US 12,228,107 B2
Correcting pitch angle
Johnny Nielsen, Svenstrup J (DK); Jens Van Schelve, Oporto (PT); Goncalo Lucas Marcos, Cascais (PT); Dan Hilton, Gjern (DK); and Kristian Kiib, Skødstrup (DK)
Assigned to VESTAS WIND SYSTEMS A/S, Aarhus N (DK)
Appl. No. 17/417,082
Filed by VESTAS WIND SYSTEMS A/S, Aarhus N (DK)
PCT Filed Dec. 3, 2019, PCT No. PCT/DK2019/050377
§ 371(c)(1), (2) Date Jun. 21, 2021,
PCT Pub. No. WO2020/125885, PCT Pub. Date Jun. 25, 2020.
Claims priority of application No. PA 2018 70838 (DK), filed on Dec. 20, 2018.
Prior Publication US 2022/0074386 A1, Mar. 10, 2022
Int. Cl. F03D 7/02 (2006.01)
CPC F03D 7/0224 (2013.01) [F05B 2260/70 (2013.01); F05B 2270/328 (2013.01); F05B 2270/331 (2013.01); F05B 2270/802 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method of correcting a pitch angle deviation of a blade of a wind turbine, the wind turbine comprising a plurality of blades, the method comprising:
providing first blade load measurements for each blade of the plurality of blades, wherein the first blade load measurements are measured during operation of the wind turbine in a first operational mode;
determining calibration parameters to correct for differences between the first blade load measurements of each blade;
providing second blade load measurements for each blade of the plurality of blades, wherein the second blade load measurements are measured during operation of the wind turbine in a second operational mode, wherein a wind speed experienced by the wind turbine is lower during the first operational mode than during the second operational mode;
applying the calibration parameters to the second blade load measurements to determine calibrated blade load measurements;
identifying a difference between the calibrated blade load measurements of each blade, and wherein identifying the difference between the calibrated blade load measurements comprises:
determining a target blade load by determining an average of the calibrated blade load measurements from each blade of the plurality of blades; and
identifying a difference between the calibrated blade load measurements of at least one blade and the target blade load;
estimating the pitch angle deviation of the at least one blade of the plurality of blades responsible for the identified difference, and wherein estimating the pitch angle deviation comprises estimating the pitch angle deviation for the at least one blade responsible for the difference between the calibrated blade load measurements of the at least one blade responsible and the target blade load; and
altering a pitch angle of the at least one blade to correct for the pitch angle deviation, wherein in altering the pitch angle of the at least one blade to correct for the pitch angle deviation, the plurality of blades are made to have a substantially same pitch error and one or more blades of the at least one blade become misaligned or further misaligned with respect to a pitch error of zero degrees after the altering of the pitch angle of the at least one blade, and
wherein identifying the difference between the calibrated blade load measurements of each blade comprises binning the calibrated blade load measurements for each blade according to a wind speed or pitch angle associated with each measurement.