Two-Axes Solar Tracker System and Apparatus for Solar Panel and Likes
The present invention relates to a simplified and lower cost two-axes tracker for solar PV (photovoltaic) or CPV (concentrated photovoltaic) solar panel, as well as heliostat solar reflectors and solar Stirling engine. In particular, the disclosure addresses a simplified and gravity centered tracker structure with low cost single or dual linear actuators mounted on the side of ground post which is easier for replacement and maintenance at lower cost.
This application is based on and claims benefit of U.S. Provisional Application Ser. No. 61/274,927, filed on Aug. 24, 2009.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates to a simplified and lower cost two-axes tracker for solar PV (photovoltaic) or CPV (concentrated photovoltaic) solar panel, as well as heliostat solar reflectors and solar Stirling engine. In particular, the disclosure addresses a simplified and gravity centered tracker structure with low cost single or dual linear actuators mounted on the side of ground post which is easier for replacement and maintenance at lower cost.
2. Description of the Prior Art
Photovoltaic solar panels are gradually becoming a fixture on roof tops in residential street. The sun exposure to fix panel on the roof is proportional to sine of sun elevation angle to the panel. In other words, solar collection on horizontal flat panel at sunrise and sunset are near zero at lowest elevation angle. At 34 degree latitude location, solar panel could collect 49% more power if mounted on a two-axes solar tracker relative to a horizontal fixed panel. The PV panels commonly seen on residential roof are not practical to have a solar tracker. In a solar farm, mounting photovoltaic solar panels on a tracker is feasible if the tracker cost is not predominant. In CPV (Concentrated Photovoltaic) systems, the solar panels must face the sun directly to concentrate solar beam with optical accessory. The cost of traditional two-axes tracker constitute a major cost item for PV and CPV systems. In PV systems, if the solar tracker cost more than half of the solar panels cost, it might be as well ignore the solar tracker since the improvement does not worth the investment. In addition, moving parts of solar tracker has lower reliability than fixed parts. However, it is mandatory for CPV systems to collect sun rays perpendicular to the panel to function properly.
In concentrated solar thermo power (CSP) applications, solar trackers are also used to reflect and concentrate sun rays to a center chamber. A great number of solar reflectors are attached to two-axes trackers in a large field to collect the solar energy focusing on a centralized heating chamber of water or molten salt for turbo engine electricity generation. Such large solar plant is commonly called “heliostat”. The cost of solar trackers constitutes a major portion of total cost for heliostat farm. In yet another field of application, the solar thermo Stirling engine also needs two-axes sun tracking to collect concentrated solar rays to heat up the Stirling engine in order to generate electricity. This disclosure will benefit the solar thermo concentration with its simplified installation, lower parts cost, lower maintenance and longer durability for a large solar farm.
A typical two-axes solar tracker consists of a ground post secured to the ground structure with concrete base. A better ecological ground post uses a helical pile post drilling directly into the ground without concrete base. On top of the ground post, a slewing drive is mounted to support the weight of solar panel and azimuth rotation at the same time. On top of the slewing drive, a linear actuator is attached between the slewing drive and solar panel structure for the lifting of solar panel in the elevation direction. Two axes of motions in azimuth and elevation will drive the solar panel to face the sun directly.
However, there are a few drawbacks with a traditional tracker. 1) The slewing drive not only has to support the entire weight of the panel, but also has to bear the lateral force and torque caused by constant tilting and the wind load on the solar panel. 2) The weight of solar panel and torque caused by the lateral force makes the size of slewing drive highly dependant on the size and weight of solar panel. The components of worm drive and the rotating gear must be packaged together with the ball bearings which support the entire weight and torque applied to the slewing drive, which makes the slewing drive very bulky. 3) If any fault occurred in the slewing drive, the entire solar panel has to be dismantled in order to repair or replace the slewing drive. 4) With the lifting mechanism of a single solar panel by the linear actuator, the center of gravity of solar panel with respect to the pivoting point of slewing drive is constantly changing which mandate the slewing drive to carry the maximum torque possible. Therefore, the slewing drive and the linear actuator must be designed for the maximum torque and lateral force of the tilted panel, which makes a traditional two-axes tracker very bulky and costly. This disclosure proposes a simplified solar tracker at a very low cost, light weight and low maintenance for the benefit of coming solar energy revolution.
