Wind Turbine Rotor Blade Ice Mass Quantification via Natural Frequency Shift
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Solution Overview
Problem
Existing methods for determining ice accumulation on wind turbine rotor blades can only recognize ice accumulation qualitatively, failing to provide a quantitative measurement, which is necessary for assessing the risk and optimizing defrosting strategies.
Innovation Solution
A method that determines the natural frequency of rotor blades in an ice-free state, calculates a shift factor for increased ice accumulation, and compares current natural frequencies to derive the amount of ice accumulation, allowing for both qualitative and quantitative assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ice detection methods are used, then ice accumulation can be detected qualitatively, but a quantitative measurement of ice buildup cannot be provided
Solution Approach 1:
The patent applies mechanical vibration by determining the natural frequency of rotor blades through vibration analysis. Sensors detect vibrational characteristics of the rotor blades, and changes in natural frequency are used to quantify ice accumulation mass. This transforms the physical state of ice buildup into measurable vibrational parameters, enabling precise quantitative measurement rather than just qualitative detection.
2Productivity
If rotor blade surface area is increased to improve energy capture, then the risk of ice accumulation increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the natural frequency of rotor blades and comparing it against baseline values. When frequency shifts indicate ice accumulation, the system provides quantitative feedback about the ice mass, enabling operators to make informed decisions about when to activate de-icing systems or shut down the turbine, thus managing the harmful effect of ice on larger rotor surfaces.
3Object-affected harmful factors
If de-icing systems are activated to remove ice, then ice accumulation is reduced, but energy consumption increases
Solution Approach 1:
The patent applies parameter changes by using natural frequency as a critical parameter to monitor ice accumulation. By tracking changes in this physical parameter, the system can determine the exact moment when de-icing should be activated or deactivated, optimizing the timing and duration of de-icing operations to minimize energy consumption while effectively managing ice accumulation risks.
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
Enables accurate determination of ice accumulation, with an accuracy better than 50 kg, facilitating the optimization of defrosting processes and identifying potential imbalances in wind turbines.
Implementation Method 1
determining a base value for at least one natural frequency of the rotor blade when vibrating in an ice-free state
Data Source
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AI summary
Embodiments of the invention describe a method for ascertaining a value of an ice buildup quantity on at least one rotor blade (111, 112) of a wind turbine (100) and to the use thereof. The method has the steps of ascertaining a base value (G) for at least one natural frequency of the rotor blade when vibrations are excited in an ice buildup-free state; ascertaining a shift base factor for shifting the at least one natural frequency relative to the ice buildup-free state in the event of an ice buildup quantity which is increased by a specific value; detecting a measurement value or a measurement value curve of a measurement variable which is suitable for determining the current natural frequency of the rotor blade (111, 112); determining the current natural frequencies of the rotor blade (111, 112); and deriving a current shift factor by comparing the current natural frequencies with the base value (G), comparing the current shift factor with the shift base factor, and deriving a value for the ice buildup quantity using the comparison.