Abstract:
An assembly is disclosed for adjusting the position of a solar array or device to enable it to maintain a desired solar energy reception throughout each day&#39;s operation of the assembly. Solar panels are mounted on a first axle and a second axle, and the axles are mutually orthogonal. The assembly also includes a first motor for rotating the array and the panels relative to the first axle in a direction providing azimuth angle position adjustment and a second motor for rotating the array and the panels and the second axle in a direction providing elevation angle position adjustment. The motors are electrically connected to and powered by their respective solar panels. Divider circuits control the current fed into the motors to control the rotational movement in order to control the azimuth and elevation orientation of the panels and also control the orientation of the array so that it continually faces the sun throughout the diurnal operation of the assembly and so that it maintains the desired degree of solar energy reception throughout the day. The orientation of one of the panels enables it to reposition the assembly for operation at each successive sunrise.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     (not applicable) 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     (not applicable) 
     NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT 
     (not applicable) 
     INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ON COMPACT DISC 
     (not applicable) 
     BACKGROUND OF THE INVENTION 
     1) Field of the Invention 
     The invention relates to systems used for enhancing the solar energy received by a solar array and, more particularly, to such systems which maintain the solar array in its desired position of facing the sun throughout diurnal operation of the system using the electrical power generated by a solar panel. 
     2) Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98 
     Worldwide energy demands have been steadily increasing as more people in more countries use energy consuming technologies in their daily lives. Fossil fuel sources of energy have therefore been increasing in cost as a result of this increasing demand. However, many alternatives to non-renewable energy sources such as nuclear energy and wind power devices have not been able to meet this increasing demand with clean, safe and non-polluting methods of utilization. 
     In the current field of exploiting renewable energy sources, there is a great increase worldwide in the use of solar energy facilities that use photovoltaic cells. Photovoltaic cells used for converting sunlight into electrical energy are placed in arrays and used for a variety of purposes. They are used as utility interactive power systems, as power supplies for remote or unmanned sites, as cellular phone switch site power supplies and as housing complex power supplies. Such arrays are able to produce from several kilowatts to over a hundred kilowatts of energy and can be installed wherever there is a reasonably flat area with exposure to the sun for significant portions of the day. 
     Companies producing and designing solar panels are receiving considerable funding from government sources in order to produce more efficient and cheaper designs. It is thus expected that the use of solar panels will become more widespread in the near future as the funding yields the anticipated improvements in solar panel designs. Many of the new designs are expected to be in the chemistry and structural makeup of the photovoltaic cells which are the constituents of the solar panels. 
     The efficiency and output of solar panels have been increased by panel clustering into the smallest possible space by forming large surfaces at a single level. But, this solution hinders panel cooling, reducing their yield due to the temperature increase at a ratio of 0.5% per degree Centigrade. This clustering is further limited due to panel expansion since the support structures are rigid and occasionally surrounded by a frame enclosing them, generating stresses between panels due to nighttime and daytime temperature differences. Such designs also have the important shortcoming of inherent structural instability as a result of asymmetrical static loads which has limited their use. Consequently, other ways of improving the performance of the solar panels have been developed which focus on maximizing the sunlight received by the photovoltaic cells. 
     A general principal is that the power generated by a solar panel depends strongly on the angle between the direction of propagation of solar rays irradiating the panel and a normal to the surface of the panel. Various forms of solar trackers have been developed for use with arrays of panels of photovoltaic cells to optimize the orientation of the solar panels so that it is normal to the direction of propagation of the solar rays throughout the day thereby increasing the concentration of light energy on the panels. 
     One type of conventional tracker used for solar power panels and solar collectors to improve their efficiency mounts the collector on a north-south axis and rotates it from east to west to follow the sun&#39;s apparent movement from sunrise to sunset. Typically, such systems include a pair of photovoltaic cells mounted on the solar collector or panel one cell of which views the eastern quadrant (90 degrees) of the horizon (when the collector and the cell are positioned in a horizontal plane) and the other cell of which views the western quadrant of the horizon. A difference in outputs between the cells indicates an error point at the sun, and thus the outputs of the cells are used to correctly reposition the solar collector. However, such systems are error prone. The presence of clouds and especially a single bright cloud can draw a photocell away from pointing at the sun and cause a drive system to miss-position a collector. 
     Another type of solar tracker system has photovoltaic panels configured in rows supported on a torque tube that serves as an axis. A tracker drive system rotates or rocks the rows to keep the panels as orthogonally oriented (relative to the sun) as possible. Typically, the rows are arranged with their axes disposed in a north-south direction and the trackers gradually rotate the rows of panels throughout the day from an east-facing direction in the morning to a west-facing direction in the afternoon. Subsequently, the rows of panels are manually brought back to the east-facing orientation for the next day. 
     A solar collector arrangement of this type is disclosed in U.S. Pat. No. 6,058,930 to Shingleton. In the Shingleton system, a tracker is associated with at least one row of panels. A north-south oriented torsion tube defines a north-south axis and an array of flat rectangular solar are attached in a generally balanced fashion on opposite sides of the torsion tube. The system uses at least one pier, and the footing of the pier is supported in the earth. A pivot member is affixed to the pier above its footing and the torsion tube is journalled in this pivot member. This permits the array of solar panels to be rotated on the north-south axis to follow the motion of the sun relative to the earth. The Shingleton arrangement is designed to enable the system to tolerate the stresses and loads that are imposed on the components of pier mounted solar array systems. However, an important disadvantage of such arrangements is that since many such conventional pier mounted designs do not track the apparent movement of the sun solar energy collection is not optimum and the panels have to be made larger than otherwise would be deemed necessary in order to improve upon the solar energy received. This basic design thus requires that it be made large which imposes heavy loads on the components thereof rendering them more failure prone than smaller system designs. 
