Multilevel current converter with function of processing direct current fault

The present invention discloses a converter processing a multi-level DC fault function having a three-phase bridge rectifier circuit; each arm three-phase bridge rectifier circuit to the DC power from the access terminal end in turn is coupled by a bridge arm switch is turned on, the reactor and a multi-level modular unit connected in series; each series having a DC fault processing unit common DC bus two three-phase bridge rectifier circuit. Multi-level inverter according to the present invention a modular multi-level sub-module full bridge unit concatenation and DC fault processing unit is provided on the DC side, so that the low-frequency switching system, a smaller device loss, harmonic small; when the DC-side short circuit fault, the system can be self-limiting remove DC fault currents, without configuring the large rating of the switching device or plurality of switching devices in series-parallel, greatly reduce the cost of the corresponding reduced size and weight of the system, may be widely used in the new energy grid, urban distribution, island power transmission, high-capacity long-distance transmission and other occasions.