BRIEF SUMMARY OF THE INVENTIONWith the above mentioned deficiencies, the subject disclosure may resolve some or all of the issues related to a traditional two-axes tracker. In the first aspect of the invention, the disclosed two-axes tracker is designed to keep the solar panel weight and lateral force away from the azimuth and elevation drives. The weight of the solar panel will sit on top of rotating head, which is looping directly on top of the ground post with upper and lower bearings fitting in-between. The rotating head and bearings not only carry the entire panel weight in the vertical direction, but also leveraged on the torque caused by the wind load of solar panel in the lateral direction. In addition, the upper and lower bearings are selectively using low cost, maintenance free bushing materials for long term usage. Therefore, the azimuth drive, which is attached to the side between the lower post and upper rotating head, is free from both the vertical (gravitational weight) and lateral torque of the solar panel. Hence, the azimuth drive demands very little force for turning the entire solar panel.
In another aspect of the disclosure, the solar tracker will be divided into two sections of equal weight carried by a horizontal beam (tubing) with center of gravity on top of the cylindrical rotating head. Each section of the solar panels are also balanced on the horizontal beam, enabling rotation of two solar panel sections around the center line of gravity on the horizontal beam freely. Therefore, the elevation drive of the solar panel also demands very little force for rotation similar to the azimuth drive.
In another aspect of the disclosure, the azimuth and elevation drivers can be mounted as an accessory to the side of the ground post and rotating head with nuts and bolts, which can be easily installed, removed, replaced in routine maintenance by a single person. This is the major difference from the traditional tracker, where the slewing drive is located at the center between the ground post and solar panel. If anything happen to the slewing drive, the entire solar panel has to be removed or dismantled. By attaching the azimuth drive on the side proposed by this disclosure, it can extend the life of solar tracker by routine maintenance or replacement of low cost linear actuator.
In yet another aspect of the disclosure, the two-axes solar tracker is designed with a wind lock device which can be activated whenever a strong wind exceeds a threshold. The wind lock device uses electromagnetic force to lock up the solar tracker in wind neutral position firmly on the ground post using two electromagnetic activated locks. This will bear the vibration and pounding of solar tracker exercised on the linear actuators during strong wind. Furthermore, in windy areas with constant blowing wind, this wind lock device can be used in a stepwise wind lock to protect the linear actuators between activations. This will greatly prolong the life span of linear actuator and the solar tracker from wind abuse.
These and other features, aspects and advantages of the present disclosure will become understood with reference to the following description, appended claims and accompanying figures.
Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.
Tracker Supporting StructureAs shown in
Alternative to flanged bushing 22 is using a single piece tapered roller bearing 19, or using a combination of thrust roller bearing 18 on the top and a cylindrical bushing identical to 34 at the side wall. However, the top end of ground post needs to be welded with a cylindrical neck to fit into the center hole of a tapered roller bearing or a thrust roller bearing. The advantage of using thrust roller bearing is that its diameter does not have to fit exactly the inner diameter of rotating head; since identical cylindrical bushings 34 are used at top and bottom ends to facilitate rotating head coaxial rotating and bear the lateral force. Alternative to cylindrical bushing 34 is a cylindrical roller bearing, or specifically a needle bearing to narrow the gap between the rotating head and the ground post. Using roller bearing, the rotating head can be rotated faster with less friction. However, solar tracker azimuth rotation of 180 degrees in 12 hours daylight is a very slow rotation which enables the usage of lower cost bushings. In addition, the force needed for rotation is mainly to counter the wind load on solar panel with a small proportion used for rotating head.
Flanged bushing, disk or washer bushings seem to provide the best combination of lower cost and maintenance free for long term usage under rough weather conditions. In addition, the cylindrical bushing, circular flanged bushing and disk or washer bushing designed for industrial heavy machinery are commercially available in many sizes. The bushings are made of porous alloy, brass, bronze or synthetic materials. It also provides low friction rotation and low maintenance with one time solid lubricant for long term usage under extreme weather conditions.
