In order to reduce the capacitor volume of the modular multi-level converter,a modular multi-level converter with the hybrid submodule based on capacitor voltage ripple compensation is proposed. Firstly,the system structure of the proposed hybrid modular multi-level converter and the mechanism of reducing the capacitor volume are introduced,and the switching principle of the hybrid submodule is analyzed in detail. Secondly,the energy fluctuation of capacitors is analyzed to size the capacitance of all capacitors,and the overall capacitor volume is evaluated and compared with the conventional half-bridge modular multi-level converter. Finally,the effectiveness of the proposed structure and control is verified by simulation and experimental results. The results show that the proposed structure in this paper can greatly enhance the energy utilization ratio of the capacitors in the modular multi-level converter with lower switching device cost,thus,reducing the capacitor volume and improving the system power density.