DESC:FIELD
The present disclosure relates to the field of mechanical engineering. Particularly, the present disclosure relates to the field of solar panels.
DEFINITION
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise.
Backtracking: The term “backtracking” hereinafter refers to a process for reducing the angle which the plane of solar panel makes with respect to the surface of the earth where the solar panel is mounted.
BACKGROUND
Solar panels are mounted on vertical posts for trapping sunlight and converting sunlight to energy. Typically this arrangement is in areas where abundant sunlight is available. However, as a result of the movement of the earth, the direction and alignment of the solar panel with respect to the sun varies with respect to the time of the day, and the day of the year, and the latitude and longitude of the place where the solar panel is fixed. The solar panel is required to be angularly displaced during the day to track the apparent movement of the Sun. The solar panels are angularly displaced so that the sun’s rays are roughly perpendicular to the surface of the solar panel for optimally capturing the maximum solar energy in the panel. This requires the use of a tracking apparatus.
A solar tracker is a device that orients a solar panel, mirrors or lenses toward the sun. Solar trackers are used to minimize the angle of incidence between the incoming sunlight and a photovoltaic panel, thereby increasing the amount of energy produced from a fixed amount of power generating capacity. The angle attained by the solar panel for capturing maximum sunlight at high altitude, affects the high wind withstanding capability of the solar panel thus increasing the chances of damaging the solar panel. In order to prevent damaging of the solar panel during heavy winds, the solar panel is backtracked to zero degrees. The backtracking of the solar panel to zero degrees increases the wind withstanding capabilities of the solar panel.
Further, in conventional apparatus a single critical wind speed is set as a threshold for all angles of tilt of the solar panel. In case if the speed of the wind increases beyond the threshold, then the solar panel is backtracked to zero degrees tilt with respect to the ground. However, backtracking of the solar panel to zero degrees affects the angle of incidence of solar rays on the solar panel, thereby affecting the generation of electricity.
Hence, there is a need of an inclination based backtracking apparatus for a solar tracker that alleviates the aforementioned problems.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide an inclination based backtracking in solar trackers to withstand high wind speed.
Another object of the present disclosure is to provide an inclination based backtracking in solar trackers that is cost effective.
Still another object of the present disclosure is to provide an inclination based backtracking in solar trackers that is not complex.
Yet another object of the present disclosure is to provide an inclination based backtracking in solar trackers that requires less power for operation.
Yet another object of the present disclosure is to provide an inclination based backtracking in solar trackers that requires less maintenance.
Still yet another object of the present disclosure is to provide an inclination based backtracking in solar trackers that reduces the loss of energy due to backtracking.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages an inclination based backtracking apparatus for a solar panel. The apparatus comprises a vertical post, a bearing, a torque tube, a linear actuator, and a backtracking unit. The bearing is mounted on the vertical post. The torque tube is coupled to the bearing and is adapted to facilitate mounting of the solar panel thereon. The torque tube is configured to be angularly displaced with respect to the vertical post. The linear actuator is pivotally mounted on the vertical post and is pivotally connected to the torque tube, the linear actuator is configured to angularly displace the solar panel via the torque tube. In an embodiment, the torque tube is coupled to the bearing via a shaft.
The backtracking unit is configured to detect the speed of wind, and is further configured to control the backtracking of the solar panel based on the detected speed of wind.
In an embodiment, the backtracking unit includes a data repository, a wind speed detection unit, a motor driver, an angle detection unit, and a processing unit.
The data repository is configured to store a look-up table having a pre-determined threshold wind speed tolerance value associated with each angle of tilt of the solar panel. The wind speed detection unit is configured to detect the speed of wind, and is further configured to generate a digital value corresponding to the speed of wind. In an embodiment, the wind speed detection unit includes at least one wind speed sensor and a signal conditioning unit. At least one wind speed sensor is configured to sense the speed of wind and generate a sensed signal. The signal conditioning unit is configured to cooperate with the wind speed sensor, and is further configured to generate a digital value from the sensed signal.
The motor driver is configured to drive the linear actuator. The angle detection unit is configured to detect an angle of the solar panel with respect to the ground, and is further configured to generate an angle value corresponding to the detected angle of the solar panel with respect to the ground.
