ADAPTIVE NONLINEAR CONTROL OF DOUBLY-FED INDUCTION MACHINE IN WIND POWER GENERATION

This paper presents an adaptive nonlinear controller for Doubly-Fed Induction Generator (DFIG) in wind power generation. The control objective is to extract the maximum power (Maximum Power Point Tracking) and have a specified reactive power at the generator terminal despite the variable wind speed and the unknown mechanical parameters and mechanical torque. To achieve such a decoupled control, the nonlinear Backstepping approach was combined with the field orientation principle. The induction machine is controlled in a synchronously reference frame oriented along the stator voltage vector position. The mathematical development of the nonlinear Backstepping controller design is examined in detail. The overall stability of the system is shown using Lyapunov approach. Application example on stabilizing a DFIG-based Wind Energy Conversion System (WECS) subject to large mechanical parameters uncertainties has been given to illustrate the design method and confirm the robustness and validity of the proposed control.