     The most efficient trackers, for absorbing maximum sunlight in a given day, have been multiple axis trackers, which rotate about more than one axis so as to follow both the azimuth variation (progression of the sun&#39;s bearing angle i.e., east to south to west), and the sun&#39;s change in elevation angle from the horizon. These types of trackers can provide annual energy output improvements of 30%. These types of trackers are particularly beneficial to concentrating solar collectors. In such concentrating solar collectors, the received solar radiation is converted into a concentrated radiation beam before it is directed to the solar cells, and such designs are very sensitive to the angle of incidence of the solar radiation. Of the two solar tracker axes, azimuth orientation and elevation (or tilt) orientation, the first is more important since it provides a substantially greater energy production gain. In addition, the azimuth tracking axis can furthermore be easily carried out since it is exclusively a time function and therefore uniform throughout the year. In contrast, the tilt axis varies according to both the elevation changes as the sun moves during the day and the seasonal changes due to the tilt of the earth&#39;s orbit and its tracking is therefore more complex. Consequently, most large trackers presently installed provide only single axis tracking, and conventional multi axis systems presently installed generally have an inordinate degree of complexity. Their complexity presents numerous potential malfunction problems and inaccuracies. Reversing motors and computer driven reversing mechanisms as utilized in some of these systems also add to the cost. Many such systems also utilize very sophisticated and high precision components that must be shielded from environmental elements to which exposed in order to provide a reasonable degree of longevity. The required shielding structures and subsystems add to the cost and also add to the weight of the system necessitating structural reinforcements or higher strength support structures along with higher power motors. 
     Due to the complexity and structural instability problems associated with conventional solar tracking systems in addition to their increased cost, solar panel installations are typically of the fixed position type. They are fixed in a position in which the panels are oriented toward the south, depending on whether the installations are located north or south of the equator. The angle of inclination depends on the latitude of the installation site. But for such solar panel installations that are fixed in position, the exploitation of the solar radiation received is not as high as it otherwise could be since the direction of the perpendicular to the solar panel coincides rarely if ever with the direction of the solar rays on an annual basis. Consequently, the annual energy output of such solar installations is much less than optimal. 
     What is therefore needed is a structurally simple yet accurate system for tracking the sun&#39;s apparent diurnal movement. What is also needed is such a system which is capable of maximizing the solar energy gathering efficiency of the system for which the tracking is provided. 
     BRIEF SUMMARY OF THE INVENTION 
     It is a principal object of the present invention to provide a solar tracker that will continuously and automatically track the sun&#39;s apparent diurnal movement. 
     It is another object of the invention to provide a solar tracker that will automatically reposition the tracker after the end of diurnal operations thereof for optimal reception of the solar rays at the beginning of successive diurnal operations. 
     It is an object of the present invention to provide a simplified solar tracker that is relatively inexpensive and which does not require a high degree of maintenance. 
     It is an object of the present invention to provide a solar tracker that is simple in structure and function so that it has a high degree of reliability. 
     It is an object of the present invention to provide a solar tracker that has relatively few components so that there are few components that can break down or malfunction thereby providing enhanced reliability. 
     It is an object of the present invention to provide a solar tracker that maximizes the duration of solar energy reception of its diurnal operation. 
     It is an object of the present invention to provide a solar tracker that is capable of providing a high degree of accuracy. 
     It is an object of the present invention to provide a solar tracker having a separate drive mechanism and a separate axle for each degree of rotational movement for improved accuracy. 
     It is also an object of the present invention to provide a solar tracker having a separate control subsystem for each degree of rotational movement for improved accuracy. 
     It is an object of the present invention to provide a solar tracker that may be used for various types of solar energy collection applications. 
     It is an object of the present invention to provide a solar tracker for a solar array that may be any suitable desired shape and size. 
     It is yet another object of the present invention to provide a solar tracker assembly capable of operation with substantially uniform tracking sensitivity throughout the year. 
     Basically, the assembly of the present invention utilizes motors powered by solar panels and controlled by other assembly components to track the sun&#39;s apparent diurnal movement. The assembly of the present invention thereby maintains the solar power array as well as any other suitable solar power panel, array or collector for which its tracking function may be used at a desired optimal orientation relative to the solar rays. The solar power array is independent of the solar panel or panels driving the axles. The power panel might therefore be utilized to convert solar energy to generate electricity and/or heat. The assembly utilizes driver solar panels that activate the motors that mechanically rotate the entire system. 
