NZ715055B2 - Single axis solar tracking system - Google Patents
Single axis solar tracking system Download PDFInfo
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- NZ715055B2 NZ715055B2 NZ715055A NZ71505514A NZ715055B2 NZ 715055 B2 NZ715055 B2 NZ 715055B2 NZ 715055 A NZ715055 A NZ 715055A NZ 71505514 A NZ71505514 A NZ 71505514A NZ 715055 B2 NZ715055 B2 NZ 715055B2
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- tracker
- ocm2
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- ocm1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S30/00—Arrangements for moving or orienting solar heat collector modules
- F24S2030/10—Special components
- F24S2030/13—Transmissions
- F24S2030/131—Transmissions in the form of articulated bars
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S30/00—Arrangements for moving or orienting solar heat collector modules
- F24S2030/10—Special components
- F24S2030/13—Transmissions
- F24S2030/134—Transmissions in the form of gearings or rack-and-pinion transmissions
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S30/00—Arrangements for moving or orienting solar heat collector modules
- F24S2030/10—Special components
- F24S2030/13—Transmissions
- F24S2030/136—Transmissions for moving several solar collectors by common transmission elements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S30/00—Arrangements for moving or orienting solar heat collector modules
- F24S2030/10—Special components
- F24S2030/15—Bearings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S30/00—Arrangements for moving or orienting solar heat collector modules
- F24S2030/10—Special components
- F24S2030/19—Movement dampening means; Braking means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S25/00—Arrangement of stationary mountings or supports for solar heat collector modules
- F24S25/60—Fixation means, e.g. fasteners, specially adapted for supporting solar heat collector modules
- F24S25/65—Fixation means, e.g. fasteners, specially adapted for supporting solar heat collector modules for coupling adjacent supporting elements, e.g. for connecting profiles together
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S30/00—Arrangements for moving or orienting solar heat collector modules
- F24S30/40—Arrangements for moving or orienting solar heat collector modules for rotary movement
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S30/00—Arrangements for moving or orienting solar heat collector modules
- F24S30/40—Arrangements for moving or orienting solar heat collector modules for rotary movement
- F24S30/42—Arrangements for moving or orienting solar heat collector modules for rotary movement with only one rotation axis
- F24S30/425—Horizontal axis
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S30/00—Arrangements for moving or orienting solar heat collector modules
- F24S30/40—Arrangements for moving or orienting solar heat collector modules for rotary movement
- F24S30/42—Arrangements for moving or orienting solar heat collector modules for rotary movement with only one rotation axis
- F24S30/428—Arrangements for moving or orienting solar heat collector modules for rotary movement with only one rotation axis with inclined axis
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S30/00—Arrangements for moving or orienting solar heat collector modules
- F24S30/40—Arrangements for moving or orienting solar heat collector modules for rotary movement
- F24S30/45—Arrangements for moving or orienting solar heat collector modules for rotary movement with two rotation axes
- F24S30/452—Vertical primary axis
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S40/00—Safety or protection arrangements of solar heat collectors; Preventing malfunction of solar heat collectors
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S50/00—Arrangements for controlling solar heat collectors
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S50/00—Arrangements for controlling solar heat collectors
- F24S50/20—Arrangements for controlling solar heat collectors for tracking
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
- H02S20/00—Supporting structures for PV modules
- H02S20/30—Supporting structures being movable or adjustable, e.g. for angle adjustment
- H02S20/32—Supporting structures being movable or adjustable, e.g. for angle adjustment specially adapted for solar tracking
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B10/00—Integration of renewable energy sources in buildings
- Y02B10/20—Solar thermal
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/40—Solar thermal energy, e.g. solar towers
- Y02E10/47—Mountings or tracking
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
Abstract
solar tracking system with a plurality of tracking assemblies moved by a single motor (14). A method and system that prevents overloading the motor or tripping a circuit breaker due to an obstructed or impeded tracker includes sensing movement (162) of the tracker assemblies and entering into obstruction clearing modes. Obstruction clearing mode 1 (OCM1) (168) is a high frequency adjustable mode that prompts movement for an adjustable period of time. If movement commences, the system returns to a normal mode. If there is no movement, the system enters into an obstruction clearing mode 2 (OCM2) (176) which is an adjustable lower frequency series of attempts. If there is no movement, no further attempts are made. Each of these steps are monitored and controlled remotely. There are two types of secure connections for drivelines, torque tubes or affixing driveline linkages for high torque conditions. ruction clearing modes. Obstruction clearing mode 1 (OCM1) (168) is a high frequency adjustable mode that prompts movement for an adjustable period of time. If movement commences, the system returns to a normal mode. If there is no movement, the system enters into an obstruction clearing mode 2 (OCM2) (176) which is an adjustable lower frequency series of attempts. If there is no movement, no further attempts are made. Each of these steps are monitored and controlled remotely. There are two types of secure connections for drivelines, torque tubes or affixing driveline linkages for high torque conditions.
Description
SINGLE AXIS SOLAR TRACKING SYSTEM
RELATED APPLICATIONS
This application is a continuation-in-part application of US. Patent Application Serial
No. 12/137,764, entitled "SINGLE AXIS SOLAR TRACKING SYSTEM". filed June 12,
2008, which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
Field of the Invention (Technical Field):
The presently claimed invention relates to solar energy production and more
particularly to a method and apparatus for constructing mechanically linked, single axis
solar ng systems of various tracking ries to follow the diurnal motion of the
sun.
Background Art:
Solar tracking systems utilized in renewable energy production are s that track
the motion of the sun relative to the earth to maximize the tion of solar energy.
Solar trackers move to keep solar modules perpendicular to the sun in either one or
two axes. The presently claimed invention applies to photovoltaic modules (PV) for
ting electrical power, but may be applied to any solar energy collection device,
such as solar thermal or material exposure testing devices. Solar trackers have been
successfully deployed in the ry; however, the prior art designs have not
adequately addressed the initial installation costs, flexibility in adaptation to site
conditions, and reliability over the vely long lifetime (20+ years) of the system. In
choosing a solar tracker system. one must consider all of the following variables:
. PV module cost,
. land cost, site ry and availability,
. installation labor cost,
0 material cost,
SUBSTITUTE SHEET (RULE 26)
o meteorological data,
0 operation and nance costs,
0 overall efficiency increase that the r provides.
The state of the art approaches have not fully optimized the combination of all the
relevant cost issues. The energy gain provided by trackers is dependent upon the
tracking geometry of the system and the location of the lation. A dual axis (D/A)
tracker keeps the collector perpendicular to the sun on both axis’, and provides the
greatest gain in energy production at any location. Single axis (S/A) trackers are fixed
in one axis and typically track the daily motion of the sun in the other axis. Single axis
tracker ries include tilted elevation, azimuth, and horizontal. Tilted elevation
S/A trackers are tilted as a function of the location’s latitude and they track the sun’s
daily motion about that tilted axis. Azimuth S/A rs are tilted at an optimum angle
and follow the daily motion of the sun by rotating about the vertical axis. Horizontal S/A
trackers are configured parallel to the ground and rotate about a North/South horizontal
axis to track the sun’s daily motion. The energy gained varies for each type of tracking
geometry and is dependent upon the latitude of the installation and the weather
conditions at the installation location. Solar tracking systems for PV modules are
commercially ble in single axis tilt and roll, single axis horizontal, single axis fixed
tilt azimuth, and dual axis ries.
