Apparatus for conversion of an electric current - having at least one phase module (2a, 2b, 2c) which has an AC voltage connection (3 1, 3 2, 3 3) and at least one DC voltage connection (p, n) with a phase module branch (6p1, 6p2, 6p3, 6n1, 6n2, 6n3) being formed between each DC voltage connection (p, n) and each AC voltage connection (3 1, 3 2, 3 3) and with each phase module branch (6p1, 6p2, 6p3, 6n1, 6n2, 6n3) having a series circuit of submodules which each have a capacitor and at least two power semiconductors (T1, T2), - having measurement sensors for provision of actual values, and - having regulation means (9, 10) which are connected to the measurement sensors and are designed to regulate the apparatus as a function of the actual values and predetermined nominal values, characterized in that the regulation means (9, 10) have a current regulation unit and drive units which are each associated with one phase module branch, with the current regulation unit being designed to provide branch voltage nominal values for the drive units, and with the drive units being connected between the submodules and the current regulation unit and being designed to produce control signals for said submodules, - with the drive units obtaining capacitor voltage values of all submodules of the phase module branch assigned thereto as submodule actual values, summing said submodule actual values to obtain a branch energy actual value and feeding the branch energy actual value to the current regulation unit, - with the drive units obtaining a branch voltage nominal value from the current regulation unit, - and with the drive units generating control signals for the submodules assigned thereto in such a way that the voltage across the series circuit of said submodules corresponds as closely as possible to the respective branch voltage nominal value. - having at least one phase module (2a, 2b, 2c) which has an AC voltage connection (3 1, 3 2, 3 3) and at least one DC voltage connection (p, n) with a phase module branch (6p1, 6p2, 6p3, 6n1, 6n2, 6n3) being formed between each DC voltage connection (p, n) and each AC voltage connection (3 1, 3 2, 3 3) and with each phase module branch (6p1, 6p2, 6p3, 6n1, 6n2, 6n3) having a series circuit of submodules which each have a capacitor and at least two power semiconductors (T1, T2), - having measurement sensors for provision of actual values, and - having regulation means (9, 10) which are connected to the measurement sensors and are designed to regulate the apparatus as a function of the actual values and predetermined nominal values, characterized in that the regulation means (9, 10) have a current regulation unit and drive units which are each associated with one phase module branch, with the current regulation unit being designed to provide branch voltage nominal values for the drive units, and with the drive units being connected between the submodules and the current regulation unit and being designed to produce control signals for said submodules, - with the drive units obtaining capacitor voltage values of all submodules of the phase module branch assigned thereto as submodule actual values, summing said submodule actual values to obtain a branch energy actual value and feeding the branch energy actual value to the current regulation unit, - with the drive units obtaining a branch voltage nominal value from the current regulation unit, - and with the drive units generating control signals for the submodules assigned thereto in such a way that the voltage across the series circuit of said submodules corresponds as closely as possible to the respective branch voltage nominal value.