Abstract: In response to the stable operation demand of modular multilevel converter（MMC）with singlephase

short circuit fault，a passivity-based method based on dual-port controlled Hamiltonian with dissipation（Dual-

PCHD）model was proposed. To make the grid-connected positive sequence and negative sequence current

subsystems have synchronous and progressive tracking characteristics，the Dual-PCHD model of MMC under

unbalanced grid was established and the interconnection matrix of current subsystems was designed. From the energy point of view，the global energy function was designed to obtain passivity-based control law. The fast suppression of the negative sequence current and the asymptotic tracking of the desired trajectory of the positive sequence current were achieved. At the same time，the global and gradual stability of the closed control system was guaranteed. It is shown by the simulation results based on Matlab/Simulink that the proposed method has the advantages of good dynamic performance，wide stability range and strong robustness when the single-phase short circuit fault，active power mutation and internal bridge arm resistance parameter perturbation occurring at the same time.

      Key words: modular multilevel converter（MMC）；dual-port controlled Hamiltonian with dissipation（Dual-

PCHD）model ；passivity-based control ；progressive tracking of the positive sequence current ；fast suppression of the negative sequence current