On top of the rotating head, an elongated cylindrical horizontal beam (tubing) 50 is secured with U-clamps 44 to the top plate 36 with a cylindrical bushing looped in between as illustrated in
At this point, those skilled in the art may vary the rotating head attachment to the horizontal beam in many ways. For example, a square or rectangle beam may replace the cylindrical beam as long as the section atop the rotating head is cylindrical; such as a square beam can fit inside cylindrical tube in the middle section. A square or rectangle beam may be more convenient for solar panel frame mounting.
Azimuth Rotation with Single Linear Actuator
In
Those skilled in the art can easily change the configuration of the linear actuator attachment with different length and different angle of attachment between the ground post, rotating head, and it is not necessary to form a right triangle in the initial position. By changing this attachment, it may make azimuth rotation to a greater angle. But it does not change the essence of the disclosure of using linear actuator to do the azimuth rotation.
Elevation Rotation with Linear Actuator
As one can observe in
To those skilled in the art, the V-shaped bar and horizontal bar can be changed in shape and attachment mechanism, such as changing of V-shaped bar 51 into U-shaped and changing single bar 49 into parallel bars to hinge linear actuator from both sides.
Alternative Elevation Rotation with Non Rotating Beam
If flat photovoltaic solar panels are mounted on the tracker, the crossing beam may be a reversed T-beam with the height of T matching the solar panel depth. Preferred embodiment of the T-beam is made from bended metal strip with a center reversed U-shaped T-post as depicted in
The alternative installation using rotation of T-beam rather than rotation of horizontal beam can accommodate larger tracker frame for larger solar panel output. Comparing to previous embodiment with one bushing carrying the entire tracker load, the tracker frame rotation on horizontal beam distributes the larger tracker load on multiple bushings. Furthermore, non-rotating of the horizontal beam put less stress on the elevation linear actuator. The alternative installation is preferred on larger tracker.
Azimuth Rotation with Dual Linear Actuators
Yet another aspect of the disclosure is the use of two linear actuators for azimuth rotation as illustrated in
The rotating mechanism of dual linear actuators is illustrated in
The advantages of using two linear actuators are twofold; 1) the rotating head 30 can be rotated more than 180 degrees to around 240 degrees, 2) two shorter linear actuators are used instead of a single long actuator. By rotating 240 degrees, the area of the world between two Tropics zones can benefit without moving the actuators whenever the Sun orbit is crossing the Zenith point. These tropical zones of the world enjoy the most sunshine days throughout the year. The disadvantage of dual linear actuator is that the actuators must be very short to make clearance for the solar panels in low elevation angle. However, if traditional lifting of solar panel for elevation rather than rotating for elevation is used, the dual linear actuators may not have the problem of clearance.
Azimuth Rotation with Stepping Motor and Geared Drive
Yet another aspect of the disclosure is the use of direct stepping motor drive with gear ring looped on either the rotating head or the ground post as illustrated in
Another alternative of geared ring with stepping motor is using a horizontal worm drive gear 32 mating with a slanted gear ring 41 as depicted in the lower right corner of
The advantage of this approach is the stepping motor and geared ring takes little space on the rotating head and ground post to avoid interference with elevation actuator. Also, the rotating head can be rotated 360 degrees potentially. It could be lower cost if mass production of identical geared motor is needed in a large scale solar farm. However, the disadvantages of this approach are: 1) The gear ring and stepping motor are exposed to adverse weather condition which need to be covered and sealed to protect the gear and motor, 2) The gear ring and rotor gear has to be custom made for every size of rotating head, 3) The mating between gear ring and stepping motor must be tightly fitted which may become a problem after wind load damage and long term vibration, 4) Replace the wear out gear ring must remove the rotating head or two piece gear ring being designed.
