A Novel Modified Droop Control Strategy for SoC Balancing of Distributed ESS under Sudden Load Changes Considering Communication Delays

Today, the application of Energy Storage Systems (ESSs) in Microgrids (MGs) is expanding promptly. Due to the highly dynamic characteristics of MGs, coordinated control of ESS charging and discharging—commonly referred to as State of Charge (SoC) balancing—is critical. This study introduces an innovative modified droop control strategy designed to achieve SoC balancing among distributed ESSs (DESSs) in MGs. In the modified droop control method against sudden load changes, which causes the voltage and frequency of MG to affect the amount of ESS charging and discharging and ultimately SoC balancing of DESSs in MG. To better emulate real-world conditions, communication delays in links among DESSs are also taken into account. Unlike many earlier works, the proposed method is validated on an isolated AC MG with DESSs. The results confirm that the method reliably maintains SoC balancing of DESSs under these scenarios and effectively avoids imbalance issues.