Transient Performance Iprovement of Wind Turbines with Doubly Fed Induction Generators Using Fractional Order Control Strategy

Application of fractional order proportional integral (FOPI) controller to improve transient performance of wind turbine (WT) with Doubly fed induction generator (DFIG) is presented and studied in this paper. By small signal analysis، it is found that the dynamic behavior of the DFIG based WT، during the variation of operating conditions، is strongly affected by the stator dynamics. Since the DFIG electrical dynamics are nonlinear، the linear control (PI) scheme cannot work properly under change in wind speed and stator modes are not damped appropriately. The proposed fractional order controller generalizes the conventional integer order PI controller whose integral order are fractional number rather than integer. This expansion can provide more flexibility in achieving control objectives. By time domain simulations، a comparative analysis is made with respect to the standard PI controller to demonstrate effectiveness of the fractional order PI () controller during wind speed perturbation.