Azimuth Rotation with Stepping Motor and Magnetic Rotor
Yet another aspect of the disclosure is the use of direct stepping motor drive without a geared ring on the rotating head. Instead, a permanent or electromagnetic magnetic rotor 321 is used for the rotor of the stepping motor with or without reduction gear as depicted at the lower left corner of
The advantage of magnetic rotor is the simplicity and lower cost of the azimuth drive. Without the gear ring and geared rotor, it removes the problem of corrosion, rain and dust cover, maintenance and lubrication. The ratio of the diameter of rotating head 30 divided by the diameter of magnetic rotor 321; multiplied by the steps per revolution of stepping motor will be the azimuth resolution in one revolution. A resolution of one to two degrees is adequate for a photovoltaic solar panel. Higher degree of resolution needs reduction gear in the rotor for higher precision systems such as CPV or Heliostat tracker.
Wind Lock Devices for Azimuth and Elevation RotationsIt is shown in
A proposed solution to the above problem is using an electromagnetic wind lock devices 65 as depicted in
In this disclosure, we propose an even more useful application of the wind lock device. In windy places such as costal areas when the solar panel is under constant wind assault, the linear actuators will be under perpetual wind abuse and prone to failure. An innovative idea is adopting a stepwise wind lock to counter constant blowing wind using the same wind lock device. The procedure of stepwise wind lock is described as follows: 1) The wind locking period down-counter reaches zero at the tracker controller, 2) The electromagnetic solenoid 64 is commanded by the controller to release rod 63 to unlock position, 3) The linear actuator 28 or 58 is commanded by controller to rotate one step in azimuth or elevation direction, 4) The wind lock rod 63 is activated to lock up the tracker in current position and the tracker controller restart the locking period down counter.
It is a very slow motion for the tracker rotation in a day. The most azimuth rotation is 180 degrees, while the most elevation rotation is only 90 degrees. If the rotation is happened at equinox day with 12 hours of day light, each degree of azimuth rotation takes 4 minutes while elevation rotation takes 8 minutes. On the other hand, each step of linear actuator activation may take only fraction of second. Therefore, the solar tracker is in the locking state for majority of time. The wind locking between consecutive activations will alleviate the linear actuator from constant wind load vibration and pounding. This will prolong the life of linear actuators and therefore increase the life of solar tracker in windy areas.
Mounting Two-Axes Solar Tracker on Light PoleThe horizontal beam 50 is held on by the flange of the rotating head 30 and secured with U-bolts to the body of rotating head 30 horizontally. Multiple cylindrical bushings 56 are looped on the horizontal beam for the elevation rotation of solar panels 52. It is identical to the elevation rotation with non-rotating beam discussed previously. In addition, a rechargeable battery and controller box 45 is attached at convenient location of the light pole for night time lighting.
The attachment of azimuth rotation with single or dual linear actuators is similar to those described in
The construction of inner tubing 20 and outer rotating head 30 will depend on whether the tubing can be looped on the pole from the top. It will be easier with a complete rotating assembly built and looped from the top before the light fixture is installed. However, retrofitting on existing light pole will be a challenging engineering problem. It will require inner tubing, outer tubing and thrust washer to be built in half cylinders or rings and mated to make full cylindrical inner and outer tubing. Furthermore, the mating seams of each cylinder and each washer ring are preferred to be interleaved while mounting to provide better security for the mating seams.
Although various aspects of the disclosed two-axes tracker have been shown and described, modification may occur to those skilled in the art upon reading the specification. Furthermore, many aspects of the disclosed two-axes tracker is not limited to photovoltaic panel tracking application, but can be applied to much broader aspect of solar tracking, or satellite tracking For example, the disclosed two-axes tracker can be used for a concentrated photovoltaic panel; a dish concentrator for Stirling engine, a heliostat solar reflector, a linear trough solar concentrator, a solar thermo concentrator or a satellite dish antenna. The present application includes such applications or modifications and limited only by the scope of the claims.
