Abstract: MMC-DVR combined with dynamic voltage regulator（DVR） and modular multilevel converter（MMC） can be used to solve the problem of sag/swell compensation for medium and high voltages. Since MMC-DVR is a non-linear system,the compensation effect of linear control methods such as PID commonly used in DVR systems is not satisfactory. To this end,this paper proposes a passive nonlinear control method for the MMC-DVR system,which can be deeply integrated in the wind farm grid-connected system,and can solve the negative problems such as power quality degradation. First,the circuit topology and working principle of MMC-DVR are introduced,and the mathematical model under the static and rotating coordinate system is established. Then,the passive control method is proposed to solve the problem. Finally,the MMC-DVR control system is built on Matlab/Simulink software experimental platform,and the experimental results verify the feasibility and superiority of the passive nonlinear control strategy proposed in this paper.