     In operation, when sunlight illuminates a driver solar panel of the tracker, the solar energy is converted to electrical energy which is transmitted to the motor for activation thereof. The motor will rotate the driver solar panel as long as the driver panel is receiving sufficient sunlight to match or exceed the electrical power requirement of the motor. When the solar energy converted into electrical power falls below the threshold power requirement of the motor, the motor stops and thereby the rotation of the driver panel stops. The driver panel thus powers the motor so that it rotates the driver panel to the point at which it is positioned/oriented relative to the solar rays such that the angle of inclination of the solar rays incident thereon yields the desired optimal aggregate solar radiation received by the driver panel, and beyond this point the motor stops The driver panel thus is stopped at an orientation where it does not receive the desired aggregate degree of solar radiation and in effect the driver panel is moved to the point where it is slightly ahead of the earth&#39;s rotation. Subsequently, the earth&#39;s rotation will “catch up” with the driver panel so that it approaches receiving the desired optimal solar radiation at which point the motor starts up and rotates the driver panel but again stops when it goes beyond the point at which the driver panel receives sufficient radiation to power the motor or to turn on activation output controls of associated control components and circuitry. Thus, the start and stop process of the motor continually repositions the driver panel so that the angle of incidence of the solar radiation on its face is ninety degrees, or that deemed optimal. In effect, the assembly of the invention follows the sun by avoiding it. 
     It is a crucial feature of the invention that the panel orientation control positions the panel so that it does not exceed a certain level of solar energy output. However, the power panel, which is generally what the tracker is intended to provide tracking for, need not be at the same orientation and thereby at the same degree of inclination relative to the solar rays as the solar driver (or tracker) panel. Instead, the power panel may be positioned at an angle relative to the solar panel such that the power panel is ahead of the tracker panel with regard to the sun&#39;s diurnal movement. Thus, the power panel may, for example, be positioned so that it is continually receiving the optimal solar energy while the solar tracker panel is receiving less than that optimal amount of energy. Moreover, the power panel may be angularly positioned relative to the solar panel at such a select angle that it receives any desired degree of solar energy relative to the maximal amount that can be received when the solar rays are at a normal angle of incidence on the power panel. 
     In order to ensure that the motor is started and stopped at the precise solar panel orientations which provide the desired energy output, a passive zener circuit is provided to prevent an “overshoot” of the optimal orientation and other spurious motion. The output of the zener circuit can be directly injected into the driving motor. This output can also be directed to a relay that can control the current flow from the driver panel to the motor. The control circuitry and optional relay operate to start the motor when the electrical voltage or current output from the solar panel rises to a predetermined value and stop the motor when it drops below a predetermined value. These components narrow the range of solar energy received and thereafter converted to electrical energy and utilized to power the motor. Consequently, they prevent the panel from being rotated too far beyond the optimal orientation position and additionally can be adjusted to prevent the motor from stopping too far below the optimal orientation position. These components thus effectively function to keep the panel at a desired optimal orientation (and, more specifically, within a desired range of orientation parameters) relative to the sun throughout the day. 
     The solar panel is mounted on a rotatable shaft or axle which is connected to the motor. Preferably, the motor is connected to a base shaft, and the base shaft is affixed to a base structure or ground such that the base shaft does not rotate relative to the base structure or ground. But, the motor rotates relative to the base shaft and thereby the base structure or ground. The base shaft can be vertically upright with the azimuth adjustment primary solar driver panel and motor positioned and affixed so as to enable rotation of the motor relative to the base shaft and thereby the azimuth primary driver panel in an east-west direction so that the azimuth primary driver panel tracks the apparent east-west movement of the sun. This azimuth tracking substantially provided by the azimuth adjustment primary solar driver panel enhances the solar energy collecting capability of the driver panels as well as a solar power array or any other structure which the assembly of the invention may be used for. 
     Since the angle of incidence of the solar rays on the solar panel varies in accordance with the tilt movement of the earth and the daily motion of the sun in the sky from dawn to sunset, second driver (or tracker) panels (more specifically a second pair of driver panels) and motor combination are provided to correct for this type of movement. For this set of components, the rotating shaft or axle is oriented in an east-west direction and can thereby control the elevation of the entire system. The rotating axle is orthogonal to the base shaft or axle so that they, in combination, provide two degrees of movement. Each of the second driver panels and second motor utilize a second control circuit and a second relay which function the same as the first control circuit and first relay. These second components enable elevation angle position adjustment of the panels in order to correct for seasonal changes in the tilt position of the earth. Additionally, the second driver panels as well as the first driver panels are rigidly connected to the rotatable axle. The rotatable axle is rigidly connected to the second motor so that the second motor and rotatable axle rotate both pairs of tracker panels simultaneously. Also, the first motor and base shaft (or axle) rotate the second motor as well as both pairs of panels simultaneously. The elevation adjustment panels and motor combination also correct for changes during the day in the apparent position of the sun relative to its midday position when it is at its highest apparent position in the sky. The initial positioning of the second axle (as well as the entire tracker) need not be set relative to the earth axis. Tilt thus need not be accurately set because the elevation components position the axle relative to the sun&#39;s apparent position and thereby relative to the earth axis as accurately as may be desired. 
     At the end of the day&#39;s operation the assembly is placed in position for the next day&#39;s operation by means of incorporation of an azimuth adjustment return panel. Thus, the assembly components used to provide azimuth position adjustment (or correction) incorporate essentially a pair of panels placed back to back with the panel faces i.e., the surfaces having solar cells to receive the solar rays, at opposite sides thereof. The same azimuth motor can be employed to rotate the rotatable axle and panels from the sunset position to the sunrise position. In effect there are two driver panels using the same motor but at different times of the day. The angle between the back to back panels is selected so that at the end of the day&#39;s operation, one of the pair that has not been illuminated during that day&#39;s operation is positioned for reception of solar rays at sunrise at the desired optimal angle of incidence. Thus, one of the pair that was the “back” (or return) panel during the particular day&#39;s operation is positioned facing the direction of the sun at sunrise for reception of solar rays at the succeeding sunrise at the desired optimal angle of incidence. Thus, the motors rotate the panels to follow the sun&#39;s apparent position in the sky until sunset. Due to the angular positioning of the panels, during operation one of the panels is always shading the other. 
