Static Stable Working Zone of Grid-Connected Converter Connecting with Synchronous Generator

Grid-connected converter (GCC) and synchronous generator (SG) are important power interface devices in grid-connected power generation systems. The coupling between GCC and SG under weak grid conditions directly affects the static stability of the power system. In this paper, for the two-machine system composed of renewable-energy grid-connected converter and SG, the static stability and static limit power under weak grid conditions are studied. Firstly, starting from the basic working principles of GCC and SG, the mathematical models are established. Secondly, based on the fundamental frequency equivalent circuit of the two-machine system, the output active power characteristics of GCC and SG are studied. On this basis, the eigenvalue analysis method is used to derive the static stability criterion of the system and the constraint relationship of the static limit power between GCC and SG. Finally, the correctness of theoretical analysis is verified by Matlab/Simulink simulation.