Fault Ride-Through Improvement of DFIG-WT by Integrating a Two-Degrees-of-Freedom Internal Model Control

A novel two-degree-of-freedom internal model control (IMC) controller that improves the fault ride-through (FRT) capabilities and crowbar dynamics of doubly fed induction generator (DFIG) wind turbines is presented. As opposed to other control strategies available in the open literature, the proposed IMC controller takes into account the power limit characteristic of the DFIG back-to-back converters and their dc-link voltage response in the event of a fault and consequent crowbar operation. Results from a digital model implemented in Matlab/Simulink and verified by a laboratory scale-down prototype demonstrate the improved DFIG FRT performance with the proposed controller.