The invention relates to control of a wind turbine to address varying drivetrain loading. This is obtained by determining a modification signal to be set as a control signal. A signal indicative of a speed of the electrical generator a signal indicative of a requested output power are received. The signal indicative of a speed is filtering to isolate frequencies in a selected disturbance frequency band to generate a disturbance signal. The disturbance signal is phase shifted and combined with a requested output power to obtain the modification signal.

The invention relates to a method for controlling power generation of a VSM wind turbine. The wind turbine comprises a machine side converter, a line side converter, a DC link, and an electric storage device electrically connected to the DC link. The method comprises determining a first power control signal to the machine side converter, determining a second power control signal for controlling a desired output power of the line side converter based on a storage device voltage error, and a power production reference, and determining a charging current reference for controlling charging and discharging of the electric storage device based on a DC-link voltage error.

A method for controlling a converter, preferably a generator-side active rectifier of a power converter of a wind power installation, comprising: specifying a target value for the converter; specifying a carrier signal for the converter; capturing an actual value; determining a distortion variable from the target value and the actual value; and determining driver signals for the converter on the basis of the distortion variable and the carrier signal.

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.

The present application provides a method and a system for controlling continuous high voltage ride-through and low voltage ride-through of a permanent magnet direct-driven wind turbine. The method includes: determining a transient time period during which the wind turbine is transitioned from a high voltage ride-through state to a low voltage ride-through state; controlling the wind turbine to provide, during the transient time period, a gradually increasing active current to the point of common coupling; and controlling the wind turbine to provide, during the transient time period, a reactive current to the point of common coupling according to an operation state of the wind turbine before the high voltage ride-through state.

A method for providing grid-forming control of a double-fed wind turbine generator connected to an electrical grid includes receiving at least one control signal associated with a desired total power output or a total current output of the double-fed wind turbine generator. The method also includes determining a contribution of at least one of power or current from the line-side converter to the desired total power output or to the total current output of the double-fed wind turbine generator, respectively. The method also includes determining a control command for a stator of the double-fed wind turbine generator based on the contribution of at least one of the power or the current from the line-side converter and the at least one control signal. Further, the method includes using the control command to regulate at least one of power or current in the stator of the double-fed wind-turbine generator.

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.

Aspects of the present invention relate to a method of voltage control for at least one wind turbine generator configured to absorb and supply reactive power on demand, the method comprises: receiving a dispatch signal from a power plant controller indicating a reactive power set point; determining a terminal voltage level of the at least one wind turbine generator; generating a reactive power correction value based on a deviation of the terminal voltage level from a voltage set point; adjusting the reactive power set point by the reactive power correction value; and controlling the at least one wind turbine generator according to the adjusted reactive power set point.

A method for operating a wind farm having a string (S1-S3) of wind turbines (100-100c) which are electrically connectable with each other and a grid (510, 550) is disclosed. Each wind turbine includes a rotor (106) with rotor blades (108), a power conversion system (118, 210, 238) mechanically connected with the rotor (106), and at least one auxiliary subsystem (105, 109). The method includes operating the wind turbines of the string in an island operating mode in which the wind turbines are not connected with the grid, and the respective at least one auxiliary subsystem is supplied with electric power generated by the power conversion system of the respective wind turbine; detecting that the rotor of one of the wind turbines is exposed to a wind condition at which at least one of the rotor blades is at risk of stalling at the currently generated electric output power; and increasing the electric power generated by the power conversion system of the one of the wind turbines by an electric power amount which is sufficient for suppling the at least one auxiliary subsystem of at least one of the other wind turbines of the string.

A method (1000, 1001) for operating a wind turbine (100-100d) is disclosed. The wind turbine includes a rotor (106) with rotor blades (108), a power conversion system (118, 210, 234) mechanically connected with the rotor (106), a first subsystem (310 ), a second subsystem (320), and an internal electric power distribution system (300-301b, 321, 322) connectable with the first subsystem (310) and the second subsystem (320). During operating (1100) the wind turbine (100-100d) in a normal operating mode in which the power conversion system (118, 210, 234) converts input motive power into electrical output power (P), the method (1000) includes detecting (1200) an increased power demand of the first subsystem (310), and actively increasing (1300) an amount (P1) of electric power (Pint) flowing through the internal electric power distribution system (300-301b, 321, 322) to the first subsystem (310) if a power demand of the second subsystem (320) is at least reduced.