A novel hierarchical optimization energy management strategy of intelligent multi-port energy router in expressway DC microgrid

Distributed photovoltaic (PV) generation and intelligent transportation devices are increasingly integrated into expressway DC microgrids, causing DC-bus voltage fluctuations due to PV intermittency and exposing the limitations of existing architectures in supporting flexible multi-directional energy flows. To address these challenges, this research proposes an integrated "Source-Grid-Load-Storage" operational framework enabled by an Intelligent Multi-port Energy Router (IMER). A model predictive control (MPC) scheme is designed for the grid-side port converter to enhance DC bus voltage regulation and transient performance. Considering the distinct characteristics of each port, a hierarchical optimization energy management strategy based on power-adaptive matching is further developed to coordinate multi-port power allocation. Simulation and hardware-in-the-loop experiments verify that the proposed MPC approach improves voltage stability and accelerates dynamic energy dispatch, while the hierarchical strategy ensures coordinated power sharing and system balance under both grid-connected and islanded modes, enhancing operational flexibility and reliability in expressway DC microgrids.