Hierarchical coordinated control of multi bus-based DC microgrid considering fault occurred in buses

摘要

Multi bus-based dc microgrid has serious merits such as the higher reliability of power supply and flexibility of distributed energy and loads connecting into the system. Its stable operation would be destroyed by the power fluctuation and bus faults. Therefore, the coordinated control strategy, including five hierarchical levels, is proposed to ensure the stable operation of dc microgrid. The stable operation in case of bus non-fault is guaranteed by the 1st to 4th control levels and the reliable operation is safeguarded by the 5th control level after fault occurred in one of the buses. The bus voltage acts as a monitor of supply-demand balance, and it's controlled in allowable fluctuation range, which is proved by a dc microgrid model in MATLAB/ Simulink. Meanwhile, the reliability and effectiveness of the proposed control strategy for the DC MG operating in both islanding and grid-connected modes is verified.