Wind Turbine Pitch Control Using Turbulence-Based Blade Load Limits
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Solution Overview
Problem
The increasing length of rotor blades in wind turbines has heightened the risk of collisions with the tower, particularly under conditions of high wind turbulence.
Innovation Solution
A method that dynamically adjusts the pitch angle of rotor blades based on real-time measurements of bending moments and wind turbulence intensity, generating an output signal to control the pitch setting system and reduce deflection towards the tower when the maximum allowed bending moment is exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pitch angle is continuously adjusted to prevent rotor blade collision with the tower, then the safety against collision is improved, but the annual energy production is reduced due to unnecessary pitching maneuvers
Solution Approach 1:
The patent changes the parameter of maximum allowed bending moment based on wind turbulence intensity. When wind turbulence intensity increases, the maximum allowed bending moment is reduced, triggering pitch angle adjustment. This dynamic parameter adaptation allows the system to maintain safety under turbulent conditions while avoiding unnecessary pitching during calm periods, thus preserving energy production.
Solution Approach 2:
The control system continuously monitors wind turbulence intensity and bending moment, using this feedback to dynamically adjust the pitch angle only when necessary. The system compares real-time turbulence data against thresholds and adjusts pitch accordingly, creating a feedback loop that prevents collision while minimizing energy loss from excessive pitching maneuvers.
2Reliability
If the maximum allowed bending moment is set to a low fixed value to prevent collision, then the safety margin is improved, but the operational flexibility and energy production are reduced
Solution Approach 1:
The patent transforms the static maximum allowed bending moment into a dynamic parameter that adapts to changing wind turbulence conditions. The system continuously adjusts the allowable bending moment based on real-time turbulence measurements, enabling operational flexibility while maintaining safety margins. This dynamic approach replaces fixed conservative limits with adaptive thresholds.
Solution Approach 2:
The maximum allowed bending moment is changed from a fixed parameter to a variable parameter dependent on wind turbulence intensity. When turbulence is low, higher bending moments are permitted, increasing operational flexibility. When turbulence increases, the limit is reduced to maintain safety, thus adapting the parameter to environmental conditions.
Data Source
AI summary
The method is for operating a wind turbine having a rotor with at least one rotor blade, a tower and a pitch setting system. First information is provided which is representative for a bending moment of the rotor blade. Second information is provided which is representative for the wind turbulence intensity at the rotor. Third information is provided which is representative for a predetermined maximum allowed bending moment of the rotor blade. The maximum allowed bending moment depends on the wind turbulence intensity at the rotor. Fourth information is determined depending on the first, second and third information and is representative for whether the bending moment exceeds the maximum allowed bending moment. If so, an output signal is generated and configured to cause the pitch setting system to change the pitch angle of the rotor blade to reduce deflection of the rotor blade towards the tower when passing the tower.