Claims
1. A two-axes solar tracker apparatus comprising:
- a ground post made of an elongated cylindrical tubing including a top end and a bottom end;
- wherein said top end providing support to a rotating head; and wherein said top end of said ground post is either open or closed; and wherein said bottom end of said ground post being secured into a substructure such as ground;
- said rotating head is made of a larger cylindrical tubing sealed with a top plate; wherein the inner wall of said rotating head is looped on the outer wall of said ground post with two bushings or bearings fitting in the gap at the top and the bottom ends;
- an elongated cylindrical horizontal beam (tubing) is attached and balanced on top of said rotating head directly or via a cylindrical bushing;
- a tracker frame is mounted on said horizontal beam symmetrically on two sides of said rotating head and symmetrically versus said horizontal beam;
- one or two azimuth linear actuators attached horizontally to the side between said ground post and said rotating head for driving the rotating head and tracker frame in azimuth rotation; and
- one elevation linear actuator attached vertically between said rotating head and said tracker frame for driving said tracker frame in elevation rotation with axis of rotation centered on said horizontal beam.
2. The solar tracker apparatus of claim 1 wherein all tracker frame, post, tubing and components are made of rustproof steel metal or rustproof metal alloy materials.
3. The solar tracker apparatus of claim 1 wherein the azimuth rotation is facilitated by said outer rotating head looped on said inner ground post with said upper and lower bushings or bearings in-between providing coaxial rotation of said rotating head versus said ground post; and wherein said upper bushings or bearings further carry the load of said rotating head and said tracker frame.
4. The solar tracker apparatus of claim 1 wherein said top bushing is a cylindrical flanged bushing with flange fitting the inner wall of said rotating head; and wherein the body of said flanged bushing fitting the inner wall of said ground post; and wherein an optional washer bushing is fittingly sitting on top of said flanged bushing facilitating easier rotation; and wherein said lower bushing is a cylindrical bushing.
5. The solar tracker apparatus of claim 1 wherein said top bushing is a combination of one or two disk bushings or washer bushings fitting at the top end with a first cylindrical bushing fitting at the top side wall; and wherein said two disk or washer bushings with lubricant sides face each other facilitating easier rotation; and wherein a second cylindrical bushing fits at the lower side wall.
6. The solar tracker apparatus of claim 1 wherein said top bearing is a tapered roller bearing; and wherein said bottom bearing is a cylindrical bushing; and wherein said top bearing is replaced by a combination of a thrust roller bearing at the top end and a cylindrical bushing at the top side wall; and wherein both said cylindrical bushings at the side wall is replaced by roller bearings or needle bearings.
7. The solar tracker apparatus of claim 1 wherein the azimuth rotation of said rotating head is driven by one linear actuator with its jack head and body hinged on extended brackets to the sides of said rotating head and said ground post, respectively; and wherein said attachment positions of said jack head and said body of linear actuator is reversed.
8. The solar tracker apparatus of claim 7 wherein a first bracket is fixed to the side of said rotating head with the jack head of said linear actuator hinged at the end of said first bracket horizontally; and wherein the body of said linear actuator is fixed to a rotating arm; and wherein said rotating arm is hinged on a second bracket fixed on the ground post; and wherein said linear actuator rotates horizontally by the extension of said jack head together with said rotating arm.
9. The solar tracker apparatus of claim 8 wherein said second bracket is duplicated on the opposite side of said ground post for the hinging of said rotating arm to rotate said rotating head in opposite plane.
10. The solar tracker apparatus of claim 1 wherein the azimuth rotation of said rotating head is driven by dual linear actuators hinged on brackets to the sides of said rotating head and said ground post, respectively.
11. The solar tracker apparatus of claim 10 further comprising:
- an upper and a lower brackets fixed to the sides of said rotating head and said ground post respectively; wherein said two linear actuator bodies are hinged on the open ends of said upper and lower brackets respectively; and wherein said two linear actuators rotates horizontally versus said upper and lower brackets, respectively; and
- a rotating ring fittingly looped on said ground post between said upper and lower brackets; and
- wherein an horizontal arm is attached to the side of said rotating ring; and wherein the end of said horizontal arm is attached with a vertical tubing for hinging; and wherein the jack heads of said two linear actuators are hinged on top and bottom ends of said vertical tubing; wherein said rotating head is rotated in azimuth direction more than 180 degrees by the extension of said jack heads of said lower linear actuator and said upper linear actuator together.
