The present invention relates to a method of determining an induction factor between the rotor plane (PR) and a measurement plane (PM), involving measuring the wind speed in at least two measurement planes (PM), determining the wind speed in rotor plane (PR) by use of a Kalman filter from the measurements, and measuring the induction factor by use of an adaptive Kalman filter from the measurements and the wind speed in rotor plane (PR).

Techniques for controlling the yaw of a wind turbine system by controlling a plurality of yaw drive actuators. Based on a requested motor speed reference as an input signal, and a mean motor speed reference as a feedback signal, the method determines a required motor torque reference as an output signal for the plurality of yaw drive actuators. The plurality of yaw drive actuators rotates a nacelle or a structure comprising a plurality of nacelles such that an even load distribution is provided for the plurality of yaw drive actuators.

Disclosed are a method and apparatus for detecting a yaw-to-wind abnormality. The method includes: acquiring a wind direction deviation angle within a specified time period; calculating a power performance index, wherein the power performance index is a dimensionless number used to characterize power generation performance of a wind turbine; determining an optimal wind direction deviation angle based on the power performance index; determining a current wind direction deviation angle according to probability distribution of the wind direction deviation angle; and if a difference between the optimal wind direction deviation angle and the current wind direction deviation angle is greater than a preset threshold, determining that a yaw-to-wind abnormality is detected. Compared with the related technology in which yaw-to-wind detection is performed through a power fitting curve, in the technical solution according to the embodiments of the present disclosure, a power index is directly used, which avoids the problem of poor power curve fitting effect and improves the accuracy of yaw-to-wind detection.

A method of determining an offset angle to the wind direction measured from a wind vane of a wind turbine includes the steps of: defining a plurality of power bins representing an interval of power which can be produced by the wind turbine, calculating an efficiency of the wind turbine for a plurality of time slots, determining a power output of the wind turbine for the plurality of time slots, comparing the efficiency of the wind turbine in two different time slots, and updating a value of the one of the power bins representing the interval of power determined for one of the compared time slots. The value of the power bin is updated with the result of the highest efficiency or a value derived from the highest efficiency multiplied with a constant.

Systems and methods enable yaw offsets on wind turbines in a wind farm. A wind turbine yaw controller receives a present wind direction signal from a local wind direction sensor and aligns the wind turbine in a substantially perpendicular direction based upon the present wind direction signal. A yaw controller is retrofitted between the wind direction sensor and the yaw controller to provide an adjusted wind direction signal to the yaw controller based upon the present wind direction signal and a yaw offset signal. An offset table relating yaw offsets with wind direction signal values may be stored locally at a wind turbine or at a site controller in communication with the wind tribune. Each wind turbine in the wind farm may be retrofitted with the yaw controller to enhance the power output of the wind farm by adjusting the wake effect between wind turbines of the wind farms.

A wind turbine comprising a tower (2) with a tower wall and having at least one nacelle (3) mounted thereon, and a yaw system (1) interconnecting the tower (2) and at least one nacelle (3) is disclosed. The yaw system (1) comprises a yaw claw (4) comprising an upper radially extending part (5), a lower radially extending part (6) and an axially extending part (7) interconnecting the upper radially extending part (5) and the lower radially extending part (6), thereby defining a space. A sliding bearing connection with at least two axial sliding surfaces (9, 10) and at least one radial sliding surface (11) is arranged between the yaw claw (4) and a flange (8) arranged in the space defined by the yaw claw (4). At least one yaw drive (13) comprising a toothed gear (14) is arranged in meshing connection with a toothed yaw ring (12). The axially extending part (7) of the yaw claw (4) and the meshing connection between the toothed gear (14) and the toothed yaw ring (12) are arranged at the same side of the tower wall.

An information generating device includes a control unit for causing a motor to rotate a pinion gear meshing with a ring gear while a predetermined braking force is applied to brake rotation of a turnable part of a wind turbine, thereby causing a fastening part to deform, where the fastening part is provided to fixedly attach the motor to a target part, a deformation amount obtaining unit for obtaining an amount of deformation experienced by the fastening part, and an information generating unit for generating correlation information indicating a correspondence between a driving torque of the motor and the amount of deformation experienced when the driving torque is used to rotate the motor.

A novel lightweight high efficiency wind generator with low noise and low vibrational levels comprising a vertical mast with a rotation element mounted at the top of the mast, with a frame attached to the rotation element with its bottom, such that the rotation element provides axial rotation of the frame in the range from 0° to 360°, is disclosed. The frame comprises a three-dimensional truss frame construction with traverses, to which at least one rigid closed elliptical base is attached. The at least one elliptical base carries a guide rail with grooves, the guide rail comprises at least one pair of rollers in the grooves which can rotate and roll in the grooves along the entire closed circuit of the elliptical base. Along the entire contour of the elliptical base blades are radially fixed and arranged in one plane using carriages.

A controller for the yaw function is coupled with a yaw system for controlling the operation of yaw motors in the yaw function of a wind turbine. A control signal is provided to the controller that is reflective of a grid condition of an electric grid. The control signal is evaluated, and the controller selectively delays the yaw function based upon the control signal. In another embodiment, the yaw system includes brakes for the yaw motors that are coupled with an independent power supply. The controller selectively delays the yaw function if the brake power supply is not operational.

A method for determining a yaw position offset of a wind turbine (1) is provided. A neighbouring wind turbine (2) of the wind farm is identified, the neighbouring wind turbine (2) being arranged in the vicinity of the wind turbine (1). Produced power data and/or wind speed data from the wind turbine (1) and from the neighbouring wind turbine (2), is obtained during a period of time, and a yaw position offset of the wind turbine (1) is derived, based on the obtained produced power data and/or wind speed data, and based on the geographical positions of the wind turbine (1) and the neighbouring wind turbine (2). A local maximum and a local minimum being separated by an angular difference in yaw position being substantially equal to 180°.