All trackers must be built strong enough to resist the wind forces in any tracking
position or be “stowed” to reduce the effect of extreme wind forces. s also
require periodic ng, which in many locations is ily accomplished by rain
“washing” the modules. Snow can affect tracker operations, due to the occurrence of
ice or the weight of snow on modules, or snowdrifts that interfere with tracker
movement and the collection of solar energy. In addition, construction materials,
electronics, drive components, and motors must be able to operate within temperature
and climate constraints.
In many ations, the horizontal single axis tracker is the most cost effective tracker
geometry. A horizontal S/A tracker structure may be supported at many points along
SUBSTITUTE SHEET (RULE 26)
the rotating axis and, therefore, requires less complexity and less material for
construction than other ng ries. The key to successful design of a tracking
apparatus for PV modules is to e the maximum overall economic benefit, such as
the initial apparatus cost, the installation cost, the land utilization, the cost and
efficiency of the solar modules, and the ion and maintenance costs as well as the
efficiency gain provided by the tracking geometry. As the cost of steel and other
fabrication material rises, the horizontal tracking geometry is increasingly desirable. It
minimizes the structural material requirements by keeping the s at a relatively
low profile to the foundation, and at a minimum overhung moment load relative to the
rotating axis t requiring special connections to rotate the system about its center
of gravity.
The prior art horizontal axis trackers typically have connected each row of modules
together with a linear motion linkage in an effort to minimize the number of drive motors
required. Prior art mechanically linked horizontal and tilted single axis tracking systems
require substantial mechanical linkages structurally capable of resisting high force
loading due to overhung solar module weight and large forces induced by the wind.
The oming of this prior art system is that all of the wind forces are concentrated
to a single point, through the mechanical e. The embodiment of the presently
claimed invention specifically eliminates the need for a robust mechanical linkage
e of resisting oad forces induced by the wind. The design of the current
embodiments eliminates the transmittance of these wind forces to the linkage, and
racts the al wind forces locally, within each tracker row or array such that
the wind force is not transmitted to the e. The prior art also requires a separate,
large foundation, or foundations, to anchor a single drive ism that rotates many
rows of modules with a linear motion motor. One such device is a horizontal, single
axis tracking system described in US Patent No. 6,058,930, to Shingleton. In this
system, the horizontal rows of modules are linked together with a linear motion linkage
and operated by a single linear actuator attached to a separate, large foundation. In
addition to the prior art horizontal axis, mechanically linked trackers require generally
flat or graded terrain for proper operation. Many columns must be installed at height
SUBSTITUTE SHEET (RULE 26)
elevations and locations requiring high tolerance within 100+ columns, across two
dimensions in a large area, for mechanical linkages between rows to line up for
operation. This often requires extensive and costly site preparation. Some prior art
linked ntal trackers have embodiments that allow for installation on ting
terrain, but require expensive joints that must be fabricated onsite that also must resist
the large forces d by the wind. These high force loaded pivoting joints are
generally complicated and expensive to construct. Another disadvantage of the prior
art is that they are designed as large rectangles with a linkage running down the center
of the array field. If the installation field is not suitable in the shape of a rectangle,
these systems are often employed in less than m configurations where fewer
modules are controlled by the linkage. This is r cost increase factor for the prior
art in many installations. The linear motion linkage of the prior art represents an
excess of material and a labor-intensive installation cost component. The linkage must
be robust in order to directly resist the force of an entire field of many rows of trackers
to one large linear drive that must be affixed to a large separate linear actuator drive
foundation. The separate, large foundation is necessary to anchor the drive
ism and must resist very high forces induced by the wind to the entire tracker
field. In addition, the flexibility in site layout is impacted by the linear motion linkage
since the drive connection must lly run, centered in the rows, and be installed in
a straight perpendicular line. The ical linkage of the prior art must be fixed at a
right angle to the torsion tube and cannot deviate from perpendicular, ore, not
allowing the system to conform to irregular installation site boundaries.
Tracking geometries other than the horizontal single axis require‘more land area for
installation. In a field of trackers, all the tracker geometries except for the horizontal
axis tracker must be spaced in two dimensions, East/West and South, so as not
to shade each other. The horizontal axis tracker need only be spaced apart in the
East/West dimension to alleviate shading and, therefore, requires much less land to
implement. Land contour and shape also critically control the cost of the installation of
most horizontal single axis tracker systems.
SUBSTITUTE SHEET (RULE 26)
WO 86079
Another type of horizontal axis tracker is not linked together and typically includes
multiple PV modules mounted astride a torque tube. These are designed as
independently motor driven rows. These horizontal trackers are driven individually by a
motor/gear drive system and the PV array is rotated about the center of gravity of the
PV module tracking system. Rotating the array about the center of gravity eliminates
the moment loads applied to the gear drive by the overhung weight of the solar
modules. In order to rotate the array about the center of y, this type of horizontal
tracker design requires more structural material and more costly torque tube
connections and gs than the present horizontal axis tracker embodiments. Other
disadvantages of these r designs include a higher projected wind area that
requires more structural material and large foundations to resist r moment loads
and larger capacity drives to overcome moment loading from the solar modules that are
mounted at a larger distance from the torque tube due to the taller profile of the array.
They also have more complex bearing and support points that rotate the PV modules
about the center of gravity of the tracker, and use a motor per single tracker row, which
equates to increased cost, maintenance, and decreased reliability.
A third tracker geometry is a tilted, single axis tracker. Often termed a tilt and roll
tracker, it is tilted in ion and then rotates about that tilted axis. This type of
tracker typically offers increased gain over a horizontal tracking system, but at an
added cost that should be critically analyzed prior to deployment. These costs include
the ement for more land due to the spacing necessary for shading in both the N/S
and E/W dimensions and a more complex structure requiring more structural material
because of increased projected height from foundation. These systems are also not
capable of automatic stow during high winds since the elevation angle is fixed and
therefore, must be urally capable of withstanding all wind forces. r tilted
single axis ry is a fixed tilt azimuth tracker. A fixed tilt azimuth tracker is tilted in
elevation and then rotates about a vertical axis. This design, although typically more
structurally stable than a tilt and roll tracker, suffers from the same cost drawbacks as
the tilt and roll design; although, the performance gain may make the tilted single axis
geometry economic for some lations.
