# US 2021/0277869 A1 · Method and system for controlling a wind turbine to reduce nacelle vibration > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0277869 A1 - Document ID: US20210277869A1 - Status: Published application - Kind: A1 - Application number: 17/259,473 - Filed: 2019-07-03 - Published: 2021-09-09 - Earliest claimed: 2018-07-11 - Assignees: Vestas Wind Systems A/S - Applicants: Vestas Wind Systems A/S - Inventors: Karthik VASUDEVAN; Poul Brandt CHRISTENSEN; James Alexander NICHOLS; Jacob Deleuran GRUNNET - Web page: https://patentgrep.com/patent/US20210277869A1 ## CPC - F03D 7/0224: {Adjusting blade pitch} - F03D 17/00: Monitoring or testing of wind motors, e.g. diagnostics (testing during commissioning of wind motors F03D13/30) - F03D 7/024: {of individual blades} - F03D 7/0296: {to prevent, counteract or reduce noise emissions} - F05B 2240/912: on a tower - F05B 2260/962: by means creating "anti-noise" - F05B 2260/966: by correcting static or dynamic imbalance - F05B 2270/328: Blade pitch angle - F05B 2270/329: Azimuth or yaw angle - F05B 2270/331: Mechanical loads - F05B 2270/334: Vibration measurements - Y02E 10/72: Wind turbines with rotation axis in wind direction - Y02E 10/728: Onshore wind turbines - 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 The present invention relates to a method of controlling a wind turbine comprising a tower supporting a rotor comprising a plurality of pitch-adjustable rotor blades. The method includes obtaining a movement signal indicative of a lateral movement of the tower; determining a pitch modulation signal, based on the movement signal, for actuating a rotor blade to produce a desired horizontal force component to counteract the lateral movement of the tower; determining a radial force component acting on a rotor blade; determining a phase offset parameter for the rotor blade based on the radial force component; and, transforming the pitch modulation signal into a pitch reference offset signal for the rotor blade based on the phase offset parameter. ## Claims ### Claim 1 A method of controlling a wind turbine comprising a tower supporting a rotor comprising a plurality of pitch-adjustable rotor blades, the method comprising: obtaining a movement signal indicative of a lateral movement of the tower; determining a pitch modulation signal, based on the movement signal, for actuating a rotor blade to produce a desired horizontal force component to counteract the lateral movement of the tower; determining a radial force component acting on a rotor blade; determining a phase offset parameter for the rotor blade based on the radial force component; and transforming the pitch modulation signal into a pitch reference offset signal for the rotor blade based on the phase offset parameter. ### Claim 2 (depends on 1) The method of claim 1, wherein the radial force component is determined based on a deflection of the rotor blade. ### Claim 3 (depends on 2) The method of claim 2, wherein the deflection is in the flapwise direction of the rotor blade. ### Claim 4 (depends on 1) The method of claim 1, wherein the radial force component is determined based on a distance the rotor blade deflects from a longitudinal axis of the rotor blade. ### Claim 5 (depends on 4) The method of claim 4, wherein the distance extends perpendicularly from the longitudinal axis of the rotor blade to the tip of the rotor blade. ### Claim 6 (depends on 4) The method of claim 4, wherein the distance is determined based on the thrust acting on the rotor blade. ### Claim 7 (depends on 4) The method of claim 4, wherein the distance is scheduled according to an operating condition of the wind turbine. ### Claim 8 (depends on 4) The method of claim 4, wherein the distance is determined based on the bending moment of the rotor blade. ### Claim 9 (depends on 1) The method of claim 1, wherein the radial force component is determined based on an integration of the lift force along the rotor blade. ### Claim 10 (depends on 1) The method of claim 1, wherein the horizontal force component is a component of a resultant force based on an edgewise force acting on the rotor blade and the radial force component. ### Claim 11 (depends on 1) The method of claim 1, wherein the phase offset parameter is determined based on additional in-plane force components. ### Claim 12 (depends on 1) The method of claim 1, wherein the phase offset parameter is determined based on an azimuth angle of the rotor blade. ### Claim 13 A controller of a wind turbine control system comprising a processor and a memory module, wherein the memory module comprises a set of program code instructions which when executed by the processor implement an operation of controlling a wind turbine comprising a tower supporting a rotor comprising a plurality of pitch-adjustable rotor blades, the operation comprising: obtaining a movement signal indicative of a lateral movement of the tower; determining a pitch modulation signal, based on the movement signal, for actuating a rotor blade to produce a desired horizontal force component to counteract the lateral movement of the tower; determining a radial force component acting on a rotor blade; determining a phase offset parameter for the rotor blade based on the radial force component; and transforming the pitch modulation signal into a pitch reference offset signal for the rotor blade based on the phase offset parameter. ### Claim 14 (canceled) ### Claim 15 (canceled) ### Claim 16 (depends on 13) The controller of claim 13, wherein the radial force component is determined based on a deflection of the rotor blade. ### Claim 17 (depends on 16) The controller of claim 16, wherein the deflection is in the flapwise direction of the rotor blade. ### Claim 18 A wind turbine, comprising: a tower; a rotor supported by the tower and comprising a plurality of pitch-adjustable rotor blades; and a controller comprising a processor and a memory module, wherein the memory module comprises a set of program code instructions which, when executed by the processor, configures the processor to perform an operation, comprising: obtaining a movement signal indicative of a lateral movement of the tower; determining a pitch modulation signal, based on the movement signal, for actuating a rotor blade to produce a desired horizontal force component to counteract the lateral movement of the tower; determining a radial force component acting on a rotor blade; determining a phase offset parameter for the rotor blade based on the radial force component; and transforming the pitch modulation signal into a pitch reference offset signal for the rotor blade based on the phase offset parameter. ### Claim 19 A program product comprising a storage medium containing code which, when executed by one or more processors, configures the one or more processors to perform an operation, comprising: obtaining a movement signal indicative of a lateral movement of a tower supporting a rotor comprising a plurality of pitch-adjustable rotor blades; determining a pitch modulation signal, based on the movement signal, for actuating a rotor blade to produce a desired horizontal force component to counteract the lateral movement of the tower; determining a radial force component acting on a rotor blade; determining a phase offset parameter for the rotor blade based on the radial force component; and transforming the pitch modulation signal into a pitch reference offset signal for the rotor blade based on the phase offset parameter ### Claim 20 (depends on 19) The program product of claim 19, wherein the radial force component is determined based on a deflection of the rotor blade, and wherein the deflection is in the flapwise direction of the rotor blade.