An Imbalance-Status-Enabled Autonomous Global Power-Sharing Scheme for Solid-State Transformer Interconnected Hybrid AC/DC Microgrids

This paper proposes a novel imbalance-status (IS)-enabled autonomous global power-sharing scheme for a solid-state transformer (SST) interconnected hybrid AC / DC microgrid system. Firstly, the proposed scheme globally estimates instantaneous active power imbalances according to the existing droop regulation characteristics of each sub-microgrid, and normalizes these imbalances by introducing the definition of IS. Next, three novel IS-enabled controllers are designed for the SST’s three core converters, to autonomously share the power imbalances in the entire system. Then, the control parameters of the proposed scheme are optimized through small-signal analysis. The control effectiveness and flexibility of the proposed scheme in realizing global power-sharing function are verified by controller hardware-in-loop experiments in RT-LAB platform.