Gershgorin-Circle Based Low-Complexity Generalized Nyquist Stability Criterion for DFIG Driven Wind Turbines

Recently, the stability issue caused by interactions between the doubly-fed induction generator (DFIG)-based wind turbines (WTs) and weak grids has attracted great concerns. Considering the complexity of the grid-connected system, an effective and intuitionistic stability criterion is quite essential. This paper proposes a Gershgorin-circle based low-complexity generalized Nyquist stability criterion (LC-GNSC) for the DFIG-based WTs. Firstly, the system stability criterion, named LC-GNSC, is put forward by analyzing the distance relationship between the center of Gershgorin-circle and prohibited area. Then the explicit small-signal admittance model of the DFIG system is established. Based on the proposed criterion, the impacts of the key physical and control parameters on system stability are further investigated in detail. Finally, simulations and experiments are conducted to verify the accuracy of the proposed stability criterion.