عنوان مقاله [English]
This paper represents two main contributions. Firstly, a new state space model is represented for doubly fed induction generators (DFIG) by adding the uncertainty in the state equation. Secondly, a direct active and reactive power control (DPC) is designed for wind power systems with DFIG. The proposed DPC strategy employs a nonlinear sliding mode control scheme to directly calculate the required rotor and grid control voltages so as to eliminate the instantaneous errors of active and reactive powers. Constant converter switching is achieved by using space vector modulation, which eases the design power converter and the ac harmonic filter. As a result, no extra current control loops are required, and hence the design is simplified and the transient performance is improved. Finally, the proposed controller is applied to control a 2-MW grid-connected DFIG system, and the simulation results effectiveness of proposed control system.