The goal of this project is to study the behavior of the wind turbine generator operated under variable speed with pitch-control capability under turbulent winds. The proposed structure in the present study is a cascaded doubly-fed induction generator operating in a variable speed connected to the grid. The cascaded doubly fed induction generator (CDFIG) consists of two induction generators, with p1 and p2 pole-pairs respectively, connected in cascade to eliminate the brushes and copper rings in the traditional doubly fed induction machine (DFIM). The paper aims to develop a system of pitch control for large wind turbine. Therefore, the dynamic behavior of a wind generator, including models of the wind turbine, CDFIG, ac/ac converter, and power control system were studied. Simulation results of the dynamic models of the wind generator are presented, for different operating points, to show the best performance of the proposed system.

Keywords: Cascaded doubly fed induction generator, Variable speed wind turbine, Ac/ac converter, Pitch control