Large signal stability analysis of the DC microgrid with the storage system

In a DC Microgrid, the loads are interfaced through power electronic converters. These loads behave as constant power loads (CPLs) when tightly regulated. CPLs have negative incremental impedance which may cause instability. Consequently, the stability analysis is very important to ensure the whole system stable, especially in island mode. This paper investigates the large signal stability of the DC Microgrid, considering the effects of the CPLs and the storage system. Based on mixed potential theory, the large signal stability criteria are derived, and quantitatively describe the relationship between system parameters and the stability. The proposed criteria are simple and straightforward. The power of the storage system and the negative incremental impedance of the CPLs are both taken into account to ensure stability. The results indicate the criteria could guarantee the whole system stable during large disturbances.