Method for operating a modular multilevel converter, modular multilevel converter and computer program

摘要

The invention relates to a method for operating a modular multilevel power converter, which has a plurality of power converter branches, in each of which series circuits of bridge modules are arranged, the bridge modules each having a bridge circuit in the form of a half bridge or a full bridge of power semiconductors and at least one switchable via the bridge circuit capacitor wherein the method provides at an output side of the power converter an output AC voltage having an output frequency, wherein the desired time amplitude characteristic of the output AC voltage of the power converter is synthesized by a modulation AC voltage having a modulation frequency generated by the bridge modules from one or more power converter branches is higher than the output frequency, wherein the modulation AC voltage in the cycle of the modulation frequency, the output AC voltage alternately exceeds and undershoots et, and by each one a power converter branch associated energy regulator, the switching times of the power semiconductors of the bridge modules of this power converter branch are controlled with the control goal of minimizing the energy variation of the power converter branch. The invention further relates to a modular multilevel power converter designed in this manner and to a computer program with program code means set up to carry out a method of the aforementioned type.