Wind Turbine Control via Observer-Based Wind Speed Estimation
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Solution Overview
Problem
Modern wind turbines face challenges in accurately controlling their operation due to variations in wind speed across the rotor area, which are difficult and costly to measure, leading to inefficiencies in control strategies that rely on rotational speed-power curves and fixed blade angles, especially during transitions from partial to full load modes.
Innovation Solution
A method using an observer model, potentially a Kalman filter, estimates wind speed by incorporating measured rotor speed, pitch angles, and generator torque, along with expected wind variations, allowing for dynamic adjustments of blade angles and torque to optimize wind turbine operation based on estimated wind speed rather than relying solely on rotational speed-power curves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wind speed is measured using sensors in the large rotor area, then wind speed data can be obtained for control, but measurement precision and reliability deteriorate due to wind condition variations across the area
Solution Approach 1:
The patent introduces an observer as an intermediary computational model that indirectly estimates wind speed by processing measurements of rotor speed, pitch angles, and generator torque through a mathematical model of the wind turbine system, avoiding direct wind speed measurement sensors in the rotor area
Solution Approach 2:
The patent replaces physical wind speed measurement sensors with a computational estimation system (observer) that uses electrical and mechanical measurements (rotor speed, pitch angles, generator torque) processed through aerodynamic and mechanical models to derive wind speed information
2Adaptability or versatility
If rotational speed-power curves with fixed blade angles are used for control, then control simplicity is maintained, but adaptability deteriorates during transitions from partial to full load modes
Solution Approach 1:
The patent transitions from static fixed blade angle control to dynamic pitch angle control where the pitch angles of rotor blades are continuously adjusted based on real-time operating conditions and the estimated wind speed, enabling adaptive optimization across different load modes
Solution Approach 2:
The patent changes the control parameters from fixed blade angles to variable pitch angles that are dynamically adjusted, and from indirect speed-based control to direct wind speed estimation-based control, allowing the system to adapt to varying wind conditions and load modes
3Reliability
If multiple wind speed measurements at different locations are considered, then control accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple measurement inputs (rotor speed, pitch angles, generator torque) into a unified wind speed estimation through the observer model, combining information from different sources to achieve reliable control without requiring multiple separate wind speed measurement systems
Data Source
AI summary
A method for controlling a wind turbine using an estimated wind speed is provided. The wind turbine has a rotor rotatable with a variable rotor speed and having rotor blades with adjustable pitch angles and a generator adapted to control a generator torque or a generator output power. The method comprises measuring the rotor speed, determining a common pitch angle representative of at least one or all pitch angles of the rotor blades, determining the generator torque or an output power of the generator and estimating the wind speed by means of an observer. The observer uses a model of the wind turbine as an observer model, uses as input variables, the measured rotor speed, the determined common pitch angle and the determined generator torque or the determined output power, and incorporates expected variations of the wind as at least one stochastic variable.