12. The solar tracker apparatus of claim 1 wherein the azimuth rotation of said rotating head versus said ground post is driven by a stepping motor with geared rotor attached on the sides of either said ground post or said rotating head; and wherein a geared ring mated to said geared rotor is looped and fixed on said rotating head or ground post, opposite to said stepping motor attachment; and wherein said geared ring is replaced by a half circle geared ring attached onto said rotating head.
13. The solar tracker apparatus of claim 1 wherein the azimuth rotation of said rotating head is driven by a stepping motor linked to a worm gear attached on the sides of either said ground post or said rotating head horizontally; and wherein a slanted teeth geared ring, mating to said worm gear, is fixed on either said rotating head or said ground post, opposite to said worm gear and stepping motor attachment; and wherein said slanted teeth geared ring is replaced by a half circle slanted geared ring attached onto said rotating head.
14. The solar tracker apparatus of claim 1 wherein the azimuth rotation of said rotating head versus said ground post is driven by a stepping motor with permanent or electromagnetic rotor attached on said ground post with rotor in close contact with said rotating head made of magnetic attractable material; and wherein activated magnetic attraction provide gearless friction force for the rotation of said rotating head.
15. The solar tracker apparatus of claim 1 wherein said horizontal beam is secured and balanced on top of said rotating head via a cylindrical bushing looped on the middle of said horizontal beam facilitating rotation of said horizontal beam; and wherein two-sided symmetrical tracker frame is mounted on said horizontal beam and balanced on said rotating head; and wherein each side of said tracker frame is further balanced on said horizontal beam with the elevation rotating axis centered on said horizontal beam.
16. The solar tracker apparatus of claim 1 wherein said horizontal beam is fixed and secured directly on top and balanced on said rotating head; and wherein said horizontal beam is looped with multiple cylindrical bushings for the mounting of crossing beams of said tracker frame; and wherein said tracker frame is rotated around said fixed horizontal beam with elevation rotating axis centered on said horizontal beam.
17. The solar tracker apparatus of claim 1 wherein a linear actuator with its body hinged vertically on a fix arm attached to said rotating head, and wherein the jack head of said linear actuator is hinged directly on said tracker frame, or hinged vertically on fix arms attached to said horizontal beam; and wherein the extension of the jack head of said linear actuator rotates said tracker frame in elevation direction with rotating axis centered on said horizontal beam.
18. The solar tracker apparatus of claim 1 wherein said tracker frame is made of crossing reversed T-beams mounted and balanced on said horizontal beam; and wherein said crossing reversed T-beams are made of bended sheet metal with reversed U-shaped center T-post in the middle for the mounting and securing of said photovoltaic solar panels.
19. The solar tracker apparatus of claim 1 wherein two electromagnetic wind lock devices with one attached on said ground post adjacent to said rotating head, and the other attached on said top plate adjacent to said horizontal beam; and wherein two drum shaped rod heads are in the center of solenoid of said wind lock devices; and wherein said rod head are attracted to said rotating head and said horizontal beam upon solenoid activation; and wherein said tracker will be locked in desired wind lock position by electromagnetic attraction force.
20. The solar tracker apparatus of claim 19 wherein said wind lock devices are activated between consecutive steps of azimuth and elevation driver activation in a stepwise wind lock of said two-axes solar tracker rotation.
21. The solar tracker apparatus of claim 1 wherein said tracker load may be a photovoltaic solar panel, a concentrated photovoltaic panel, trough or dish concentrator, a heliostat solar reflector, a solar thermo concentrator or a satellite dish antenna.
22. The solar tracker apparatus of claim 1 wherein said rotating head and attachment to ground post is modified to be mounted on a light post; wherein an cylindrical inner tubing with a lower extruded flange ring is attached to support the tracker frame; and wherein an outer flanged bushing rotating head is looped fittingly and matched with the inner tubing flange ring with a thrust washer bushing and optional cylindrical bushings inserted in-between for easier rotation; and wherein a horizontal beam mounted with two sided tracker frames and solar panels is balanced on the flange and secured on the body of said rotating head.
23. The solar tracker apparatus of claim 22 wherein said inner tubing with flange ring, said outer flanged bushing and said thrust washer bushing are made from half cylinders or rings and mated in the middle to make a full cylinder or ring; and wherein the mating seams of each cylinder and each ring are interleaved for retrofit mounting on said light pole.
