Research On Stability Region Analysis And Enhancement Method Of DC Microgrid Based On Hybrid Potential Function

The large signal stability of the DC microgrid is the basis for the safe and reliable operation of the DC microgrid system.Improving the stability domain of the microgrid is beneficial to ensure reliable power supply,high-quality power quality and good economy.This paper adopts the theory of mixed potential function based on the Lyapunov stability principle to analyze and evaluate the large-signal stability of the DC microgrid,and study the system of the DC microgrid under different working modes and multi-converter grid-connected load mutations.stability.First,based on the power requirements of homes and buildings,the power levels of household loads,and the voltage levels of distributed energy sources,a typical 100kW optical storage DC microgrid system was constructed,and the optical storage DC microgrid system was analyzed according to the trend of the microgrid.Three typical operating modes of microgrid.The theory of the mixed potential function of the circuit system is introduced,the equivalent circuit and the mixed potential function of the typical DC microgrid in different modes are established,and the stability criterion and the asymptotic stability region of the DC microgrid in each operating mode are given..The stability of the DC microgrid is analyzed by comparing the size of the progressive stability region of the microgrid and the stability margin of the DC bus voltage when the load is loaded and unloaded between the basic coordinated control and the improved control.In view of the impact of the step change of load power on the stability of DC microgrid,the coordinated control of hybrid energy storage of battery and supercapacitor is introduced in the In view of the impact of the step change of load power on the stability of DC microgrid,the coordinated control of hybrid energy storage of battery and supercapacitor is introduced in the microgrid to smooth the transient imbalance of the entire system power caused by the sudden change of load power,and enhance the system’s performance.Inertia improves the stability of the DC microgrid.The Matlab/Simulink simulation model of DC microgrid was established,which verified the effective feasibility of applying hybrid potential function theory to analyze and enhance the stability of DC microgrid.Designed and developed a 100kW DC microgrid experimental system based on RT-BOX.Experimental results show that the introduction of hybrid energy storage and coordinated control of batteries and supercapacitors in the microgrid can enhance the progressive stability region of the DC microgrid and improve the DC bus voltage fluctuations of the DC microgrid caused by the step change of load.