Sliding-Mode-Based Improved Direct Active and Reactive Power Control of Doubly Fed Induction Generator Under Unbalanced Grid Voltage Condition

This paper proposes an improved direct active and reactive power control (dpc) strategy for a gridconnected doubly fed induction generator (dfig) based wind-turbine system under unbalanced grid voltage condition. the method produces required rotor voltage references based on the sliding mode control (smc) approach in stationary reference frame, without the requirement of synchronous coordinate transformation, and therefore causes a simpler design for power control system. under unbalanced grid voltage condition two control targets, removing the stator active and reactive power oscillations, can be obtained simultaneously. moreover this control method reduces the thd of the stator current. also it is shown that not only the proposed control method has a high-speed dynamic response but it also is stable during wind speed and system parameters variations. simulation results for a 2kw dfig confirm prominence of the proposed control strategy.