Abstract: A control method for controlling a wind turbine comprising a rotor hub with a shaft and at least two blades, and a nacelle rotatably coupled to the tower through a yaw system, is provided. The control method includes steps for measuring a first periodic variable relating to the nacelle, measuring a second periodic variable relating to the shaft, estimating a yaw moment based on the data obtained from the first variable, processing the signal corresponding to the estimated yaw moment to extract a 1P frequency component from the signal, calibrating the yaw moment estimated, and adjusting the pitch angle of the corresponding blade to counteract the 1P frequency component of the estimated signal of the yaw moment after calibration, in turn comparing it with the signal of the second variable, is also provided.

Abstract: Control system to prevent wind turbine misalignment situations employing mathematical algorithms implemented in the wind turbine controller. Different optimization algorithms have been analyzed getting results that yaw the nacelle of the wind turbine to positions that would maximize the efficiency function. Control system for detecting and preventing wind turbine misalignment situations that comprises a parameters acquisition unit that relates the wind direction with the deviation of the wind turbine nacelle, a wind turbine efficiency function calculation unit and a deviation comparison unit of the nacelle.

Abstract: Control system to prevent wind turbine misalignment situations employing mathematical algorithms implemented in the wind turbine controller. Different optimization algorithms have been analyzed getting results that yaw the nacelle of the wind turbine to positions that would maximize the efficiency function. Control system for detecting and preventing wind turbine misalignment situations that comprises a parameters acquisition unit that relates the wind direction with the deviation of the wind turbine nacelle, a wind turbine efficiency function calculation unit and a deviation comparison unit of the nacelle.

Abstract: A method for alleviating rotor asymmetric loads in a variable-speed wind turbine having pitch and torque control means comprising the following steps: providing a control law that determines the pitch to be applied individually to each wind turbine blade for counteracting rotor asymmetric loads (such as wind shear, upflow, yaw misalignment) using wind speed and wind direction measurements at the wind turbine, values of the wind features that cause rotor asymmetric loads and configuration parameters of the wind turbine (whether real-time values or statistical values at the wind turbine site), said pitch to be added to the collective pitch ?0; implementing said control law in the wind turbine control means. The invention also refers to a wind turbine control system arranged for implementing said method.

Abstract: Method for the identification in operation of the drive train main vibration frequency of a wind turbine, comprising online steps of: a) obtaining a input signal (r) of the generator speed (?); b) filtering the generator speed input signal (r) for obtaining a generator speed signal (r1) in a suitable band for representing the oscillating signal (o) comprised in the input signal (r) of the generator speed (?); c) extracting the drive train main vibration frequency (f) from said filtered signal (r1). The invention also comprise a method of damping the drive train vibrations of a wind turbine comprising steps of setting the generator torque reference (Trref) as a function of the generator speed (?) and of the drive train main vibration frequency (f) identified by the above mentioned method and wind turbine control system implementing said damping method.

Abstract: Improved wind turbine control methods and systems. The invention relates to a method for the operation of a variable speed wind turbine having pitch and torque control means that include additional steps for providing to the pitch control means in case of a wind gust a pitch angle reference increment D?ref in the amount needed for avoiding that the aerodynamic torque added by the wind gust exceeds a predetermined limit. The present invention also relates to a wind turbine comprising a control system arranged for performing an additional regulation in case of wind gust.

Abstract: Wind turbine comprising: a tower (13) and a nacelle (21) housing a generator (19) driven by a wind rotor; measuring devices of at least wind speed V, generator speed ?, pitch angle ?i of each blade, power P, wind turbine accelerations in two perpendicular directions Ax, Ay, yaw angle Yw; azimuth position of the wind rotor AZ in which the control system connected to said measuring devices and to at least pitch and torque control actuators is also arranged for performing an active pitch angle regulation when the wind turbine is in an idling situation above Vout changing the pitch angle ?i of each blade for minimizing the wind turbine vibrations depending at least on the measured values of wind speed V, wind turbine accelerations Ax, Ay in two perpendicular directions, yaw angle Yw, azimuth position of the wind rotor AZ and pitch angle ?i of each blade.