     At sunrise the (return) panel facing east rotates the axles in the opposite rotational direction of the motion during the day. This is achieved by wiring the return panel to the azimuth motor in opposite polarity to the wiring for daylight operation. This electrical arrangement is made possible because of the blocking ability of the zener diodes. The sunrise-to-sunset connection of the panels to the motor and the return connection of the back (return) panel are connected to the same terminals of the azimuth motor with no adverse effect electrically. A little after sunrise, the daytime (primary) panel&#39;s voltage will take control of the motor&#39;s rotation. The reason for the reverse rotational motion is to avoid wrapping wires around axles and other components. Alternatively, sliding brush type contacts can be used to deliver power to the motors. However, if such sliding contacts are used, the motion of the azimuth motor relative to the base shaft can be made in the same direction throughout successive days&#39; operation and not produce wrapping the wires around the axles with 360 degree motion. It should be noted that the elevation adjustment (second) panels at sunset are nearly ideally positioned by mirror symmetry for initial operation at sunrise if the azimuthal position of the panels is set via panel rotation so that the panel faces east at sunrise. This feature is provided by the integral construction of the elevation panels consisting of a pair of panels facing in the same general direction. 
     The faces of each pair of azimuth adjustment panels are facing outwardly and away from each other so that only one of the panel faces can be properly illuminated. Thus, the invention has the important feature that the daily tracking is provided without the necessity of either manual reset, or mechanical or electronic reset at the end of each day. It instead provides fully automatic operation day after day. The tracker invention also has the advantageous features that there are a minimal number of moving parts and a minimal number of components which provide reliability as well as weight savings. These features also enable the entire structural surface area of the assembly to be smaller thereby minimizing vulnerability of the entire installation to wind forces that compromise the practicality of conventional trackers. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a perspective view of a first embodiment of the solar tracker assembly shown connected to a solar array which the assembly is designed to position in accordance with its tracking of the sun&#39;s apparent diurnal movement across the sky. 
         FIG. 2  is a top diagrammatic view of the first embodiment of the solar tracker assembly showing the first embodiment in more detail and also showing the return components thereof. 
         FIG. 3  is a side diagrammatic view of the first embodiment of the solar tracker assembly showing the invention in more detail and also showing the elevation components thereof. 
         FIG. 4  is a block diagram of the first embodiment of the assembly with a schematic representation of the means for controlling the motor component thereof. 
         FIG. 5  is a perspective view of the second embodiment of the solar tracker assembly shown connected to a solar array which the assembly is designed to position in accordance with its tracking of the sun&#39;s apparent diurnal movement across the sky. 
         FIG. 6  is a top diagrammatic view of the second embodiment of the solar tracker assembly showing the second embodiment in more detail and also showing the return components thereof. 
         FIG. 7  is a side diagrammatic view of the second embodiment of the solar tracker assembly showing the invention in more detail and also showing the elevation components thereof. 
         FIG. 8  is a block diagram of the second embodiment of the assembly with a schematic representation of the means for controlling the motor component thereof. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings,  FIG. 1  shows the solar tracker assembly of the invention generally designated by the numeral  10 .  FIGS. 1 and 2  also show the assembly  10  connected to and being used to position a solar power panel array  12  so that the power array  12  is facing the sun throughout the day and so that the solar rays  14  illuminating the solar array  12  are at a desired angle of incidence to provide a desired concentration of solar energy on the solar array  12  and thereby enhance solar ray reception thereof. 
     As shown in  FIGS. 1 and 2 , the assembly  10  of the invention includes an azimuth adjustment primary (or first) driver solar panel  16  consisting of a multiplicity of interconnected solar photovoltaic cells  18 . The driver panel is shown as rectangular but may be of any other suitable shape. The solar panel  16  has a front side or face  20  and a back side  22 . The face  20  is designed for reception of solar energy via solar rays  14  incident thereon. 
     The driver panel  16  is rigidly connected to a second rotatable shaft or axle  44 . A first electric motor  26  is rotatably connected to a first base shaft or axle  24  which in turn is rigidly connected to a secure base or foundational structure so that the axle  24  is rigid relative thereto. The motor  26  is electrically connected to the solar panel  16  via first electric wires or first set of electrical wires  28  so that the panel  16  can provide electric power to the motor  26 . 
