Wind Turbine Thrust-Limiting Control System
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Solution Overview
Problem
Wind turbines experience high mechanical load and stress, particularly on towers, due to peak thrust forces caused by varying wind speeds and turbulence, which existing control methods fail to adequately address without significantly impacting power production.
Innovation Solution
A thrust-limiting control system that combines inputs from wind and turbulence estimators to regulate pitch angle, using a subtraction function and post-processing to generate signals for reducing thrust forces, incorporating additional parameters like generator torque and rotor inertia for efficient load management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If pitch regulation is used to control power production in high wind speeds, then power production is controlled, but maximum thrust load peaks occur in the regulation range (8-12 m/s)
Solution Approach 1:
The control system performs preliminary action by detecting the onset of pitch regulation in the 8-12 m/s wind speed range and preemptively adjusting control parameters to prevent thrust load peaks before they occur. The system monitors wind speed and pitch angle to identify when pitch regulation begins and applies corrective control signals to maintain optimal thrust levels.
Solution Approach 2:
The invention changes operational parameters by modifying the relationship between pitch angle and thrust control in the critical wind speed range. Instead of relying solely on pitch regulation for power control, the system adjusts multiple parameters including pitch rate, pitch angle limits, and control response characteristics to eliminate thrust peaks while maintaining power production control.
2Strength
If thrust limitation is applied to reduce mechanical load, then mechanical load on tower and blades is reduced, but power production may be impacted
Solution Approach 1:
The control system applies local quality by implementing thrust limitation only in the specific wind speed range (8-12 m/s) where pitch regulation causes thrust peaks, rather than applying universal thrust limitation across all operating conditions. This localized approach reduces mechanical load where needed while preserving power production capability in other wind speed ranges.
Solution Approach 2:
The system applies partial action by using moderate thrust limitation that is sufficient to reduce peak loads but not so aggressive as to significantly impact power production. The control adjusts the degree of thrust limitation dynamically based on actual thrust measurements and wind conditions, applying just enough control action to eliminate peaks while maintaining acceptable power output.
3Productivity
If existing control methods are used without thrust limitation, then power production is maintained, but mechanical stress on towers increases
Solution Approach 1:
The invention implements feedback control by continuously monitoring actual thrust forces using measurements from accelerometers or load cells on the tower. The measured thrust feedback is combined with wind speed and pitch angle information to dynamically adjust control signals, ensuring that mechanical stress on the tower is reduced while maintaining power production through adaptive control.
Solution Approach 2:
The control system achieves multi-functionality by simultaneously performing power production control, thrust limitation, and mechanical stress reduction through a unified control algorithm. The system integrates multiple control objectives into a single control framework that manages pitch regulation and thrust limitation together, eliminating the need for separate control systems and achieving both productivity and structural protection.
Data Source
AI summary
The present invention relates to a control system for thrust-limiting of wind turbines, which wind turbine comprises at least one tower, which tower carries at least one nacelle which nacelle comprises a rotating shaft, which shaft is rotated by one or more blades, which blades at pitch regulated by a pitch control system. It is the object of the present invention to reduce mechanical load and stress of a wind turbine. A further object is to reduce the maximal load on tower of a wind turbine. The thrust-limiting control system performs control of the pitch angle, which thrust-limiting control system performs regulation of the pitch angle based on at least a first input from a wind estimator and a second input from a turbulence estimator. By thrust-limiting control, reduction in the maximum mechanical load on a tower, or maybe also a nacelle, can be achieved by a relatively high percentage of the load in a way where it has only very limited influence on the power production of the wind turbine.