SUBSTITUTE SHEET (RULE 26)
The last tracking geometry is a dual-axis (D/A) tracker. D/A trackers provide the
greatest performance gain over all the entioned tracking geometries since they
keep the solar modules perpendicular to the sun in both axes. There are; however,
several practical disadvantages of these s: more land is required due to
spacing necessary for shading in two dimensions; a more complex structure is
necessary that requires more structural material as a result of increased projected
height from the earth and foundation; and a second drive axis for elevation is
necessary, which increases complexity, expense, and maintenance issues. In addition,
D/A systems typically use two drive motors per a relatively small surface area of solar
modules that results in ses in both initial cost and subsequent nance
costs. Some types of solar collectors, concentrating collectors for example, require D/A
tracking to e.
As previously ted, an ideal solar tracking system will operate in all types of
ions. This includes situations whereby a tracker’s movement is impeded by
obstructions or the like. If there are no safeguards in place, permanent damage can
result in the tracker system when an obstruction condition exists. In addition, human
intervention may be necessary to cure the condition. mes, timely human
intervention is ible if the trackers are in remote locations and secondly, sending
out a technician for every obstruction condition can be very costly.
Another need in a solar tracker system is the ability to have flexibility in the design of
the systems to support different lengths of driveshafts for differing terrain conditions
and systems. Presently, the ation of specific length of driveshafts requires field
welding and painting. A similar problem exists for torsion tubes. A design for ing
a simple method to join torsion tube segments together in the field is necessary.
SUMMARY OF THE INVENTION (DISCLOSURE OF THE INVENTION)
The presently claimed invention solves all of the problems listed above. An object of
the presently claimed invention is to ically link multiple solar trackers in a large
array configuration so that they operate in unison, driven by a single motor and r
controller. The mechanical linkage system is favorably designed such that it must only
SUBSTITUTE SHEET (RULE 26)
be capable of withstanding the relatively low forces required to effect movement of the
trackers without the requirement to resist the larger forces induced from the wind that is
applied to the array of trackers.
Another object of the presently claimed invention is to contain these al wind
forces within the supports of each individual solar r so that no extra foundations
or ments are necessary. A further object is to apply the drive principals to
various solar single-axis tracking geometries to maximize the economic performance
for each solar tracking application.
The mechanical drive system of the presently claimed invention advantageously links
IO multiple single axis trackers er, moving many trackers h a simple and
structurally minimal linkage to decrease cost and se long-term reliability. The
uration of the mechanical linkage and gear drive assemblies allows the motor to
move the linked trackers, yet eliminates the transmission of the external wind forces to
the drive linkage. By exploiting the “one way” drive properties of the presently claimed
invention, the mechanical linkage need only transmit the vely small forces
necessary to move the tracker, and is not subject to the relatively high forces induced
by the wind on the tracker. An added benefit of the system is that a relatively small
motor can move a large area of solar modules.
The drive system of the presently claimed invention is applicable to all solar tracking
geometries. The mechanical drive configuration results in a very reliable, flexible, low
cost tracking method that is easy to install and maintain. The various embodiments of
the presently claimed invention apply the drive system to the appropriate tracking
ry in order to maximize the economic benefit of the ng system.
One aspect of the disclosed embodiments is to drive mechanically linked multiple rows
of a horizontal S/A solar tracking collector assembly. Rows of solar modules are
formed by affixing the solar modules to a general ntally positioned n tube
having its long axis oriented in a North/South (N/S) direction. Each row includes one or
more supports to the North and South of center and as well as the possible use of a
center support. A bearing is affixed at each torsion tube support such that rotary
SUBSTITUTE SHEET (RULE 26)
motion of the torsion tube may be affected through a single stage worm-gear drive
ly or through a worm-drive gear assembly, which includes a second stage gear
that is affixed to the torsion tube and one or more supports. A driven, rotating drive
shaft is affixed to both sides of the rive assembly. The drive shaft may be
positioned at right angles to the torsion tube and ed to each worm-gear drive to
enable rotary motion of the torsion tube by ng rotary motion to the driVen drive
shaft. Back g of the gearbox from wind forces applied to the system is virtually
eliminated through the ties inherent in the design of the primary worm-drive gear
assembly located at each tracker. The worm-drive gear assembly can be efficiently
driven by the input of rotary motion from the drive shaft to the worm, but is very
inefficient at transmitting rotary motion applied by the system on theworm-gear.
Therefore, moment forces, induced by the wind, applied to the solar array cannot be
ively transmitted to the drive shaft linkage. The result is that the drive shaft does
not need to resist the forces of the wind on the array and only transmits the driving
force from the motor through a highly geared transmission system. This enables the
drive shaft to be minimally constructed and allows for flexibility in its design and layout
within the solar tracker array field.
A further embodiment of this aspect of the presently d ion is to incorporate
articulating joints at the ends of each drive shaft to enable the tracker rows to vary in
height and/or to translate in the MS direction. The articulated drive shaft adds flexibility
in array field layout. Array fields using articulating drive shaft joints may be ucted
on undulating or slanted terrain and may be tailored to irregular installation site
boundaries. .The horizontal axis S/A tracker minimizes the required structural
components, allows for a high—density ratio of installed modules to land area, and
provides peak performance of a horizontal single axis solar tracking system through the
use of a programmable backtracking scheme for early morning and late evening solar
energy collection.
in addition to minimizing the number and weight of structural components, the
horizontal tracking system reduces on-site construction labor and installation
requirements. It also provides a means for stowing the array of modules in the event of
SUBSTITUTE SHEET (RULE 26)
a hurricane, typhoon, or other potentially destructive weather event. Another object of
the horizontal tracker embodiment is that even as module costs considerably decline, it
should remain competitive as ed with fixed-mounted arrays since it incorporates
a minimal amount of structural material.
A second ment of the claimed invention is to drive multiple tilt and roll S/A solar
trackers using the same drive principles as in the ntal tracking . In this
embodiment, variations of the worm-drive gear system can be effectively used to drive
multiple tilt and roll solar trackers in an array field using only one motor and controller.
Articulating joints on the drive shafts may also be incorporated’ to e the same
flexibility as in the horizontal S/A tracker application.
A third embodiment of the presently d invention is to incorporate the drive
system into a field application of multiple fixed tilt azimuth trackers. A specially
designed vertical axis bearing may be designed into the support post of the tracker to
place the gear drive connection close to the base of the tracker support in order to
e clearance for the rotary drive linkage system underneath the solar module
array. A more conventional bearing system, such as a slew drive may also be
orated in the fixed tilt azimuth tracking ry if it is properly designed to
withstand the load forces applied near the base of the array support. Another favorable
application of the drive system is to incorporate the linked worm-gear drive into a
carousel type fixed tilt azimuth ng array field. In this embodiment, the tilted solar
array is rotated on a large area circular bearing to track the sun. The carousel tracker
may also be constructed in a low profile design for rooftop applications.
