Modified controls for Doubly Fed Induction Generator under unbalanced voltage distortion for torque stability and PI-Fuzzy Controller

This paper presents a new vector Hysteresis Current Control (HCC), which is applied on a three-phase three-level Voltage Source Inverter (VSI) and torque stability using PI-Fuzzy Controller (PI-F). The proposed control technique is used to control the active and reactive power of wind turbines by means of controlling the rotor currents of the Doubly Fed Induction Generator (DFIG) during grid voltage distortion for Torque Stability Controller (TSC) using PI-F. These control techniques use single or multiple applications of hybrid PI-F with anti-windup and Notch filter to eliminate the second-order harmonic components and negative sequence components. In the newly proposed SFOC-based scheme, PI controllers with Fuzzy, Notch filters and the TSC are utilized. The designed system consists of an induction generator with slip ring and power-electronics converters at both rotor and grid sides. The modifications are applied to the rotor side converter (RSC). Simulations in Matlab/Simulink illustrate the enhanced stability of torque, active and reactive powers delivered by DFIG in both the PWM controller (PWM) and HCC schemes. Moreover, comparisons in simulation results, obtained separately from all the presented control structures, are provided to evaluate the effectiveness of the newly proposed scheme.