The processing unit is communicatively coupled with the wind speed detection unit, the data repository, the angle detection unit, and the motor driver. The processing unit includes a crawler and extractor, a comparator, and a computation unit.
The crawler and extractor is configured to receive the angle value, and is further configured to crawl though the look-up table using the angle value to extract a pre-determined threshold wind speed tolerance value associated with the angle value.
The comparator is configured to compare the extracted pre-determined threshold wind speed tolerance value with the digital value corresponding to the speed of wind. The computation unit is configured to compute a backtracking angle value for which the solar panel is adapted to withstand the speed of wind using the digital value corresponding to the speed of wind, when the extracted pre-determined threshold wind speed tolerance value is less than the digital value corresponding to the speed of wind. Further, the motor driver is configured to backtrack the solar panel based on the computed backtracking angle value.
In another embodiment, the computation unit is configured to generate an enable signal for activating a tracking unit which is coupled to the solar panel, when the extracted pre-determined threshold wind speed tolerance value is greater than the digital value corresponding to the speed of wind.
In an embodiment, the apparatus includes a feedback unit. The feedback unit is coupled to the processing unit and the linear actuator. The feedback unit is configured to generate a feedback signal based on the position of the linear actuator, and is further configured to transmit the feedback signal to the processing unit.
In still another embodiment, the processing unit is selected from the group consisting of an ARM processor, a PIC microcontroller, an ASIC (application specific integrated circuit), a microcontroller, an FPGA processor, and a processor.
In an embodiment, the tracking unit is configured to operate in a training mode, a normal mode, an idle mode, wherein:
? in the training mode, the tracking unit is trained using a predetermined formulae to calculate the solar azimuth and zenith angles of the Sun;
? in the normal mode, the tracking unit is configured to track the Sun using the calculated solar azimuth and zenith angles of the Sun; and
? in the idle mode, the backtracking unit is activated.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
An inclination based backtracking in solar trackers of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a schematic view of the inclination based backtracking apparatus;
Figure 2 illustrates a block diagram of a backtracking unit of the inclination based backtracking apparatus of Figure 1;
Figure 3a illustrates a perspective view of a first position of the solar panels of the inclination based backtracking apparatus of Figure 1 indicating maximum operation critical wind speed and maximum tilt;
Figure 3b illustrates another perspective view of a second position of the solar panels of the inclination based backtracking of Figure 1 indicating maximum absolute wind speed and zero degrees tilt;
Figure 4 illustrates a table indicating probability of occurrence of different range of tilt angles; and
Figure 5 illustrates a graph indicating wind speed resistance of a solar panel versus tilt angles of the solar panel.
LIST OF REFERENCE NUMERALS USED IN DETAILED DESCRIPTION AND DRAWINGS
100 – Inclination based backtracking apparatus
105 – Solar panel
110 – Bearing
115 – Torque tube
140 – Linear actuator
145 – Vertical post
200 – Backtracking unit
202 – Processing unit
204 – Motor driver
206 – Wind speed detection unit
208 – Battery
210 – Feedback unit
212 – Data repository
214 – Angle detection unit
DETAILED DESCRIPTION
The present disclosure envisages an inclination based backtracking apparatus for a solar tracker that is designed to overcome the drawbacks of the conventional solar backtracking apparatus. A preferred embodiment of the inclination based backtracking apparatus, of the present disclosure will now be described in detail with reference to the accompanying drawing. The preferred embodiment does not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
Figure 1 illustrates a schematic view of an inclination based backtracking apparatus (100) (hereinafter referred to as “the apparatus 100”) for a solar tracker. Figure 2 illustrates a block diagram of a backtracking unit (200) of the inclination based backtracking apparatus (100). Figure 3a illustrates a perspective view of a first position of a solar panel of the inclination based backtracking apparatus (100) of Figure 1 depicting maximum operation critical wind speed and maximum tilt. Figure 3b illustrates another perspective view of a second position of the solar panel of the inclination based backtracking apparatus (100) depicting maximum absolute wind speed at zero degrees tilt. Figure 4 illustrates a table indicating probability of occurrence of different range of tilt angles and Figure 5 illustrates a graph indicating wind speed resistance of a solar panel versus tilt angles of the solar panel.