The embodiments described in this application are intended to provide a cost effective,
long life and low maintenance solution for implementing solar tracking of photovoltaic
(PV) or other solar modules for solar energy ations. The presently claimed
invention addresses the general problem of how best to mount and track PV modules
in order to maximize the economic return from a system lation, while incorporating
a similar drive system and principles for each tracking geometry. Since the presently
d invention may be incorporated in various tracking geometries, it allows for
SUBSTITUTE SHEET (RULE 26)
consideration of the balance between module efficiency as it relates to solar tracking
geometries, land use, materials utilization, ion and maintenance costs, weather,
climate, and installation cost. The current embodiment of the mechanically linked
system is superior to the prior art because it eliminates the need for the drive system to
resist the high load forces induced by the wind. Other benefits include the elimination
of large te foundation(s) to mount the drive system, the linkage requires less
material than the prior art, the linkage also allows for much greater flexibility in field
‘ layout of the trackers and a single motor can drive a much larger tracker field.
The drive system of the presently claimed invention allows the linkage to be configured
two ways: 1) with rigid, connecting drive shafts for ment on even terrain or 2)
with articulating or universal joints at the end of the drive shafts for use on uneven
terrain or irregularly-shaped layouts. Both linkages may be ed within a single
tracker system to install on a field consisting of a combination of even and uneven
terrain or irregularly shaped installation sites.
The red system also has an adjustable limit for the driveline torque applied by the
motor to the driveline. The system monitors the torque via clutch slippage or poWer to
the motor, sensors that monitor the movement of the tracker or other methods of
monitoring, to determine an event that obstructs the movement of the tracker. A
remote location monitors the status of each r system and sends commands via a
2O communication system. Once the monitors or sensors detect an obstruction event, the
system enters into an obstruction clearing mode 1 (OCM1), which is an adjustable high
frequency series of attempts to move the obstructed tracker for an able
ermined amount of time. If the tracker begins normal movement as one of the
series of attempts, the system continues in a normal fashion. If the ction
condition persists after the predetermined period of time, the system enters into an
obstruction clearing mode 2 (OCMZ). This mode is an able lower frequency
mode for an adjustable longer predetermined period of time. Again, if during this mode
the tracker moves in a normal fashion, the system reverts to normal operation. if the
obstructed condition persists after the OCM2, the remote location is advised and
SUBSTITUTE SHEET (RULE 26)
2014/033762
maintenance personnel can be sent to the location. The remote location, during this
entire process receives information and may send commands to the tracker system.
The obstruction clearing and monitoring system may be designed to prevent over-
torque damage to the driveline or other components and prevents breakers from
tripping which involves a visit by maintenance personnel to reset the breaker.
r feature in the claimed invention is a method and system for securely
connecting a round torsion tube or driveshaft to driveline linkage, such as an
lating joint, or to splice two ends of a round tube in a tracker system. The
preferred system has a first end with an 8 shaped configuration and a second end with
the same 8 shaped configuration; r, the second end is smaller to allow the
second end to be inserted into the first end. In the valley of the 8 shape are keys that
are bolted through the first end and second end to form a tight, concentric, keyed
driveline connection. This method and system allows for inexpensive fabrication of
varying length tubes in a factory and requires no field welding or preparation. The
resultant connection is easy to assemble, is adjustable in length, provides for excellent
concentricity, tightness, and the ability to transmit high torque loads without failure.
A second connection method and system are disclosed for a square tube or driveshaft
uration. A coupler is provided with a spacer plate for insertion into a corner of the
coupler. A first end of the square tube is inserted into coupler and spacer plate until it
contacts a stop pin in the coupler. The second end is similarly ed. Push bolts are
tightened into threaded apertures in the coupler, pushing spacer plate onto the first and
second ends of the square tube. In addition, gouge bolts are tightened into additional
threaded apertures, through the space plate and gouge into the first and second end.
This connection also avoids field welding and provides for a tight and efficient
connection for all square tube splicing in tracker systems.
Other objects, advantages and novel features, and further scope of applicability of the
tly claimed invention will be set forth in part in the detailed description to follow,
taken in conjunction with the accompanying drawings, and in part will become nt
to those d in the art upon examination of the following, or may be d by
SUBSTITUTE SHEET (RULE 26)
2014/033762
practice of the claimed invention. The objects and advantages of the claimed invention
may be realized and attained by means of the instrumentalities and combinations
particularly pointed out in the appended claims.
BRIEF PTION OF THE DRAWINGS
The accompanying drawings, which are incorporated into and form a part of the
specification, illustrate several embodiments of the presently claimed invention and,
together with the description, serve to explain the ples of the claimed invention.
The drawings are only for the purpose of illustrating preferred embodiments of the
claimed invention and are not to be construed as limiting the claimed invention. The
gs are included in the description below.
Fig. 1A shows the mechanically linked horizontal tracker embodiment with a worm-gear
ly for driving a spur gear rack and another worm-gear assembly for driving a D-
Ring chain drive.
Fig. 1B shows a worm-gear assembly for driving a cable drive.
Fig. 2 shows a direct drive horizontal tracker .
Fig. 3A shows the worm-gear assembly for the D-ring chain drive embodiment.
Fig. 3B shows the worm-gear assembly for the spur gear rack ly.
Fig. 4 shows the articulating joints.
Fig. 5 is an ion showing hydraulic dampeners installed on each tracker row to
enable greater capacity per row.
Fig. 6 shows the mechanically linked worm-drive gearbox incorporated into a tilt and
roll solar r.
Fig. 7 shows the mechanically linked worm-drive gearbox incorporated into a fixed tilt
azimuth tracker.
Fig. 8A shows the rotating support tube assembly of Fig. 7.
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Fig. BB shows a ear ly affixed to the vertical support of a fixed tilt
h tracker.
Fig. 9 shows the mechanically linked worm-drive gearbox incorporated into a fixed tilt
carousel solar tracker.
Fig. 10 is a flow chart showing the preferred adjustable limit embodiment for over
torque conditions.
Fig. 11 shows an exploded view of the preferred connection for a circular or round shaft
to a t end.
Fig. 12 shows the embodiment of Fig. 11 in a connected state.
Fig. 13 shows an exploded view of the preferred square tube coupler.
Fig. 14 shows the embodiment of Fig. 13 in a completed state.
Fig. 15 shows the preferred square tube coupler ing two square tubes.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
(BEST MODES FOR CARRYING OUT THE INVENTION!
IS The presently claimed invention has four tracker embodiments, a horizontal axis, a
fixed tilt azimuth, tilt and roll, and a carousel tracker with the commonality of being
linked er mechanically and operated by a rotary driven worm-drive system. All
the tracker geometries incorporate a worm-gear primary drive, attached to the tracker
frame, either directly, or through a secondary stage such as a spur gear rack, D-ring
chain drive, or cable system mounted to one or two column supports for the tracker.
The sed embodiment allows many tracker rows to be driven by one drive motor
through the mechanical drive shaft linkage, which does not need to resist the external
forces applied to the array.
