Wind Turbine Blade Flutter Control via Dynamic Overspeed Thresholds
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Solution Overview
Problem
Conventional wind turbine blade fluttering speed optimizations result in unnecessary shutdowns due to lowered safety overspeed thresholds, impacting availability and power production, and previous attempts to increase fluttering speed through structural modifications are costly and increase blade weight.
Innovation Solution
A method and device that dynamically adjust the overspeed threshold based on pitch angle and wind speed to prevent blade fluttering, using a control system to set a final overspeed threshold value that is equal to or smaller than the minimum of preliminary values, thereby reducing shutdowns and structural modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the safety system overspeed threshold is lowered to avoid blade fluttering, then blade structural integrity is protected, but unnecessary shutdowns occur reducing availability and power production
Solution Approach 1:
The patent applies dynamics by making the overspeed threshold dynamic rather than static. The threshold is continuously adjusted based on real-time operating conditions including pitch angle and wind speed. This allows the threshold to adapt to actual fluttering risks, maintaining high reliability when needed while avoiding unnecessary shutdowns when safe operation is possible.
Solution Approach 2:
The patent changes the parameter of overspeed threshold from a fixed value to a variable that depends on pitch angle and wind speed. By monitoring these parameters and adjusting the threshold accordingly, the system optimizes the balance between safety and productivity, allowing operation at higher speeds when conditions permit while preventing fluttering when risks are present.
2Stability of the object's composition
If structural blade properties are changed to increase fluttering speed, then blade stability is improved, but blade mass and weight significantly increase
Solution Approach 1:
The patent replaces mechanical/structural modifications with a control system approach. Instead of physically reinforcing blades to increase fluttering speed, the system uses sensors and control algorithms to monitor operating conditions and dynamically adjust the overspeed threshold, achieving blade stability protection without adding weight.
Solution Approach 2:
The patent changes the operational parameters (overspeed threshold) rather than the physical parameters (blade structure). By adjusting the threshold based on pitch angle and wind speed, the system achieves improved blade stability while avoiding the weight penalty associated with structural modifications.
3Reliability
If a fixed low overspeed threshold is used to prevent fluttering, then blade safety is ensured, but shutdowns occur in regions where fluttering would not occur
Solution Approach 1:
The patent makes the overspeed threshold dynamic by linking it to real-time pitch angle and wind speed measurements. This allows the threshold to be higher in operating regions where fluttering is not a risk and lower in regions where it is, ensuring blade safety while maintaining operational continuity in safe regions.
Solution Approach 2:
The patent applies local quality by making the overspeed threshold specific to each operating condition rather than uniformly low across all conditions. The threshold is tailored to the local operating environment (pitch angle and wind speed), allowing safe operation in regions where fluttering would not occur while maintaining protection where it would.
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 reduces unnecessary shutdowns and structural modifications, enhancing the structural integrity and safety of wind turbines while maintaining availability and power production, and reducing the risk of blade damage and repair costs by correlating overspeed thresholds with hazardous operation regions.
Implementation Method 1
defining a fluttering rotor speed at and above which a predetermined fluttering of at least one of the blades occurs
Data Source
AI summary
A device and a method of controlling blade instabilities of a wind turbine is provided. The method including the following steps: defining at least one preliminary overspeed threshold value; defining a fluttering rotor speed at and above which a predetermined fluttering of at least one of the blades occurs, the fluttering rotor speed is defined as a function of the pitch angle and/or as a function of the wind speed; setting a final overspeed threshold value to be equal to or smaller than a minimum rotor speed of the at least one preliminary overspeed threshold value and the fluttering rotor speed at the actual pitch angle and/or at the actual wind speed; and controlling the rotor speed to not exceed the final overspeed threshold value.