A modular multi-level converter comprising: a plurality of sub-modules comprising switching elements; and a central control unit configured to sequentially assign an address to each of the plurality of sub-modules from the front according to a placement sequence of the plurality of sub-modules for distinguishing each of the plurality of sub-modules, determine switching operation conditions of the plurality of sub-modules based on the assigned addresses, and output switching signals corresponding to the determined switching operation conditions, wherein the switching operation conditions include a charging operation condition, a discharging operation condition, and a bypassing operation condition, characterized in that the central control unit is configured to allow discharging operations to be performed sequentially from the sub-module having a lowest address, based on a target voltage and charged voltages of the plurality of sub-modules, wherein the lowest address is assigned to the front most one of the sub-modules, and a highest address is assigned to the sub-module which is disposed at the last, wherein, when sub-modules operating under the discharging operation condition are determined, the central control unit stores information on a sub-module having the last address from among the sub-modules operating under the discharging operation condition, wherein the central control unit confirms a sub-module which has the last address and has performed a discharging operation at a previous point in time, and allows a discharging operation to be sequentially performed starting from a sub-module which has the next address after the address of the confirmed sub-module, wherein the plurality of sub-modules are a half-bridge shape. a plurality of sub-modules comprising switching elements; and a central control unit configured to sequentially assign an address to each of the plurality of sub-modules from the front according to a placement sequence of the plurality of sub-modules for distinguishing each of the plurality of sub-modules, determine switching operation conditions of the plurality of sub-modules based on the assigned addresses, and output switching signals corresponding to the determined switching operation conditions, wherein the switching operation conditions include a charging operation condition, a discharging operation condition, and a bypassing operation condition, characterized in that the central control unit is configured to allow discharging operations to be performed sequentially from the sub-module having a lowest address, based on a target voltage and charged voltages of the plurality of sub-modules, wherein the lowest address is assigned to the front most one of the sub-modules, and a highest address is assigned to the sub-module which is disposed at the last, wherein, when sub-modules operating under the discharging operation condition are determined, the central control unit stores information on a sub-module having the last address from among the sub-modules operating under the discharging operation condition, wherein the central control unit confirms a sub-module which has the last address and has performed a discharging operation at a previous point in time, and allows a discharging operation to be sequentially performed starting from a sub-module which has the next address after the address of the confirmed sub-module, wherein the plurality of sub-modules are a half-bridge shape.