Horizontal Single Axis
The mechanically linked horizontal, single axis embodiment of the presently claimed
invention is a tracking ly 10 for pointing one or more solar panels or PV
s 12 towards the sun, as shown in Fig. 1A. Drive mechanism 14, in this case a
drive motor, provides the power to a drive shaft 28 and associated linkage to move PV
SUBSTITUTE SHEET (RULE 26)
modules 12. The preferred driving mechanism 14 is a drive motor with a brake 15 for
limiting motor run-on after rgizing and resisting motor coast and back forces. In
the embodiment of Fig. 1A, drive mechanism 14 rotates drive shaft 28, which in turn
drives ear assembly or drive box 26, as described below. In the embodiment
shown in Fig. 1A, a drive ear assembly is erring the power to drive shaft
28. This assembly utilizes a rotating torsion tube 16, in this case, horizontal, in the
North/South direction, on which PV modules 12 are mounted, using mounting methods
well known in the art, such as U bolts 18, clamps or other well know module mounting.
systems. Torsion tube 16 is inserted into bearings 20, with bearing surfaces such as
no maintenance polymer bushings, which are attached to support columns 22. Drive
mechanism or motor 14 drives a worm—gear drive box 26, which in turn, rotates the
torsion tube 16 directly, as shown in Fig. 2, or drives a ary element, which in
turn drives the torsion tube. In Fig. 1A, the secondary element is a spur gear rack 30 or
D-ring chain drive 34, which is affixed to torsion tube 16. The ary element can
also be a cable drive assembly or other drive assemblies well known in the art. (Not
shown). Thus, when activated by drive mechanism 14 PV modules 12 are rotated. A
second, third, etc. tracking assembly, similar to tracking assembly 10 can be connected
to drive shaft 28, in this embodiment on shaft end 30, with a separate and similar worm
assembly. This can be repeated for several tracking assemblies. Thus, one motor 14
can drive a plurality of tracking assemblies. ically linking the rs in a field
reduces the system xity, operation and maintenance costs, and increases
reliability.
Fig. 2 shows a direct drive horizontal r . In this embodiment, motor 14
directly drives worm-gear assemblies 26, which rotate torsion tubes 16. This provides
rotation movement to PV s 12.
Figs. 3A and 3B show the worm-gear assemblies. One of the worm-gear assemblies
26 and 26’ are provided at each tracker location and are driven by drive shaft or by
drive mechanism. Typically, this assembly contains worm 36 and worm-gear 38.
Worm 36 is affixed to drive shaft 28 by means well knoWn in the art. Fig. 3A shows
worm-gear assembly 26 for driving a D-ring chain drive. Worm-gear 38 is affixed to
SUBSTITUTE SHEET (RULE 26)
sprocket 41 for D-ring chain drive assembly 34. Fig. BB shows worm-gear assembly
26’ for driving spur gear rack assembly 30 by affixing drive gear 42 of spur gear rack
assembly 30 to worm—gear 38. Any ation of worm-gear assemblies 26 and 26’
can be used in the four embodiments as described herein. Fig. 1B shows the worm—
gear assembly 26” driving a cable drive 33.
With the mechanically linked worm-drive ly 26 and 26’ design, the site may be
graded level to achieve the simplest installation. The mechanically linked design can
also be deployed on an ungraded, slanted, or undulating terrain with the addition of
articulating joints 40, such as swivel connections or universal joints in the drive shafts
IO 28. Fig. 4 shows an embodiment of a r system for use on uneven terrain.
Articulating joints 40 sate for the non-linearity between the trackers in both the
ntal and vertical direction to allow drive shaft 28 to connect to the next tracker
without precision leveling and precise on of the next tracker in relation to the first
tracker. Again, this articulating joint feature can be used with any of the embodiments
disclosed herein.
If it is determined not to grade the site level, then only the columns for each single
tracker row must be located with precision. Columns for subsequent trackers in a field
may be located with little elevation nce relative to other tracker rows. Field site
ation, such as grading, is then zed since the column height from tracker to
tracker may be varied.
Referring again to Fig. 1A, support columns 22 are preferably ated from round
steel galvanized tubing. In a ground based installation, multiple columns 22 are
vertically attached to the earth in a straight line using a concrete foundation, columns
driven into the ground, a screw type foundation or other foundation arrangement (not
shown). For mounting to other structures such as a commercial rooftop or carport,
columns 22 are attached to the structure support members (not . It may be
desirable when mounting to another structure to use an A-Frame support design
instead of a vertical tube column in order to distribute the forces over a greater area to
the host structure (not shown).
SUBSTITUTE SHEET (RULE 26)
Torque tube 16, preferably square, may be inserted into polymer UHMW gs 20
designed to center the square torsion tube into the round g housing at the top of
columns 22. This torque tube 16 may be comprised of several pieces joined together.
Thejoints may be formed by a swaged connection where one tube is formed with a
smaller section to fit into the next tube (not shown). These joints may then be welded
together to insure a secure connection (not shown). All welds should be cleaned and
painted to avert corrosion.
Bearing assembly 20, preferably UHMW bearings, is installed on the top of the columns
22, which preferably is a set of tubes joined at ninety degrees (90°), forming a tee. The
vertical portion of the tube may form a sleeve to mount over or inside of column 22.
This sleeve may be secured to the column with set bolts that burrow into the round
, and may be further secured with a roll pin pressed into a hole in the two parts,
or may simply be welded to the column. g assembly 20 may also be fabricated
with a plate or plates that bolt to a vertical support (not shown).
Inside the horizontal tube of the bearing tee is an injection-molded polymer bearing, or
the like, that has an inside shape conforming to torque tube 16, and a round outside
diameter. This bearing may be made from a polymer material such as UHMW
polyethylene with UV inhibitors and may be filled with a ant. This bearing may be
formed by two separate pieces to facilitate installation into the tee housing.
Spur-gear rack 30, D-ring chain drive ly 34 or cable drive system (not shown),
is connected to torque tube 16 preferably in the center of the tracker row. A circular
gear or D-ring chain drive assembly 30 allows for a constant leverage point to resist
wind-load forces applied to the array. Linear actuator driven s translate linear
motion into rotary motion, and must resist higher loads due to the fact that the
attachment of the actuator to the torque tube changes angle as a cosine function while
the tracker rotates. This s in the linear actuator having to resist higher loads than
a circular gear or chain drive . rive gearbox 26 is mounted to one or two
of the center support columns 22 of the tracker, and coupled to a spur-gear rack, D-ring
chain drive 30 or cable drive. Each tracker row worm-drive gearbox 26 is connected to
SUBSTITUTE SHEET (RULE 26)
the next using rotating drive shafts 28. The design of ear drive 26 and linkage
system eliminates the transfer of wind-load forces to the linkage. The worm-gear drive
mechanism 26 resists the wind-load forces locally, within the tracker supports, at each
tracker. This design incorporates a ng drive shaft—linked 28, worm-gear drive
system 26 to rotate many trackers with one motor.
