According to the basic theories of power angle and small-signal stability of synchronous generators

the small-signal stability of the doubly-fed induction generator(DFIG)based wind turbine is analyzed in terms of voltage vector space relationships and the small-signal analysis model. Firstly

the power angle of DFIG-based wind turbine is defined according to the space relationship between the terminal voltage and the internal electric potential. Then

the small-signal analysis model of DFIG-based wind turbine is built based on the dynamic equations of phase-locked loop(PLL). And the similarity of DFIG-based wind turbine is studied compared with that of synchronous generator. Furthermore

the impacts of PLL parameters on the small-signal stability of DFIG-based wind turbine are analyzed. The study shows that the PLL parameter is determinant to the small-signal stability of DFIG-based wind turbine. The small-signal instability of DFIG-based wind turbine may occur with inappropriate selection of parameters of PLL. Finally

the influences of PLL with different parameters on the power angle variation and the small-signal stability of DFIG-based wind turbine are verified by modal analysis and time domain simulation.