Active Noise Control in Wind Turbines for Noise Reduction

A wind farm noise and vibration reduction system that uses active noise control and passive noise control techniques to effectively reduce wind turbine blade noise and vibration. The system involves installing secondary sound sources on the wind turbine blades, collecting blade noise signals, and using adaptive filtering algorithms to generate control signals that drive the secondary sources to emit offsetting sound waves. Passive mufflers are also used to control mid- and high-frequency noise. This allows real-time adaptation to blade noise changes, improving noise reduction and energy savings without increasing blade resistance or impacting performance.

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Reducing noise from wind turbine blades by using sensors and actuators on the blade surface to actively cancel out edge noise. The blade has sensors spaced non-uniformly along the edge to detect flow characteristics. An actuator near the sensor provides an anti-noise signal based on the sensor data. This cancels out flow-induced edge noise generated by the blade. By arranging the sensors and actuator with spacing that avoids aliasing, it allows separation of efficiently radiated noise vs inefficient noise.

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Reducing noise from wind turbines using an active noise cancellation system. The system has sensors on the blades and tower to measure blade tip turbulence and tower-side noise. An actuator on the blade emits an anti-noise signal based on the sensor outputs. This cancels out blade tip noise in the far field. By coordinating blade and tower sensors, the system can adaptively cancel noise as the blade position changes.

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Active noise control for wind turbines to reduce noise levels near residential areas without shutting down the turbines. The method involves monitoring the noise levels in the surrounding sensitive areas and selectively adjusting the wind turbine operation to mitigate the noise. This is done by comparing the sensitive area noise levels to a background level and choosing a noise reduction control scheme based on that difference. The chosen scheme, like varying generator speed, is then implemented to reduce the wind turbine noise. The goal is to effectively reduce wind turbine noise without resorting to shutdowns or other measures that impact power generation.

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Active noise reduction for wind turbines that uses sensors and actuators on the blades and tower to cancel trailing edge noise. The system has unsteady pressure sensors on the blades to detect turbulent flow conditions. Noise sensors on the tower or nacelle measure blade noise. An adaptive filter controlled by a unit on the blades generates an anti-noise signal based on the sensor outputs. Actuators like speakers emit the anti-noise to counter blade noise. The filter adjusts based on blade orientation to optimize cancellation when the blade is downward.

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Method to construct a high-quality reference signal for active noise control (ANC) systems in fan ducts using microphone arrays. The method aims to improve the quality of the reference signal in feedforward ANC systems by accounting for coherent and incoherent interferences in fan ducts. It involves using a microphone array in the duct to capture the fan noise and extracting the fan rotational noise component using beamforming. This extracted signal is used as the reference for the ANC. It also compensates for signal delays in the duct using quadratic interpolation. This improves the reference signal quality by reducing interference compared to using a single microphone.

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Active noise cancellation system for wind turbines that reduces noise emissions using sensors and actuators on the blades and tower. The system has unsteady pressure sensors on the blades, a noise sensor on the tower/nacelle, and a control unit. The control unit uses the blade pressure sensor output to generate an anti-noise signal that is sent to an actuator on the blade. It also uses the tower noise sensor to adjust the anti-noise signal. This active cancellation aims to counteract the blade trailing edge noise that contributes to wind turbine noise. The control unit can adapt the cancellation based on blade orientation using sensors on the blade.

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Active noise reduction system for power transformer boxes that uses reversed sound waves to cancel out the original noise. The system has a microphone inside the transformer box to capture the noise, a processor to reverse process the sound, and a speaker outside the box to emit the reversed sound. The reversed sound waves interfere with the original noise to reduce it. The transformer box has shock absorbers and sliding rods to adjust the position of the microphone and speaker for optimal noise cancellation.

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Active noise control method and system for wind turbines to reduce operating noise without structural modifications. The method involves identifying and analyzing the wind turbine's noise frequencies, then generating inversely phased noise at those frequencies in the turbine's vicinity using active speakers. This superposition of sounds cancels out the original noise to reduce overall noise levels. The system includes microphones, a controller, and speakers positioned around the turbine.

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Active noise reduction system for wind turbines using active silencers to significantly reduce wind turbine noise without requiring modifications to the turbine itself. The system consists of a microphone to collect turbine noise, a signal analyzer to extract the noise characteristics, and an anti-noise generator to create a matching noise waveform. This anti-noise is then output through a dynamic speaker to cancel out the original turbine noise.

