Abstract
Many wind turbines are still controlled using gain scheduled, PI(D) controllers. Another option is to use a state feedback controller, such as LQG control. However, for wind turbines that is not straight forward solution, because the system is non-linear and the impact of pitching on the states varies in time. This paper presents a variation on state feedback control. An Extended Kalman Filter is combined with gain scheduling of the state feedback gains depending on aero-dynamic sensitivities, which enables an approximation of non-linear control. This controller structure is intended to be used in more comprehensive controller optimisation studies. The scheduled state feedback controller shows good behaviour and can outperform the original PID controller.
Highlights
A wind turbine controller decides the balance between yield on the one hand and wind turbine loading, actuator effort and power quality on the other hand
Most modern wind turbine controllers behave dependent on the mean wind speed: in conditions below rated wind speed, wind turbines generally follow a basic control law, where the torque is set directly based on the rotor speed
The following methodology is used to design the controller: 1) An Extended Kalman Filter is designed 2) The states of this filter are augmented with the integral of the rotor speed setpoint error 3) Locally stabilising, Linear Quadratic Regulator (LQR) state-feedback controllers are designed for different realisations of the states of the system
Summary
A wind turbine controller decides the balance between yield on the one hand and wind turbine loading, actuator effort and power quality on the other hand. If the wind speed is sufficiently high, the controller maintains the rotor speed at the rated-rotor speed by varying the pitch angle of the blades. This is commonly achieved by using a proportional–integral (PI) controller on the pitch angle [1], possibly containing a derivative term (D). Because the effect of a change in pitch angle on the rotor speed is dependent on the pitch angle, the controller gain is scaled depending on the pitch angle. The PI(D) controller is used to control a non-linear system, where the non-linearity of the control input on the system is considered and other non-linearities are ignored This type of controller can perform well, especially if it is extended with further situation specific adaptions [3]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
