A method for operating a first wind turbine and a second wind turbine, the second wind turbine being located in the wake of the first wind turbine. A prediction model is fed with a current wind value of the first wind turbine, in order to predict a future time point at which the area swept by the rotor of the second wind turbine becomes partially overlapped by the wake of the first wind turbine. The second wind turbine reacts to the prediction in that a control signal is generated in order to alter the pitch angle of a rotor blade of the second wind turbine relative to the pitch angle of another rotor blade of the second wind turbine. The invention additionally relates to a control system suitable for executing the method. Implementation of the disclosed method by a control system can reduce the loading of the second wind turbine.

There is presented a wind turbine system, wherein the wind turbine system is comprising a support structure, a plurality of wind turbine modules mounted to the support structure wherein each of the plurality of wind turbine modules comprises a rotor, and wherein the wind turbine system further comprises a control system, wherein the control is arranged to execute a wind turbine system transition from a first system operational state of the wind turbine system to a second system operational state of the wind turbine system, and wherein the wind turbine system transition is performed by executing a plurality of wind turbine module transitions from a first module operational state of a wind turbine module to a second module operational state of the wind turbine module wherein the plurality of wind turbine module transitions are distributed in time with respect to each other.

The present invention relates to control of a wind turbine system comprising a plurality of wind turbine modules mounted to a common support structure, i.e. to control of a multi-rotor wind turbine system. The invention discloses a control system for a multi-rotor wind turbine system which comprises local controllers operable to control the wind turbine modules in accordance with local control objectives and a central controller configured to monitor the operation of the wind turbine system and based thereon calculate the local control objectives. The central controller is implemented as a model predictive controller (MPC).

A wind turbine system comprising a plurality of wind turbine modules mounted to a support structure, wherein each of the wind turbine modules comprises a rotor including one or more variable-pitch blades, each defining a respective blade pitch angle and being controlled by a pitch control system, and a control system operable to control the blade pitch angles of the plurality of blades of the wind turbine modules. The control system is configured to identify the presence of a predetermined stop condition and, in dependence thereon, is operable to control the blade pitch angles of the respective blades to predetermined stop positions that reduce oscillation of the support structure. Aspects of the invention also relate to a method of controlling a wind turbine system, to a controller for implementing the method, and to a computer program product.

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.

Systems, methods, and non-transitory computer readable media including instructions for coordinating MPPT operations for a cluster of geographically-associated fluid turbines are disclosed. Coordinating MPPT operations for a cluster of geographically-associated fluid turbines includes receiving data from the cluster of geographically-associated fluid turbines; determining changes to total power output of the cluster based on changes in loading states of individual fluid turbines in the cluster; selecting a combination of loading states for the individual fluid turbines in the cluster to coordinate total power output for the cluster; and transmitting the selected combination of loading states to at least some of the individual fluid turbines in the cluster in order to vary rotational speeds of the at least some of the individual fluid turbines in the cluster.

Systems, methods, and non-transitory computer readable media including instructions for synchronizing a plurality of geographically-associated fluid turbines. Synchronizing a plurality of geographically-associated fluid turbines includes receiving first signals indicative of a phase of a rotational cycle of first rotating blades of a first turbine configured to generate a downstream fluid flow; receiving second signals indicative of a phase of a rotational cycle of second rotating blades of a second turbine configured to receive at least a portion of the downstream fluid flow and generate a differential power output; determining from the first and second signals that greater aggregate power output is achievable through blade phase coordination; determining a phase correction between the first and second rotating blades based on the first and second signals to achieve the greater aggregate power output; calculating coordinating signals based on the phase correction; and outputting the coordinating signals to impose the phase correction.

Techniques for controlling the yaw of a wind turbine system by controlling a plurality of yaw drive actuators. When the yaw drive actuators are applying the same torque to all the motors, this can lead to some motors overspeeding, if the motor is not engaged when the yaw system is activated. Therefore, if the actual motor speed reference of a yaw drive actuator is higher than a specific motor speed reference, then an output signal to reduce the actual motor speed reference is applied to the yaw drive actuators with an actual motor speed reference higher than the specific motor speed reference.

A wind turbine system comprising a plurality of wind turbines mounted to a support structure including a tower, wherein each of the plurality of wind turbines includes a rotor and a power generation system driven by the rotor, and at least one of a rotor blade pitch adjustment means and a generator power control means. The system further includes control means that receives vibration data associated with the support structure and which is configured to determine a damping control command for a respective one of the plurality of wind turbines, wherein the or each of the wind turbines includes a damping controller that receives a damping control command and which is operable to apply a damping control input to one or both of the blade pitch adjustment means and the generator power control means so as to counteract the measured vibration of the support structure. A benefit of the invention is that the operation of the multiple turbines of the system is used to reduce the effects of structural vibration by damping that vibration in an active manner.

A method for operating a plurality of wind turbines, in which a first current estimated wind value is derived from operating parameters of a first wind turbine, and in which a second current estimated wind value is derived from operating parameters of a second wind turbine. A prediction model is applied to derive, from the first current estimated wind value and the second current estimated wind value, a wind prediction, applicable to a future time point, for a third wind turbine. The wind prediction is processed in a controller, in order to generate a control signal for the third wind turbine that is effective before the future time point. The invention additionally relates to an associated control system. The loading for particular wind turbines can be reduced in that the wind conditions are predicted for a future time point.