Design and Analysis of DFIG Grid Interconnected System Using Hysteresis Controller for Power Quality Enhancement

In a DFIG grid interconnected system the stator is connected to the grid and that of the rotor turbine side has been connected to wind velocity. PI controller controls both the grid side controller and rotor side controller in such a manner that, it linearizes the system so as to control the system gain parameter. During unsymmetrical fault condition the system behaves as a nonlinear control system there by restricting the PI controller to act on and control the system gain. Therefore in this paper an attempt has been made to design a Hysteresis PI controller which we can control the non-linearity present in the system during the dynamic changes due to unsymmetrical fault condition. The robustness of the control has been tested under different conditions of system such a variation of wind speed at the input of the turbine, unsymmetrical fault in the grid side. A MATLAB Simulink model has been developed to check the robustness of the controller.