Wind Turbine Tower Vibration Control via Diameter Segmentation
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Solution Overview
Problem
Existing wind turbine tower designs face impermissible stress due to transverse vibrations caused by vortex shedding, which are not adequately addressed by current technologies.
Innovation Solution
The method involves determining a design wind speed and natural frequencies of the tower system, then adjusting the tower diameter in specific sections to deviate from critical diameters, creating excitation sections with different diameters to reduce vortex shedding frequency and vibration amplitudes, thereby minimizing stress from transverse vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tower diameter is optimized for load-bearing capacity and stability, then the tower strength is improved, but the tower becomes more susceptible to transverse vibrations at critical diameters
Solution Approach 1:
The patent applies local quality by creating an excitation section with a different diameter than the main tower body. This localized diameter change (reduction or enlargement by at least 10%) specifically targets the region where transverse vibrations occur most intensely (the upper third to half of the tower height), while maintaining the optimal diameter for the majority of the tower structure. This resolves the contradiction by preserving overall strength while locally modifying the vibration-prone area.
Solution Approach 2:
The patent employs parameter changes by deliberately altering the diameter parameter in the excitation section to deviate from the critical diameter that would resonate with the tower's natural frequency. By changing the diameter parameter in this specific region, the vortex shedding frequency is shifted away from the tower's natural frequency, eliminating resonant vibrations while maintaining the tower's overall structural integrity.
2Length of moving object
If the tower diameter is reduced to avoid blade-tower contact, then the clearance is improved, but the tower becomes more vulnerable to vibration-induced stress
Solution Approach 1:
The patent applies segmentation by dividing the tower into distinct sections: a main tower body with one diameter optimized for structural strength and blade clearance, and a separate excitation section with a different diameter specifically designed to control vibration characteristics. This segmentation allows each section to be optimized for its specific function without compromising the other.
3Ease of manufacture
If the tower is designed with uniform diameter for simplicity, then the manufacturing ease is improved, but the tower experiences excessive stress from vortex shedding at natural frequencies
Solution Approach 1:
The patent applies local quality by creating an excitation section with a different diameter than the main tower body. This localized diameter change (reduction or enlargement by at least 10%) specifically targets the region where transverse vibrations occur most intensely (the upper third to half of the tower height), while maintaining the optimal diameter for the majority of the tower structure. This resolves the contradiction by preserving overall strength while locally modifying the vibration-prone area.
Solution Approach 2:
The patent employs parameter changes by deliberately altering the diameter parameter in the excitation section to deviate from the critical diameter that would resonate with the tower's natural frequency. By changing the diameter parameter in this specific region, the vortex shedding frequency is shifted away from the tower's natural frequency, eliminating resonant vibrations while maintaining the tower's overall structural integrity.
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
This approach effectively reduces the excitation of transverse vibrations, ensuring the tower is not subjected to excessive stress, thereby enhancing its structural integrity and serviceability.
Implementation Method 1
Transverse vibrations are caused by mutually successive, quasi-periodically replacing vortices, so-called Kármán vortices
Implementation Method 2
a critical diameter is determined at which the vortex shedding frequency of the tower, subjected to the design wind speed, corresponds to the tower natural frequency, and the tower thus oscillates at the tower natural frequency
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The method involves determining the construction wind speed depending on the average wind speed at a site of the wind energy plant and determining an initial diameter for the tower (16). The tower natural frequency of the wind energy plant is determined. A critical diameter is determined, in which the tower oscillates with the tower natural frequency. A predetermined difference value of the critical diameter is set when the initial diameter does not deviate from the critical diameter by the predetermined difference value. An independent claim is included for a tower of a wind energy plant with a conical transition area.