As shown in Fig. 5, ic dampeners 32 may be installed along the length of torque
tube 16 at column locations 22, to decouple the structure from wind-induced forces.
Harmonic dampeners 32 increase the number of s that can be mounted onto a
longer torque tube 16 without increasing the stiffness and cost of the supporting
structure. Using dampeners 32 eliminates the need to se the size of torsion tube
16, while allowing more modules 12 to be d onto the same cross-section size
tube 16. The result is that the center of gravity of the array remains close to bearings
, which minimizes the ng weight loading to the drive system and spreads the
cost of the gear drive over a larger tracker row size.
As shown in Figs. 1A and 2, a row of single solar modules 12 connects to a torsion
tube 16 with a mounting apparatus 18 sing a module frame clamp, a module
laminate connection or a module-mounting rail. Connection 18 to torque tube 16 may
be made using a square bend U bolt or two bolts and a plate to form a clamp around
torque tube 16 or module mounting rails. This arrangement forms a long row of solar
modules 12 that rotate East and West as drive system 14 rotates torque tube 16. An
important consideration is to minimize the over-hung rotational moment that the
overhung weight of the modules creates. This may be accomplished by directly
connecting the module frames to torque tube 16, or if necessary, using a module rail
with a minimum depth, or offset, from the surface of torque tube 16.
Mechanical/y linked Ti/ted S/A r
The mechanically linked tilt and roll, single axis 44 embodiment of the present ion
is a tracking system for pointing one or more solar panels or PV modules 12 towards
the sun, and is shown in Fig. 6. Drive mechanism (not shown) as previously described,
provides the power and linkage to move PV modules 12 via drive shaft 28. Drive
SUBSTITUTE SHEET (RULE 26)
mechanism utilizes a rotating torsion tube 16, in this case, tilted, in the South
ion, orating mounting rails on which PV modules 12 are mounted. n
tube 16 is inserted into the upper bearing 20, with bearing surfaces such as no
nance polymer bushings, which is ed to the upper support columns 22. A
combination thrust and radial bearing can be incorporated into worm-drive gearbox 26
to resist the downward and radial forces exerted on the array. As previously described,
motor (not shown) drives a worm-gear drive box 26, which in turn, rotates the torsion
tube 16 directly or drives a secondary element, which in turn drives the n tube. A
spur gear rack or D-ring chain drive, as previously described can be affixed to torsion
IO tube (not . Thus, when activated by drive mechanism, PV modules 12 are
rotated. Thus, one motor can drive a plurality of drive mechanisms. The mechanically
linked tilt and roll tracker 44 ts the same “one way” drive ism as the
horizontal tracking system embodiment and thereby transmits only the forces
necessary to rotate the PV array and the wind forces are resisted locally within each
tracker array.
Mechanically Linked Fixed Tilt Azimuth Tracker
The mechanically linked fixed tilt azimuth single axis tracker 50 embodiment of the
presently claimed invention is shown in Fig. 7. This embodiment is also a tracking
system for pointing one or more solar panels or PV modules 12 towards the sun. The
preferred drive mechanism was previously described and is similar to the description.
Drive mechanism utilizes a rotating support tube assembly 52, in this case, vertical,
and incorporating a structure with ng rails 54 on which PV modules 12 are
mounted. As in the previous embodiments, a worm-gear assembly 56 is driven by
drive shaft 28, which in turn rotates outer vertical tube 58 along with mounted PV
modules 12. The rotating tube assembly 52 is shown in Fig. 8A. Outer vertical support
tube 60 is inserted over top gs 62 that are affixed to the top and the
ference of inner vertical support tube 64. Top bearing 62 preferably includes a
thrust and radial bearing surface as achieved for example with a tapered roller bearing.
Drive motor (not shown), as previously described, drives worm-gear drive box 66,
which in turn, rotates the torsion tube 68 directly or drives a secondary element which
SUBSTITUTE SHEET (RULE 26)
in turn drives the torsion tube (not shown). A spur gear rack or D-ring chain drive can
also be affixed to torsion tube 68, as previously described. To more clearly shown the
drive mechanism for this embodiment, Fig 8B shows a close up view of worm 70
driving ar ear 72, causing outer vertical support tube 60 to rotate. Thus,
when activated by drive mechanism PV modules 12 are d. Another design of the
fixed tilt azimuth tracker incorporates a slew drive bearing and worm-drive mechanism
to rotate and support the PV array. The gear drive is located sufficiently low on the
support structure so that the rotating linkage does not interfere with the PV modules as
they rotate. For a mechanical linkage as shown in Fig. 7, drive shaft 28 is driven by a
IO motor through a worm-gear drive box 56, which in turn is affixed to a second drive
mechanism for concurrently rotating a second set of PV modules 12. Thus, one motor
24 can drive a plurality of drive mechanisms. The ically linked fixed tilt azimuth
tracker exploits the same “one way" drive mechanism as the horizontal tracking system
embodiment thereby resisting the wind forces y within each tracked array.
Mechanically Linked el Azimuth Tracker
The mechanically linked carousel azimuth tracker is shown in Fig. 9. The mechanically
linked carousel azimuth single axis tracker embodiment of the presently claimed
invention is also a tracking system for pointing one or more solar panels or PV modules
12 towards the sun. Drive mechanism, previously described, provides the power and
linkage to move PV modules 12 for each carousel tracker assembly 70. In this
embodiment, each el tracker assembly 70 is rotated in , as shown. Drive
mechanism provides the power and linkage to move PV modules via drive shaft 28.
Drive mechanism es a mechanically linked worm-drive gearbox 72 in conjunction
with a large diameter, bearing ring 74 on which PV array 12 rotates. Worm-drive
gearbox 72 rotates large diameter ring 74 through the uses of a secondary assembly
such as a rack and pinion gear, chain drive or cable drive system (not shown).
Rotating drive shaft 28 rotates the worm, which in turn rotates the worm-gear, which
then rotates a spur gear, pulley or chain sprocket, which rotates large diameter bearing
ring 74. The g incorporates both radial and thrust g surfaces. These
bearing surfaces may be constructed of polymer gs, or ed rollers. PV
SUBSTITUTE SHEET (RULE 26)
array 12 of carousel tracker 70 may also be configured in a low profile to minimize wind
loads and may be suitable for use on p applications. Carousel tracker 70 exploits
the same mechanically linked “one way" drive mechanism as the horizontal tracking
system embodiment and thereby allowing many trackers to be driven by one motor.
The external wind forces on the rs are ed locally within each tracked array.
Tracker Controller
The microprocessor tracker control system may incorporate a global positioning system
(GPS) to obtain location and time information and to tically update and
compensate for the internal clock drift of the electronics. Time, date, and location
information will be used by the microprocessor controller to calculate the solar position
and move the tracking system to maximize the exposure of the modules to the sun.
