A modified vector control strategy for DFIG based wind turbines to ride-through voltage dips

Abstract

This paper proposes a new indirect power
control strategy and a novel crowbar protection
technique for the doubly fed induction generator
(DFIG) used in the wind power generation systems.
The main difficulty for a DFIG to ride through severe
unbalanced grid voltage dips is the large transient
currents induced in the rotor windings, which may
damage the ac excitation converter. The proposed
control is capable of suppressing the transient
oscillations of fault currents. The crowbar protection is
able to limit the peak values of the fault rotor currents
under a preset threshold. Simulation results prove that
with this control scheme the DFIG is capable of riding
through the severe unbalanced grid voltage dips.