Impacts of Interactions between Grid-forming and Grid-following Converters on Stability of Hybrid System Connected to Weak Grid

This paper investigates the impacts of interactions between grid-forming and grid-following VSCs on the stability of hybrid system connected to weak grid. To begin with, the stability analysis model and the interaction analysis model of the hybrid VSCs system connected to the weak power grid are established. The self-influence and the inter-influence components are defined to quantify the interaction degree between grid-forming and grid-following VSCs. Then, combined with the Bode diagram and modal analysis method, the influence of the interaction between grid-forming and grid-following VSCs on the stability of system is analyzed by investigating self-influence and the inter-influence components with variations of operating points and control parameters. Finally, the above analysis results are verified by hardware-in-the-loop test platform.