Solar trackers incorporating torsion limiters
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Solution Overview
Problem
Solar tracking systems face challenges in resisting high hinge moment forces, which can lead to torsional divergence and increased structural loading, necessitating strong torsional members that are costly and heavy due to the need to counteract wind-induced forces at a single point.
Innovation Solution
Incorporating a torsion limiter, such as a torque limiting clutch, at the output of a primary gearbox before the engagement of a secondary gear rack in each tracker row, allowing the system to resist torsion forces at multiple points and reducing peak torsion forces, thereby minimizing structural requirements and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the hinge moment is resisted at a single point in the structure, then the tracker can maintain structural integrity, but the torsional forces on the torsion tubes become large requiring strong and heavy structural members
Solution Approach 1:
The patent divides the single-point resistance system into multiple resistance points along the torsion tube. Torque limiting devices are installed at multiple locations (e.g., at each tracker row) to resist hinge moment forces, distributing the torsional load across multiple segments of the structure rather than concentrating it at one point.
Solution Approach 2:
The patent changes the structural parameter from single-point to multi-point force resistance. By installing torque limiting devices at multiple positions along the torsion tube, the system transforms how torsional forces are distributed, reducing the peak torsional stress on any single section and allowing for lighter structural members.
2Strength
If strong torsional members are used to resist high hinge moment forces, then the tracker can counteract wind-induced forces, but the material cost and structural weight increase
Solution Approach 1:
Instead of using one extremely strong torsional member, the patent segments the resistance function across multiple weaker torque limiting devices distributed along the structure. Each device handles a portion of the total hinge moment, allowing the use of lighter materials overall while maintaining equivalent or superior torsional resistance.
Solution Approach 2:
The torque limiting devices act as intermediary elements between the wind loads and the main torsion tube. These devices provide localized torque resistance that protects the torsion tube from excessive torsional stresses, allowing the tube itself to be designed with lighter material while still achieving the required overall torsional resistance.
3Quantity of substance
If the tracker structure is made flexible to reduce material weight, then cost is reduced, but torsional divergence and dynamic forces increase under wind loading
Solution Approach 1:
The torque limiting devices are installed in advance as protective elements that cushion the flexible structure against excessive torsional forces. When wind loads exceed the preset torque threshold, these devices slip or disengage, preventing the transmission of harmful torsional divergence forces to the flexible structure while allowing normal operational flexibility.
Solution Approach 2:
The torque limiting devices provide preliminary anti-action against torsional divergence by being pre-configured to resist torque up to a specific threshold. This preliminary resistance prevents the flexible structure from experiencing harmful dynamic forces while still allowing the structure to remain flexible and use less material.
4Force
If a torque limiting clutch is installed at the gearbox output, then peak torsion forces are reduced and structural requirements are minimized, but the device complexity increases
Solution Approach 1:
The torque limiting clutch is designed as a relatively simple, cost-effective component that can be mass-produced and installed at multiple locations. While it adds some device complexity, the individual clutch units are simple mechanical devices with no complex control systems, making the overall complexity increase manageable while achieving significant reductions in structural requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The torsion limiter effectively reduces wind-induced torsion forces, allowing the tracker to move to positions where torsion is minimized, and provides overload relief, reducing the need for strong structural components and lowering material and installation costs while protecting against obstructions.
Implementation Method 1
a friction drive system for frictionally coupling the support beam to the support pillar
Implementation Method 2
The torque limiting clutch is located at an output of the gear assembly and prior to a location where the gear drive system engages the gear rack. When a level of torque on the gear assembly exceeds a preset level the clutch slips, releasing the torque on the gear-driven mechanical unit and limiting a hinge moment about the rotational axis.
Data Source
Figure 1A~1D
Figure 2
Figure 3
AI summary
A solar tracker assembly comprises a support column, a torsion beam connected to the support column, a mounting mechanism attached to the torsion beam, a drive system connected to the torsion beam, and a torsion limiter connected to an output of the drive system. When an external force causes a level of torsion on the drive system to exceed a pre-set limit the torsion limiter facilitates rotational movement of the solar tracker assembly in the direction of the torsion, thereby allowing the external force to rotate about a pivot axis extending through the torsion beam. Exemplary embodiments also include methods of aligning a plurality of rows of solar trackers.