Large Signal Stability Analysis of Microgrid System Based on Power Converter System

With the wide application of distributed power and energy storage systems in the microgrid, the instability caused by its complex interface converter structure cannot be ignored. Moreover Constant power loads (CPL) may cause system instability due to the negative impedance characteristic. This paper is based on the two-stage DC-DC-AC power converter system (PCS) and considers the CPL in the microgrid system. Based on the mixed function method, the stability criterion of PCS system under bidirectional working state is obtained. The criterion provides a basis for the design of control parameters of the system, and the allowable maximum load power jump value is obtained. The simulation and experiment results verify the validity of the criterion.