Research on the Stability of Multi-converter DC Microgrid Based on Improved Impedance Analysis Method

The scale of DC microgrid systems continues to increase, and a large number of converters are integrated into the power grid, resulting in severe stability problems, and the traditional impedance analysis method has certain limitations in establishing an equivalent model of complex topological networks. To this end, this paper proposes an improved impedance analysis method based on the generalized impedance ratio, first popularizes the concept of traditional impedance ratio, establishes a system equivalent model according to the port characterristics, and derives the concept of generalized impedance ratio to characterize system stability. The system is further modeled with small signals, and a stability criterion based on the generalized impedance ratio is obtained for stability analysis. Finally, the correctness and effectiveness of the stability analysis of the proposed method in the multivariate DC microgrid system are verified by example analysis and time domain simulation.