Abstract: A method of determining rotor speed of a wind turbine. The method involves receiving angular velocity sensor data indicative of an angular velocity of the wind turbine rotor hub, provided e.g., by a gyroscope and receiving acceleration sensor data indicative of an acceleration of the rotor hub in at least one radial direction relative to an axis of rotation of the rotor hub. The method further involves determining first and second estimated rotational speeds of the rotor hub based on the respective angular velocity sensor data and acceleration sensor data. The method also involves determining a correction value based on a difference between the first and second estimated rotational speeds, and applying the correction value to the first estimated rotational speed to determine the true current rotor speed of the wind turbine.

Abstract: A method of correcting a pitch angle deviation of a blade of a wind turbine is provided. First blade load measurements measured when the wind turbine was operating in a first operational mode are provided, and used to determine calibration parameters. Second blade load measurements measured when the wind turbine was operating in a second operational mode are provided, and the calibration parameters applied to determine calibrated blade load measurements. A pitch angle deviation of at least one blade of the turbine is estimated based on an identified difference between the calibrated blade load measurements, and a pitch angle is adjusted to correct for the pitch angle deviation.

Abstract: The invention provides a method of determining tower top acceleration of a wind turbine. The method includes receiving acceleration data from a plurality of acceleration sensors positioned in a nacelle of the wind turbine, including data indicative of a measured acceleration in a direction along at least one measurement axis of each respective acceleration sensor at a current time step. The method includes determining a predicted tower top acceleration of the wind turbine tower at the current time step, the predicted tower top acceleration being determined in dependence on a kinematic model of the wind turbine, and on a determined estimation of tower top acceleration at a previous time step. The method includes determining an estimated tower top acceleration of the wind turbine tower at the current time step by updating the predicted tower top acceleration based on the measured acceleration from each of the acceleration sensors.

Abstract: The invention relates to determining rotor speed of a wind turbine. The invention involves receiving angular velocity sensor data indicative of an angular velocity of the wind turbine rotor hub, provided e.g by a gyroscope and receiving acceleration sensor data indicative of an acceleration of the rotor hub in at least one radial direction relative to an axis of rotation of the rotor hub. The invention involves determining first and second estimated rotational speeds of the rotor hub based on the respective angular velocity sensor data and acceleration sensor data. The invention involves determining a correction value based on a difference between the first and second estimated rotational speeds, and applying the correction value to the first estimated rotational speed to determine the true current rotor speed of the wind turbine.

Abstract: A wind turbine comprising: a tower; a first arm extending from the tower; a first rotor-nacelle assembly disposed on the first arm; a first movement sensor disposed on the first arm or on the first rotor-nacelle assembly and arranged to generate first movement data based on movement of the first arm or of the first rotor-nacelle assembly; a second arm extending from the tower; a second rotor-nacelle assembly disposed on the second arm; a second movement sensor disposed on the second arm or on the second rotor-nacelle assembly and arranged to generate second movement data based on movement of the second arm or of the second rotor-nacelle assembly; and a control system coupled to the first and the second movement sensors and arranged to receive and to process the first and second movement data; wherein the control system is arranged to determine an oscillation characteristic of the wind turbine from the first and the second movement data.

Abstract: A wind turbine comprising: a tower; a first arm extending from the tower; a first rotor-nacelle assembly disposed on the first arm; a first movement sensor disposed on the first arm or on the first rotor-nacelle assembly and arranged to generate first movement data based on movement of the first arm or of the first rotor-nacelle assembly; a second arm extending from the tower; a second rotor-nacelle assembly disposed on the second arm; a second movement sensor disposed on the second arm or on the second rotor-nacelle assembly and arranged to generate second movement data based on movement of the second arm or of the second rotor-nacelle assembly; and a control system coupled to the first and the second movement sensors and arranged to receive and to process the first and second movement data; wherein the control system is arranged to determine an oscillation characteristic of the wind turbine from the first and the second movement data.

Abstract: This application describes a method of detecting an error in a rotor angle sensing system of a wind turbine, where the wind turbine comprises a rotor including a plurality of wind turbine blades, a blade load sensor associated with a respective one of the wind turbine blades, and a rotor angle sensing system configured to output a rotor angle signal. The blade load sensor is configured to output a measured blade load signal. The method comprises generating an estimated blade load signal based on at least the rotor angle signal; comparing the estimated blade load signal with the measured blade load signal to determine a phase difference between them; and identifying an error if the phase difference between the estimated blade load signal and the measured blade load signal exceeds a predetermined threshold.

