Mixed potential function modeling and stability analysis of DC microgrid with hybrid energy storage

Abstract Aiming at the large disturbance stability problem of hybrid energy storage DC microgrid with constant power load, based on deducing the equivalent model of hybrid energy storage system (HESS) pulse-width modulated switching network, a stability criterion and analysis method of DC microgrid containing the HESS based on mixed potential function theory is proposed. Firstly, considering the charge-discharge characteristics of HESS, the operating states of the DC microgrid system containing the HESS are divided into buck and boost operating modes. Then, the mixed potential function model of the DC microgrid system based on the equivalent model of pulse-width modulated switching network is established for the above two operating modes respectively; Finally, the third stability theorem of the mixed potential function theory is applied to derive the large disturbance stability criterion of the DC microgrid under buck and boost operating modes respectively. This criterion gives the stability operating conditions of each converter control parameter. The accuracy of the proposed stability analysis method and the validity of the mixed potential function criterion are verified by simulation.