     In operation, the driver panel  16  converts solar energy of the solar rays  14  irradiating it to electrical current which it feeds to the motor  26  causing the motor  26  to rotate itself relative to the axle  24  and thereby rotate the panel  16  relative to the base structure. The axle  24  and motor  26  are oriented to rotate to follow the azimuth of the sun. The axle  24  may be set so that it is generally parallel to the earth&#39;s axis (not shown). The motor  26  is set up and connected to the axle  24  such that it rotates the motor  26  and axle  44  and panel  16  in an east to west direction. Thus, the motor  26  rotates itself and the axles  44  and panel  16  away from and ahead of the sun&#39;s apparent movement relative to the earth (and the assembly  10 ). The motor  26  continues to rotate the panel  16  until it no longer receives sufficient electrical energy from the panel  16  to activate or actuate it. The motor  26  and the axle  44  and panel  16  therefore stop with the driver panel  16  at a position where the angle of incidence of solar radiation irradiating it is less than optimal. This angle of incidence a where the driver panel  16  as well as the power panel  12  are stopped may be slightly less than, or substantially less than, perpendicular depending on the particular requirements of the solar power panel or cooker  12  or the application for which the tracker assembly  10  is being utilized.  FIG. 2  illustrates the angle of incidence a formed by the irradiation of the panel  16  by solar ray  14 , and it is representative of that formed by irradiation of other panels as well. The rotational movement of the solar panel  16  relative to and on said first axle  24  essentially functions to allow adjustment of azimuth angle orientation with reference to earth spherical coordinates of the solar panel  16 . This achieves the objective of providing position adjustment of the solar panel  16  such that it corresponds to rotational movement of the earth relative to the sun Additionally, this rotation function thus provides azimuth angle adjustment or tracking for the azimuth panel  16  as well as the power panel  12  and other associated structures. The solar power panel  12  is preferably rigidly connected to the axle  44  via a connector  11  so that rotation of the panel  16  also results in rotation of the power panel  12 . 
     Since the motor  26  is preferably a conventional electric motor, it characteristically may be able to rotate relative to the axle  24  and rotate the axle  44  and azimuth panel  16  throughout a broad range of electrical energy parameters. It is therefore desirable to narrow the range of voltage or amperage fed into the motor  26  and in this manner accurately control the operation of the motor  26 . To accomplish this goal, the assembly  10  incorporates a relay  30  and an azimuth electrical output control means  32 . The electrical output control means  32  preferably controls the voltage from the solar panel  16  being fed into the motor  26  and, more specifically, controls the voltage from the solar panel  16  being fed into the relay  30 . The energizing voltage of the relay is selected so that it is within the energy output range of the panel and the energy requirements of the motor  26 . The electrical output control means  32  feeds electrical current to the relay at a level high enough to energize the relay when the electrical output from the panel  16  is at a predetermined value or at a predetermined range of values. The control means cuts off the electrical current to the relay when the electrical output from the panel  16  is less than that predetermined value or range of values. Alternatively, the control means may cut off the electrical current to the relay when the electrical output from the panel  16  is at or less than another predetermined value or range of values such that there are two critical predetermined values or range of values, one for energizing and one for de-energizing. Since the motor rotates the panel in only one direction which is that in which it tends to attempt to place the panel  16  ahead of the sun&#39;s apparent movement, the fall below the predetermined value will occur when the motor  26  has rotated the panel  16  too far such that the sun&#39;s subsequent apparent movement will result in the panel becoming closer to the optimal position thereby increasing the energy output from the panel and activating the motor  26  again. 
     Preferably, the electrical output control means  32  comprises a voltage divider circuit which preferably includes a first resistor  34 , a second resistor  36  and a zener diode  38 , as shown in  FIG. 3 . The electrical output voltage V is fed to the two resistors  36  and  38  which are connected in series and schematically shown as R1 and R2. The resistor  36  is preferably variable. The voltage across R2 is Vin=V×R2/(R1+R2). This voltage is less than the voltage V generated by the solar panel  16 . When the output voltage V is large enough, the voltage Vin exceeds the zener diode threshold and the relay is activated so that the motor receives sufficient energy for activation and thereby rotation of the axle and solar panel  16 . When the output voltage V drops to the level where Vin drops below the zener diode threshold the current to the relay cuts off and the electrical current to the motor  26  is also cut off so that the motor stops and rotation of the axle and solar panel stops. Upon further movement of the sun and the attendant increase in the voltage V, the zener diode will again conduct tripping the relay and producing motor activation. Setting the value of R2 can be done at the time of construction of the assembly  10  or in the field. 
     The azimuth angle tracking function provided by solar azimuth panel  16 , motor  26  and associated components provides substantial enhancement of the amount of energy the solar panel receives in diurnal periods of operation. However, adjustment for the tilt of the earth on its axis during the year is also desirable to further enhance the solar energy the solar panel receives annually. Elevation angle adjustment is therefore provided by means of elevation adjustment panels (or second pair of panels)  40  and  41  in conjunction with a second motor  42 , the second axle  44 , a second set of electrical wires  46 , a second relay  48  and a second electrical output control means  50 . The pair of preferably identical panels  40  and  41  are angularly positioned with respect to each other. The top panel  40  is tilted upward so that it is oriented to receive sunlight during the early (before noon) daylight hours. The lower panel  41  is preferably tilted downward and positioned underneath the top panel  40  so that it is oriented to not receive sunlight during the early daylight hours but is rather in the shadow of the panel  40  during these early daylight hours. Both panels  40  and  41  are connected to the elevation motor  42  via the set of electrical wires  46  (preferably a pair for each panel  40  and  41 ) but with opposite polarities. From sunrise to solar zenith the top panel  40  energizes the elevation motor  42  to follow the upward rise of the sun. During this time the lower panel is in the shade of the top panel  40 . After noon the sun&#39;s elevation decreases to the point where the upper panel&#39;s active surface goes into the shade and the lower panel&#39;s output takes control of the elevation motor until sunset. It is not necessary for both the panels in the elevation pair to have a common physical connection. The upper and lower panels can be located anywhere along axle  44  or any extension of shaft  44  as long as its angular orientation with respect to the rest of the elements of system  10  is maintained. Similarly, the panel  16  can likewise be located anywhere on axle  44  or any extension of axle  44  as long as its angular orientation with respect to the rest of the elements of system  10  is maintained. The second relay  48 , as with the first relay  30 , has an energizing voltage which is selected to conform to the energy requirements of the second motor  42 . The second electrical output control means  50  preferably comprises a pair of second output control means  50  with one of the pair connected to the panel  40  and the other of the pair connected to the panel  41 . The second output control means  50  includes a first elevation resistor  52 , a second elevation resistor  54  and an elevation zener diode  56 . Alternatively, however, since the solar panels can act as electrical diodes when an external current is fed into them, the panels per se may be substituted for the diodes and thus used to pass electrical current in one direction only and thereby eliminating the need for a diode in the output control means. With such an alternative design, the panels would be electrically connected to suitable resistors and not to diodes. The second output control means  50  (and its components) in purpose and function is the same as the first electrical output control means  32 . The upper solar panel  40 , as with solar panel  16 , has a front side or face  37  and a back side  39 . The face  37  is designed for reception of solar energy via solar rays  14  incident thereon. The lower solar panel  41  similarly has a front side or face  43  and a back side  35 . The face  43  is designed for reception of solar energy via solar rays  14  incident thereon. 
