Dynamic Thrust Limits for Wind Turbines
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Solution Overview
Problem
Modern wind turbines face high aerodynamic thrust and resulting structural loads, particularly in turbulent winds, which can lead to fatigue damage and reduced energy output due to the need to operate below defined thrust limits, even in optimal conditions.
Innovation Solution
Defining multiple thrust limits based on wind speed distribution and turbulence probability isolines allows for dynamic adjustment of thrust levels, prioritizing structural safety in high turbulence and maximizing energy production in low turbulence conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single thrust limit is defined for wind turbines, then structural safety is improved, but energy output is reduced due to conservative operation below the thrust limit even in low turbulence conditions
Solution Approach 1:
The patent applies dynamics by transitioning from a static, single thrust limit to dynamic, adaptive thrust limits that vary with turbulence conditions. Multiple thrust limits are defined corresponding to different turbulence intensity levels, allowing the system to adaptively select appropriate limits based on real-time wind conditions. This resolves the contradiction by enabling conservative operation only when necessary (high turbulence) while allowing more aggressive operation when safe (low turbulence).
Solution Approach 2:
The patent changes the parameter of thrust limits from a single fixed value to multiple variable values based on turbulence intensity. By introducing turbulence-dependent thrust limits, the system can adjust operational parameters dynamically, improving energy capture in low turbulence while maintaining structural safety in high turbulence conditions.
2Strength
If thrust limits are defined to prevent high aerodynamic thrust, then blade root bending loads are reduced, but fatigue life is still compromised in highly turbulent winds due to repeated high load events
Solution Approach 1:
The patent applies preliminary action by pre-defining multiple thrust limits corresponding to different turbulence intensity levels before operation. These pre-established limits allow the control system to proactively adjust operations based on predicted or measured turbulence conditions, preventing excessive loads before they occur and thereby protecting against fatigue damage accumulation.
Solution Approach 2:
The patent implements feedback mechanisms through load monitoring systems that continuously measure actual blade root bending loads and turbulence conditions. This feedback enables the system to verify whether defined thrust limits are adequate and to adjust operational parameters in real-time, ensuring fatigue life is protected while optimizing energy production.
3Ease of operation
If a single thrust limit is used across all wind conditions, then control strategy is simplified, but site-specific wind characteristics and turbulence patterns cannot be optimized
Solution Approach 1:
The patent applies segmentation by dividing the continuous range of turbulence conditions into discrete levels, each with its own thrust limit. This segmentation approach maintains relative simplicity in control implementation while enabling site-specific optimization through turbulence-dependent limit selection. The segmented structure allows easy integration with existing control systems.
Solution Approach 2:
The patent creates a universal framework that can be applied across different wind turbine sites by defining multiple thrust limits that can be selected based on local turbulence characteristics. This multi-functional approach allows the same basic control strategy to adapt to various site-specific conditions, combining simplicity with versatility.
Data Source
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AI summary
A method for defining a plurality of thrust limits for a wind turbine having a rotor with a plurality of blades and being located at a site. The thrust limits define values of aerodynamic thrust on the rotor not to be exceeded in operation. The method comprises providing a wind speed distribution representative for the site, and defining a plurality of isolines of constant turbulence probability representing a turbulence parameter as a function of wind speed. The turbulence parameter is indicative of wind speed variation. The isolines correspond to quantile levels of turbulence of the wind speed distribution. Turbulence ranges may be defined with respect to the isolines and thrust limits can be defined for the turbulence ranges. The disclosure also relates to methods of operating wind turbines using thrust limits and to wind turbines with suitable control systems.