DFIG performance improvement in grid connected mode by using fractional order [PI] controller

•Fractional order [PI] controller is proposed in the rotor side converter of DFIG.•An analytical approach is developed to ensure the frequency domain specifications.•Controllers are applied in the internal and external control loops of the RSC.•Active power, rotor speed and current profiles are improved during various faults.•Effectiveness of the proposed method is compared with conventional PI controller.