converter cell for cascade converters and a control system and method for operating a converter cell

摘要

converter cell for cascade converters and a control system and method for operating a converter cell. The present invention relates to a cascade electric converter and a method for operating a cascade electric converter which are described. The cascade converter comprises: a converter cell including a cell capacitor and at least one phase conductor having at least two electrical valves, at least one phase conductor being connected in parallel to the cell capacitor; and a control system for controlling the switching of electric valves of at least one phase conductor. The control system is configured to, upon detection of a need to pass the converter cell, control the switching of the electric valves so that the cell capacitor is short-circuited through a phase conductor to obtain a current advance through of the phase conductor, thereby creating a permanent current passage through the converter cell.