DESC:FIELD OF THE INVENTION:

The present invention covers a solar tracking system and, in particular relates to a mechanical system coupled with electronically controlled motors for maintaining various solar geometries (solar panel, solar dish, Fresnel etc) in a desired or optimum orientation with respect to the motion of the sun throughout the day.

BACKGROUND OF THE INVENTION:

Solar energy systems need to track the sun to maximize their efficiency for concentrating solar energy systems such as parabolic dish, trough etc., it is necessary to continuously track the sun throughout the day, while for photovoltaic (PV) cells, it is highly recommended for the PV panels to track the sun for higher efficiency.

Various prior art devices have been used to position the collector aligned to the sun’s position throughout the day, ranging from manual adjustment, clockwork adjustment, thermo mechanical adjustment, photoelectric sensors, and combinations of the above. The prior art is available with various mechanical trackers which have either complex designs or designs which needs specifically manufactured parts for the particular tracker. Also, these trackers are not compatible and economically viable for small applications such as solar cookers or low-capacity PV panel for household.

Presently the most effective and simple designs are based on two axes tracking as they are considerably more efficient than the other single axis and polar axis designs and can collect typically 75% - 80% of solar radiations. The two axis designs are typically different from each other in respect of the mechanism used for driving the structure along tracked path and also in respect of the logic used for giving inputs to the prime movers (mostly AC/DC motors / stepper motors). The different logics used are sensor based, complex algorithms, astronomical clock based etc. Such systems can be bulky and quite expensive.

The different mechanism and structures used in the prior art are discussed in U.S. Patent No. 4332238 [P1], 6284968 [P2], European patent EP 2 194 343 A1 [P3] and International Publication No. WO 90/13147 [P4] under Patent Cooperation Treaty (PCT). The sensor-based trackers although are very accurate but fails in condition such has cloudy weather and also are costly. Sensor has disadvantage of dust cover, cloud impact and chance of malfunctioning. The complex algorithms-based designs required costly controllers to process the information and the astronomical clock-based designs require complex gear trains to translate the motion along tracked path all of this adds to the complexity and cost of the system.

The design used in P1 consist of a rotating base in form of a big gear which is rotated by small gear mounted on motor shaft for azimuth tracking and complete collector is pivoted on a U frame with separate motor at the pivot point to rotate the collector for altitude angle tracking. This design has to be inherently big and heavy thus will less efficient and base gear needs to be specially manufactured as per the requirement thus adding to the cost of the design.

Similarly, the design used in P3 consist of big hollow shaft which is fixed to ground using 3 bearing point thus making a tripod shape and the hollow shaft housed and another shaft inside it which is rotated on the central axis using very complex gear train and system of pawls thus giving controlled motion for azimuthally tracking. All of these again adds to the complexity and required component which needs to be specifically manufactured for these trackers.

OBJECTIVES OF THE PRESENT INVENTION:

To overcome some of the problems and shortcoming of the prior art a need exists for new and improved solar tracking subsystem with simplistic and cost-effective design.

It is an objective of this invention to provide a sun tracking system for solar energy systems.

It further objective of the invention to provide a dual axis solar tracking system.

It is yet another objective of the inventionto provide a solar tracking system that comprises tripod shape stand with a T bar assembly and a ring structure pivotal to the horizontal section of T-bar.

It is yet another objective of the inventionto provide a solar tracking system with a tripod stand that can be fixed to the ground and that T-bar assembly can be mounted on the tripod stand by means of guide bushings and thrust bearings along the vertical section of T-bar.

It is yet another objective of the inventionto provide a solar tracking system with a T-bar that can be rotated on its vertical axis by means of electronically controlled DC motor thus providing freedom to track the sun in respect to the solar azimuth angle.

It is the further objective of the invention is to provide a solar tracking system comprising of a base structure pivotal to horizontal section of T-bar that can be rotated about the horizontal axis of T-bar by means of another electronically controlled DC motor thus providing freedom to the track the sun in respect to the zenith angle.

