Novel IoT-Based Droop Control for Battery SoC Balancing Among Multiple Microgrids

Abstract

Energy storage systems are a crucial part of microgrids, making up for their autonomous operation. Therefore, much research has focused on increasing their lifetime and operational efficiency. One of the most viable topics is maintaining connected energy storage units (ESUs) at the same state of charge (SoC). Droop control techniques have been developed in centralized, decentralized, and distributed fashions. This paper proposes a novel IoT-based droop control that can achieve SoC balancing not only within the same microgrid but also between multiple microgrids. The proposed architecture increases reliability and flexibility while allowing the system to be expanded, reconfigured, or upgraded, enabling the plug-and-play capability more easily. First, the proposed IoT-based hierarchical control and communication architecture is presented. Then, the proposed SoC balancing technique and its coordination with IoT architecture are introduced. Through 24-hour simulations, the proposed technique’s scalability, adaptiveness, and robustness are validated under different scenarios, including the operation of any microgrids or ESUs with different capacities and the operation in case of a communication failure. Finally, the IoT value chain of the proposed technique is experimentally validated using a physical laboratory microgrid that uses HTTP protocol to send and receive data through the ThingSpeak IoT-cloud service.