Multiport Energy Router for DC Grid Clusters

The dc micro-grid has emerged as an increasingly popular solution for localized energy integration and dispatching. With multiple dc micro-grids in a system, an effective dc tie can facilitate various generation, storage, and consumption modes. It enhances energy versatility and contributes to improved energy resiliency. Hence, this article introduces the concept of a multiport energy router (MER) that aims to multiplex dc power across various dc communities all with close-margin bus voltages. The proposed MER functions as a "super node" following Kirchhoff's current law (KCL). It incorporates a unique partial power topology, enabling direct control of dc current flow between any two buses or toward local energy storage, solely based on bus voltage differences. To align modulation and control with industrial standard frameworks and provide flexibility in controlling energy storage current, a multidimension space vector modulation method is proposed. The instantaneous power theory is redefined for the dc energy router's operation. The power transfer efficiency of the standard half-bridge partial power topology is empirically verified through rigorous testing. Various operational scenarios are examined to demonstrate the feasibility of the MER concept, with findings supported by both simulation and experimental data.