As the connection port of the AC microgrid and DC microgrid, the modular multilevel converter with battery energy storage system (MMC-BESS) can not only complete the electric energy conversion quickly and smoothly, but also has the energy storage function, which can stabilize the power of the AC/DC hybrid microgrid fluctuation effectively. In this paper, based on MMC-BESS with bidirectional DC/DC converter structure, PI control and peak current control are combined to study. In this paper, based on MMC-BESS with bidirectional DC/DC converter structure, PI control and peak current control are combined to study. The simulation results show that, compared with the average current control method, the bidirectional DC/DC converter adopts the peak current control method to improve the response speed of battery charging and discharging, reduce the current fluctuation, and make the battery charging and discharging reach the stable state faster.