Wind Turbine Torque Limiting Using Dynamic Envelope Control
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Solution Overview
Problem
Wind turbines face challenges in handling varying torque loads due to the unpredictable nature of wind, leading to fatigue and extreme loads on drivetrain components, which can require oversized and expensive components to withstand large load cycles, reducing power production.
Innovation Solution
Implementing a dynamic torque limit system that tracks torque variations using envelope signals, setting upper and lower limits based on previous values to manage torque within a defined band, allowing for optimized power production while minimizing component stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conservative torque limits are set to handle large load cycles, then reliability of drivetrain components is improved, but power production is reduced significantly
Solution Approach 1:
The patent applies dynamics by transitioning from static torque limits to dynamic torque limits that adapt in real-time. The system continuously updates the torque limit based on the envelope signal derived from historical torque data, allowing the limit to follow the general trend of torque variations. This dynamic adjustment enables the system to maintain reliable component protection while maximizing power production by avoiding unnecessary conservative restrictions.
Solution Approach 2:
The patent changes the parameter of torque limit from a fixed value to a dynamically varying value. By calculating the envelope signal from previous torque values and using it to set the torque limit, the system transforms the torque limit parameter to adapt to changing operating conditions. This allows the torque limit to be higher during favorable conditions and lower during extreme conditions, resolving the contradiction between reliability and productivity.
2Strength
If oversized components are used to withstand large load cycles, then strength of drivetrain components is improved, but device complexity and cost increase
Solution Approach 1:
The patent changes operational parameters (torque limits) rather than physical parameters (component size). By dynamically adjusting the torque limit based on the envelope signal, the system protects existing components from excessive loads without requiring oversized design. This approach maintains component strength through intelligent control rather than physical over-engineering, reducing device complexity and cost.
3Device complexity
If static torque limits are used, then device complexity is reduced, but adaptability to varying wind conditions deteriorates
Solution Approach 1:
The patent implements feedback by continuously monitoring torque values and using them to update the envelope signal, which in turn adjusts the torque limit. The system feeds back historical torque information through the envelope calculation to dynamically set appropriate limits. This feedback mechanism enables the system to adapt to varying wind conditions automatically while maintaining relatively simple device architecture.
Solution Approach 2:
The system performs self-service by automatically adjusting its own torque limits based on observed torque patterns. The envelope signal is generated autonomously from historical data, and the torque limit is self-regulated without requiring complex external control systems. This self-adjusting capability provides adaptability to varying conditions while keeping device complexity low.
Data Source
AI summary
Techniques are provided for control of a wind turbine where a torque limit is set based on a control signal. A current torque value of a rotor of the wind turbine is determined and compared to an upper torque limit value and the control signal is modified if the current torque value is larger than the upper torque limit value. The upper torque limit value is based on a lower envelope signal which tracks the current torque value if the current torque value is lower than or equal to the previous lower envelope value and is set as a rising signal if the current torque value is higher than the previous lower envelope value. The upper torque limit is set to be a first amount higher than the lower envelope signal.