Wind Turbine Rotor Imbalance Detection in the Azimuth Domain
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Solution Overview
Problem
Existing wind turbine systems lack efficient methods to quickly detect and safely stop a rotor imbalance, which can lead to catastrophic events such as tower collapse or rotor disintegration due to major blade damage or loss.
Innovation Solution
A method using azimuth-domain transforms to analyze dynamic characteristics of the wind turbine, enabling rapid detection of significant rotor imbalances by measuring and processing data at specific azimuth angles, followed by initiating a controlled rotor stop through pitching mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional time-domain or frequency-domain methods are used to detect rotor imbalance, then the detection system can identify imbalances, but the detection speed is insufficient to prevent catastrophic events
Solution Approach 1:
The patent transforms the detection approach from time-domain or frequency-domain analysis to azimuth-domain analysis. By organizing vibration data according to rotor azimuth positions rather than time sequences, the system can detect imbalances within a single rotation cycle, dramatically reducing detection time while maintaining reliability through the azimuth-specific structural response patterns.
2Speed
If the rotor is stopped using mechanical braking, then the rotor can be brought to a complete stop, but the mechanical braking system may cause additional structural damage or fail under extreme conditions
Solution Approach 1:
The patent replaces the mechanical braking system with an aerodynamic braking mechanism. By pitching the rotor blades to a feathered position (edge-on to the wind), the system uses aerodynamic forces to rapidly decelerate the rotor without mechanical contact, eliminating the risks associated with mechanical brake failure or damage under extreme imbalance conditions.
3Loss of time
If azimuth-domain transform is applied to detect rotor imbalance, then fast detection is achieved, but the system complexity increases due to additional processing requirements
Solution Approach 1:
The patent extracts only the azimuth-domain components relevant to imbalance detection from the vibration signal, rather than performing comprehensive time-frequency analysis. By focusing specifically on the azimuth-positioned vibration characteristics and their transformation, the system achieves rapid detection with reduced computational complexity compared to full-spectrum analysis methods.
Data Source
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AI summary
Systems, methods, and computer program products for monitoring occurring rotor imbalances. A dynamic characteristic sensor (40) determines the value of a dynamic characteristic of a wind turbine (10), e.g., of a nacelle (14) thereof, such that the dynamic characteristic includes a component aligned with a rotor plane (50) of the rotor (16). The dynamic characteristic is sampled when the rotor (16) of the wind turbine (10) is at each of a plurality of azimuth angles (ψn) to produce a sequence of dynamic values (a(ψ)). An azimuth-domain transform is applied to the sequence of dynamic values (a(ψ)) to generate at least one inverse-angle component (A(γk)). Rotor imbalances are then detected based on the inverse-angle component (A(γk)), such as by comparing a value of the inverse-angle component (A(γk)) to a threshold, and the rotation of the rotor is stopped.