Abstract: Methods of measuring a stall condition of a rotor of a wind turbine are disclosed. In one aspect a stall parameter is obtained on the basis of the power parameter and a thrust parameter; and the stall parameter compared with a threshold to determine a stall condition of the rotor.

Abstract: A method of controlling a wind turbine connected to an electrical grid is provided. The method comprises generating a turbine control reference signal and a grid control reference signal. The turbine control reference signal is provided to a machine side unit of a power or torque control system of the turbine to control the amount of energy generated by the turbine. The grid control reference signal is provided to a line side unit of the power or torque control system to control the amount of energy transferred to the electrical grid based on the grid control reference signal.

Abstract: Aspects of the present invention relate to controlling a wind turbine having a tower damping system actuable to control components of vibrational movement of the tower, a side-side component of a vibrational movement of the tower in a horizontal plane; and a fore-aft component of the vibrational movement of the tower in the horizontal plane are determined; and a control signal based on the side-side and fore-aft components is determined such that the tower damping system produces a force that increases or decreases the vibrational movement of the tower such that the side-side and fore-aft components are substantially equal.

Abstract: A method of controlling a wind turbine blade of a wind turbine comprising: providing data comprising a plurality of pitch angles of the wind turbine blade and corresponding expected power coefficients for the wind turbine, each pitch angle corresponding to a maximum expected power coefficient for a degradation state of the wind turbine blade; obtaining a current power coefficient of the wind turbine; determining a desired pitch angle for the wind turbine blade, the desired pitch angle being equal to a pitch angle from the dataset corresponding to an expected power coefficient equal to the current power coefficient; and changing a pitch angle of the wind turbine blade to the desired pitch angle.

Abstract: Methods of measuring a stall condition of a rotor of a wind turbine are disclosed. In one aspect a stall parameter is obtained on the basis of the power parameter and a thrust parameter; and the stall parameter compared with a threshold to determine a stall condition of the rotor.

Abstract: A method for controlling a wind energy farm is disclosed. A wake state of the wind energy farm is determined, including determining wake chains defining wake relationships among the wind turbines of the wind farm under the current wind conditions. For at least one of the wind turbines of the wind energy farm, a lifetime usage is estimated, based on an accumulated load measure for the wind turbine. In the case that the estimated lifetime usage is below a predefined lifetime usage limit, the wind turbine is operated in an overrated state, while monitoring wake effects at each of the wind turbines. In the case that a downstream wind turbine detects wake effects above a predefined wake threshold level, at least one wind turbine having an upstream wake relationship with the downstream wind turbine is requested to decrease the generated wake, e.g. by decreasing power production.

Abstract: The invention relates to a method for controlling a yaw offset of a plurality of wind turbines. The method uses a decision function which generates an activation parameter for determining if the yaw offset control of a specific wind turbine should be enabled or disabled. The decision function depends on two or more variables comprising a wind direction variable indicative of the wind direction of the specific wind turbine, and a wind variation variable defining at least a wind variation range where yaw offset control is disabled or enabled. Based on the decision function it is determined if a yaw offset should be added to the current yaw setting of the specific wind turbine.

Abstract: Techniques for controlling rotor speed of a wind turbine. One technique includes defining a system model describing resonance dynamics of a wind turbine component, such as a wind turbine tower, where the system model has a nonlinear input term, e.g. a periodic forcing term. A transform is applied to the system model to obtain a transformed model for response oscillation amplitude of the wind turbine component, where the transformed model has a linear input term. A wind turbine model describing dynamics of the wind turbine is then defined, and includes the transformed model. A model-based control algorithm, e.g. model predictive control, is applied using the wind turbine model to determine at least one control output, e.g. generator torque, and the control output is used to control rotor speed of the wind turbine.

Abstract: The present invention relates to a method of controlling a wind turbine comprising a tower supporting a rotor comprising a plurality of pitch-adjustable rotor blades. The method includes obtaining a movement signal indicative of a lateral movement of the tower; determining a pitch modulation signal, based on the movement signal, for actuating a rotor blade to produce a desired horizontal force component to counteract the lateral movement of the tower; determining a radial force component acting on a rotor blade; determining a phase offset parameter for the rotor blade based on the radial force component; and, transforming the pitch modulation signal into a pitch reference offset signal for the rotor blade based on the phase offset parameter.

Abstract: An apparatus for monitoring an ambient environment of a wind turbine is described. The apparatus comprises a cooling system comprising first and second heat exchangers, and a fluid circuit arranged to enable coolant to flow between the first and second heat exchangers. The apparatus further comprises a processor configured to: monitor one or more operational parameters of the cooling system; determine an efficiency of the cooling system based on the monitored one or more operational parameters; and calculate a liquid water content of the ambient environment based on the measured efficiency of the cooling system.

