A method for adjusting a multi-dimensional operating space of a wind turbine includes receiving, via a central multi-dimensional operating space controller, a plurality of signals from a plurality of requestors of modified operating space. Each of the plurality of signals includes a data structure having requested set points for a plurality of dimensions in the operating space. The method also includes tracking, via the central multi-dimensional operating space controller, current set points for the plurality of dimensions in the operating space. Further, the method includes dynamically determining, via the central multi-dimensional operating space controller, an output signal based on the requested set points, the output signal comprising one or more changes for the current set points for the plurality of dimensions in the operating space. Moreover, the method includes controlling the wind turbine based on the output signal so as to provide a modified multi-dimensional operating space.

There is provided a method and system for operating a turboprop engine of an aircraft. When a resulting value for Ng is between at least one upper limit and at least one lower limit, the output power is governed as a function of the target power. When the resulting value for Ng is on or outside of the at least one upper limit and the at least one lower limit, the output power is governed as a function of the maximum Ng and the minimum Ng.

A method for defining a plurality of thrust limits for a wind turbine having a rotor with a plurality of blades and being located at a site. The thrust limits define values of aerodynamic thrust on the rotor not to be exceeded in operation. The method comprises providing a wind speed distribution representative for the site, and defining a plurality of isolines of constant turbulence probability representing a turbulence parameter as a function of wind speed. The turbulence parameter is indicative of wind speed variation. The isolines correspond to quantile levels of turbulence of the wind speed distribution. Turbulence ranges may be defined with respect to the isolines and thrust limits can be defined for the turbulence ranges. The disclosure also relates to methods of operating wind turbines using thrust limits and to wind turbines with suitable control systems.

A method for controlling a multirotor wind turbine is disclosed. A first operational state of each of the energy generating units of the wind turbine is obtained. A difference in thrust acting on at least two of the energy generating units is detected. At least one constraint parameter of the set of operational constraints is adjusted in accordance with prevailing operating conditions and in accordance with the detected difference in thrust, and a new operational state for at least one of the energy generating units is derived, based on the at least one adjusted constraint parameter, the new operational state(s) counteracting the detected difference in thrust. Finally, the wind turbine is controlled in accordance with the new operational states for the energy generating units.

A method of operating a wind turbine having a rotor. Sensor data is received from one or more sensors of the wind turbine and maximum load values are obtained on the basis of the sensor data. The maximum load values are indicative of maximum loads acting on a component of the wind turbine such as a rotor blade. An estimated extreme load value, such as a 50-year return load, is obtained on the basis of the maximum load values and compared with a reference value. A maximum thrust limit is set on the basis of the comparison, and the wind turbine is operated in accordance with the maximum thrust limit so that a wind thrust force acting on the rotor does not exceed the maximum thrust limit.

Embodiments herein describe a wind turbine controller that includes a thrust limiter for controlling the thrust of the blades of wind turbine using an estimate of the air density at the wind turbine. In one embodiment, the controller receives the blade flap load indicating the current load on one of the blades which varies linearly to the air density experienced by the wind turbine. In one embodiment, the controller determines the mean of a plurality of the blade flap load values measured during a predefined time period. Using a transfer function, the controller converts the mean of the blade flap loads to an estimate of the air density at the turbine. Generally, higher air density results in greater loads on the blades while lower air density results in lower loads on the blades.

The present invention relates to a method for stabilizing a rotor of a wind turbine during a time period following an abnormal grid event, the method comprising the steps of detecting an occurrence of the abnormal grid event, reducing an allowable rotor thrust from a first thrust limit to a second thrust limit, detecting that the abnormal grid event has ended, and maintaining the second thrust limit a selected time period after the abnormal grid event has ended. The present invention further relates to a wind turbine controller and a computer program product for performing this method.

A method for operating a wind farm having a first wind power installation and a second wind power installation, to an associated wind power installation and to an associated wind farm. The second wind power installation is located in the wake of the first wind power installation in at least one wake wind direction. A tip-speed coefficient is determined from the ratio of a second tip-speed ratio of the second wind power installation and a first tip-speed ratio of the first wind power installation and a pitch-angle coefficient is determined from the ratio of a second pitch angle of the second wind power installation and a first pitch angle of the first wind power installation. The method comprises: determining a turbulence metric, in particular a turbulence intensity, at the second wind power installation; operating the first wind power installation and the second wind power installation in the wake wind direction in a part-load range, wherein the tip-speed coefficient and/or the pitch-angle coefficient are/is a function of the turbulence metric at the second wind power installation and are/is greater than one.

The present invention relates to a control system for thrust-limiting of wind turbines, which wind turbine comprises at least one tower, which tower carries at least one nacelle which nacelle comprises a rotating shaft, which shaft is rotated by one or more blades, which blades at pitch regulated by a pitch control system. It is the object of the present invention to reduce mechanical load and stress of a wind turbine. A further object is to reduce the maximal load on tower of a wind turbine. The thrust-limiting control system performs control of the pitch angle, which thrust-limiting control system performs regulation of the pitch angle based on at least a first input from a wind estimator and a second input from a turbulence estimator. By thrust-limiting control, reduction in the maximum mechanical load on a tower, or maybe also a nacelle, can be achieved by a relatively high percentage of the load in a way where it has only very limited influence on the power production of the wind turbine.

A method is provided for operation of a wind turbine having rotor blades attached to a hub, wherein a controller compensates for torsionally induced blade twist. The method includes operating the wind turbine according to a rated power output curve and maximum design thrust value, and periodically or continuously detecting for induced torsional twist in the rotor blades. Upon determination of torsional twist being induced in the rotor blades, the method includes adjusting the maximum thrust value in the control program to compensate for the induced twist. The wind turbine controller then controls pitch of the rotor blades as a function of the increased maximum thrust value so that power output of the wind turbine is not unnecessarily limited or increased by the induced twist on the rotor blades.