Abstract: Aiming at the sub/super-synchronous oscillation phenomenon occurring in a direct driving wind farm in Western China,the grid connected system model of aggregation wind turbine is established on the Matlab/Simulink software in this paper. Combined with the impedance analysis method,the influences of SVG steady-state operating point,phase-locked loop,AC current loop and DC voltage sharing control on the impedance characteristics and stability of the system are studied. Finally,the simulation verification is carried out. The results show that the stability of the system decreases with the increase of SVG output power. With the increase of SVG PLL bandwidth,the system stability gradually decreases. With the increase of voltage loop bandwidth,the stability of the system decreases gradually. With the decrease of SVG current loop bandwidth,the stability of the system decreases.