Observer-Based LQR for Wind Energy Conversion Systems with Single Measurement

Abstract

The control system in wind energy conversion systems is used for tracking the optimal power via regulating the rotor speed of the generator. In this paper, we proposed a novel observer for estimating not only aerodynamic torque in wind energy conversion systems, but also d-axis and q-axis currents. Therefore, in the proposed control system, only the rotor speed of the generator is required to be measured. It should be noted that this is the first time, such a control system can do that for wind energy conversion systems. To form a complete control system, we use linear optimal control method for tracking the optimal trajectory of a generator. In this paper, the permanent magnet synchronous generator is used. In addition, on the basis of the Lyapunov theory and Sum-Of-Square technique, the conditions for observer synthesis are derived in the main theorem. The simulation results show that our control system with proposed robust observer can effectively track the speed reference in the conditions of unknown wind speed and stator currents.