The solar tracking thms are well known and published. The system may also
have external inputs such as a wind speed monitor to enable the trackers to be
tically feathered in the event of a severe windstorm. The control system may
include a manual override function to manually late the r position for
installation or maintenance. This control system may also incorporate diagnostics,
such as tracker functionality and/or array output monitoring.
The control system interacts with the motorized n of the drive system and the
data collection system. The gear~drive assembly will incorporate a position feedback
mechanism, preferably digital, to allow the microprocessor to move the tracker into a
desired position and keep track of whether the tracker is functioning properly. The
motorized assembly incorporates an end of travel indicator that will allow the
rocessor to know that it is in the “end” position assuring that the motor will not
drive the trackers. past their mechanical limits, and ng the position of the r to
reset itself once per day to avoid accumulation of position error. The motor should
incorporate a means of dynamic overload protection. If the tracker fails to move due to
mechanical failure or motor overload, the control system should be capable of detecting
the malfunction, stop the operation, and record or transmit the information.
SUBSTITUTE SHEET (RULE 26)
Many of the zed tracker drives may be connected to a single controller in either a
wired or wireless network configuration. Multiple master controllers in a large solar field
configuration may be networked together. The control system may record and
communicate current tracker positions. it may also record and communicate faults in
the tracker system to a supervisory control system. Other enhancements to the control
system may include PV output monitoring on each tracker. Since the entire module
output falls to near zero if it is partially shaded, it is necessary to incorporate a back-
ng scheme, which will rotate the modules in the opposite direction of the sun, in
order to eliminate one tracker from shading r in the early g and evening,
as the sun is close to the horizon. The back-tracking scenario may be calculated from
the sun angle, the height of the array, and the spacing between rs. Individual
rs may back-track at different rates based upon the mounting height of the
trackers in relation to the adjoining trackers.
For smaller installations where fewer trackers are installed, a simpler optical, closed
loop tracking system can be used instead of the open loop microprocessor control as
described above.
Fig. 10 is a flow chart that shows the preferred method of incorporating an adjustable
limit to the driveline torque that can be applied by the motor to a driveline. In most
tracker systems, when a tracker is impeded by an obstacle, or heavy snow load or the
like, the circuit breaker for the motor is tripped causing a person to go out to the stuck
tracker to reset the t breaker even if the obstacle is removed or the stuck condition
goes away. For example, if a heavy snow has fallen and temporarily impedes the
nt of the tracker. The presently claimed invention provides a system to
temporarily remove power to the motor for a predetermined amount of time and to then
provide power to the motor again once the impeded condition is cleared or to continue
to prevent power to the motor if the condition continues after at least one reset cycle.
The determination of the amount of ine torque or lack of movement of the tracker
can be accomplished in several methods. Clutch slippage can be determined, a sensor
can be mounted on the tracker to sense nt, the amount of power used by the
motor canbe monitored for a predetermined level or any other r method can be
SUBSTITUTE SHEET (RULE 26)
employed, each of these methods, collectively defined, as sensing movement of the
r assembly.
Referring to Figs. 1 and 10, the preferred system and method first calculates a position
150 in a programmable logic control (PLC) 152, as performed in most tracker systems.
The system then sends a prompt to move the tracker 154, if necessary. If the tracker is
in a correct position and does not need to be moved 156 the system reverts to
calculate position 150 mode. This information is conveyed to a remote Supervisory
Control And Data Acquisition ) 180, via an onboard controller 17. SCADA 180
es communication to and from one or more tracker systems via typical
communication networks 19. If the r es movement 158, a prompt is sent to
tracker motor 14 to move the tracker. Tracker position ck 160 is provided from
tracker motor 14 and a determination as to whether the tracker is moving 162, via a
movement sensor 21. If the tracker is moving 164, the system is operating normally
and the system feeds back to calculate position 150 mode. if the tracker is not moving
166, the system enters into obstruction clearing mode 1 (OCM1) 168 and PLC 152
sends a signal to SCADA 180. OCM1 168 is typically a high frequency t to
move the tracker for a predetermined amount of time by prompting 170 tracker motor
14 and sending a signal to calculate position 150. For example, this can be once per
minute for a thirty minute period of time. The frequency and the time period are fully
adjustable by a user. OCM1 168 is typically ient to compensate for a momentary
wind event or a temporary obstruction. If the tracker moves as instructed during the
OCM1period, the tracker is operating in a normal fashion again and reported 172 to
SCADA 180 and to calculate position 150.
After the ermined amount of time is exhausted in OCM1 168 mode and there is
still a no movement condition, a prompt 174 is provided and the system enters an
ction clearing mode 2 (OCM2) 176 via a message from SCADA 180. OCM2 176
is typically a lower frequency attempt to move the tracker, for example once every
twenty s, for a longer period of time, for example two weeks. Again, the
frequency and time period are fully adjustable by the user. OCM2 176 is designed for
longer term obstruction events, such as a lingering snow storm. If during OCM2 176
SUBSTITUTE SHEET (RULE 26)
time period, the tracker begins movement, this is reported 178 to SCADA 180 and to
calculate position 150 and the system operates in a normal fashion. If after the OCM2
time period and no movement of the tracker are measured, the system ceases all
movement attempts and reports to SCADA 180 that a malfunction condition exists and
maintenance crew can be dispatched to the site.
The state of the art presently requires welded terminations or s which are very
costly and ible for drive-shafts. A welded termination is typically used by welding
the end to a driveline yoke or the like. Round tubing is the most efficient and requires
the least al for uction for transmitting torque. Figs. 11 and 12 show the
preferred embodiment for a coupler for round tubes or a tor to the driveline
linkage, such as u-joints as shown in the figures. As shown in Fig. 11, coupler 100 is
formed on round shaft 110. Coupler 100 has an 8 shaped end 112 with opposing
indented grooves 114, which are semicircular and located in the center of 8 shaped
ends 112. One or more coupler apertures 118 are drilled through opposing indented
grooves 114, as shown. lndented s 114 are configured to accept half round
shaped compression keys 116. Compression keys 116 have complimentary key
apertures 120 that correspond to coupler apertures 118 for insertion of coupler bolts
122, coupler washers 124, coupler lock s 128, and r nuts 126.
Component end 130 has a similar 8 shaped component end 132 that is red to
be ed inside of 8 shaped end 112 within an optimized tolerance. Inside
component indented grooves 134 is an elongated slot 136 for accepting bolts 122 and
to make the connection adjustable. Fig. 12 shows the connection n coupler 100
and component end 130 with bolts 122 inserted through opposing compression keys
116, coupler apertures 118, elongated slot 136 and tightened coupler nuts 126. The
structural elements and compression method for coupling round shaft 110 to
component 138 provides for an easy system for ing a robust connection. This
also provides for a tight, concentric and keyed driveline connection that is inexpensive
to fabricate and will accommodate varying length drive-shafts in the factory and does
not require field welding or painting. The resulting connection is easy to assemble, is
SUBSTITUTE SHEET (RULE 26)
adjustable in length and has excellent concentricity, tightness, and the ability to
transmit high torque loads.
