A controller structure for a wind turbine having an aerodynamic rotor with at least one rotor blade, wherein the controller structure is designed to control a rotation speed of the rotor of the wind turbine, wherein the controller structure is designed as a cascade control arrangement and has an outer control loop and an inner control loop, wherein the inner control loop receives an input signal which comprises a change in the rotation speed, an acceleration of the rotation speed, a function of the change in the rotation speed and/or a function of the acceleration of the rotation speed.

The present invention relates to a method for controlling a wind turbine, the wind turbine comprises a rotor connected to a generator, and a rotational speed controller configured to control a speed of the rotor in response to a generator speed reference, and a power controller to control an electric power production, the method comprises the step for receiving a boost command to request a power boost event, so to increase the electrical power production, and imposing a dead band with a dead zone value limit to the rotational speed controller, and wherein the dead band imposes a zero signal to be send to the rotational speed controller, when a speed error is within the dead zone value limit and wherein the dead band imposes an error signal to be send to the rotational speed controller, when a speed error is greater than the dead zone value limit, the error signal being a function of the speed error and the dead zone value limit. The invention also relates to a wind power plant comprising a power plant controller and at least one wind turbine with a control system according to the above mentioned method.

Provided are modeling method and device of a floating wind turbine, which relate to the technical field of wind turbine modeling. The modeling method and device of a floating wind turbine can acquire pre-set state variables and input variables of the floating wind turbine, construct a nonlinear model based on the state variables and the input variables, and establish a control-oriented linear parameter varying model corresponding to the nonlinear model according to the nonlinear model, so as to control the floating wind turbine based on the control-oriented linear parameter varying model. The nonlinear model comprises: a drivetrain subsystem model, a tower subsystem model, a floating platform subsystem model, and a mooring subsystem model.

A fault-tolerant control method and apparatus of a floating wind turbine are provided. The fault-tolerant control method and apparatus of a floating wind turbine can acquire a low-order nonlinear model of a pre-established floating wind turbine, establish a switching linear model of the floating wind turbine based on the low-order nonlinear model, acquire a modal parameter of the current floating wind turbine, and determine based on the modal parameter a sub-model that the floating wind turbine currently satisfies, so as to establish a switching sliding mode surface and a full-order state observer of the floating wind turbine based on the sub-model and the modal parameter, and further calculate a feedback output of a controller of the floating wind turbine according to the switching sliding mode surface and the full-order state observer.

A control system for a floating offshore wind turbine (FOWT). The FOWT includes a floating base, a tower, a nacelle, and rotor with blades that harvest energy from wind passing the FOWT. Without a rigid support, however, the FOWT is able to move. The controller uses generator speed and platform pitch position of the FOWT as inputs and manipulates blade pitch and torque resistance to achieve stability.

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.

The invention provides a wind turbine having a system for positioning the rotor in an azimuthal reference position Az.sub.ref and for maintaining it therein for a predetermined period of time, the wind turbine being arranged in test mode. Said rotor positioning system comprises a first controller (31) configured to generate a generator speed reference .sub.ref from the difference between the rotor azimuthal reference position Az.sub.ref and the rotor azimuthal measured position Az.sub.meas and a second controller (35) configured to generate a generator torque reference T.sub.ref from the difference between said generator speed reference .sub.ref and the generator speed measured .sub.meas.

A method is provided for controlling a wind turbine that has a generator that is controlled via a converter in a boost operation, in which an electrical power that is fed into an electrical transmission network is increased via a generative deceleration of the generator. The method comprises using a control to determining a set point value for a generator torque depending on an actual value of a rotational speed. The determined set point value for the generator torque is applied to a generator via a limiter with a predefinable upper and lower limit. Determining the set point value for the generator torque in boost operation that leads to an increased fed-in electrical power in response to a boost signal; and limiting a temporal change of the set point value for the generator torque in a recovery operation in response to a recovery signal.

A motion controller for a floating wind turbine with a plurality of rotor blades, is arranged to control a motion of the floating wind turbine in a yaw direction. The controller adjusts the blade pitch of each rotor blade so as to create a net force to control the motions. The controller includes a control action which is proportional to a yaw offset angle and/or a control action which is proportional to an integral of the yaw offset angle.

The present invention relates to a method for controlling a wind turbine, the wind turbine comprises a rotor connected to a generator, and a rotational speed controller configured to control a speed of the rotor in response to a generator speed reference, and a power controller to control an electric power production, the method comprises the step for receiving a boost command to request a power boost event, so to increase the electrical power production, and imposing a dead band with a dead zone value limit to the rotational speed controller, and wherein the dead band imposes a zero signal to be send to the rotational speed controller, when a speed error is within the dead zone value limit and wherein the dead band imposes an error signal to be send to the rotational speed controller, when a speed error is greater than the dead zone value limit, the error signal being a function of the speed error and the dead zone value limit. The invention also relates to a wind power plant comprising a power plant controller and at least one wind turbine with a control system according to the above mentioned method.