Impact of PLL Control on Small-Signal Stability of Wind DFIGs

This paper investigates the small-signal stability of wind doubly fed induction generators. Precisely, the impact of the phase locked loop control on the small-signal stability of wind doubly fed induction generators is addressed. Modal analysis technique is used. Making use of a very detailed model of the wind generator, stability conditions in terms of the ratio between the bandwidth of generator current controllers and the bandwidth of phase locked loop controller have been obtained. In addition, the sensitivity with respect to the grid impedance is studied.