Abstract

This paper addresses the problem of power regulation and control of wind turbines using an output feedback scheme formulated as a well-defined LMI problem. To this aim, first a piecewise linear (PWL) model is constructed for the wind turbine system with the wind speed as a parameter. Then, using the achieved PWL model a set of output feedback controllers are formulated and solved as an LMI problem. To implement the designed controller in practice, two different approaches are proposed, i.e. online and offline approaches. In the first approach (online), an exact optimal control law is obtained by online evaluation of the PWL model and then solving the associated LMI problem which leads to a relatively high computational complexity. To deal with this computational complexity an alternative approximate approach is proposed which puts parts of online computations to offline precalculation with the cost of sub-optimality. In this approach the controller is predesigned for some predefined operating points and then the sub-optimal controller is achieved by introducing a convex combination of pre-calculated controllers while guaranteeing the constraints satisfaction. Finally, the performance and characteristics of the proposed approaches are verified using simulation results.