Submodule for a modular multilevel converter, having - a half-bridge that forms an input terminal (Et) of the submodule and comprises a first and a second half-bridge output terminal (101, 102), and - a series circuit unit that is connected, at a first terminal, to the first half-bridge output terminal and, at a second terminal, to the second half-bridge output terminal, wherein the series circuit unit comprises a first and a second switching unit (310, 320) and a capacitor and the electrical connection point between the two switching units (310, 320) of the series circuit unit forms an output terminal (At) of the submodule, characterized by - a bidirectionally switchable switching device that is able to switch current on and off independently of the current flow direction and is connected, at a terminal, to the output terminal (At) of the submodule and, at another terminal, to the second half-bridge output terminal and thus to the second terminal of the series circuit unit, - wherein the half-bridge forms a series circuit having two series-connected semiconductor switches (110, 120), whose electrical connection point forms the input terminal (Et) of the submodule, and comprises a capacitor connected in parallel with the series circuit and whose outer terminals form the first and the second half-bridge output terminal (101, 102) of the half-bridge, - one of the two terminals of the capacitor of the series circuit unit forms the second terminal of the series circuit unit and is connected to one of the two terminals of the capacitor of the half-bridge and the two capacitors (C1, C2) and the switching units (310, 320) of the series circuit unit form an electrical loop, and - the bidirectionally switchable switching device is connected, at its other terminal, to the electrical connection point between the capacitor of the half-bridge and the capacitor of the series circuit unit. - a half-bridge that forms an input terminal (Et) of the submodule and comprises a first and a second half-bridge output terminal (101, 102), and - a series circuit unit that is connected, at a first terminal, to the first half-bridge output terminal and, at a second terminal, to the second half-bridge output terminal, wherein the series circuit unit comprises a first and a second switching unit (310, 320) and a capacitor and the electrical connection point between the two switching units (310, 320) of the series circuit unit forms an output terminal (At) of the submodule, - a bidirectionally switchable switching device that is able to switch current on and off independently of the current flow direction and is connected, at a terminal, to the output terminal (At) of the submodule and, at another terminal, to the second half-bridge output terminal and thus to the second terminal of the series circuit unit, - wherein the half-bridge forms a series circuit having two series-connected semiconductor switches (110, 120), whose electrical connection point forms the input terminal (Et) of the submodule, and comprises a capacitor connected in parallel with the series circuit and whose outer terminals form the first and the second half-bridge output terminal (101, 102) of the half-bridge, - one of the two terminals of the capacitor of the series circuit unit forms the second terminal of the series circuit unit and is connected to one of the two terminals of the capacitor of the half-bridge and the two capacitors (C1, C2) and the switching units (310, 320) of the series circuit unit form an electrical loop, and - the bidirectionally switchable switching device is connected, at its other terminal, to the electrical connection point between the capacitor of the half-bridge and the capacitor of the series circuit unit.