24. A two-axes solar tracker system comprising:
- a ground post made of an elongated cylindrical tubing including a top end and a bottom end; and wherein said top end providing support to a rotating head; and wherein said bottom end being secured into a substructure such as ground;
- said rotating head is made of a larger cylindrical tubing sealed with a top plate; wherein said rotating head is looped on said ground post with multiple bearings fitting in the gaps between said ground post and said rotating head;
- an elongated horizontal beam is attached and balanced on top of said rotating head;
- a tracker frame is mounted on said horizontal beam symmetrically on two sides of said rotating head and symmetrically versus said horizontal beam;
- an azimuth motor driver attached between said ground post and said rotating head for driving said rotating head and said tracker frame in azimuth rotation; and
- an elevation linear actuator attached between said rotating head and said tracker frame (or said horizontal beam) for driving said tracker frame in elevation rotation.
25. The solar tracker system of claim 24 wherein the azimuth rotation is facilitated by said rotating head looped on said inner ground post with said upper and lower bearings in-between for the coaxial rotation of said rotating head versus said ground post.
26. The solar tracker system of claim 24 wherein the azimuth rotation of said rotating head versus said ground post is driven by single linear actuator attached on the sides between said rotating head and said ground post.
27. The solar tracker system of claim 24 wherein said tracker azimuth rotation plane is reversed to opposite side plane by changing the attachment of said linear actuator to the opposite side of said ground post.
28. The solar tracker system of claim 24 wherein the azimuth rotation of said rotating head versus said ground post is driven by linked dual linear actuators attached on the sides of said rotating head and said ground post, respectively; and wherein the combination of said dual linear actuators extensions rotate said rotating head more than 180 degrees in azimuth direction versus said ground post.
29. The solar tracker system of claim 24 wherein the azimuth rotation of said rotating head versus said ground post is driven by a stepping motor with geared rotor and a gear ring attached of the ground post and rotating head, respectively; and wherein said geared rotor is a worm drive rotor.
30. The solar tracker system of claim 24 wherein the azimuth rotation of said rotating head versus said ground post is driven by a stepping motor with a permanent or an electromagnetic gearless rotor with magnetic attraction force for rotation.
31. The solar tracker system of claim 24 wherein elevation rotation of the tracker frame is via rotation of said horizontal beam pivoted on top of said rotating head; and wherein the elevation rotation axis is center on said horizontal beam.
32. The solar tracker system of claim 24 wherein said horizontal beam is fixed and secured directly on top of said rotating head; and wherein the elevation rotation is facilitated by the rotation of said tracker frame with rotating axis pivoted on said horizontal beam.
33. The solar tracker system of claim 24 wherein the elevation rotating is driven by linear actuator hinged between said rotating head and said tracker frame or an extension arm fixed to said horizontal beam; and wherein the extension of said linear actuator rotates said tracker frame in elevation direction with rotating axis centered on said horizontal beam.
34. The solar tracker system of claim 24 wherein two electromagnetic wind lock devices are installed between said ground post and said rotating head; and between said rotating head and said horizontal beam or tracker frame; wherein the activation of magnetized attraction force will lock said tracker at any desired azimuth and elevation position, respectively.
35. The solar tracker system of claim 34 wherein said wind lock devices are activated between consecutive steps of azimuth and elevation rotations in a stepwise wind lock of said solar tracker rotation.
36. The solar tracker system of claim 24 wherein said two-axes tracker is used for a concentrated photovoltaic panel, trough of dish concentrator, a heliostat solar reflector, a solar thermo concentrator or a satellite dish antenna.
37. The solar tracker system of claim 24 wherein said rotating head and attachment to the ground post is modified to be mounted on a light post for the charging of hybrid or electric automobile during the day, or for the storage of electricity generated by solar panel for night lighting.
Type: Application
Filed: Aug 7, 2010
Publication Date: Feb 24, 2011
Inventor: HENRY H. LIAO (Los Alamitos, CA)
Application Number: 12/852,454