Research on control characteristics of voltage source converter--high voltage direct current（VSC-HVDC） system is currently limited to the connection to the equivalent AC grid

thus

the model of VSC system connected to AC system with inertia should be established

and the analysis on interaction between internal characteristics of AC system and VSC is of important significance. Firstly

we used a synchronous generator（SG） to simulate the AC system with inertia so as to propose a small signal model of VSC system connected to synchronous generator

and verified the validity of the established model. Secondly

we analyzed the degree of correlation between eigenvalues and state variables with participation

factor method. Thirdly

combining with eigenvalue analysis and simulation

we studied the influences of parameters on the characteristic roots of the system

respectively

such as the transmission line

inertia constant of synchronous generator

and damping coefficient. Finally

we analyzed the influences of VSC controller parameters on the stability of the system. The results have proved that the small signal stability of the system will decrease with the decrease of short circuit ratio（SCR） and the decrease of impedance angle of line. When the inertia constant is greater than 1.2 s

the small signal stability of system will enhance and then decrease but will not lose stability. When the damping coefficient of SG ranges from 0

0

.5 pu

the small signal stability of system will enhance and then decrease

and the controller parameters also affect the small signal stability of system

so stability will be optimized by adjusting these types of parameters within limits.