Active Disturbance Rejection Control for DFIG Based Wind Farms Under Unbalanced Grid Voltage

Abstract

This paper presents a method for controlling a doubly fed induction generator used in the conversion of wind power under an unbalanced supply voltage, to eliminate the oscillations, which may occur, due to the presence of negative sequence in the electromagnetic torque and active power delivered to the network. Control strategy based on the voltage oriented control VOC, is used to control the direct and quadrature currents, in both the positive and negative sequence for the network side and rotor side converter. For its robustness to uncertainties that may arise into the physical plant parameters and the needless exact knowledge of physical system, the active disturbance rejection control based on an extended state observer is used to overcome the internal and external uncertainties. Simulations are carried out using Matlab Simulink.