     In operation, the upper and lower panels  40  and  41  convert solar energy of the solar rays  14  irradiating them (depending on the time of day) to electrical current which one of these panels  40  or  41  feeds to the motor  42  causing the motor  42  to rotate the axle  44  and the panel  40  (as well as the panel  16 ). The axle  44  can have any convenient orientation and is preferably tangent to the earth&#39;s surface. The axle also may be oriented so that it is generally perpendicular to the earth&#39;s axis (not shown). The motor  42  is set up and connected to the axle such that it rotates the axle  44  and panels in a north to south as well as a south to north direction depending on which panel is powering it. As the sun&#39;s apparent position in the sky rises in the early daylight hours, the upper panel  40  energizes and activates and powers the motor  42  to rotate the axle  44  and panels upwardly in accordance with the sun&#39;s apparent upward movement. The motor  42  continues to rotate the axles and panel until it no longer receives sufficient electrical energy from the panel  40  to activate or actuate it (at approximately solar zenith or, more preferably, just past solar zenith). As the sun&#39;s apparent position drops after noon, the lower panel  41  comes out of the shadow of panel  42  and provides sufficient electrical energy to power the motor  42 . Due to the opposite polarity connection of the panel  41  to the motor  42 , the panel  41  powers the motor  42  to rotate the axle  44  and panels down as the sun&#39;s apparent position in the sky drops. 
     Basically, the motor  42  rotates the axle  44  and panels  16  and  40  away from and ahead of the sun&#39;s apparent movement relative to the earth (and the assembly  10 ). The motor  42  and the axle  44  and panels therefore stop with the panel  40  at a position where the angle of incidence of solar radiation irradiating it is less than optimal. This angle of incidence where the panel  40  as well as the power panel  12  are stopped may be slightly less than, or substantially less than, perpendicular depending on the particular requirements of the solar power panel or array  12  or the application for which the tracker assembly  10  is being utilized. This rotation function thus provides elevation angle adjustment or tracking for the panel  40  as well as the power panel  12  and other associated structures. Although the drive means are disclosed as electric motors, other alternative electromechanical means such as, for example, an actuator can also be utilized for rotating the axles  24  and  44 . 
     The first axle  24  may be set so that it is parallel to the earth axis. However, it need not be because the elevation angle adjustment provided by the invention  10  compensates for errors in parallel positioning of the first axle  24  relative to the earth axis. Moreover, the elevation angle adjustment components of the invention  10  allow the first axle  24  to be positioned on the installation site without reference to the earth axis. 
     Since at sunset the diurnal rotation of the azimuth primary panel  16  positions it so that it is facing away from the sunrise position of the sun, the assembly  10  incorporates an azimuth return panel  17  to reposition the assembly  10  for the succeeding day&#39;s operation. Thus, the azimuth primary panel  16  and the azimuth return panel  17  together provide proper azimuth angle adjustment during day after day operation. The first pair of panels (or pair of azimuth adjustment panels)  16  and  17  and the second pair of panels  40  and  41  are rigidly secured to each other at edges  25  and  27  thereof so that they maintain their relative angular position. The edge  25  is preferably approximately parallel to earth axis when in operation and preferably located at the east ends or end portions  31  and  33  thereof and, for panels  40  and  41 , the edges  27  are at end portions  47  and  49  thereof. Alternatively, the edge  25  may be other than approximately parallel to earth axis when in operation if the particular application has other angle of incidence requirements. 
     The first set of electrical wires  28  provides electrical connection from the solar panels  16 ,  17  to the motor  26  for providing power thereto. The second set of wires  46  is also included for providing electrical connection from the solar panels  40  and  41  to the motor  42  for providing power thereto. The electrical wires  28  and  46  are also flexible to prevent interference with the operation of the axles  24  and  44  as well as associated structures. 
