Energy-based large-signal stability analysis of DC microgrid considering dynamic interactions between multiple converters

DC Microgrid is widely investigated and developed for the flexible integration of renewable energy. However, a practical DC microgrid is easily subject to various disturbances, such as pulse power load, load change and grid faults. Due to the multi-loop coupling and the dynamic interactions between multiple converters, the large-signal stability of DC microgrid is difficult to be predicted. In this paper, an analytical large-signal stability (LSS) criterion is proposed for the multiple converters system of DC microgrid. Considering both source converters and load converters, dynamic models are firstly established. Based on the mixed potential function theory (MPT), the LSS criterion is developed for the system with different load models, including constant power load and dynamic power load. Furthermore, the modified LSS criterion is studied for the DC microgrid under droop control, which reveals the nonlinear correlations between stability boundaries and the load power. Eventually, extensive simulation results are presented to verify the effectiveness of the proposed stability criterion.