It is the further objective of the present invention is to provide a solar tracking system in which mechanical system is coupled with electronically controlled motors for maintaining various solar geometry (panel, dish, Fresnel etc) in a desired or optimum orientation with respect to the motion of the sun throughout the day.

Further the object of this invention is that the reliable, inexpensive, compact, and accurate means for tracking the position of the sun and it allows ease of assembly and easy mounting on the support structure, portable support and tracking device that can be easily assembled and moved from one location to the other. It is based on simple algorithm (not of sun path diagram) in design by controlling two parameters (time interval and rotation angle) to operate the system accurately.

SUMMARY OF THE PRESENT INVENTION:

This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended to determine the scope of the invention.

To overcome some of the problems and shortcoming of the prior art a need exists for new and improved solar tracking subsystem with simplistic and cost-effective design.

In one of the embodiments, the invention discloses a dual axis solar tracking system comprising;
A dual axis solar tracking system (10) comprising;
a base structure (12) adapted to mount a solar collector (13),
a stand (17) with a T-bar assembly (11) adapted to hold the base structure (12);
wherein the base structure (12) is pivotal to the horizontal section of the T- bar assembly (11);
a first motor (19) adapted to rotate the T-bar assembly (11) on its vertical axis to track the solar azimuth angle;
a second motor (14) adapted to rotate the base structure (12) on the horizontal axis of T-bar assembly to track the solar zenith angle;
wherein the second motor (14) is attached to the base structure (12) by means of a mechanical mechanism (15);
wherein the first motor (19) and the second motor (14) are electronically controlled by a control unit (20);
wherein the control logic for the first motor (19) is based on the time interval for rotation pulses and the degree of rotation in single pulse.
wherein the control logic for second motor (14) is based on the time interval for rotation pulses, the degree of rotation in single pulse, direction of rotation and predefined time duration or time range condition to be checked/met with real time clock.

In yet one of the embodiments, the present invention provides a solar tracking subsystem that comprises a base structure which can mount any solar collector of small capacity such as PV panels for household power, thermal energy storages & solar cookers with parabolic dish or Fresnel lenses etc. The other subsystem such as the small pulley belt or chain sprocket drives or worm gear set which transfer the motion from the stepper motor to the central shaft for azimuth tracking and a separate pivoted motor on central shaft with screw rods for altitude angle tracking.

In yet one of the embodiments, the present invention provides a solar tracking system wherein the logic used for the stepper motors is based on the time interval for rotation pulses and the degree of rotation in single pulse and by controlling these two parameters any level of intermittent tracking can be done.

In yet one of the embodiments, the present invention provides a solar tracking system wherein application such as solar cooker which requires focusing, the sun rays on a relatively large surface rather than in a single point the time interval for the rotation pulse can be set between 2 to 10 minutes and accordingly the degree of rotation can be varied. This allows avoiding usage of complex algorithms or sensor arrays and ultimate huge reduction in cost of the system.

In yet one of the embodiments, the present invention provides a solar tracking system that allow for ease of assembly and easy mounting on the support structure. A portable support and tracking device that can be easily assembled and moved from one location to the other and which is not based on complex algorithm (of sun path diagram) while simple in design by controlling two parameters (time interval and rotation angle) to operate the system accurately. It is further not based on sensors technique to track the sun (sensor has disadvantage of dust cover, cloud impact and chance of malfunctioning).

In yet one of the embodiments, the present invention provides a solar tracking system wherein there is a provision for mounting any collectors of small capacity such as PV panels, thermal energy storages & solar cookers with parabolic dish or Fresnel lenses etc and has a small pay load up to 30 kg and is low Maintenance (not use of sensor, manual adjustment, mechanically operated, thermo mechanical adjustments)

To further clarify the advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

These and other features, aspect, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein the device configurations described in the present invention are explained in more detail with reference to the following drawings:

Figure 1 illustrates a schematic of device illustrating features of tracking mechanism for solar zenith angle
Figure 2 illustrates a schematic of device illustrating features of tracking mechanism for solar azimuth angle.
Figure 3 illustrates a schematic of device illustrating features of a dual axis solar tracking system.

DETAILED DESCRIPTION OF THE INVENTION:
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.