The inclination based backtracking apparatus (100) for a solar panel (105) comprises a vertical post (145), a bearing (110), a torque tube (115), a linear actuator (140) and a backtracking unit (200). The bearing (110) is mounted on the vertical post (145). The torque tube (115) is coupled to the bearing (110), and is adapted to facilitate mounting of the solar panel (105) thereon. Further, the torque tube (115) is configured to be angularly displaced with respect to the vertical post (145).
The linear actuator (140) is pivotally mounted on the vertical post (145) and is pivotally connected to the torque tube (115), wherein the linear actuator (140) is configured to angularly displace the solar panel (105) by means of the torque tube (115). In an embodiment, the torque tube (115) is coupled to the bearing (110) via a shaft.
In another embodiment, the linear actuator (140) is fitted to the vertical post (145) via a pivot mount (not exclusively labelled in the figures) and a pivot pin (not exclusively labelled in the figures).
The backtracking unit (200), of the apparatus (100), is configured to detect the speed of wind, and is further configured to control the backtracking of the solar panel (105) based on the detected speed of wind.
In an embodiment, the backtracking unit (200) includes a wind speed detection unit (206), a processing unit (202), a motor driver (204), a battery (208), a data repository (212) and an angle detection unit (214).
The data repository (212) is configured to store a look-up table having a pre-determined threshold wind speed tolerance value associated with each angle of tilt of the solar panel (105). The wind speed detection unit (206) is configured to detect the speed of wind, and is further configured to generate a digital value corresponding to the speed of wind. In an embodiment, the wind speed detection unit (206) includes at least one wind speed sensor (not specifically shown in the figures) and a signal conditioning unit (not specifically shown in the figures). At least one wind speed sensor is configured to sense the speed of wind, and generate a sensed signal. The signal conditioning unit is configured to cooperate with the wind speed sensor to receive the sensed signal, and is further configured to generate a digital value corresponding to the sensed signal.
The motor driver (204) is configured to drive the linear actuator (140) associated with the solar panel (105).
The angle detection unit (214) is configured to detect an angle of inclination of the solar panel (105) with respect to the surface of the ground. The angle detection unit (214) is further configured to generate an angle value corresponding to the detected angle of inclination of the solar panel (105).
The processing unit (202) is communicatively coupled with the wind speed detection unit (206), the data repository (212), the angle detection unit (214), and the motor driver (204).
In an embodiment, the processing unit (202) includes a crawler and extractor, a comparator, and a computation unit.
The crawler and extractor is configured to receive the angle value, and is further configured to crawl though the look-up table using the angle value to extract a pre-determined threshold wind speed tolerance value associated with the angle value.
Further, the comparator is configured to compare the extracted pre-determined threshold wind speed tolerance value with the digital value corresponding to the speed of wind. In an event when the extracted pre-determined threshold wind speed tolerance value is less than the digital value corresponding to the speed of wind, the computation unit is configured to compute a backtracking angle value for which the solar panel is adapted to withstand the speed of wind using the digital value corresponding to the speed of wind. Further, the motor driver (204) is configured to backtrack the solar panel to the backtracking angle value determined by the computation unit.
In another embodiment, when the extracted pre-determined threshold wind speed tolerance value is greater than the digital value corresponding to the speed of wind then the computation unit is configured to generate an enable signal for activating a tracking unit which is coupled to the solar panel (105). In an embodiment, the tracking unit is configured to track the Sun for optimal reception of the solar rays.
In an exemplary embodiment, during a potentially damaging high speed winds, the sensed signal alerts the processing unit (202) to send control inputs to the motor driver (204). In response the motor driver (204) positions the solar panel (105) in an appropriate position with respect to the ground.
In another exemplary embodiment, the figures 3a and 3b show different positions of the solar panel (105) relative to each other. The positions of the linear actuator (140) and the solar panel (105) keep on constantly changing angularly because of the requirement of tracking the sun during the course of the day from sunrise to sunset. The figure 3a depicts a first position of the solar panel (105) wherein the surface of the solar panel (105) is tilted approximately by 50 degrees with respect to the ground thereby making approximately 90 degree angle with the rays of the sun. The dotted line shown in the figure 3a indicates the rays of the sun. The figure 3b depicts a second position of the solar panel (105) wherein the solar panel (105) maintains zero degrees angle of tilt with respect to the ground, thereby maintaining a 90 degree angle approximately with the rays of the sun during noon. The dotted line shown in figure 3b indicates the rays of the sun. The solid line in figure 3a and figure 3b indicates the direction of the wind.
