Wind Turbine Nacelle Accelerometer for Edgewise Vibration Control
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Solution Overview
Problem
Current methods for managing edgewise vibrations in wind turbine blades are inadequate, as they often require numerous expensive sensors mounted on the blades, which can be impractical for older turbines and do not effectively address vibrations at resonant frequencies, potentially leading to damage.
Innovation Solution
A method using a single accelerometer mounted in the nacelle or tower to determine whirling mode frequencies and measure acceleration signals, filtering them to isolate edgewise vibrations, and performing control actions such as adjusting blade pitch or rotational speed to mitigate excessive vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If blade-mounted accelerometers are used to monitor edgewise vibrations, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent uses the nacelle as an intermediary structure to mount the accelerometer. Instead of directly mounting sensors on the blades, the acceleration sensor is placed in the nacelle where it can indirectly measure blade vibrations through the structural coupling between the blades and the nacelle hub, thereby avoiding the complexity of blade-mounted sensors while still capturing vibration data
Solution Approach 2:
The patent creates a simplified measurement model by using a single accelerometer in the nacelle that captures the essential vibration characteristics of multiple blades. Rather than installing sensors on each blade, the system uses the nacelle's response as a representative copy of the overall rotor vibration state, reducing the number of sensors needed from many to just one
2Loss of information
If multiple accelerometers are mounted on each blade to capture vibration data, then measurement completeness is improved, but ease of operation and installation deteriorate
Solution Approach 1:
The single accelerometer mounted in the nacelle serves multiple functions simultaneously: it monitors edgewise vibrations of multiple blades, detects resonant conditions, and provides data for controlling the pitch of all blades. This multi-functional approach eliminates the need for separate sensors on each blade while maintaining comprehensive vibration monitoring capability
3Productivity
If resonant oscillations are not mitigated, then productivity is maintained, but reliability deteriorates due to component damage
Solution Approach 1:
The patent implements a closed-loop feedback control system where the accelerometer continuously monitors blade vibrations, the controller processes the vibration signals to detect resonant conditions, and the system automatically adjusts blade pitch in real-time to mitigate dangerous oscillations. This feedback mechanism allows the turbine to maintain productivity while reliably preventing component damage by dynamically responding to vibration conditions
Solution Approach 2:
The control system takes preliminary anti-action by detecting approaching resonant conditions and adjusting blade pitch before dangerous oscillations fully develop. The system proactively modifies blade angles to prevent resonant amplification rather than reacting after damage occurs, thereby maintaining both productivity and reliability
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 effectively monitors and manages edgewise vibrations without blade-mounted sensors, ensuring safe operation of wind turbines by reducing vibrations to safe levels and allowing for flexible control based on wind conditions.
Implementation Method 1
at least one accelerometer housed within a nacelle or a tower of the wind turbine
Implementation Method 2
determining a frequency spectrum of the measured acceleration signal in the proximity of the determined whirling mode frequency
Data Source
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AI summary
A method of controlling a wind turbine comprising at least one rotor blade, and at least one accelerometer housed within a nacelle or a tower of the wind turbine. The method comprises: determining a whirling mode frequency for the wind turbine; measuring an acceleration signal that is indicative of the movement of the nacelle of the wind turbine; determining a frequency spectrum of the measured acceleration signal in the proximity of the determined whirling mode frequency; determining a characteristic value that is representative of the energy content of the measured acceleration signal having the determined frequency spectrum; and performing at least one control action if the characteristic value exceeds a predetermined threshold.