Abstract: A method of controlling the operation of a variable speed wind turbine (11), tracking a power curve (25, 27) including a nominal operational region (3 ) and sub-nominal operational regions (2, 1, 0), comprising steps of: a) implementing a control strategy to follow said power curve in said nominal operational region (3) based on the use of demanded torque Td for controlling power P and on the use of demanded pitch ?d for controlling demanded torque Td; b) implementing a control strategy to follow said power curve in sub-nominal operational regions (2, 1, 0) based on the use of demanded torque Td for controlling power P and on the setting of a constant optimum value for demanded pitch ?d in each sub-nominal operational region (2, 1, 0). The invention also refers to a control system comprising one or more Adaptive Predictive Controllers (51, 53, 55, 59).

Abstract: Method for the identification in operation of the drive train main vibration frequency of a wind turbine, comprising online steps of: a) obtaining a input signal (r) of the generator speed (?); b) filtering the generator speed input signal (r) for obtaining a generator speed signal (r1) in a suitable band for representing the oscillating signal (o) comprised in the input signal (r) of the generator speed (?); c) extracting the drive train main vibration frequency (f) from said filtered signal (r1). The invention also comprise a method of damping the drive train vibrations of a wind turbine comprising steps of setting the generator torque reference (Trref) as a function of the generator speed (?) and of the drive train main vibration frequency (f) identified by the above mentioned method and wind turbine control system implementing said damping method.

Abstract: A method for alleviating rotor asymmetric loads in a variable-speed wind turbine having pitch and torque control means comprising the following steps: providing a control law that determines the pitch to be applied individually to each wind turbine blade for counteracting rotor asymmetric loads (such as wind shear, upflow, yaw misalignment) using wind speed and wind direction measurements at the wind turbine, values of the wind features that cause rotor asymmetric loads and configuration parameters of the wind turbine (whether real-time values or statistical values at the wind turbine site), said pitch to be added to the collective pitch ?0; implementing said control law in the wind turbine control means. The invention also refers to a wind turbine control system arranged for implementing said method.

Abstract: Improved wind turbine control methods and systems. The invention relates to a method for the operation of a variable speed wind turbine having pitch and torque control means that include additional steps for providing to the pitch control means in case of a wind gust a pitch angle reference increment D?ref in the amount needed for avoiding that the aerodynamic torque added by the wind gust exceeds a predetermined limit.

Abstract: Wind turbine comprising: a tower (13) and a nacelle (21) housing a generator (19) driven by a wind rotor; measuring devices of at least wind speed V, generator speed ?, pitch angle ?i of each blade, power P, wind turbine accelerations in two perpendicular directions Ax, Ay, yaw angle Yw; azimuth position of the wind rotor AZ in which the control system connected to said measuring devices and to at least pitch and torque control actuators is also arranged for performing an active pitch angle regulation when the wind turbine is in an idling situation above Vout changing the pitch angle ?i of each blade for minimizing the wind turbine vibrations depending at least on the measured values of wind speed V, wind turbine accelerations Ax, Ay in two perpendicular directions, yaw angle Yw, azimuth position of the wind rotor AZ and pitch angle ?i of each blade.

Abstract: A method of controlling the operation of a variable speed wind turbine (11), tracking a power curve (25, 27) including a nominal operational region (3) and sub-nominal operational regions (2, 1, 0), comprising steps of: a) implementing a control strategy to follow said power curve in said nominal operational region (3) based on the use of demanded torque Td for controlling power P and on the use of demanded pitch ?d for controlling demanded torque Td; b) implementing a control strategy to follow said power curve in sub-nominal operational regions (2, 1, 0) based on the use of demanded torque Td for controlling power P and on the setting of a constant optimum value for demanded pitch ?d in each sub-nominal operational region (2, 1, 0). The invention also refers to a control system comprising one or more Adaptive Predictive Controllers (51, 53, 55, 59).