Modified Control of DFIG-WT for the Smooth Generator Speed Response under Turbulent Wind

This paper presents a wind speed based active power control strategy for the smooth operation of the Doubly Fed Induction Generator based wind turbine (DFIG-WT) under turbulent wind. The basic idea behind this approach is to make the system's dynamical response slow, taking into account the wind speed in the reference electrical torque. Essentially, this approach suppress the acceleration of the turbine due to the wind speed and make the maximum power tracking slow so that the generator speed responds smooth. The implementation of the proposed control requires wind speed as input and thus it was estimated by using unscented Kalman filter (UKF). A single machine infinite bus system with the DFIG based wind energy conversion system has been considered for the studies while it's reduced order equivalent model was used for the estimation considering the wind speed as an additional state. The DFIG is employed with the control of terminal voltage, DC-link voltage and rotor reactive power. The efficacy of the proposed control approach has been tested on various wind conditions including turbulent wind obtained from the TurbSim tool by NREL.