A Positive Position Feedback controller for vibration control of wind turbines

Abstract

Wind energy has become one of the most important energy sources in the last decades. Most of this type of energy comes from turbines installed onshore though there has been a paradigm shift in this field with the installation of offshore wind turbines, anchored to the seabed or floating ones. Both offshore and onshore technologies have a set of associate problems which sometimes can compromise the turbine integrity, such as environmental disturbances or harmful vibrations. Most of these vibrations and loads are actively compensated in commercial wind turbines through strategies which can modify the turbine power reference to reduce the tower and blades oscillations, at the expense of compromising efficiency. In this work, a new type of control vibration for wind turbines based on piezoelectricity is proposed. A closed loop control is developed from the sensing of the tower vibrations, followed by an in-house designed Positive Position Feedback (PPF) controller, and with a control signal applied to the piezoelectric transducers working as actuators. To design the PPF controller, a simplified wind turbine model is created in COMSOL Multiphysics. A state-space model is obtained, parametrized, validated and used for the tuning of the PPF controller presented in this paper. Simulation results show that with a set of piezoelectric transducers located along the turbine tower, significant reduction of the tower vibrations can be achieved.