Improving Fault Ride Through Capability of DFIG with Fuzzy Logic Controlled Crowbar Protection

Doubly fed induction generators (DFIG) are sensitive to intense disturbances in the grid. Various methods such as crowbar protection circuits are used to increase the fault ride-through (FRT) capability of DFIGs. Crowbar is one of the most important protection methods used to protect the rotor side converter, rotor windings, and capacitors in the wind energy conversion system (WECS) from the damage of overcurrent/overvoltage. Setting the timing of the crowbar switch excellently is significant for the stability of the grid and the efficiency of the WECS. In this study, a Fuzzy logic controller (FLC) block has been added to control the crowbar switch to improve the timing of the crowbar and improve the FRT capability of the WECS. The performance of DFIG-based WECS with FLC under symmetric voltage dip was investigated by using Matlab/Simulink environment at a constant wind speed of 12 m/s. DC bus voltage, crowbar current, the terminal voltage of DFIG, and electromagnetic torque results were obtained. The results of the crowbar with the proposed controller and the results of the crowbar without FLC were compared. The results revealed that the proposed system is reliable, proper, and prevailing for the grid-connected DFIG under grid fault conditions.