Gelfert, J.J.Gelfert2022-03-072022-03-072009https://publica.fraunhofer.de/handle/publica/278103Apart from the rotor blades, the drive train is one of the main sources of noise in wind-turbines. Vibrations from the gear box are propagated to the turbine shaft and radiated into the environment as sound. It is possible to use mechanical vibration absorbers to reduce these vibrations. In this work a control concept for an active vibration absorber, based on piezoceramic actuators, is developed and tested. The control concept makes it possible to adjust the stiffness and damping of the piezoceramic actuators by feeding back the measured excitation and velocity. A PLL-algorithm is used to adapt the absorber frequency to the disturbance frequency by varying the stiffness of the piezoceramic actuators. Additionally, the dampingdeAktiver TilgerPiezoPLLabstimmbarSchwingungsreduzierungDämpfungSteifigkeitvibration absorberdampingadjustablevibration reduction620670diploma thesis