Wind Turbine Wind Speed Estimation Using Blade Torsion Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for estimating wind speed at wind turbines are inaccurate, especially at high wind speeds and for turbines with flexible blades, as they do not account for the torsion effect on blade pitch angles, leading to incorrect control and energy conversion.
Innovation Solution
A method that calculates an adjusted pitch angle by adding a blade torsion contribution to the measured pitch angle, based on rotational speed and design parameters, to estimate wind speed more accurately, using a blade torsion look-up table or model-based simulation, and iteratively refines the estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wind speed is measured at a point behind the rotor, then the measurement is easy to obtain, but the measured wind speed does not reflect the actual wind speed at the rotor position
Solution Approach 1:
The patent replaces direct physical measurement with a computational estimation approach. Instead of measuring wind speed directly at the rotor position, the system uses measurements from accessible locations combined with aerodynamic models and blade response data to calculate the wind speed at the rotor, thereby achieving accurate measurement without physical intrusion into the rotor area
Solution Approach 2:
The patent introduces blade pitch angle and blade torsion as intermediary parameters. The blade acts as a mediator that transmits information about the wind conditions at the rotor to sensors that can measure pitch angle, allowing indirect determination of rotor-position wind speed through the blade's elastic response
2Measurement precision
If a single point wind speed measurement is used, then the measurement system is simple, but it does not reflect variations in wind speed across the rotor area
Solution Approach 1:
The patent makes the blade pitch angle measurement system serve multiple functions: it simultaneously controls blade pitch for power optimization and provides data for wind speed estimation. The same pitch actuator and sensor infrastructure is used both for active control and for observing blade torsion to infer wind conditions, eliminating the need for separate measurement devices
Solution Approach 2:
The blade itself serves as both the object being controlled and the measurement sensor. The blade's elastic deformation under wind load automatically provides information about the wind conditions, so the system uses the blade's own response to itself to generate measurement data without requiring external sensing infrastructure
3Measurement precision
If blade torsion is not accounted for in pitch angle, then the control system is simpler, but the wind speed estimation becomes inaccurate at high wind speeds and with flexible blades
Solution Approach 1:
The patent performs preliminary characterization of blade torsion behavior through finite element analysis and experimental testing to create lookup tables or analytical models. This pre-computed torsion data is then used during operation to correct pitch angle measurements, avoiding the need for complex real-time torsion calculations while maintaining accuracy
Solution Approach 2:
The patent implements feedback by using the measured pitch angle and estimated wind speed to continuously update the torsion compensation. The system monitors the relationship between pitch commands and actual blade response, and uses this feedback to refine the torsion correction applied to wind speed estimates, improving accuracy over time
Data Source
AI summary
A method for estimating a wind speed at a wind turbine is disclosed, said wind turbine comprising a rotor carrying a set of wind turbine blades, each wind turbine blade having a variable pitch angle. A blade torsion contribution, representing torsion introduced in the wind turbine blades, is derived, based on an obtained rotational speed, ω, of the rotor, and an obtaining a pitch angle, θ, of the wind turbine blades. An adjusted pitch angle, θ′, is calculated as a sum of the obtained pitch angle, θ, and the derived blade torsion contribution, and a wind speed, vest, is estimated, based on the obtained rotational speed, ω, and the calculated adjusted pitch angle, θ′. An accurate and reliable estimate for the wind speed is thereby obtained. The wind turbine may be controlled in accordance with the estimated wind speed, vest.