Abstract: Bidirectional DC-DC converter is the key equipment to realize the power balance of DC microgrid，

and the accurate distribution of load current is one of the main objectives of multi converter parallel control. Aiming

at the current sharing problem of bidirectional DC-DC converter，a current sharing control based on AC voltage

small signal injection was proposed. The charging and discharging switching strategy of bidirectional DC-DC

converter was designed，and a small AC voltage signal was injected into the voltage of high voltage side of bidirectional DC-DC converter，and the reactive power generated by AC voltage was used to coordinate the current of each converter，so as to realize the accurate load distribution of bidirectional DC-DC converter under multiple

charging and discharging conditions. Finally，the feasibility and effectiveness of the proposed method were verified

by experiments.

      Key words: bidirectional DC-DC converter；current sharing control；frequency droop；Q—V droop control