     The invention  10  has the first pair of panels (or first panels)  16  and  17  as well as the second pair of panels (or second panels)  40  and  41  positioned so that they are at an acute angle relative to each other. That acute angle is a select and specific angle determined by the position of the panels  16  and  40  at sunset and the desired position that the return panel  17  should be placed in at sunrise. The angle may, for example, be twenty-five degrees. The selection of that angle places the azimuth adjustment return panel  17  in position for facing the sun and receiving the solar rays at the optimal angle of incidence (or other desired angle) at sunrise following the end of the diurnal operation of the assembly  10 . During one day&#39;s operation, the panels  16  and  40  are being irradiated and therefore providing electrical power to the respective motors  26  and  42 . As a result of the controlled rotation of the panel pairs and the respective angles of each pair, on the sunrise of the succeeding day the return panel  17  is facing the sun and therefore providing electrical power to the respective motor  26 . The azimuth electrical output control means  32  preferably comprises a pair of azimuth electrical output control means  32  (which are structurally identical to each other) one connected to the panel  16  and the other connected to the panel  17  and both connected to the motor  26 . Since the panel  17  is wired, via respective pair of the first set of electrical wires  28 , with opposite polarity (with reference to the wiring of panel  16 ) to the motor  26 , the panel  17  rotates the motor  26 , axle  44  and panels in the opposite direction from that of the preceding day so that the panel  17  rotates the assembly components back to the position of the prior sunrise and thereby at a position to track the sun&#39;s apparent movement during that day&#39;s operation. Thus, there is no necessity for reset (either manual or by other external means) of the panels at the end of the day&#39;s operation. The assembly  10  automatically positions its components for optimal reception of the solar rays at every succeeding sunrise. In addition, the entire installation may be mounted on gimbals or other suitable mechanical structures capable of allowing bidirectional rotation. 
       FIG. 5  shows the second embodiment of the solar tracker assembly of the invention generally designated by the numeral  110 .  FIGS. 5 and 6  also show the assembly  110  connected to and being used to position a solar power panel array  112  so that the power array  112  is facing the sun throughout the day and so that the solar rays  114  illuminating the solar array  112  are at a desired angle of incidence to provide a desired concentration of solar energy on the solar array  112  and thereby enhance solar ray reception thereof. 
     As shown in  FIGS. 5 and 6 , the assembly  110  of the invention includes an azimuth adjustment primary (or first) driver solar panel  116  consisting of a multiplicity of interconnected solar photovoltaic cells  118 . As with embodiment  10 , the solar panel  116  has a front side or face  120  and a back side  122 . The face  120  is designed for reception of solar energy via solar rays  114  incident thereon. 
     As with embodiment  10 , the driver panel  116  is rigidly connected to a second rotatable shaft or axle  144 . A first electric motor  126  is rotatably connected to a first base shaft or axle  124  which in turn is rigidly connected to a secure base or foundational structure so that the axle  124  is rigid relative thereto. The motor  126  is electrically connected to the solar panel  116  via first electric wires or first set of electrical wires  128  for providing electric power to the motor  26 . 
     In operation, the driver panel  116  is functionally and structurally identical to driver panel  16  of embodiment  10 . Therefore, the description of driver panel  116  and its associated components will not be repeated to promote brevity. 
     Since the motor  126  as with motor  26  is preferably a conventional electric motor, it characteristically may be able to rotate relative to the axle  124  and rotate the axle  144  and panel  116  throughout a broad range of electrical energy parameters. It is therefore desirable as with motor  26  to narrow the range of voltage or amperage fed into the motor  126  and in this manner accurately control the operation of the motor  126 . To accomplish this goal, the assembly  110  incorporates a relay  130  and an azimuth electrical output control means  132 . The electrical output control means  132  and relay  130  are structurally and functionally identical to control means  32  and relay  30  of embodiment  10  so their description will not be repeated. 
     Preferably, the electrical output control means  132  comprises a voltage divider circuit which preferably includes a first resistor  134 , a second resistor  36  and a zener diode  138 , as shown in  FIG. 7 . These components function the same as correspondingly numbered components of embodiment  10  so their description will not be repeated. 
     Elevation angle adjustment is provided by means of elevation adjustment (or a pair of second) solar panels  140  and  141  in conjunction with a second motor  142 , the second axle  144 , a second set of electrical wires  146 , a second relay  148  and a second electrical output control means  150 . The elevation angle adjustment components of embodiment  110  are generally the same as those of embodiment  10 . Similar to embodiment  10 , the pair of preferably identical panels  140  and  141  are angularly positioned with respect to each other. However, these components are different from those correspondingly numbered components of embodiment  10  in that the panels  40  and  41  of embodiment  10  are oriented so that they are angled outwardly relative to the axle  44  whereas the panels  140  and  141  are oriented so that they are angled inwardly relative to the axle  144 . The top panel  140  is similarly tilted upward, but in an opposite direction from panel  40 , so that it is oriented to receive sunlight during the early (before noon) daylight hours. The lower panel  41  is preferably similarly tilted downward, but in an opposite direction from panel  41 . As with embodiment  10 , panel  141  is positioned underneath the top panel  140  so that it is oriented to not receive sunlight during the early daylight hours but is rather in the shadow of the panel  140  during these early daylight hours. As with embodiment  10 , both panels  140  and  141  are connected to the elevation motor  142  via the set of electrical wires  146  (preferably a pair for each panel  140  and  141 ) but with opposite polarities. As with embodiment  10 , from sunrise to solar zenith the top panel  140  energizes the elevation motor  142  to follow the upward rise of the sun. During this time the lower panel is in the shade of the top panel  140 . After noon the sun&#39;s elevation decreases to the point where the upper panel&#39;s active surface goes into the shade and the lower panel&#39;s output takes control of the elevation motor until sunset. It is not necessary for both the panels in the elevation pair to have a common physical connection. The upper and lower panels can be located anywhere along axle  144  or any extension of shaft  144  as long as its angular orientation with respect to the rest of the elements of system  110  is maintained. Similarly, the panel  116  can likewise be located anywhere on axle  144  or any extension of axle  144  as long as its angular orientation with respect to the rest of the elements of system  110  is maintained. The second relay  148 , as with the first relay  130 , has an energizing voltage which is selected to conform to the energy requirements of the second motor  142 . The second output control means  150  preferably comprises a pair of second output control means (each of which is structurally identical to the other)  150  with one of the pair connected to the panel  140  and the other of the pair connected to the panel  141 . The second output control means  150  includes a first elevation resistor  152 , a second elevation resistor  154  and an elevation zener diode  156 . The second output control means  150  (and its components) in purpose and function is the same as the first electrical output control means  132 . The upper solar panel  140 , as with solar panel  116 , has a front side or face  137  for receiving solar radiation and a back side  139 . The lower solar panel  141  similarly has a front side or face  143  and a back side  135 . Unlike panels  40  and  41  of the first embodiment, the sides  139  and  135  are positioned so that they are facing inwardly generally toward each other. The face  143  is designed for reception of solar energy via solar rays  114  incident thereon. The faces  137  and  143  are oppositely positioned such that they face outwardly and generally away from each other. Although the drive means are disclosed as electric motors, other alternative electromechanical means can be utilized for rotating the axles  124  and  144 . 