The term “some” as used herein is defined as “none, or one, or more than one, or all.” Accordingly, the terms “none,” “one,” “more than one,” “more than one, but not all” or “all” would all fall under the definition of “some.” The term “some embodiments” may refer to no embodiments or to one embodiment or to several embodiments or to all embodiments. Accordingly, the term “some embodiments” is defined as meaning “no embodiment, or one embodiment, or more than one embodiment, or all embodiments.”

The terminology and structure employed herein is for describing, teaching and illuminating some embodiments and their specific features and elements and does not limit, restrict or reduce the spirit and scope of the claims or their equivalents.

More specifically, any terms used herein such as but not limited to “includes,” “comprises,” “has,” “consists,” and grammatical variants thereof do NOT specify an exact limitation or restriction and certainly do NOT exclude the possible addition of one or more features or elements, unless otherwise stated, and furthermore must NOT be taken to exclude the possible removal of one or more of the listed features and elements, unless otherwise stated with the limiting language “MUST comprise” or “NEEDS TO include.”

Whether or not a certain feature or element was limited to being used only once, either way, it may still be referred to as “one or more features” or “one or more elements” or “at least one feature” or “at least one element.” Furthermore, the use of the terms “one or more” or “at least one” feature or element do NOT preclude there being none of that feature or element, unless otherwise specified by limiting language such as “there NEEDS to be one or more . . . ” or “one or more element is REQUIRED.”

Unless otherwise defined, all terms, and especially any technical and/or scientific terms, used herein may be taken to have the same meaning as commonly understood by one having ordinary skills in the art.

Reference is made herein to some “embodiments.” It should be understood that an embodiment is an example of a possible implementation of any features and/or elements presented in the attached claims. Some embodiments have been described for the purpose of illuminating one or more of the potential ways in which the specific features and/or elements of the attached claims fulfil the requirements of uniqueness, utility and non-obviousness.

Use of the phrases and/or terms such as but not limited to “a first embodiment,” “a further embodiment,” “an alternate embodiment,” “one embodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or variants thereof do NOT necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or alternatively in the context of more than one embodiment, or further alternatively in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.

Any particular and all details set forth herein are used in the context of some embodiments and therefore should NOT be necessarily taken as limiting factors to the attached claims. The attached claims and their legal equivalents can be realized in the context of embodiments other than the ones used as illustrative examples in the description below.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

While the invention is susceptible to various modifications and/or alternative adaptations, specific embodiment thereof has been shown by way of examples and will be described in detail below. However, it should be understood, that it is not intended to limit the invention to the particular structural arrangement disclosed, but on the contrary, the invention is to cover all modifications, structural adaptations and alternative falling within the spirit and the scope of the invention as defined herein.

Figure 3 illustrates an overall layout of the preferred embodiment of present invention illustrating a dual axis solar tracking system (10) according to an embodiment of the present invention. The system (10) is adapted for East-West Rotation & North-South Rotation and continually faces the sun because they can move in two different directions. The system (10) is adapted to follow the sun vertically and horizontally and help obtain maximum solar energy generation.

