Based on the structure and mathematical model of the DFIG with Crowbar

the stator flux equation of the DFIG during asymmetrical grid fault is studied. The simulation model of DFIG is constructed based on PSCAD. For the asymmetrical grid fault

dynamic response of DFIG stator flux is simulated and analyzed. A series of dynamic response processes caused by negative sequence components of the stator flux are studied

such as current imbalance

electromagnetic torque oscillation

power fluctuation

etc. It is found that the Crowbar protection circuit has contributed to the LVRT of DFIG

but can't restrain the negative sequence component. During asymmetrical grid fault

the electromagnetic torque vibration is larger

influences the stable operation of the wind turbine.