Asymmetrical Fault Ride-Through Control for DFIGs: A Solution Simultaneously Supporting Grid Codes and System Constraints

During asymmetrical grid faults, the control of the doubly fed induction generator (DFIG) must simultaneously consider both grid code requirements and the system’s intrinsic constraints. This work proposes an asymmetrical grid fault ride-through control strategy for DFIG simultaneously considering dc-link voltage limitation, positive- and negative-sequence reactive current requirements, and electromagnetic torque oscillations. The method effectively mitigates RSC over-modulation imposed by the dc-link voltage limit and maintains control of the DFIG during asymmetrical grid faults while providing reactive current support. By fully utilizing the dc-link voltage, electromagnetic torque oscillations are minimized to the greatest extent possible. Meanwhile, the range of operating conditions within which the reactive current requirements can be satisfied is significantly expanded. The effectiveness of the proposed strategy is verified bybothsimulationsandexperimental data.