The present invention relates to a method for operating a wind power installation, comprising the steps of: sensing at least one angular velocity of the wind power installation, in particular by use of a rotation rate sensor in a hub of the wind power installation, preferably for the purpose of sensing a tilt of the nacelle; sensing a reference value for the at least one sensed angular velocity; determining at least one state variable of the wind power installation from the at least one angular velocity and the reference value; controlling the wind power installation in dependence on the state variable, in particular such that the state variable becomes smaller.

A method of operating a wind turbine wherein the wind turbine includes a doubly-fed induction generator that converts rotational mechanical power to electrical power. The method includes operating the wind turbine in a first operational mode in which a speed of a rotor of the wind turbine is controlled to maximize the power generation by the wind turbine. Upon a monitored parameter reaching or dropping below a respective threshold, the wind turbine is operated in a second operational mode. The monitored parameter may include at least one of the rotational speed of the rotor, the rotational speed of the doubly-fed induction generator, a wind speed, an active electrical power, or generator torque. Operating the wind turbine in the second operational mode may include increasing the rotational speed of the doubly-fed induction generator at the expense of the generation of active electrical power by the power generating system.

A modular wind turbine system and a method of use thereof are provided. The system comprises: a mounting frame; a fixed toroidal support structure attached to the mounting frame, the toroidal support structure having a concave portion and a convex portion; a wind turbine located proximal to the concave portion of the toroidal support structure, wherein the wind turbine travels about at least a portion of the concave portion of the toroidal support structure; and a first baffle, wherein the first baffle extends about the portion of the concave portion of the toroidal support structure about which the first turbine travels, wherein the baffle surrounds a portion of the wind turbine opposite the fixed toroidal support structure, and wherein the baffle includes at least one component selectively variably adjustable so as to vary the force, direction, or disruption of flow of fluid thereby, relative to the wind turbine.

A method for operating a plurality of wind energy installations configured for supplying electric power to an electrical supply system, that each have an aerodynamic rotor with rotor blades and an electrical generator and also operating equipment, is disclosed. The wind energy installations are operated while they are not connected to the electrical supply system, where at least one of the wind energy installations produces electric power and inputs the electric power into a local DC voltage system that connects the wind energy installations if the at least one of the wind energy installations currently produces more power than needed for supplying its own operating equipment. Additionally or alternatively, the operating equipment is supplied totally or in part with power from the local DC voltage system if the at least one of the wind energy installations currently produces less power than needed for supplying its operating equipment.

A controller for a wind turbine including a rotor and a nacelle arranged on a tower is provided, the tower having a fundamental frequency close to or below a rated rotational frequency of the rotor. The controller includes a rotor speed control module including a first linear time invariant control system adapted to generate a first pitch control signal based on a rotor speed error signal, a tower damping module including a second linear time invariant control system adapted to generate a second pitch control signal based on a nacelle acceleration signal, and an output module adapted to output a pitch control signal based on the first pitch control signal and the second pitch control signal. Furthermore, a wind turbine and a method of controlling a wind turbine is provided.

A method is disclosed for controlling a wind turbine generator to provide power above a rated level. The wind turbine includes one or more electrical components that conduct current from the internal generator to supply the external grid. The control method calculates the maximum current that the electrical components can carry at the ambient temperature. The calculated current is combined with a measurement of the voltage and an estimate of reactive power in the system to give a maximum power at which the wind turbine can operate without the maximum allowable current being exceeded for the electrical components. The electrical components may be housed in the main electrical panel of the wind turbine.

Embodiments of the present invention provide methods and apparatus for increasing turbulent mixing in the wake of at least one wind turbine. Doing so, increases efficiency of a wind turbine located in the wake by transferring energy to the wake that was lost when the wind passed through the upwind turbine. Turbulent mixing may be increased by changing the induction factor for a rotor by, for example, altering the pitch of the blades, the RPMs of the rotor, or the yaw of the nacelle. These techniques may be static or dynamically changing. Further, the different induction factors for a plurality of wind turbines may be synchronized according to a predetermined pattern to further increase turbulent mixing.

A hydraulic control system HCS for controlling a variable ratio transmission of a power generating system. A hydraulic motor/pump unit 140 is operably connected to a superposition gear, and is connected to a hydraulic circuit that comprises an orifice 28 and/or a relief valve 29 that opens at a predetermined hydraulic pressure. The hydraulic circuit switches between a variable low-speed operating mode and a torque limiting high-speed operating mode. In the torque limiting high-speed operating mode the hydraulic motor/pump unit 140 is driven by the superposition gear and drives hydraulic fluid through the orifice 28 and/or relief valve 29 to provide a passive torque limiting function. In the variable low-speed operating mode the hydraulic motor/pump unit 140 drives the superposition gear and the hydraulic control system provides a desired rotor 101 speed by controlling hydraulic fluid flow rate through the hydraulic motor/pump unit 140.

A method is for controlling a wind turbine. The wind turbine has a tower, a nacelle, a rotor with at least two rotor blades and a yaw system with at least one yaw drive configured to rotate the nacelle about a vertical axis of the tower (yaw axis). A control signal for the at least one yaw drive depends on at least one signal indicative of the wind direction. The control signal for the at least one yaw drive further depends on at least one value indicative of a vibration mode of the rotor blades.

A control arrangement for a variable-speed wind turbine includes a loading analysis module configured to analyse a number of environment values to establish whether the momentary wind turbine loading is lower than a loading threshold when the rotational speed of the aerodynamic rotor has reached its rated value; and a speed boost module configured to determine a speed increment for the rotational speed of the aerodynamic rotor if the wind turbine loading is lower than the loading threshold.