Adaptive Multimode Droop-Based Distributed Energy Management for Standalone Hybrid AC/DC Microgrid

Abstract

The utilization of renewable energy resources (RERs) in microgrids (MGs) has increased significantly in recent years, especially for standalone applications with techno-economic purposes. However, the wide diversification and the stochastic nature of RERs introduces substantial challenges for MG operation and energy exchange under various operational modes. A multimode adaptive droop-based distributed energy management strategy is proposed for a hybrid AC/DC microgrid, incorporating a congregated energy storage system (CESS) to overcome issues associated with distributed counterpart. The MG is fed by wind and solar energy, supported by a CESS comprising supercapacitor stacks, batteries, and a hydrogen management system, to foster reliable power delivery irrespective of RERs fluctuations. The suggested strategy allocates the battery state of charge and supercapacitor voltage to designate operational modes, considering the readiness and constraints of each source and storage unit. The primary objective is to stabilize the DC bus voltage and regulate the point of common coupling voltage and frequency during any conceivable mode. Furthermore, an efficient battery energy storage controller is proposed and adaptively regulated during charging and discharging to avoid battery over-charging and over-discharging. Case studies validate the performance of the proposed scheme across all operational modes, revealing superior performance without reliance on communication links.