Design of robust controller for wind turbines

To optimise the performance of the wind generation, wind turbines employ variable speed (VS) variable pitch (VP) control system. Wind turbine is a complex nonlinear mechanical system exposed to uncontrolled wind profiles. Due to this, dynamic and parametric uncertainties arise in the mathematical model of the wind turbines over different operating conditions. This makes the turbine controller design a challenging task. This paper addresses the problem of designing robust control system for wind turbines in the presence of uncertainties using Minimax LQG (linear quadratic gaussian) design methodology. Using this approach the parameter variations and the model uncertainties are represented using Integral Quadratic Constraints (IQCs). Controllers are synthesised using LMI approach. The designed controllers provide robust performance in the presence of the specified uncertainties. Controllers are designed for a test case system and simulation results are presented.