Abstract: A method of controlling a wind turbine is provided, comprising identifying an out-of-vertical load acting in a first direction on the wind turbine. A direction of a wind load acting on the wind turbine is determined. If there is a degree of alignment between the direction of the wind load and the first direction, the wind turbine is controlled to reduce the wind load.

Abstract: A method of controlling a wind power plant including an energy storage device, the wind power plant being connected to a power grid and comprising one or more wind turbine generators that produce electrical power for delivery to the power grid, the method comprising: processing input data related to one or more inputs to the wind power plant to determine a probability forecast for each input; and controlling charging and discharging of the energy storage device in accordance with each probability forecast and a prescribed probability of violating one or more grid requirements.

Abstract: A method of controlling pitch of individual blades in a wind turbine is described, together with a suitable controller. Wind speed is determined as a function of azimuthal angle. Wind speed is then predicted for individual blades over a prediction horizon using this determination of wind speed as a function of azimuthal angle. The predicted wind speed for each individual blade is used in a performance function, which is optimized to control individual blade pitches.

Abstract: Controlling a wind turbine including measuring a wind speed for a location upwind of a wind turbine. Using the measured wind speed, a changed steady-state deflection of a structure of the wind turbine is predicted. The predicted changed steady-state deflection corresponds to a time when wind from the location is incident on the wind turbine. Oscillations of the structure are damped relative to the changed steady-state deflection. By damping the oscillations relative to the changed steady-state deflection, movements of the structure may be minimized when there is no predicted change in steady-state deflection, while permitting more rapid movements during transitions from one steady-state deflection to the predicted steady-state deflection, allowing more of the available power to be captured by the wind turbine.

Abstract: A method of controlling a wind power plant including an energy storage device, the wind power plant being connected to a power grid and comprising one or more wind turbine generators that produce electrical power for delivery to the power grid, the method comprising: processing grid data related to the power grid to determine a probability forecast for a future state of the grid; and controlling charging and discharging of the energy storage device in accordance with the probability forecast.

Abstract: A control system and method of control are disclosed. A model predictive control, MPC, unit is configured to determine a control signal for controlling an operation of the wind turbine based at least in part on a cost function comprising a wear cost relating to one or more types of wear of the winding turbine, and a corresponding cost weighting, which defines a relative weighting of the wear cost in the cost function. A weighting determination unit is configured to receive a reference signal comprising a target wear, receive a feedback signal comprising a wear measure of the wind turbine, and determine, based at least in part on a difference between the target wear and the wear measure, a weighting adjustment for at least part of the cost weighting of the cost function. The MPC unit then sets the cost weighting based at least in part on the weighting adjustment.

Abstract: The present invention provides a method and controller for controlling noise emissions from individual blades (18) of a wind turbine (10), the method (60) comprising defining (720) a wind turbine model (321) describing dynamics of the wind turbine (10), the wind turbine model (321) including a description of intensity and direction of noise emissions from each individual blade (18) as a function of azimuthal angle (312); and applying (730) a model-based control algorithm (32) using the wind turbine model (321) to determine at least one control output (331), and using (740) the at least one control output (331) to control noise emissions from each individual blade (18).

Abstract: Embodiments herein describe a method and associated controller for a wind turbine. The method comprises determining one or more characteristics of a sensor signal received from a mechanical sensor of the wind turbine; determining, based on the one or more characteristics of the sensor signal, an icing condition of the wind turbine; and controlling operation of one or more wind turbine systems based on the determined icing condition.

Abstract: A method of controlling a wind turbine connected to an electrical grid is provided. The method comprises generating a turbine control reference signal and a grid control reference signal. The turbine control reference signal is provided to a machine side unit of a power or torque control system of the turbine to control the amount of energy generated by the turbine. The grid control reference signal is provided to a line side unit of the power or torque control system to control the amount of energy transferred to the electrical grid based on the grid control reference signal.

Abstract: According to an embodiment of the present invention there is provided an apparatus for controlling a sub-system of a wind turbine. The apparatus comprises a cooling system comprising first and second heat exchangers, and a fluid circuit arranged to enable a coolant to flow between the first and second heat exchangers; and a processor. The processor is configured to: monitor one or more operational parameters of the cooling system; determine an icing risk based on the one or more operational parameters; and generate a control signal for output to the wind turbine sub-system in dependence on the determined icing risk.