Identification of unstable system using LQG controller

In this paper we apply predictor-based system identification technique to unstable system to identify system dynamics. Due to instability, we need to avoid diverging output by designing controller which can keep the system poles inside unit circle in discrete time domain. This technique is applied to identify highly oscillatory wind turbine systems. In both cases, the I/O data collected by forming feedback controller (in this case, LQG controller in 1-DOF) have been successfully used for identification of unstable and oscillatory wind turbine systems. Its effectiveness is demonstrated with simulation using the Matlab^©.