In an exemplary embodiment, on detecting that the wind speed value is greater than the pre-determined threshold value, the processing unit (202) is configured to generate and transmit command signals to the motor driver (204), which further generates control inputs for the linear actuator (140) for orienting the solar panel (105) to an appropriate angle at which the solar panel (105) can successfully withstand the speed of the wind.
In another exemplary embodiment, if the wind speed value is less than the pre-determined threshold value, then the tracking unit is configured to receive at least one position co-ordinate signal and at least one global time signal from the GPS unit (not shown in the figures). After receiving the at least one position co-ordinate signal and the at least one global time signal, the tracking unit is then configured to calculate the solar azimuth and zenith angles of the Sun using the at least one position co-ordinate signal and the at least one global time signal based on the at least one astronomical formula. Subsequent to the position of the Sun, the tracking unit is further configured to generate and transmit tracking signals to the motor driver (204), for moving the linear actuator (140) to orient the solar panel (105) at an appropriate position.
In an embodiment, the tracking unit is configured to operate in a training mode, a normal mode, an idle mode, wherein:
? in the training mode, the tracking unit is trained using a predetermined formulae to calculate the solar azimuth and zenith angles of the Sun;
? in the normal mode, the tracking unit is configured to track the Sun using the calculated solar azimuth and zenith angles of the Sun; and
? in the idle mode, the backtracking unit (200) is activated.
In an embodiment, the duty cycle of the pulses generated by the motor driver (204) changes every day based on an angle of the Sun.
In yet another exemplary embodiment, as illustrated in figure 4 and figure 5, the apparatus 100 has a different predetermined critical wind speed limit for different angles of tilt that the solar panel (105) can withstand. The solar panel (105) has a maximum operating critical wind speed limit of 17 meters per second at 50 degrees angle of tilt and the maximum operating critical wind speed of 47 meters per second at zero degrees angle of tilt. As soon as the wind speed increases above the critical wind speed limit, the apparatus (100) enables backtracking of the solar panel (105), i.e., the angle of tilt of the solar panel (105) is reduced to an appropriate angle with respect to ground such that the solar panel (105) can withstand the current wind speed. In an embodiment, it can be observed that the probability of occurrence of 50 degrees of tilt of the solar panel with respect to the ground is only 3.75 % for which the major designing of the solar panel is done. The advantage of this can be taken to determine the maximum wind speed resistance at each angle of inclination.
In an embodiment, if the wind speed of 18 meters per second occurs once in three months (hypothetical data), then the probability of backtracking in any month is one in three. However, in case of inclination based backtracking, the calculation is as follows,
Probability of occurrence of 45-50 degree of tilt is 3.75% i.e. 1 in 26.67.
Total probability = (1/26.67)*(1/3) = 1 in 80.
So the probability of backtracking is reduced dramatically in this case from 1:3 to 1:80.
In an operative configuration, if the angle of the solar panel (105) with respect to ground is 50 degrees and in case if the wind speed increase to 25 meters per second, which is greater than the maximum critical pre-determined wind speed of 17 meters per second at 50 degrees of tilt. The apparatus (100) enables backtracking of the solar panel (105) and subsequently reduces the angle of the solar panel (105) from 50 degrees to a suitable angle which in this case is around 15 degrees with respect to the ground so that the solar panel (105) can withstand the current wind speed of 25 meters per second.
In an embodiment, the apparatus (100) further includes a feedback unit (210). The feedback unit (210) is coupled to the processing unit (202) and the linear actuator (140). The feedback unit (210) is configured to generate a feedback signal based on the position of the linear actuator (140), and is further configured to transmit the feedback signal to the processing unit (202).
In another embodiment, the processing unit (202) is selected from the group consisting of an ARM processor, a PIC microcontroller, an ASIC processor, a microcontroller, an FPGA processor and a microprocessor.
