A new technology of modular multilevel structure is proposed for dynamic voltage restorer. Modular multilevel structure is easy to expand and implement. It also has a common DC bus

which makes it possible for achieving four-quadrant operation easily. The topological structure and working characteristics of the modular multilevel dynamic voltage restorer are introduced and theoretically analyzed in this paper. In contrast with several corresponding strategies

the in-phase compensation strategy

sub-module capacitance voltage hierarchical control strategy and carrier phase shifted PWM modulation control strategy are proposed

which are suitable for modular multilevel dynamic voltage restorer. Simulation models are built by using software PSCAD. The validity and feasibility of control strategies of modular multilevel dynamic voltage restorer are testified through simulation analysis.