Sinusoidal Output Current Implementation of DFIG Using Repetitive Control Under a Generalized Harmonic Power Grid With Frequency Deviation

The paper presents the control strategy of stator current harmonic distortion performance improvement for doubly fed induction generator (DFIG) using bandwidth-based repetitive control (BRC) under generalized harmonic grid voltage. The control target is to eliminate the DFIG stator current $6n \pm 1$ harmonic components; thus, sinusoidal stator output current can be injected into the power grid. Considering that the frequency deviation always occurs in the practical grid, the BRC regulator is designed on the basis of conventional repetitive control regulator with the introduction of control bandwidth. The closed-loop operation stability considering different bandwidth and gain parameter is also analyzed. Finally, the availability of the proposed BRC control strategy under generalized harmonic grid voltage is verified by experimental results.