In an embodiment, the apparatus (100) is powered by an auxiliary solar panel. The auxiliary solar panel acts as a primary power source for the apparatus (100). Further, the battery (208) is provided as a secondary power source for the apparatus (100) which provides power to the apparatus (100) to operate independently for 4-5 days.

TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of an inclination based backtracking apparatus for a solar tracker that:
• provides backtracking of the solar panels to withstand high wind speed;
• is not complex;
• is cost effective;
• reduces loss of energy due to backtracking;
• requires less power for operation; and
• requires less maintenance.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:1. An inclination based backtracking apparatus (100) for a solar panel (105), said apparatus (100) comprising:
a vertical post (145)
a bearing (110) mounted on said vertical post (145);
a torque tube (115) coupled to said bearing (110) and adapted to facilitate mounting of said solar panel (105) thereon, said torque tube (115) configured to be angularly displaced with respect to said vertical post (145);
a linear actuator (140) pivotally mounted on said vertical post (145) and pivotally connected to said torque tube (115), said linear actuator (140) configured to angularly displace said solar panel (105) via said torque tube (115); and
a backtracking unit (200) configured to detect the speed of wind, and further configured to control backtracking of said solar panel (105) based on the detected speed of wind.
2. The apparatus as claimed in claim 1, wherein said backtracking unit (200) includes:
o a data repository (212) configured to store a look up table having a pre-determined threshold wind speed tolerance value associated with each angle of tilt of said solar panel (105)
o a wind speed detection unit (206) configured to detect the speed of wind, and is further configured to generate a digital value corresponding to the speed of wind;
o a motor driver (204) configured to drive said linear actuator (140);
o an angle detection unit (214) configured to detect an angle of said solar panel with respect to the ground and is further configured generate an angle value; and
o a processing unit (202) communicatively coupled with said wind speed detection unit (206), said data repository (212), said angle detection unit, and said motor driver (204), said processing unit (202) includes:
? a crawler and extractor configured to receive said angle value and is further configured to crawl though said look up table using said angle value to extract a pre-determined threshold wind speed tolerance value associated with said angle value;
? a comparator configured to compare said extracted pre-determined threshold wind speed tolerance value with said digital value corresponding to the speed of wind; and
? a computation unit configured to compute a backtracking angle value for which said solar panel is adapted to withstand said speed of wind using said digital value corresponding to the speed of wind, when said extracted pre-determined threshold wind speed tolerance value is less than said digital value corresponding to the speed of wind;
wherein said motor driver (204) is configured to backtrack said solar panel based on said computed backtracking angle value.
3. The apparatus as claimed in claim 2, wherein said computation unit is configured to generate an enable signal for activating a tracking unit coupled to said solar panel (105), when said extracted pre-determined threshold wind speed tolerance value is greater than said digital value corresponding to the speed of wind.
4. The apparatus as claimed in claim 2, wherein said apparatus (100) includes a feedback unit (210) coupled to said processing unit (202) and said linear actuator (140), said feedback unit (210) is configured to generate a feedback signal based on the position of said linear actuator (140), and is further configured to transmit said feedback signal to said processing unit (202).
5. The apparatus as claimed in claim 2, wherein said processing unit (202) is selected from the group consisting of an ARM processor, a PIC microcontroller, an ASIC (application specific integrated circuit), a microcontroller, an FPGA processor, and a processor.
6. The apparatus as claimed in claim 3, wherein said tracking unit is configured in a training mode, a normal mode, an idle mode, wherein:
? in said training mode, said tracking unit is trained using a predetermined formulae to calculate the solar azimuth and zenith angles of the Sun;
? in said normal mode, said tracking unit is configured to track the Sun using said calculated solar azimuth and zenith angles of the Sun; and
? in said idle mode, said backtracking unit (200) is activated.
7. The apparatus as claimed in 1, wherein said wind speed detection unit (206) includes:
? at least one wind speed sensor configured to sense speed of wind and generate a sensed signal; and
? a signal conditioning unit configured to cooperate with said wind speed detector and is further configured to generate a digital value from said sensed signal.
8. The apparatus as claimed in 1, wherein said torque tube (115) is coupled to said bearing (110) via a shaft.