Stability Analysis of Multiple Grid-Connected Battery Energy Storage Systems with A Distributed Cooperative Control

Battery energy storage system (BESS) plays a crucial role in the integration of renewable energy by balancing supply and demand, providing frequency regulation, and supporting voltage stability. However, for multiple grid-connected BESS systems, traditional power control methods, which focus on the dynamics of individual BESS, often neglect the interactions between BESSs. It results in idle power capacity and slow response times during transient events. To address these issues, a distributed cooperative control strategy based on a consensus algorithm has been proposed to improve the overall system's response speed and ensure steady-state power sharing according to the state of charge (SOC). However, few researchers have conducted the stability analysis of multiple BESSs under the distributed control scheme, and the interaction has not been thoroughly investigated. This paper addresses this gap by developing an impedance model for multiple BESSs by incorporating a secondary control layer. The modeling accuracy is validated through EMT simulations. Using Nyquist stability criterion, the paper compares the stability of BESSs with distributed cooperative control to traditional power control methods, demonstrating the advantages of the proposed approach. Additionally, the impact of cooperative control parameters and communication faults on system stability is analyzed. The time-domain simulations confirm the accuracy of the stability analysis.