# US 9,435,320 B2 · Mitigating wind turbine blade noise generation in view of a minimum power generation requirement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,435,320 B2 - Document ID: US9435320B2 - Status: Granted - Kind: B2 - Application number: 13/681,266 - Filed: 2012-11-19 - Published: 2014-05-22 - Granted: 2016-09-06 - Earliest claimed: 2012-11-19 - Assignees: Elwha LLC - Applicants: Elwha LLC - Inventors: William David Duncan; Roderick A. Hyde; David B. Tuckerman; Lowell L. Wood, Jr. - Web page: https://patentgrep.com/patent/US9435320B2 ## CPC - F03D 7/0296: {to prevent, counteract or reduce noise emissions} - F03D 7/022: {Adjusting aerodynamic properties of the blades} - F03D 7/024: {of individual blades} - F05B 2270/333: Noise or sound levels - Y02E 10/72: Wind turbines with rotation axis in wind direction - F03D: WIND MOTORS - F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract Described embodiments include a wind turbine system. In this embodiment, the system includes a wind turbine including a rotor blade having a controllable feature and attached to a rotor hub drivingly coupled to an electric generator. The controllable feature is configured if activated to decrease a noise generated by the rotor blade and correspondingly to decrease electric power generated by the electric generator. The wind turbine system includes a sensor configured to detect a parameter indicative of present or possible future noise generation state of the rotor blade. The wind turbine system includes a noise manager circuit configured to select a noise mitigation measure responsive to the detected parameter and in compliance with a minimum electric power generation requirement assigned to the wind turbine. The wind turbine system includes a control circuit configured to activate the controllable feature in response to the selected noise mitigation measure. ## Claims ### Claim 1 A system comprising: a wind turbine including a rotor blade having a controllable feature and attached to a rotor hub drivingly coupled to an electric generator, the controllable feature configured if activated to decrease a noise generated by the rotor blade and correspondingly to decrease electric power generated by the electric generator; a sensor configured to detect a parameter indicative of a present or possible future noise generation state of the rotor blade; a noise manager circuit configured to select a noise mitigation measure responsive to the detected parameter and in compliance with a minimum electric power generation requirement assigned to the wind turbine; and a control circuit configured to activate the controllable feature in response to the selected noise mitigation measure. ### Claim 2 (depends on 1) The system of claim 1, wherein the controllable feature includes an airflow-modifiable region of the rotor blade located at a portion of a longitudinal length of the rotor blade. ### Claim 3 (depends on 1) The system of claim 1, wherein the controllable feature includes a controllable rotor blade pitch. ### Claim 4 (depends on 1) The system of claim 1, wherein the sensor is configured to detect a vortex induced noise. ### Claim 5 (depends on 1) The system of claim 1, wherein the sensor includes a microphone. ### Claim 6 (depends on 1) The system of claim 1, wherein the sensor includes a pressure sensor. ### Claim 7 (depends on 1) The system of claim 1, wherein the sensor includes a vibration or an accelerometer sensor. ### Claim 8 (depends on 1) The system of claim 1, wherein the parameter includes a parameter indicative of noise generated by airflow across the rotor blade. ### Claim 9 (depends on 1) The system of claim 1, wherein the parameter includes a parameter indicative of an atmospheric variation approaching the rotor blade. ### Claim 10 (depends on 1) The system of claim 1, wherein the parameter includes a parameter indicative of noise received by a noise-alleviation zone. ### Claim 11 (depends on 10) The system of claim 10, wherein the noise-alleviation zone includes a land area having a noise tolerance rating. ### Claim 12 (depends on 1) The system of claim 1, wherein the parameter includes a parameter indicative of a noise produced or propagated by airflow across the rotor blade. ### Claim 13 (depends on 1) The system of claim 1, wherein the parameter includes a parameter indicative of a noise produced or propagated by unstalled airflow across the rotor blade. ### Claim 14 (depends on 1) The system of claim 1, wherein the parameter includes turbulence induced noise. ### Claim 15 (depends on 1) The system of claim 1, wherein the minimum electric power generation requirement is responsive to a time of day. ### Claim 16 (depends on 1) The system of claim 1, wherein the minimum electric power generation requirement is responsive to a weather condition. ### Claim 17 (depends on 1) The system of claim 1, wherein the minimum electric power generation requirement is responsive to a wind direction. ### Claim 18 (depends on 1) The system of claim 1, wherein the minimum electric power generation requirement is responsive to a target cumulative electric power generation requirement over a period of time. ### Claim 19 (depends on 1) The system of claim 1, wherein the minimum electric power generation requirement includes a maximum allowable percentage reduction in present electric power generation. ### Claim 20 (depends on 1) The system of claim 1, wherein the minimum electric power generation requirement is responsive