A Novel Direct Power Control for DFIG With Parallel Compensator Under Unbalanced Grid Condition

This article presents a voltage-modulated direct power control (VM-DPC) with an additional parallel compensator for the doubly fed induction generator under unbalanced grid conditions. The proposed method not only guarantees a satisfying steady-state performance but provides also a regulating property of the negative-sequence output currents through designed negative-sequence parallel compensator. It can provide symmetrical stator currents and suppress the ripples in both active and reactive powers under unbalanced grid conditions. The performance of the proposed method are verified by comparing it with three different control strategies in simulations carried out in MATLAB/Simulink SimScape Power System. Finally, the effectiveness of the proposed method is evaluated in an experimental prototype, which proves the proposed VM-DPC with the additional compensator has a satisfactory steady-state performance and a fast power transient response under unbalanced grid conditions.