A converter includes multiple submodules that are serially connected on the input side to a DC power supply circuit via an inductor. Each submodule has an input-side half bridge and an at least single-phase output-side full bridge and an intermediate circuit capacitor connecting the half bridge and the full bridge forming an intermediate DC voltage circuit. According to the method, the submodules are alternately connected to the power supply circuit, thereby also connecting the intermediate circuit capacitor of the respective connected submodule to the power supply circuit, and the intermediate circuit voltage dropping across the respective intermediate circuit capacitor of each submodule is measured. The submodule to be connected is selected according to the voltage deviation of the corresponding intermediate circuit voltage from a specified target voltage value.