Enhanced Grid-Connected Operation of DFIG Using Improved Repetitive Control Under Generalized Harmonic Power Grid

This paper presents the control strategy of achieving sinusoidal stator current of doubly fed induction generator using improved repetitive control (RC) regulator under generalized harmonic grid voltage. The improved RC regulator, with the larger magnitude response at the higher control frequency due to the magnitude response compensation unit, is proposed to restrain the stator current higher harmonic sequence more effectively. Besides, the appropriate phase leading compensation can also be automatically introduced by the improved RC regulator. The steady-state control performance and the closed-loop operation stability using the improved RC regulator are discussed in this paper. The availability of the proposed strategy under generalized harmonic grid voltage is verified by experiment results.