Wind Turbine Blade Pitch Control Under Yaw and Wake Loads
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Solution Overview
Problem
Conventional wind turbine blade pitching systems struggle to maintain pitch references under conditions of high yaw misalignment, high shear, or wake situations, leading to increased loads and risks of overloading mechanical components due to insufficient pitch forces or hydraulic pressure.
Innovation Solution
A method and device that prioritize individual pitch references over collective pitch references by calculating tracking errors and applying corrective offsets to ensure all blades reach their desired positions, thereby reducing excessive loads on turbine components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual pitch control is applied to reduce loads on turbine components, then mechanical loads are reduced, but the pitch system may become unable to reach desired pitch references under certain wind conditions
Solution Approach 1:
The control system continuously monitors the actual pitch position of each blade and compares it with the desired pitch reference. When a deviation is detected (tracking error exceeds threshold), the system automatically adjusts the collective pitch reference to ensure the individual pitch control can still achieve its load reduction objective, creating a closed-loop feedback mechanism that adapts to changing wind conditions.
Solution Approach 2:
The system dynamically adjusts the collective pitch reference based on real-time tracking errors of individual blades. Instead of using a fixed collective pitch reference, the controller modifies it adaptively when individual blades cannot reach their desired positions, allowing the system to maintain load reduction effectiveness under varying wind conditions while preserving individual pitch control capabilities.
2Productivity
If the pitch system operates with insufficient pitch force or low hydraulic pressure, then power production may be maintained, but the system cannot overcome large wind forces and reach pitch references
Solution Approach 1:
The system proactively detects when tracking errors exceed predefined thresholds, indicating that the pitch system cannot reach desired positions under current conditions. By anticipating this limitation and automatically adjusting the collective pitch reference beforehand, the system prevents pitch reference violations while maintaining power production, rather than reacting after the problem occurs.
Solution Approach 2:
The controller changes the operating parameters of the pitch system by adjusting the collective pitch reference when individual pitch control demands cannot be met. This parameter adaptation allows the system to operate reliably under constrained conditions (insufficient pitch force or hydraulic pressure) while maintaining both power production and pitch control effectiveness within available capabilities.
3Productivity
If conventional controllers are used under high yaw misalignment or wake conditions, then basic power production is maintained, but excessive loads occur and mechanical components risk overloading
Solution Approach 1:
The system pre-calculates individual pitch references for each blade based on predicted wind conditions and rotor position. By preparing corrective pitch actions in advance and having ready-adjustable collective pitch references, the system can respond immediately to high yaw misalignment or wake conditions, applying load reduction before excessive mechanical loads develop on turbine components.
Data Source
AI summary
A method and a device for pitching blades of a wind turbine is provided. The wind turbine is configured to collectively pitch all blades by a collective pitching degree and to individually pitch each blade by an individual pitching degree. If it is determined that at least one blade is unable to reach its individual pitch reference, the individual pitch reference for this blade is prioritized against the collective pitch reference.