Aiming at the problem of weak stability of the grid-connected system when a virtual synchronous generator (VSG) is connected to a strong power grid

we put forward a strategy for enhancing the stability of the VSG grid-connected system based on parameter sensitivity and virtual impedance. Based on the dq-axis impedance model of the VSG grid-connected system

the stability of the system is analyzed. In view of the phenomenon that the higher power grid strength may facilitate the greater risk of instability of the VSG grid-connected system in the process of stability analysis

the magnitude of the parameter sensitivity obtained from the impedance model is adjusted to increase the stability margin of the eigenvalue frequency-domain curve. Accordingly

a stability enhancing strategy based on parameter sensitivity is proposed. Among them

to address the issue of the unclear value range of the virtual impedance when enhancing the system stability

a quantitative relationship between the gain margin (GM) and the virtual impedance is constructed

and a method for determining the value range of the virtual impedance based on the parameter sensitivity and the GM stability constraint conditions is proposed. The simulations by using Matlab/Simulink verify that the proposed method can be adopted to effectively improve the stability of the VSG grid-connected system.