According to the main embodiment, the dual axis solar tracking system (10) may be adapted to includes a tripod shape stand (17) with a T bar assembly (11) and a base structure (12) that is pivotal to the horizontal section of T-bar assembly (11). The tripod stand (17) can be fixed to the ground and the T-bar assembly (11) may be mounted on the tripod stand (17) by means of guide bushings and thrust bearings and brackets (16) along the vertical section of T-bar assembly (11). In the illustrated embodiment, the base structure (12) may be a ring structure, without departing from the scope of the present disclosure. However, it should be appreciated by a person skilled in the art that it should not be construed as limiting, and the base structure (12) may have any other shape, without departing from the scope of the present disclosure. The base structure (12) may include plurality of brackets (not shown in drawing) adapted to hold any suitable solar collector /device (13) such as photovoltaic panel, parabolic dish, Fresnel concentrator etc.
The dual axis solar tracking system (10) further comprises of DC stepper motors (19, 14) provided at two axes, azimuth angle rotation and zenith angle rotation respectively adapted to provides freedom to track the sun in respect to the solar azimuth angle and zenith angle. The DC motors (19, 14) are controlled by control unit (20) through computer written programs thus giving completed freedom to track the sun continuously or intermittently as required for different application.
Figure 2 illustrates an overall layout of the tracking mechanism of the dual axis solar tracking mechanism for Azimuth Angle (East – West rotation) (10b) according to an embodiment of the present disclosure.
The solar collector (13) such as photovoltaic panel, parabolic dish, Fresnel concentrator etc mounted on the base structure (12) of the dual axis solar tracking system (10) is adapted to be rotated through the T-bar assembly (11) using electronically controlled DC motors (19) which provides freedom to track the sun in respect to the solar azimuth angle.
The tripod stand (17) is adapted to be fixed to the ground and the T-bar assembly (11) is mounted on the tripod stand (17) by means of a mechanical mechanism such as guide bushings and thrust bearings along the vertical section of T-bar assembly (11). The T-bar assembly (11) is thus adapted to be rotated on its vertical axis by means of first electronically controlled stepper DC motors (19) or first motor (19) by a mechanical mechanism, thus providing freedom to track the sun in respect to the solar azimuth angle. The mechanical mechanism to rotate the T-bar assembly (11) may be a worm drive (21) comprising of a worm wheel (18) and a worm gear (18a) driven by the first the electronically controlled stepper motor DC motor (19). The worm drive (21) may be adapted to be self-locking for solar azimuth angle.
The control logic for the stepper motors is based on the time interval for rotation pulses and the degree of rotation in single pulse. Any level of intermittent tracking can be done by controlling these two parameters.
The tracking(10b) of azimuth angle as depicted in figure 2 includes control for angle steps that requires setting the number of whole steps (one whole step is equal to 1.8 degree of motor shaft) to increase or decrease as per need. The increase and decrease button may be provided in the electronic circuit. The time intervals of motor actuation requires to set the time interval for actuating pulses of motor. Minimum 1 sec to maximum 1000 seconds which can be set through increase decrease buttons.
Figure 1 illustrates an overall layout of the tracking mechanism of the dual axis solar tracking system (10) for Elevation Angle/Zenith angle (North – South rotation) (10a) according to an embodiment of the present disclosure.
The base structure (12) is pivotal to the horizontal section of T-bar assembly (11) can be rotated about the horizontal axis of T-bar assembly (11) by means of another electronically controlled stepper motor DC motors (14)/ second motor (14) by a mechanical mechanism thus providing freedom to the track the sun in respect to the zenith angle. The mechanical mechanism (15) to rotate the T-bar assembly may be a belt-pulley, rotary spur gears, screw-rods, rack-pinion gears driven by the second electronically controlled stepper motor DC motor (14).
The rotation of motor (14) shaft is according to 12 different data blocks (each data block consists of 4 data points). The data points have control variables number of whole steps (for motor shaft angular rotation) and time interval (between consecutive actuations of motor). Total time for which each data points are to be executed shall be controlled and can be pre-set such as the direction of motor rotation. The Total time of operation of each data point can also be predefined using time range (time brackets) conditions checked with use of embedded real time clock. Control buttons may be used to set the number of whole steps, time interval for each data point, total time of operation for each data point and direction of rotation may be provided.
Example 1.
Data Point Number of Whole steps (angle) Time Interval Total Time of operation of data points Direction of rotation
1 100 600 sec 5 hours Clockwise
2 70 1000 sec 1 hours Clockwise
3 70 1000 sec 1 hours Anticlockwise
4 100 6000 sec 5 hours Anticlockwise

In the above example 1 of data block there are 4 data points. Two points for Clockwise rotation and two for Anticlockwise rotation. In the first data point of example 1 there are 100 whole steps or angles to be covered per actuation/pulse of the motor in clockwise direction. Each actuation/pulse is separated by a timer interval of 600 sec and these actuation/pulses would continue for total duration of 5 hours. Similarly, the other data points describe setting of different numbers of angle to be covered per actuation/pulse of motor rotation and the time interval between each actuation/pulse and the direction of rotation of motor and the duration till each data point is continues to execute.
The electronically controlled stepper DC motors (19,14) are controlled through computer written programs with the above-mentioned logic thus giving complete freedom to track the sun continuously or intermittently as required for different applications.
The motion is transferred/translated from programmed DC motors to the mounted PV panel or concentrators by means of mechanical mechanisms (18,18a, 15) such as belt-pulley, rotary spur gears, screw-rods, rack-pinion gears etc. The mechanical system can be chosen and optimized to achieve the best cost effectiveness of overall sun tracking system for different application.

