Wind Turbine Active Noise Reduction With Blade Pressure Sensing
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Solution Overview
Problem
Modern wind turbines emit excessive noise during operation, limiting their economic viability and requiring curtailed power generation to comply with noise regulations, with passive noise reduction methods providing insufficient noise reduction.
Innovation Solution
An active noise reduction system for wind turbines using unsteady pressure sensors and actuators on rotor blades, combined with noise sensors at the nacelle or tower, to generate anti-noise signals based on pressure fluctuations and noise measurements, employing adaptive feedforward control to minimize far-field noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive noise reduction devices (serrations) are used at the trailing edge of rotor blades, then noise emission is reduced to some extent, but the noise reduction effect is limited and insufficient for meeting noise regulations
Solution Approach 1:
The patent converts the harmful trailing edge noise into a beneficial signal by using unsteady pressure sensors to detect the noise-generating flow structures. These detected fluctuations are then processed to generate anti-noise signals that actively cancel the original noise, transforming the harmful acoustic emission into an opportunity for active control and significant noise reduction while maintaining full power generation capability.
Solution Approach 2:
The patent replaces passive mechanical noise reduction structures (serrations) with an active control system consisting of unsteady pressure sensors, signal processors, and actuators. This substitution transitions from static mechanical modifications to dynamic active control, enabling adaptive noise cancellation that responds to real-time flow conditions and achieves superior noise reduction performance.
2Object-affected harmful factors
If active noise cancellation systems are used with sensors and actuators on rotor blades, then noise reduction capability is improved, but system complexity and cost increase
Solution Approach 1:
The patent implements feedback control by using unsteady pressure sensors to continuously monitor the turbulent flow conditions and noise generation at the rotor blade trailing edge. The detected signals are processed to generate anti-noise commands that are fed back to actuators for real-time noise cancellation. This closed-loop feedback mechanism enables adaptive control that automatically adjusts to varying operational conditions.
Solution Approach 2:
The patent integrates multiple functions into a unified active noise control system: unsteady pressure sensors serve both for flow condition monitoring and noise signal detection, the signal processor performs both analysis and control command generation, and the actuators provide both flow control and noise cancellation. This multi-functionality reduces overall system complexity compared to separate dedicated systems for each function.
3Measurement precision
If noise sensors are added at the nacelle or tower to improve noise measurement accuracy, then control precision is enhanced, but device complexity increases
Solution Approach 1:
The patent merges the noise measurement function with the existing unsteady pressure sensing system. The same pressure sensors used for detecting flow conditions also serve for measuring noise-generating pressure fluctuations. Additionally, noise sensors at the nacelle or tower are integrated into the unified control architecture, sharing signal processing and control commands with the blade-mounted sensors. This merging eliminates redundant systems and reduces overall complexity while maintaining high measurement precision.
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
Enhances noise reduction capabilities, improving reliability and robustness by compensating for sensor degradation and varying flow conditions, allowing operation within noise limits without curtailment.
Implementation Method 1
an unsteady pressure sensor adapted to produce an output signal corresponding to a turbulent flow condition during operation of the rotor blade
Implementation Method 2
an actuator arranged on at least one of the rotor blades... control the actuator to emit an anti-noise signal
Implementation Method 3
generates an inverted acoustic signal, negating the trailing edge noise in the far field
Implementation Method 4
at least one noise sensor adapted to produce an output signal corresponding to a noise generated by the rotor blade at the location of the noise sensor
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Wind turbine comprising a tower (2) bearing a nacelle (5) and a rotor (3) with a plurality of rotor blades (4) and an active noise reduction device (7), wherein the active noise reduction device (7) comprises at least one actuator (8), at least one unsteady pressure sensor (9) adapted to produce an output signal corresponding to a turbulent flow condition during operation of the rotor blade (4), at least one noise sensor (10) adapted to produce an output signal corresponding to a noise generated by the rotor blade (4) at the location of the noise sensor (10), and a control unit (11), wherein the unsteady pressure sensor (9) and the actuator (8) are arranged on at least one of the rotor blades (4) and the noise sensor (10) is arranged at the nacelle (5) and/or at the tower (2), wherein the control unit (11) is adapted to control the actuator (8) in dependence of the output signals of the unsteady pressure sensor (9) and the noise sensor (10) to emit an anti-noise signal at least partly reducing the noise generated by the rotor blade (4).