Solid-State Transformer Enabled DCMG Architecture with Distributed Energy Management

Abstract

This paper proposes a new topology for solid-state transformer (SST) enabled versatile DC Microgrids (DCMGs) with flexible DC links. In the proposed topology, the SST and the DCMGs are interfaced through a bi-directional DC-DC converter to create a main DC bus and dedicated DC link for each microgrid with flexible voltage level. The proposed architecture allows seamless integration of DCMGs to the SST without affecting operation and control of the SST. Moreover, an independent energy management algorithm is proposed for DCMG to achieve maximum energy utilization and minimum power exchange between the DCMG and utility AC grid through the SST. The proposed energy management algorithm features a novel battery state of charge dependent voltage droop characteristics that is integrated in the energy management algorithm to regulate the DCMG bus voltage and maintain energy balance. Seamless transition and smooth operation of the proposed DCMG architecture under grid connected mode is validated through MATLAB simulation based study.