Vestas Wind Systems A/s

Christian Jeppesen

Fabio Caponetti

Keld Hammerum

Silvia Estelles Martinez

Jesper Sandberg Thomsen

Tobias Gybel Hovgaard

Alexander Duncan Giles

Jon Sowman

Adjusting pitch of the wind turbine rotor blades to reduce fatigue of the wind turbine tower. Flap loading sensor data is received for the rotor blades, and a flap loading vector in a rotor coordinate frame of the wind turbine is obtained. The flap loading vector is transformed to obtain first and second mutually orthogonal components in a fixed wind turbine coordinate frame, and respective 3P (blade passing frequency) components in the fixed frame indicative of 3P frequency content of the wind turbine tower are determined. A control action is applied to obtain respective 3P control components for mitigating the 3P frequency content of the tower, an inverse transform is applied to the 3P control components to obtain pitch reference offset values for the respective rotor blades in the rotor coordinate frame, and blade pitch is adjusted based on the pitch reference offset values.

Wind turbine rotor blade pitch control for tower fatigue reduction

Control of a wind turbine in a stop process where a stop controller is used to pitch the blades at a number of pre-set pitch rates including a first pitch rate and a second pitch rate. The stop controller is arranged to access desired pitch angles of the stopping process and add an envelope band to the desired pitch angles. In the stop process, pitching at a selected pitch rate among the number of pre-set pitch rates is performed, and the pitch rate is changed according to criteria to keep the pitch value within the envelope band.

Stopping a wind turbine rotor using pre-set pitch rates

The present invention relates to control of a wind turbine in a stop process in response to a rotor stop signal. The rotor stop process comprises the steps of prior to receipt of the rotor stop signal, generating a stored pitch angle signal by storing pitch angle signals for at least a fraction of a rotor revolution, and determining at least one periodic component of the stored signal. The rotor blades of the wind turbine are controlled towards a feathering position using a pitch control signal containing the at least one periodic component.

Stopping a wind turbine rotor based on stored pitch angle signal

The invention provides a method for controlling a wind turbine, including predicting behaviour of one or more wind turbine components such as a wind turbine tower over a prediction horizon using a wind turbine model that describes dynamics of the one or more wind turbine components or states. The method includes determining behavioural constraints associated with operation of the wind turbine, wherein the behavioural constraints are based on operational parameters of the wind turbine such as operating conditions, e.g. wind speed. The method includes using the predicted behaviour of the one or more wind turbine components in a cost function, and optimising the cost function subject to the determined behavioural constraints to determine at least one control output, such as blade pitch control or generator speed control, for controlling operation of the wind turbine.

Wind turbine control using constraint scheduling

A method is provided for monitoring a pitch control system for a rotor blade of a wind turbine. The method comprises a step of receiving a blade pitch signal representative of a pitch position of the rotor blade, a step of determining a pitch deviation, based on the blade pitch signal and a blade pitch reference. If the determined pitch deviation exceeds a first pitch deviation threshold, a pitch deviation variable is increased by an amount that depends on the determined pitch deviation, the first pitch deviation threshold, and a duration of a time period during which the determined pitch deviation has been exceeding the first pitch deviation threshold. An error signal is provided when the increased pitch deviation variable exceeds a pitch deviation variable threshold.

Blade pitch control monitoring system for a wind turbine

Embodiments herein describe a hydraulic pitch system where a velocity (e.g., the velocity of a hydraulic cylinder or the piston rod in the cylinder) is fed forward and combined with a setting outputted by a pitch controller. The velocity of the hydraulic cylinder is derived from the reference pitch angle or a continuous pitch signal (e.g., a cyclic pitch or ramp rate) in the control system. In either case, the velocity can be determined by monitoring the change in the reference pitch angle or the continuous pitch signal. Using a gain control, the velocity is converted into a position setting of the hydraulic pitch system (e.g., a spool setting in a valve) which is combined with another position setting generated by the pitch controller.

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Aarhus, Denmark

Christian Jeppesen