In order to prolong the operation life of multiple energy storage units and improve the flexibility of microgrid scheduling

a coordinated control method of DC micro-grid based on state of charge(SOC) classification is proposed. On the basis of conventional power stratification

the priority of energy storage units is divided according to the real-time SOC value. By comparing the relationship between the disturbance power of micro-grid and the maximum suppression capacity of specific priority

the energy storage unit with corresponding priority is put into operation in different stages. On this basis

the improved e-exponential droop control with voltage feedforward compensation is designed to ensure the quality of bus voltage and make the SOC of the energy storage unit converge gradually. Finally

the model is built based on MATLAB/Simulink platform. The simulation results show that

this control method can avoid excessive charging and discharging of some energy storage units

reduce the charging and discharging time and times of energy storage units

and effectively improve the scheduling flexibility and operation economy of the micro-grid.