Large Signal Stability Analysis Method of DC Microgrid Clusters Based on Input-to-State Stability Theory

DC microgrid (DCMG) is usually composed of renewable energy system, battery energy storage system and load. For give full play to the advantages of distributed generation systems, multiple DCMGs are interconnected to form a DC microgrid clusters (DCMGCs), which can improve the stability of the cluster through flexible power flow between DCMGs. However, faced with high-order and strong coupled nonlinear dynamic characteristics, the solution of stability will encounter curse of dimension. In order to give the computable stability margin concisely and effectively, the input-to-state stability theory is proposed to analyze the stability of the cluster. For ensuring that the DCMGCs is input-to-state stable, each DCMG and its coupling relationship with adjacent DCMGs are input-to-state stable and satisfy the small-gain theory, it can be proved that the entire DCMGCs is input-to-state stable, and the stability conditions of DCMGCs are derived. Finally, the simulation model is established in MATLAB/Simulink environment to verify the correctness of the method.