Fractional-Order Sliding Mode Control for D-STATCOM Connected Wind Farm Based DFIG Under Voltage Unbalanced

This paper studies the use of distribution static synchronous compensator (D-STATCOM) integrated with wind farm based on doubly fed induction generators. The short-term energy storage system based on a supercapacitor is introduced in this study to improve the operation of D-STATCOM. The dynamic performances of the grid-connected wind farm with D-STATCOM are enhanced by the proposed control scheme, which is based on fractional-order sliding mode control theory with dual-sequence decomposition technique. Some results of simulation show that, under an unbalanced grid voltage conditions, the proposed control strategy for the D-STATCOM not only eliminates effectively the oscillations of the active and reactive powers exchanged between the wind generator and the grid but also achieves the symmetrical and sinusoidal grid currents with less harmonics.