Abstract: A method of correcting a pitch angle deviation of a blade of a wind turbine is provided. First blade load measurements measured when the wind turbine was operating in a first operational mode are provided, and used to determine calibration parameters. Second blade load measurements measured when the wind turbine was operating in a second operational mode are provided, and the calibration parameters applied to determine calibrated blade load measurements. A pitch angle deviation of at least one blade of the turbine is estimated based on an identified difference between the calibrated blade load measurements, and a pitch angle is adjusted to correct for the pitch angle deviation.

Abstract: A yaw sensor for a wind turbine comprises a plurality of rotary switches, each configured to be coupled to a yaw drive gearbox of a wind turbine nacelle, the rotary switches each being operable to activate and deactivate respective associated electrical contacts in dependence on an amount of yaw rotation of the nacelle relative to a start position. Each electrical contact is active at a plurality of first yaw rotation ranges with respect to the start position, and inactive at a plurality of second yaw rotation ranges with respect to the start position, the first and second yaw rotation ranges being interleaved.

Abstract: A yaw sensor for a wind turbine is described. The yaw sensor comprises a rotary switch, configured to be coupled to a yaw drive gearbox of a wind turbine nacelle, the rotary switch being operable to activate and deactivate an electrical contact in dependence on an amount of yaw rotation of the nacelle relative to a start position. The electrical contact is active at a plurality of first yaw rotation ranges with respect to the start position, and inactive at a plurality of second yaw rotation ranges with respect to the start position, the first and second yaw rotation ranges being interleaved, at least some of the first yaw rotation ranges having different lengths from each other and/or at least some of the second yaw rotation ranges having different lengths from each other. The electrical contact generates an electrical signal when active.

Abstract: This application describes a method of detecting an error in a rotor angle sensing system of a wind turbine, where the wind turbine comprises a rotor including a plurality of wind turbine blades, a blade load sensor associated with a respective one of the wind turbine blades, and a rotor angle sensing system configured to output a rotor angle signal. The blade load sensor is configured to output a measured blade load signal. The method comprises generating an estimated blade load signal based on at least the rotor angle signal; comparing the estimated blade load signal with the measured blade load signal to determine a phase difference between them; and identifying an error if the phase difference between the estimated blade load signal and the measured blade load signal exceeds a predetermined threshold.

Abstract: A yaw sensor for a wind turbine is described. The yaw sensor comprises a rotary switch, configured to be coupled to a yaw drive gearbox of a wind turbine nacelle, the rotary switch being operable to activate and deactivate an electrical contact in dependence on an amount of yaw rotation of the nacelle relative to a start position. The electrical contact is active at a plurality of first yaw rotation ranges with respect to the start position, and inactive at a plurality of second yaw rotation ranges with respect to the start position, the first and second yaw rotation ranges being interleaved, at least some of the first yaw rotation ranges having different lengths from each other and/or at least some of the second yaw rotation ranges having different lengths from each other. The electrical contact generates an electrical signal when active.

Abstract: A method of determining torsional deformation in a drivetrain e.g. of a wind turbine. To provide a reliable and simple deformation assessment, the method comprises the step of generating a first signal representing first rotational speed of a low speed shaft, generating a second signal representing the second rotational speed of a high speed shaft, and determining torsional deformation based on changes in the ratio between the first and second signals.

Abstract: A yaw sensor for a wind turbine comprises a plurality of rotary switches, each configured to be coupled to a yaw drive gearbox of a wind turbine nacelle, the rotary switches each being operable to activate and deactivate respective associated electrical contacts in dependence on an amount of yaw rotation of the nacelle relative to a start position. Each electrical contact is active at a plurality of first yaw rotation ranges with respect to the start position, and inactive at a plurality of second yaw rotation ranges with respect to the start position, the first and second yaw rotation ranges being interleaved.

Abstract: A method of determining torsional deformation in a drivetrain e.g. of a wind turbine. To provide a reliable and simple deformation assessment, the method comprises the step of generating a first signal representing first rotational speed of a low speed shaft, generating a second signal representing the second rotational speed of a high speed shaft, and determining torsional deformation based on changes in the ratio between the first and second signals.