Topology and Robust Power Flow Control Strategy for Grid-Forming Energy Storage Accessing Low-Voltage Distribution Station

This study presents a novel high-power density flexible interconnection topology and a robust power flow control strategy for the grid-forming-control (GFC)-based energy storage accessing low-voltage interconnection distribution station. The proposed topology consists of the three-phase parallel converter, three single-phase series converters, and a multiple-active-bridge (MAB) converter. All the DC ports of converters, energy storage, and PV panels are coupled through the MAB converter, which avoids the use of series transformers and helps improve the power density. By modeling and analyzing the power flow in the interconnection station, the proposed series converter and line impedance system is reconstructed first. Through adding a state variable with integral action to the reconstructed system, a robust control law could be designed for the new augmented to suppress the unknown disturbance. Simulation results verify the effectiveness and correctness of proposed robust power flow control in the GFC-based energy storage accessing low-voltage interconnection distribution station.