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Noise reduction system for wind turbines that can significantly reduce the noise generated by the rotating blades. The system involves capturing the noise from the turbine in a nearby location, monitoring it, and generating an opposite phase sound to cancel out the blade noise. This involves using microphones to capture the noise from a position close to the turbine, analyzing the phase of the blade noise, and then generating a sound with the opposite phase to cancel out the blade noise when it is played back. This can be achieved using a sound generation unit and an output unit. By canceling the blade noise close to the turbine, it reduces the propagation of blade noise to nearby areas.

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Reducing noise in enclosed spaces like buildings by actively canceling resonant frequencies that amplify noise. The method involves detecting the resonant frequencies using microphones in corners, passing those frequencies through bandpass filters, and then radiating canceling sounds with opposite phase from the corners. This can reduce noise by synchronizing the phase of the whole room and canceling the resonant standing waves. The resonant frequencies are unique to the space and can be separately controlled by individual filters.

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Reducing noise from wind turbines using active noise control. It involves detecting parameters indicating future noise generation and selectively activating controllable features on the blades to mitigate noise without significantly impacting power generation. The features could be airflow-modifiable regions, blade pitch changes, or other blade shape modifications. Sensors monitor blade position, vortices, pressure, etc. to detect noise potential. This allows targeted blade adjustments to reduce noise without compromising power.

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Active noise suppression system for wind turbines to reduce noise emissions from components like generators, gearboxes, and bearings. The system measures the original noise signature, calculates an inverted signature, amplifies it, and plays it through speakers to cancel out the original noise. This active noise cancellation reduces overall wind turbine noise levels below local limits.

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Active noise suppression system for wind turbines to reduce noise emissions. It involves measuring the noise signature of a component like a gearbox, inverting the waveform, amplifying it, and playing it back through speakers to cancel out the original noise. This active noise cancellation system uses a noise measuring device, controller, amplifier, and speakers to generate and emit an inverted noise waveform that cancels the original noise from the component.

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Controlling noise emissions from wind parks to meet regulatory limits by selectively reducing the noise contribution of individual wind turbines. The method involves monitoring wind park noise at specific locations using techniques like microphones, acoustic cameras, or beamforming to identify and quantify the noise produced by each turbine. By estimating the relative influence of each turbine on the overall noise, the park controller can command specific turbines to operate in a lower noise mode if overall park noise exceeds a threshold. This iterative process focuses noise reduction efforts on turbines with the greatest impact.

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Controlling the amplitude modulation of noise generated by wind turbines to reduce overall noise levels. The method involves measuring the sound characteristics of individual turbine sounds, generating additive sounds based on those characteristics, and combining them with the turbine sounds to create a resultant sound with lower peak-to-peak amplitude. By preventing constructive interference between turbine sounds or actively augmenting them, the overall noise level can be reduced. This allows higher power production compared to de-rating or continuous feathering methods.

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Controlling the amplitude modulation of noise generated by wind turbines to reduce noise levels in the far field where it may exceed regulatory limits. The method involves measuring the noise characteristics of individual turbines and generating additive sounds based on those characteristics. By coordinating the sounds across multiple turbines, it prevents constructive interference that can amplify noise. It also adds sounds that cancel or diminish the turbine noise. This reduces the peak-to-peak amplitude of the overall sound compared to the individual turbine noise.

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Active noise cancellation system for wind turbines to mitigate noise impact on nearby communities. The system uses microphones mounted on the blades to detect the noise generated by the turbine components. This detected noise is then analyzed to extract frequency components, amplitudes, and phases. Matching speakers are mounted inside the blades facing outward. The speakers emit sounds with opposite phases and frequencies to cancel the detected noise at the blade surface. This active noise cancellation reduces the noise transmitted through the blade housing and radiated into the environment. It allows higher blade tip speeds and rotor diameters without excessive noise levels.

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Active noise reduction system for wind turbines that reduces noise from wind turbines without lowering power generation. The system uses speakers outside the blades and microphones corresponding to them. It generates reduction signals based on blade rotation direction to active cancel opposite side noise. Speakers emit control sounds to reduce noise detected on the opposite side. This reduces wind turbine noise through active control without impacting power generation.

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