Abstract: A wind turbine has a Lidar device to sense wind conditions upstream of the wind turbine. Signals from the wind turbine are processed to detect an extreme change in wind direction. The detection is performed by differentiating the rate of change of wind direction and filtering for a period of time. On detection of extreme change the system controller takes the necessary evasive action which may include shutting down the turbine, commencing an immediate yawing action, and de-rating the turbine until the yawing action is complete.

Abstract: A method to individually optimize respective pitch angles of blades in a wind turbine. The method allows supplying (102) a modulation signal to modulate a pitch angle of the individual blade being optimized. The method further allows filtering (104) output power of the turbine subject to the modulating frequency to extract a power signal in a frequency spectrum including the modulating frequency. The extracted power signal and a demodulation signal are mixed (106) to generate a signal including a product of the extracted power signal and the demodulation signal. The generated signal is filtered (108) to remove the modulating frequency and extract a gradient signal effective to search a pitch angle estimate conducive to optimize output power of the turbine. The gradient signal may be integrated (110) to cause the gradient signal to converge towards an optimal pitch angle for the individual blade being optimized.

Abstract: The application describes a wind turbine having a control method and controller for performing predictive control of a wind turbine generator. Based on the measured instantaneous wind speed, it is known to provide control signals to a wind turbine in order to control the pitch of the wind turbine rotor blades and the speed of the generator. However, it is difficult using instantaneous wind speed measurements to achieve smooth control, due to finite response speeds of the associated electro-mechanical systems, as well as the constantly changing control system inputs. The predictive control system described in the application assumes a model of generator speed based on the values of the incident wind speed v(t) and the values of a control signal u(t) output to the wind turbine in a feed forward loop. Here, the control signal can be for one or more of controlling either the power setting of the generator, or the pitch angle of the rotor blades.

Abstract: A method is provided for damping an oscillatory movement of a nacelle of a wind turbine. The nacelle is attached to a tower of the wind turbine. The method involves rotating the nacelle about a yawing axis with a yawing speed, the yawing axis being aligned with a longitudinal axis of the tower, changing the yawing speed, and coordinating the yawing speed with the oscillatory movement such that a torque resulting from the change of the yawing speed damps the oscillatory movement of the nacelle of the tower.

Abstract: A wind turbine has a Lidar device to sense wind conditions upstream of the wind turbine including wind speed, direction and turbulence. Signals from the Lidar are processed to detect an event which could give rise to low cycle fatigue loading on one or more components of the wind turbine. On detection the system controller takes the necessary evasive action depending on the nature and severity of the extreme condition detected. This may include a significant reduction in power generated through reduction in rotor speed or torque, complete shutdown of the generator and yawing of the nacelle and rotor in response to a change in wind direction.

Abstract: A wind turbine has a Lidar device to sense wind conditions upstream of the wind turbine. Signals from the wind turbine are processed to detect an extreme event. On detection the system controller takes the necessary evasive action depending on the nature and severity of the extreme condition detected. This may include a significant reduction in power generated, complete shutdown of the generator and yawing of the nacelle and rotor to reduce loading on the rotor blades.

Abstract: A method to individually optimize respective pitch angles of blades in a wind turbine. The method allows supplying (102) a modulation signal to modulate a pitch angle of the individual blade being optimized. The method further allows filtering (104) output power of the turbine subject to the modulating frequency to extract a power signal in a frequency spectrum including the modulating frequency. The extracted power signal and a demodulation signal are mixed (106) to generate a signal including a product of the extracted power signal and the demodulation signal. The generated signal is filtered (108) to remove the modulating frequency and extract a gradient signal effective to search a pitch angle estimate conducive to optimize output power of the turbine. The gradient signal may be integrated (110) to cause the gradient signal to converge towards an optimal pitch angle for the individual blade being optimized.

Abstract: A wind turbine with a rotor comprising one or more rotor blades and a hub, the hub being attached to a nacelle, a yaw system for rotating the rotor to orient it in a wind direction, and one or more line of sight detectors for detecting a component of wind velocity. The one or more detectors are mounted such that they rotate under the action of the yaw system. A control system is coupled to the one or more detectors and is arranged to compare the detected wind velocity component with a wind velocity value and control the yaw system in response to the comparison. The nacelle can be rotated under control of the control system until the yaw error is substantially zero.

Abstract: A wind turbine has a scanning Lidar arranged on the nacelle. The Lidar has a single scanning beam which scans about a substantially vertical axis to sense wind related data in a measurement volume a predetermined distance from the Lidar. Fast Fourier transforms of data from a plurality of points in the measurement volume are analysed to derive a peak velocity and a measure of variance. A controller receives the peak velocity and measure of variance as inputs and generates an output if the controller determines that the input data shows that the wind conditions are such that damage to the wind turbine is likely.

Abstract: A wind turbine has a Lidar (20) device to sense wind conditions upstream of the wind turbine. Signals from the wind turbine are processed to detect an extreme change in wind direction. The detection is performed by differentiating the rate of change of wind direction and filtering for a period of time. On detection of extreme change the system controller takes the necessary evasive action which may include shutting down the turbine, commencing an immediate yawing action, and de-rating the turbine until the yawing action is complete.

Abstract: The application describes a wind turbine having a control method and controller for performing predictive control of a wind turbine generator. Based on the measured instantaneous wind speed, it is known to provide control signals to a wind turbine in order to control the pitch of the wind turbine rotor blades and the speed of the generator. However, it is difficult using instantaneous wind speed measurements to achieve smooth control, due to finite response speeds of the associated electro-mechanical systems, as well as the constantly changing control system inputs. The predictive control system described in the application assumes a model of generator speed based on the values of the incident wind speed v(t) and the values of a control signal u(t) output to the wind turbine in a feed forward loop. Here, the control signal can be for one or more of controlling either the power setting of the generator, or the pitch angle of the rotor blades.

Abstract: A wind turbine with a rotor comprising one or more rotor blades and a hub, the hub being attached to a nacelle, a yaw system for rotating the rotor to orient it in a wind direction, and one or more line of sight detectors for detecting a component of wind velocity. The one or more detectors are mounted such that they rotate under the action of the yaw system. A control system is coupled to the one or more detectors and is arranged to compare the detected wind velocity component with a wind velocity value and control the yaw system in response to the comparison. The nacelle can be rotated under control of the control system until the yaw error is substantially zero.

Abstract: A wind turbine has a Lidar device to sense wind conditions upstream of the wind turbine including wind speed, direction and turbulence. Signals from the Lidar are processed to detect an event which could give rise to low cycle fatigue loading on one or more components of the wind turbine. On detection the system controller takes the necessary evasive action depending on the nature and severity of the extreme condition detected. This may include a significant reduction in power generated through reduction in rotor speed or torque, complete shutdown of the generator and yawing of the nacelle and rotor in response to a change in wind direction.

Abstract: A wind turbine has a Lidar device to sense wind conditions upstream of the wind turbine. Signals from the wind turbine are processed to detect an extreme event. On detection the system controller takes the necessary evasive action depending on the nature and severity of the extreme condition detected. This may include a significant reduction in power generated, complete shutdown of the generator and yawing of the nacelle and rotor to reduce loading on the rotor blades.