Adaptive hierarchical control strategy for AC/DC microgrid considering SOC of energy storage

Abstract

In order to improve the reliability and flexibility of energy storage in microgrid, an adaptive hierarchical control strategy considering energy storage SOC was proposed. Firstly, the operation state of energy storage was controlled by the sequence of battery voltage, bus voltage and energy storage SOC. Secondly, the State Of Charge (SOC) of energy storage was graded and the improved droop coefficient with continuous different changing trends was set. Then, the Microgrid Interconnect Converter (MIC) adopted the outer loop normalized power sharing control and the feed-forward inner loop current control. Finally, the AC-DC hybrid microgrid simulation model of fan, photovoltaic, energy storage and load were established to verify the effectiveness of the proposed strategy. The results showed that the proposed strategy can ensure the stability of frequency and voltage of the system when dealing with the changes of external environment.