Abstract: 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.

Abstract: 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.

Abstract: Controlling a wind turbine by obtaining a movement signal indicative of a vibrational movement of a wind turbine tower is described. An actuator signal is determined based on the movement signal, the actuator signal being determined to produce a desired force to counteract the vibrational movement of the tower. A pitch reference offset signal for each one of a plurality of pitch-adjustable rotor blades is determined based on the actuator signal. An integration is then applied to the pitch reference offset signals to determine modified pitch reference offset signals based on the integrated pitch reference offset signals. A pitch signal for each of the blades is determined based on the modified pitch reference offset signals, the pitch signals being arranged to adjust the blades to provide the force that counteracts the vibrational movement of the tower.

Abstract: A method of operating a wind turbine during a service, wherein the wind turbine comprises at least one rotor-nacelle assembly, the or each rotor-nacelle assembly comprising a rotor; the method comprising: detecting that a service is to be or is being carried out on the wind turbine; and, on detecting that a service is to be or is being carried out on the wind turbine, reducing an operating level of the or each rotor-nacelle assembly.

Abstract: A wind turbine control unit includes an upsampling module that receives a first control signal that includes a current control sample value and a predicted control trajectory. The upsampling module also calculates a second control signal in dependence on the current control sample value and the predicted control trajectory. The second control signal has a higher frequency than the first control signal. The upsampling module further outputs the second control signal for controlling an actuator.

Abstract: The present invention relates to 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.

Abstract: 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.

Abstract: A method of providing safety configuration parameters for a wind turbine is provided. The method comprises receiving a safety configuration file at a location of the wind turbine, and comparing a turbine ID associated with the safety configuration file to a turbine ID of the wind turbine stored at the location of the wind turbine. A tamper check is performed on the safety configuration file to determine if data in the safety configuration file has been modified. If the turbine ID associated with the safety configuration file matches the turbine ID of the wind turbine, and if the tamper check determines that the data has not been modified, a safety configuration parameter associated with a safety system of the wind turbine is extracted from the file and stored.

Abstract: The present invention relates to a rotor control system for actuating pitch of pitch adjustable rotor blades in order to reduce vibrations of a wind turbine element, e.g. tower vibrations. A pitch modification signal is determined which is based on an m-blade coordinate transformation, such as the Coleman transformation. The m-blade coordinate transformation taking as input a first signal and a second signal. The second signal is determined by filtering the first signal with a signal filter with a quadrature phase shift filter phase response.

Abstract: A method of operating a wind turbine during a service, wherein the wind turbine comprises at least one rotor-nacelle assembly, the or each rotor-nacelle assembly comprising a rotor; the method comprising: detecting that a service is to be or is being carried out on the wind turbine; and, on detecting that a service is to be or is being carried out on the wind turbine, reducing an operating level of the or each rotor-nacelle assembly.

Abstract: A wind turbine control unit includes an upsampling module that receives a first control signal that includes a current control sample value and a predicted control trajectory. The upsampling module also calculates a second control signal in dependence on the current control sample value and the predicted control trajectory. The second control signal has a higher frequency than the first control signal. The upsampling module further outputs the second control signal for controlling an actuator.

Abstract: The present invention relates to control of wind turbines in a situation where a fault condition is detected. Control of a wind turbine is described where a control trajectory and a safe-mode trajectory are calculated based on the current operational state of the wind turbine. If the fault condition is detected the wind turbine is controlled using the safe-mode trajectory, otherwise, the normal operation of the wind turbine is continued where the wind turbine is controlled using the control trajectory.

Abstract: A wind turbine comprising a tower, a nacelle, a rotor including a plurality of blades, an electrical generator operatively coupled to the rotor, and a control system. The control system comprises: a sensing system operable to output a signal indicative of the torsional oscillation frequency of the nacelle; a torsional damping module configured to monitor the torsional oscillation signal and to determine one or more blade pitch command signals for damping the torsional oscillation of the tower, and a filter module configured to receive the one or more blade pitch command signals as inputs and to output a respective one or more modified blade pitch command signals, wherein the filter module is configured to filter the one or more blade pitch command input signals to exclude frequency components greater than the torsional oscillation frequency. Aspects of the invention also relate to a method, a computer program software product and a controller for implementing the method.

Abstract: The present invention relates to a rotor control system for actuating pitch of pitch adjustable rotor blades in order to reduce vibrations of a wind turbine element, e.g. tower vibrations. A pitch modification signal is determined which is based on an m-blade coordinate transformation, such as the Coleman transformation. The m-blade coordinate transformation taking as input a first signal and a second signal. The second signal is determined by filtering the first signal with a signal filter with a quadrature phase shift filter phase response.

Abstract: This invention relates to obtaining a movement signal indicative of a vibrational movement of a tower. An actuator signal is then determined based on the movement signal, the actuator signal being determined to produce a desired force to counteract the vibrational movement of the tower. A pitch reference offset signal for each one of a plurality of pitch-adjustable rotor blades is then determined based on the actuator signal. An integration is then applied to the pitch reference offset signals to determine modified pitch reference offset signals based on the integrated pitch reference offset signals. A pitch signal for each of the blades is the determined based on the modified pitch reference offset signals, the pitch signals being arranged to adjust the the blades to provide the force that counteracts the vibrational movement of the tower.

Abstract: A wind turbine control unit comprising a control module configured to control an actuator system by outputting a first control signal, wherein the first control signal includes a current control sample value and a predicted control trajectory; the control unit further comprising an upsampling module configured to receive the first control signal from the control module, and to output a second control signal for controlling the actuator system, the second control signal having a higher frequency that the first control signal. The upsampling module calculates the second control signal in dependence on the current control sample value and the predicted control trajectory. The embodiments provide a more accurately reproduced control signal at a higher frequency that is suitable for onward processing which does not suffer from the problems of aliasing and delay that exist with conventional upsampling techniques.

Abstract: A method of controlling a wind turbine is described. The method comprises calculating a current wear rate for each of the main bearing of a turbine rotor and the blade bearings of rotor blades mounted on the turbine rotor, and calculating a blade pitch adjustment of the rotor blades to achieved a desired ratio between main bearing wear and blade bearing wear in dependence on the calculated current wear rates of the main bearing and the blade bearings.

Abstract: The present invention relates to control of a wind turbine, and in particular it relates to a distributed control system including a blade controller for each blade of the wind turbine. The electrical connection between each blade controller and the power supply of the blade controller is arranged to be functionally isolated from the electrical connection of each other blade controller and the power supply of the respective blade controllers.

Abstract: A method is provided for controlling the shutdown of a wind turbine of the type having a rotor, the rotor including one or more wind turbine blades. The method includes dynamically determining a rotor speed reference; obtaining a measure of the rotor speed of the rotor; determining an error between the rotor speed reference and the rotor speed of the rotor; and controlling a pitch of one or more of the wind turbine blades based on the determined error. A corresponding wind turbine controller and a wind turbine including such a controller are also provided.

Abstract: A method for controlling a wind turbine during a safety operation is disclosed. A safety pitch control system is provided to pitch the blades individually at a number of pre-set approximately constant pitch rates including a first pitch rate and a second pitch rate lower than the first pitch rate. In response to a command for initiating the safety operation the blades are pitched towards a feathering position by the safety pitch control system including the blades being pitched according to a safety pitch strategy wherein for all the blades the pitch rate is changed between the first pitch rate and the second pitch rate according to a function of each blade azimuthal position. This is done such that each blade in turn is closer to the feathering position than the others.