An Improved Control Strategy for DFIG Low Voltage Ride-Through Using Optimal Demagnetizing method

Abstract

Direct connection of doubly fed induction generators (DFIG) to electricity network would cause overcurrent and DC link overvoltage during transient faults. One of the widespread methods to cope with this problem is employing crowbar; using crowbar, however, results in uncontrollability of both rotor and grid side converters. In this paper, using optimal demagnetization method, duration of this uncontrollability has been reduced; then, by injecting reactive current during fault, fault ride through is realized. The proposed method has been validated by MATLAB/SIMULINK simulation for a 9 MW generator.