Modular multilevel converter (MMC) needs a large number of voltage sensors.Thus,this paper presents a grouping control strategy to reduce voltage sensors.This control strategy divides the 2~N sub-modules into N+1 groups according to the sequence of 2~0,2~1,2~2,…,2~(N-1),2~0.Each group of sub-modules is regarded as an entirety,whose switch state must remain the same.A voltage sensor is equipped to detect the capacitance voltage of each group.On the basis of this structure,the corresponding methods of capacit...