Wind Turbine Blade Load Calibration Without Rotor Angle Signals
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Solution Overview
Problem
Existing methods for calibrating strain gauges in wind turbine rotor blades face inaccuracies due to unreliable rotor angle measurements, leading to imprecise load measurements.
Innovation Solution
A method and device for adjusting blade load measuring systems using accelerometers to measure acceleration, determining reference bending moments and axial forces without relying on rotor angle measurements, and adjusting calibration parameters to minimize deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rotor angle measurement is used for strain gauge calibration, then the calibration process can be performed, but the measurement accuracy deteriorates due to angular offset and unreliable rotor angle signals
Solution Approach 1:
The patent extracts the rotor angle measurement from the calibration process entirely. Instead of using rotor angle as an input parameter for calibration, the invention uses accelerometer measurements and gravitational force calculations that are independent of rotor angle, thereby eliminating the source of measurement error while maintaining calibration capability
Solution Approach 2:
The patent introduces accelerometers as an intermediary measurement device. Rather than directly measuring rotor angle, the system uses accelerometers to measure gravitational force components, which serve as an intermediate physical quantity that can be converted into calibration data without relying on problematic rotor angle signals
2Ease of manufacture
If rotor angle measurement system is used, then calibration can be performed, but the device complexity increases due to additional measurement requirements and error handling
Solution Approach 1:
The patent removes the rotor angle measurement system from the calibration process, eliminating the need for complex angular offset compensation algorithms and error handling procedures. The calibration process becomes simpler by relying only on accelerometer measurements and known gravitational force
Solution Approach 2:
The patent enables the calibration system to be self-sufficient by using only accelerometer measurements and pre-stored blade parameter data. The system does not require external rotor angle measurements or complex coordination between multiple measurement systems, making the calibration process more autonomous and simpler to implement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy and reliability of strain gauge calibration by eliminating the need for rotor angle measurement, ensuring precise load measurements.
Implementation Method 1
Measuring a first acceleration with a first acceleration sensor
Implementation Method 2
a first blade load measuring system with at least one strain sensor on a first rotor blade
Data Source
Figure 1~2
Figure 3~4
AI summary
Blade loads acting on a rotor blade are usually determined by taking into account the strains acting on the blade, which are detected by strain sensors. Up to now, the strain sensors have been calibrated using a rotor angle. However, detecting the rotor angle is often unreliable or inaccurate, which is why a simple and accurate calibration of the strain sensors has not yet been sufficiently achieved. According to the invention, this problem is solved by a computer-implemented method for calibrating a first blade load measurement system with at least one strain sensor on a first rotor blade of a wind turbine, comprising the following steps: measuring a first acceleration with a first acceleration sensor; determining a first reference bending moment and/or a first reference axial force based on the first measured acceleration;Determining a first measured bending moment and/or a first measured axial force based on measurements from the at least one strain sensor of the first blade load measuring system and a first set of adjustment parameters assigned to the first blade load measuring system with initial adjustment parameter values; determining a first deviation of the first reference bending moment and/or the first reference axial force from the first measured bending moment and/or the first measured axial force; adjusting the adjustment parameter values of the first set of adjustment parameters for the first blade load measuring system such that the first deviation is less than or equal to a threshold value.