A Compound Decoupling Control Strategy for DFIG Considering PLL under Weak Grid

As one of the main types of wind power generation, doubly-fed induction generator (DFIG) has been widely used with the rapid development of new energy. In this paper, the mechanism of insufficient stability of DFIG control system under weak grid is investigated. By constructing small signal model of DFIG in weak grid, the influence loop of phase-locked loop (PLL) on current closed-loop control is analyzed. Based on the small signal model, a compound decoupling control strategy considering the effect of PLL is proposed, which effectively improves the stability margin of DFIG in weak grid. The effectiveness of the proposed strategy is verified by experiments.