A Novel Hierarchical Control Scheme for Solid-State Transformer Interfaced PV and Storage System

Distributed energy (DE) is gaining more and more attention and solid-state transformer (SST) has been admitted as the most potential interface for DE. A three-layer novel hierarchical control algorithm for SST interfaced PV and storage system is proposed to use DE intelligently: primary control considering voltage or current control for PV and storage, secondary control in small time scale independent of communication with central controller achieving a seamless transfer between grid-connected state and islanding state, tertiary control in large time scale determining operation state for the system as well as energy management. Simulation and experimental results confirm the feasibility of the proposed novel control algorithm.