A novel consensus-based control method for SoC balancing of distributed energy storage systems in isolated AC microgrids

• Proposing a novel consensus-based hierarchical control method for SoC balancing of DESSs, proper power sharing, and voltage and frequency regulation in an isolated AC MG. • Implementing the proposed hierarchical control method in two levels (primary layer and secondary layer). • Considering DESSs in a four-buses MG as an isolated AC MG. • Modeling communication noise and delays on communication links to better reflect real-world conditions. The use of Energy Storage Systems (ESSs) in Microgrids (MGs) is rapidly evolving. ESSs play a crucial role in balancing power supply and demand within MGs, and they can be implemented either centrally or in a distributed manner. Given the dynamic nature of MGs, it is essential to manage the charging and discharging processes of ESSs in a coordinated way, a practice known as State of Charge (SoC) balancing. This paper presents a novel consensus-based control method for SoC balancing of distributed ESSs (DESSs), efficient power sharing, and voltage and frequency regulation in MGs. The control method operates in two layers. In the primary layer, current control, bus voltage adjustment, frequency regulation of the MG, and AC-modified droop control are implemented. In the secondary layer, a consensus algorithm is applied for SoC balancing and optimal power sharing among the ESSs. To closely mirror practical conditions, communication delays and noise on communication links between agents are also considered. Unlike previous studies, the test system topology is an isolated AC MG with DESSs. The proposed method is effective in maintaining proper SoC balancing, even under these conditions, and ensures the prevention of SoC imbalance.