Energy Filtering Using a Generalized Bandwidth-Based Control Scheme for Hybrid Real and Virtual Energy Storage Systems

Hybrid energy storage systems (HESS) involve multi-physics real energy storage and possible virtual energy storage, interfacing through power electronics. Such complex energy systems often employ a hierarchical control approach. Higher-level controls consider the energy management within the system and the dispatching of resources, while lower-level controls manage the power flow, voltage regulation, and SOC balancing of connected storage devices, realized through the connected power electronics. This work proposes a generalized bandwidth-based control scheme for HESS in a dc system that addresses the literature gap of filtration-based controls that have previously prevented them from being used in practice and also within hierarchical control strategies. The generalization unifies control objectives that are commonly considered separately for different storage devices. It also provides a flexible control design framework based on a universal energy storage model (UESM) that is applicable to many hybrid systems and storage devices. Using the UESM, control coefficients are algebraically defined by the model parameters, making this control approach suitable for many storage types. The proposed control scheme is validated on a HESS supported dc microgrid, demonstrating its effectiveness in managing the power flow and SOC regulation within the HESS, while also achieving high-level energy management objectives such as preemptive charging and peak load shaving.