Technical advantages of the invention:

The present invention has the following advantage over the prior arts:

1. Novel design that is inexpensive, reliable and accurate for tracking the position of the sun
2. The solar tracking system allow for ease of assembly and easy mounting on the support structure.
3. A portable support and tracking device that can be easily assembled and moved from one location to the other.
4. Not based on complex algorithm (of Sun path diagram) while simple in design by controlling two parameters (time interval and rotation angle) to operate the system accurately.
5. Not based on sensors technique to track the sun (Sensor has disadvantage of dust cover, cloud impact and chance of malfunctioning)
6. Provision for mounting any collectors of small capacity such as PV panels, thermal energy storages & solar cookers with parabolic dish or Fresnel lenses etc.
7. Small Pay load up to 30 kg
8. Low Maintenance (not use of sensor, manual adjustment, mechanically operated, thermo mechanical adjustments)

While specific language has been used to describe the present subject matter, any limitations arising on account thereto, are not intended. As would be apparent to a person in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.

,CLAIMS:1. A dual axis solar tracking system (10) comprising;
a base structure (12) adapted to mount a solar collector (13),
a stand (17) with a T-bar assembly (11) adapted to hold the base structure (12);
wherein the base structure (12) is pivotal to the horizontal section of the T- bar assembly (11);
a first motor (19) adapted to rotate the T-bar assembly (11) on its vertical axis to track the solar azimuth angle;
a second motor (14) adapted to rotate the base structure (12) on the horizontal axis of T-bar assembly to track the solar zenith angle;
wherein the second motor (14) is attached to the base structure (12) by means of a mechanical mechanism (15);
wherein the first motor (19) and the second motor (14) are electronically controlled by a control unit (20);
wherein the control logic for the first motor (19) is based on the time interval for rotation pulses and the degree of rotation in single pulse,
wherein the control logic for second motor (14) is based on the time interval for rotation pulses, the degree of rotation in single pulse, direction of rotation and predefined time duration or time range condition to be checked/met with real time clock.
2. The system as claimed in claim 1, wherein the base structure (12) has a plurality of brackets adapted to hold the solar collector (13).
3. The system as claimed in claim 1, wherein the base structure (12) is a ring structure.
4. The system as claimed in claim 1 wherein the solar collector (13) may be a photovoltaic solar panel, a concentrated photovoltaic panel, parabolic dish, a trough or dish concentrator, a heliostat solar reflector, a solar thermo-concentrator, a thermal energy storage or a fresnel lenses.
5. The system as claimed in claim 1, wherein the means of a mechanical mechanism (15) may be belt-pulley, rotary spur gears, screw-rods, rack-pinion gears.
6. The system as claimed in claim 1, wherein the stand (17) is a tripod.
7. The system as claimed in claim 1, wherein the system (10) is compact and portable.
8. The system as claimed in claim 1, wherein the control unit is flexible and compatible to be connected to motors of different torque ratings.
9. The system as claimed in claim 1, wherein the control unit (20) consist of driver modules for first and second motor and an embedded real time clock.
10. The system as claimed in claim 1, wherein the T- bar assembly is rotated by a worm drive (21) comprising of a worm wheel (18) and a worm gear (18a) driven by the first motor (19).
11. The system as claimed in claim 8, wherein the worm drive (21) is adapted to be self-locking for solar azimuth angle.
12. The system as claimed in claim 1, wherein the transverse motion of the mechanical mechanism (15) by the second motor is adapted for the solar zenith angle.