrangement as described above using a lever (44), rigid rod (48) and screw drive assembly (42), it is required that the pivoting means (40) remains aligned with the XY plane as this XY plane rotates about the X axis. In other words, the pivoting means (40) rotates at the same rate and the same degree as the photovoltaic panel support frames (14).

This can be achieved by connecting the pivoting means (40) to the tracking means (18).

Provision is made for a power supply unit (not shown) to power the solar tracking array (10) and the further embodiment of the solar tracking array (38). This power supply (not shown) is connected to the rotating means (18) and/or the pivoting means (40). It is also possible that the solar tracking array (10 and/or 38) could be powered by other means, but a preferred scenario is that the battery (not shown) be placed in electrical communication with another photovoltaic panel (not shown) to power the solar tracking array (10 and/or 38) and/or charge the battery (not shown). Such photovoltaic panel (not shown) could be those forming part of the solar tracking array (10 and/or 38) or an independent photovoltaic panel (not shown). A processor (not shown) forming part of the rotating assembly (24) makes the relevant astronomic calculations of the exact position of the sun based on the current time and date, depending on the geographical position of the solar tracking array (10 and/or 38). Alternatively, such calculation can be done at a remote location and transmitted to the drive assembly (24) for action. An important advantage of the present invention is that the solar tracking array (10 and/or 38) is able to orientate photovoltaic panels (12) so as to maximize solar radiation capture. The ability to track the path of the sun from East to West and/or from its rising position to its zenith improves the overall efficiency of the solar tracking array (10 and/or 38).

The computation of the sun's position is dependent on a number of factors, including the date, time, geographical location and relief of the terrain on which the solar tracking array (10 and/or 38) is installed. It is possible that data relating to these factors can be entered in directly into the processor (not shown) at the time of installation of the solar tracking array (10 and/or 38) so that the solar tracking array (10 and/or 38) can operate independently. However, it is also possible that such processor (not shown) can be in communication with a remote computer (not shown) to receive instructions. In this regard, the most preferred means would be for the processor (not shown) to be in wireless communication with the remote computer (not shown). In such an instance, the solar tracking array (10 and/or 38) would require a transmitter and receiver (not shown) in communication with the processor (not shown). The transmitter and receiver would allow for the solar tracking array (10 and/or 38) to remain in communication with a remote computer (not shown) or remote device. Such communication would allow an operator to control the solar tracking array (10 and/or 38) from a remote location.

A further aspect of the invention relates to the protection of the solar tracking array (10 and/or 38) in instances where there is a danger of damage to the solar tracking array (10 and/or 38). Foreseeable dangers emanating from nature include excessive wind speeds, hail and snow or a combination of these. In order to determine whether such danger is probable/imminent, the solar tracking array (10 and/or 38) can include instrumentation to determine the current local weather conditions. Such instrumentation could include an anemometer to determine local wind speeds (gusts and sustained speeds), barometer, to determine air pressure, thermometer etc. such instruments will need to be in communication with the processor (not shown) or with the remote computer. Depending on the solar tracking array (10 and/or 38) in question and how it has been installed, unique thresholds will apply and should a particular threshold be reached, the solar tracking array (10 and/or 38) should ideally automatically orientate the photovoltaic panel support frames (14) to an appropriate safe position.

It is a significant advantage of the solar tracking array (10 and/or 38) that all of the components used in its construction and/or installation are simple and robust, yet when combined to form the solar tracking array (10 and/or 38) provides for an overall optimal efficiency when compared to the prior art. The above solar tracking array strikes a balance between solar energy capturing efficiency, installation and maintenance costs, and overall ease of operation. Furthermore, as all of the components used in the construction and manufacturing of the present invention are standard, any faulty parts/components can be readily replaced.

Whilst only certain embodiments of the instant invention have been shown in the above description, it will be readily understood by a person skilled in the art that other modifications and/or variations of the invention are possible. Such modifications and/or variations are therefore to be considered as following within the spirit and scope of the present invention as defined herein.