To address the stable operation issue of AC/DC hybrid microgrids in islanded mode

a unified droop control strategy based on soft normally open point (SNOP) is proposed. This strategy utilizes a normalization method to combine the frequency droop characteristics of the two feeders with the DC voltage droop characteristics

based on the power balance relationship of the system. The system's operating state is determined by the AC frequency and DC voltage

and SNOP uniformly adjusts the frequency of the AC subgrid and the voltage of the DC subgrid. This ensures that the AC and DC microgrids can evenly share the total power change of the hybrid microgrid

maintaining the AC frequency and DC voltage within the permissible range of the system. Additionally

to prioritize the nearby integration of distributed energy resources and avoid unnecessary actions of SNOP

a deadband adjustment is designed. Then

the AC and DC microgrids can utilize distributed energy resources within each subgrid

thereby reducing the frequent interaction of SNOP on both the AC and DC sides. Finally

the effectiveness of the proposed unified droop control strategy is verified by MATLAB/Simulink simulations.