     The operation and function of the upper and lower panels  140  and  141  are the same as of upper and lower panels  40  and  41  of embodiment  10 . Therefore, the description thereof will not be repeated to promote brevity. 
     The first axle  124  may be set so that it is parallel to the earth axis. However, it need not be because the elevation angle adjustment provided by the invention  110  as with embodiment  10  compensates for errors in parallel positioning of the first axle  124  relative to the earth axis. 
     As with embodiment  10 , embodiment  110  also includes an azimuth adjustment return panel  117  which functions in conjunction with panel  116 . The first pair of panels  116  and  117  and the second pair of panels  140  and  141  are rigidly secured to each other at edges  125  and  127  thereof so that they maintain their relative angular position. The edge  125  is preferably approximately parallel to earth axis when in operation and preferably located at the east ends or end portions  131  and  133  thereof and, for panels  140  and  141 , the edges  127  are at end portions  147  and  149  thereof. Alternatively, the edge  125  may be other than approximately parallel to earth axis when in operation if the particular application has other angle of incidence requirements. 
     The first set of electrical wires  128  provides electrical connection from the solar panels  116 ,  117  to the motor  126  for providing power thereto. The second set of wires  146  is also included for providing electrical connection from the solar panels  140  and  141  to the motor  142  for providing power thereto. The electrical wires  128  and  146  are also flexible to prevent interference with the operation of the axles  124  and  144  as well as associated structures. 
     As with embodiment  10 , the invention  110  has the pair of panels  116  and  117  as well as  140  and  141  positioned so that each pair are at an acute angle relative to each other. That acute angle is a select and specific angle determined by the position of the panels  116  and  140  at sunset and the desired position that the return panel  117  should be placed in at sunrise. The angle may, for example, be twenty-five degrees. The selection of that angle places the return panel  117  in position for facing the sun and receiving the solar rays at the optimal angle of incidence (or other desired angle) at sunrise following the end of the diurnal operation of the assembly  110 . During one day&#39;s operation, the panels  116  and  140  are being irradiated and therefore providing electrical power to the respective motors  126  and  142 . As a result of the controlled rotation of the panel pairs and the respective angles of each pair, on the sunrise of the succeeding day the return panel  117  is facing the sun and therefore providing electrical power to the respective motor  126 . The azimuth electrical output control means  132  preferably comprises a pair of azimuth electrical output control means  132  one connected to the panel  116  and the other connected to the panel  117  and both connected to the motor  126 . Since the panel  117  is wired, via respective pair of the first set of electrical wires  128 , with opposite polarity (with reference to the wiring of panel  116 ) to the motor  26 , the panel  117  rotates the motor  126 , axle  144  and panels in the opposite direction from that of the preceding day so that the panel  117  rotates the assembly components back to the position of the prior sunrise and thereby at a position to track the sun&#39;s apparent movement during that day&#39;s operation. Thus, there is no necessity for reset (either manual or by other external means) of the panels at the end of the day&#39;s operation. In both embodiments  10  and  110 , the assembly ( 10  and  110 ) automatically positions its components for optimal reception of the solar rays at every succeeding sunrise. In addition, the entire installation may be mounted on gimbals or other suitable mechanical structures capable of allowing bidirectional rotation. 
     Accordingly, there has been provided, in accordance with the invention, an assembly which provides solar tracking and azimuth angle as well as elevation angle adjustment for enhanced annual tracking efficiency and which provides daily automatic solar tracking throughout annual usage thereof and thus fully satisfies the objectives set forth above. It is to be understood that all terms used herein are descriptive rather than limiting. Although the invention has been specifically described with regard to the specific embodiment set forth herein, many alternative embodiments, modifications and variations will be apparent to those skilled in the art in light of the disclosure set forth herein. Accordingly, it is intended to include all such alternatives, embodiments, modifications and variations that fall within the spirit and scope of the invention as set forth in the claims hereinbelow.