Modeling a DFIG based wind system for unbalanced grid voltage condition

Wind systems connected to a three-phase voltage grid often experience unbalanced voltage conditions, due to differences in the loads in the grid. This issue is particularly important in wind energy conversion systems (WECS) that use the doubly fed induction generator (DFIG). Therefore, it is important to take into account unbalanced conditions when coupling the wind generator with the grid, especially since the stator of the DFIG is directly connected to the grid. In this paper, the DFIG is modeled under low asymmetrical voltage fault in the grid in order to control the power flow between the generator and the grid. A proportional integral (PI) controller is used and simulated in the study using Matlab/Simulink. The results show that the oscillations in the electromagnetic torque and the total active power can be controlled effectively to improve the quality of the power delivered to the grid.