to a minimum monetary value of electric power generation over a period of time. ### Claim 21 (depends on 1) The system of claim 1, wherein the minimum electric power generation requirement is responsive to a noise sensitivity of a noise-alleviation zone lying potentially downwind of the wind turbine. ### Claim 22 (depends on 1) The system of claim 1, wherein the noise mitigation measure is selected in response to instantaneous values of the detected parameter. ### Claim 23 (depends on 1) The system of claim 1, wherein the noise mitigation measure is selected in response to an average value of the detected parameter over a period of time. ### Claim 24 (depends on 1) The system of claim 1, wherein the noise mitigation measure is selected in response to cumulative values of the detected parameter and electric power generation over a period of time. ### Claim 25 (depends on 1) The system of claim 1, wherein the noise mitigation measure is selected in response to weighted values of the detected parameter and electric power generation over a period of time. ### Claim 26 (depends on 1) The system of claim 1, wherein the noise mitigation measure includes changing an orientation of a portion of the rotor blade. ### Claim 27 (depends on 1) The wind turbine system of claim 1, wherein the noise mitigation measure includes dynamically shaping airflow over at least a portion of the rotor blade. ### Claim 28 (depends on 1) The wind turbine system of claim 1, wherein the noise mitigation measure includes releasing air from a region on the rotor blade. ### Claim 29 (depends on 1) The wind turbine system of claim 1, wherein the noise mitigation measure includes creating a transpiration airflow on at least a portion of the rotor blade. ### Claim 30 A system comprising: a wind turbine including a rotor blade having a controllable feature and attached to a rotor hub drivingly coupled to an electric generator, the controllable feature configured if activated to decrease a noise generated by the rotor blade and correspondingly to decrease electric power generated by the electric generator; a sensor configured to detect a parameter indicative of a present or possible future noise generation state of the rotor blade; and a controller circuit configured to select a noise mitigation measure responsive to the detected parameter and in compliance with a minimum electric power generation requirement assigned to the wind turbine, and to activate the controllable feature in response to the selected noise mitigation measure. ### Claim 31 A system comprising: a first wind turbine including a first rotor blade having a first controllable feature and attached to a first rotor hub drivingly coupled to a first electric generator, the first controllable feature configured if activated to decrease a first noise generated by the first rotor blade and correspondingly to decrease a first electric power generated by the first electric generator; a second wind turbine including a second rotor blade having a second controllable feature and attached to a second rotor hub drivingly coupled to a second electric generator, the second controllable feature configured if activated to decrease a second noise generated by the second rotor blade and correspondingly to decrease a second electric power generated by the second electric generator; a sensor configured to detect a parameter indicative of a present or possible future noise generation state of the first rotor blade or of the second rotor blade; a noise manager circuit configured to select a noise mitigation measure (i) responsive to the detected parameter and (ii) in compliance with a first minimum electric power generation requirement assigned to the first electric generator and a second minimum power generation requirement assigned to the second electric generator; and a control system configured to activate the first controllable feature or second controllable feature as appropriate to implement the selected noise mitigation measure. ### Claim 32 A method comprising: detecting a parameter indicative of a present or possible future noise generation state of a rotating rotor blade having a controllable feature and attached to a rotor hub driving an electric generator, the controllable feature configured to decrease a noise generated by the rotating rotor blade if activated; selecting a noise mitigation measure responsive to the detected parameter and in compliance with a minimum electric power generation requirement assigned to the electric generator; and activating the controllable feature of the rotating rotor blade in response to the selected noise mitigation measure. ### Claim 33 A method comprising: detecting a parameter indicative of a present or possible future noise generation state of each rotating rotor blade of at least two rotating rotor blades, each rotating rotor blade respectively having a controllable feature and attached to a respective rotor hub driving a respective electric generator, each controllable feature configured to decrease a noise generated by its respective rotating rotor blade if activated; selecting a noise mitigation measure responsive to the detected parameter and in compliance with a minimum electric power generation requirement assigned to each electric generator of the respective electric generators; and activating a controllable feature of a rotating rotor blade of the at least two rotating rotor blades as appropriate to implement the selected noise mitigation measure.