A modular multilevel converter, MMC,, wherein the MMC comprises: a) an AC to DC conversion module, comprising three branch circuits connected in parallel between output ends (V 1, V 2), each branch circuit being formed of multiple IGBT half-bridge circuits connected in series between a first and second end at which the branch circuits are connected in parallel, and an electric coupling point (N 0) of two adjacent IGBT half-bridge circuits in a middle position of the branch circuit being connected to a voltage input end (Vin) and the output ends (V 1, V 2) being connected to the first and second end, respectively; b) a DC to AC conversion module, connected between the output ends (V 1, V 2), the DC to AC conversion module being formed of multiple IGBT half-bridge circuits connected in series between a first and second end, the first and second end connected to the output ends (V 1, V 2) of the AC to DC conversion module and the DC to AC conversion module having multiple sets of output ends (V3, V4), each set of output ends (V3; V4) comprising a first output end (V 3) and a second output end (V 4), b0) wherein the series connected multiple IGBT half-bridge circuits of the DC to AC conversion module comprise a first pair of adjacent first and second IGBT half-bridge circuits and a second pair of adjacent third and fourth IGBT half-bridge circuits; b1) wherein the first output end (V 3) in each set of output ends (V3; V4) is connected to an electric coupling point (N 1) between the two adjacent first IGBT half-bridge circuit and second IGBT half-bridge circuit of the first pair amongst said series connected IGBT half-bridge circuits, and b2) wherein the second output end (V 4) in said each set of output ends (V3; V4) is connected to an electric coupling point (N 2) between the another two adjacent third IGBT half-bridge circuit and fourth IGBT half-bridge circuit of the second pair amongst said series connected IGBT half-bridge circuits; d) wherein each IGBT half-bridge circuit comprises a first capacitor (C 1), a first IGBT (IGBT 1) and a second IGBT (IGBT 2), the first IGBT (IGBT 1) and the second IGBT (IGBT 2) being connected in series and then connected in parallel with the first capacitor (Ci); the collector of the first IGBT (IGBT 1) is connected to a positive terminal of the first capacitor (C 1), the emitter of the first IGBT (IGBT 1) is connected to the collector of the second IGBT (IGBT 2) and serves as a first connection terminal, and the emitter of the second IGBT (IGBT 2) is connected to a negative terminal of the first capacitor (C 1) and serves as a second connection terminal; and d1) the second connection terminal is connected to the first connection terminal of an adjacent IGBT half-bridge circuit. a) an AC to DC conversion module, comprising three branch circuits connected in parallel between output ends (V 1, V 2), each branch circuit being formed of multiple IGBT half-bridge circuits connected in series between a first and second end at which the branch circuits are connected in parallel, and an electric coupling point (N 0) of two adjacent IGBT half-bridge circuits in a middle position of the branch circuit being connected to a voltage input end (Vin) and the output ends (V 1, V 2) being connected to the first and second end, respectively; b) a DC to AC conversion module, connected between the output ends (V 1, V 2), the DC to AC conversion module being formed of multiple IGBT half-bridge circuits connected in series between a first and second end, the first and second end connected to the output ends (V 1, V 2) of the AC to DC conversion module and the DC to AC conversion module having multiple sets of output ends (V3, V4), each set of output ends (V3; V4) comprising a first output end (V 3) and a second output end (V 4), b0) wherein the series connected multiple IGBT half-bridge circuits of the DC to AC conversion module comprise a first pair of adjacent first and second IGBT half-bridge circuits and a second pair of adjacent third and fourth IGBT half-bridge circuits; b1) wherein the first output end (V 3) in each set of output ends (V3; V4) is connected to an electric coupling point (N 1) between the two adjacent first IGBT half-bridge circuit and second IGBT half-bridge circuit of the first pair amongst said series connected IGBT half-bridge circuits, and b2) wherein the second output end (V 4) in said each set of output ends (V3; V4) is connected to an electric coupling point (N 2) between the another two adjacent third IGBT half-bridge circuit and fourth IGBT half-bridge circuit of the second pair amongst said series connected IGBT half-bridge circuits; d) wherein each IGBT half-bridge circuit comprises a first capacitor (C 1), a first IGBT (IGBT 1) and a second IGBT (IGBT 2), the first IGBT (IGBT 1) and the second IGBT (IGBT 2) being connected in series and then connected in parallel with the first capacitor (Ci); the collector of the first IGBT (IGBT 1) is connected to a positive terminal of the first capacitor (C 1), the emitter of the first IGBT (IGBT 1) is connected to the collector of the second IGBT (IGBT 2) and serves as a first connection terminal, and the emitter of the second IGBT (IGBT 2) is connected to a negative terminal of the first capacitor (C 1) and serves as a second connection terminal; and d1) the second connection terminal is connected to the first connection terminal of an adjacent IGBT half-bridge circuit.