Figs. 13, 14, and 15 show the preferred coupler for a square torsion tube or driveline.
Coupler 200 is a square tube with an internal ion larger than a torsion tube 202
or square driveline. Fig. 13 is an exploded view of coupler 200. Fig. 14 shows coupler
200 as led and Fig. 15 shows coupler 200 splicing opposing torsion tubes 202.
Coupler 200 comprises housing 204 with a length 206 sufficient to hold both ends of
torsion tube 202 in a stable position and to align two opposing torsion tubes 202.
red coupler 200 has a spacer plate 208 which is an angled structure configured
to be sandwiched between housing 204 and torsion tubes 202 when torsion tubes 202
are inserted into housing 204. Spacer plate 208 is used for r stability and
alignment of opposing torsion tubes 202. Spacer plate 208 has two through bolt
apertures 210 and a stop pin aperture 212 located substantially in the center of spacer
plate 208. Housing 204 has two threaded pressing apertures 214 with pressing bolts
216 for pressing against spacer plate 208 when pressing bolts 216 are tightened, thus,
pressing spacer plate 208 against opposing n tubes 202. g 204 also has
two threaded gouging apertures 218 and two gouging bolts 220 that are tightened into
threaded gouging apertures 218. Gouging apertures 218 are substantially aligned with
through bolt apertures 210 to allow gouging bolts 220 to contact or gouge into torsion
tubes 202 when tightened. Housing 204 ably has a stop pin 222, which can be a
rivet, bolt or pin, affixed to a center of housing 204 to serve as a stop for insertion of
torsion tubes 202 into housing 204. Although, this disclosure and the drawings show
two threaded gouging apertures 218 and two threaded pressing apertures 214 with
ponding bolts, this disclosure is intended to cover any number of them, thus the
number can be increased or decreased depending on the application.
Although this description referred to PV modules, the tly d ion can
also be used to track solar heat collectors, building shade systems, sunlight exposure
testing of materials, and other systems that require tracking of the sun.
SUBSTITUTE SHEET (RULE 26)
Although the claimed invention has been described in detail with ular reference to
these preferred ments, other embodiments can achieve the same results.
Variations and modifications of the presently claimed ion will be obvious to those
skilled in the art and it is intended to cover in the appended claims all such
modifications and equivalents. The entire disclosures of all references, applications,
patents, and publications cited above, are hereby incorporated by reference.
SUBSTITUTE SHEET (RULE 26)
Claims (11)
1. A method of adjusting a duration and frequency of obstruction clearing modes to a motor of a linked r system for driving a plurality of individual solar r 5 lies with the motor, the method comprising the steps of providing a communication system between an onboard controller on each tracker assembly and a remote supervisory control and data acquisition (SCADA); g a prompt to the motor to move the tracker assemblies towards the sun; sensing whether the tracker assemblies are moving towards the sun; 10 entering into a first obstruction clearing mode 1 (OCM1), if the tracker assemblies are not moving towards the light , the OCM1 comprising an OCM1 time period for an impeded condition of the tracker assembly to clear, wherein the OCM1 comprises an adjustable high frequency series of independent prompts to the tracker assemblies to move towards the sun; 15 entering into an obstruction clearing mode 2 (OCM2), if the tracker assemblies are not moving after an OCM1 time period, the OCM2 comprising an OCM2 time period for the impeded condition of the tracker assembly to clear, wherein the OCM2 ses an able low frequency series of independent prompts to the tracker assemblies to move towards the sun; and 20 ceasing movement attempts if the tracker assemblies are not moving towards the sun after an OCM2 time period.
2. The method of claim 1 wherein the step of providing a communication system comprises remotely monitoring the movement, prompting movement of the r 25 assemblies and commanding the tracker assemblies to enter the OCM1 or OCM2 modes.
3. The method of claim 1 wherein the step of monitoring movement of the tracker assemblies comprises a member from the group consisting of measuring clutch 30 ge, a movement sensor and ing power consumed by the motor.
4. The method of claim 1 further comprising entering into a normal mode if the tracker assemblies move correctly during the OCM1 or OCM2 modes.
5. The method of claim 1 further comprising the step of notifying maintenance personnel of a malfunction ion after the OCM2 time .
6. The method of claim 1 further comprising removing power to the motor in 5 between attempts to move the r assemblies during the OCM1 mode and OCM2 mode.
7. A system for adjusting the duration and frequency of ction ng modes to a motor of a linked tracker system for driving a plurality of individual solar tracker 10 assemblies with the motor, comprising a remote isory l and data acquisition, SCADA, configured to command and communicate with a programmable logic control, PLC; a communication system between the PLC on each tracker assembly and the SCADA; 15 a command sent by SCADA to the PLC to prompt the motor to move the tracker assemblies; a sensor configured to sense whether the tracker assemblies are moving towards the sun; the PLC configured to enter into a first obstruction clearing mode, OCM1, if the 20 tracker assemblies are not moving towards the sun, the OCM1 comprising an OCM1 time period for an impeded condition of the tracker to clear, wherein the OCM1 comprises an adjustable high frequency series of independent prompts to the tracker assemblies to move towards the sun, via command from the SCADA; the PLC further configured to enter into a second obstruction clearing mode, 25 OCM2, if the tracker assemblies are not moving after the OCM1 time period, the OCM2 comprising an OCM2 time period for the impeded condition of the tracker assembly to clear, wherein the OCM2 comprises an adjustable low frequency series of independent prompts to the tracker assemblies to move towards the sun, via command from the SCADA; and 30 the PLC further configured to cease movement attempts if the tracker assemblies are not moving towards the light source after an OCM2 time , via command from the SCADA.
8. The system of claim 7 wherein the SCADA is configured to remotely monitor the nt of the tracker assemblies.
9. The system of claim 7 wherein the sensor for monitoring movement of the 5 tracker assemblies comprises a member from the group consisting of a sensor for measuring clutch slippage, a movement sensor and a sensor for ing power consumed by the motor.
10. The system of claim 7 further comprises the PLC being configured to enter into 10 a normal mode if the tracker assemblies move correctly during the OCM1 or OCM2 modes.
11. The system of claim 7 further comprises the SCADA being ured to notify maintenance personnel of a malfunction condition after the OCM2 time period. WO 86079 ~
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/895,117 | 2013-05-15 | ||
US13/895,117 US9631840B2 (en) | 2008-06-12 | 2013-05-15 | Single axis solar tracking system |
PCT/US2014/033762 WO2014186079A2 (en) | 2013-05-15 | 2014-04-11 | Single axis solar tracking system |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ715055A NZ715055A (en) | 2020-10-30 |
NZ715055B2 true NZ715055B2 (en) | 2021-02-02 |
Family
ID=
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