Robustness investigation of the linear multi-variable control technique for power management of DFIG wind turbines

Abstract

Variable speed wind turbines are widely used in the modern power industry. These turbines that are usually driven by doubly fed induction generators (DFIGs) contain two groups of controlling variables; mechanical variables like pitch angle and electrical variables like rotor voltage. During the turbine operation, with variable wind velocity, power must be managed in two regimes; power optimisation and power limitation. In the current research, initially a non-linear simulation, based on the general wind turbine dynamic model is presented. Then, the desired controllers for both pitch angle and generator voltage components are constructed. After designing the controller, in order to investigating the controller robustness, time-varying variables like wind velocity, grid voltage amplitude, and blades pitch angle are changed from the nominal values. By surveying the simulation results it is seen that the presented control method can comply the desired targets in turbine power management.