A method of suppressing a circuit current in a modular multi-level converter for high-voltage direct current

A method for suppressing a circuit current in a modular multi-level converter for a high voltage direct current (HVDC) transmission system, the alternating current (AC) into a direct current (DC) and vice versa converts, transmits power using a DC-cable, and a modular multistage converter which generates a high voltage source by means of in-series-connecting a plurality of sub-modules, said method comprising: Receiving a circulating current (i wherein the controlling of the circulating current (i Dividing said circulating current (i Calculating the AC component (i Modeling the AC component of the circulating current has been removed from the DC,