The power fluctuation during the operation of the micro-grid will affect the stability of the system frequency

which can be suppressed effectively by the energy storage device. In view of the characteristics of different energy storage devices and the state of SOC

a kind of new hybrid energy storage system control method based on traditional droop control is proposed in this paper. The hybrid energy storage device uses the batteries and super capacitors with strong complementarity. The latter acts as the main frequency control unit to provide quickly the power response frequency change

while

the former responds to the power change of load and participates in the secondary regulation of the frequency. In addition

the SOC state of different batteries is also considered and the battery SOC can is equalized in the control process. Finally

the simulation model is set up based on Matlab/Simulink to verify the effectiveness of the proposed strategy.