This paper proposed one novel control method for modular multilevel converter(MMC) to tackle its low frequency operation problems as the module capacitor voltage ripples. Comparing with conventional control, this paper proposed one asymmetric control by alternating work sates of upper and lower arms, to achieve excellent capacitor voltage ripples suppression effect. To avoid the limited modulation range and enhance performance, hybrid or full bridge MMC structure is employed. The detailed control is analytical discussed, with full simulation results to verify the proposed methods.