Inertial Frequency Response of Wind Turbines Using Adaptive Full Feedback Linearization Control: Stability and Robustness Analysis

Abstract

It is a challenging task to affect suitably on the frequency response of a variable speed wind turbine (VSWT). The problem would be more crucial when the system is subjected to uncertainty in parameters as well as various external effects such as load changes and grid disturbances. Feedback linearization has already been applied to the VSWT, where two state variables experience instability. Hence, this paper presents a new methodology based on full-state feedback linearization in which by choosing an appropriate output, the closed-loop system is fully linearized, and the resulting linear system is stabilized by an optimal linear quadratic regulator (LQR). Since the parameters may be uncertain, the developed controller is augmented with an adaptive dynamic feedback such that all of the parameters are estimated while asymptotic stability is ensured by the Lyapunov method. Furthermore, robustness analysis is performed, and the effects of external disturbance are reduced by suitable selection of the gains. The analytical outcomes are verified through simulations, where these are compared with those of available work to show the improvement have been made by the suggested method.