Loss evaluation for modular multilevel converters with different switching strategies

Apparently, modular multilevel converter (MMC) has been extensively used in high voltage direct current (HVDC) transmission links in recent years. The efficiency of MMC stations are highly related to the switching methods and semiconductor devices. So, various switching methods and semiconductor devices have been investigated and introduced in the field. This paper settles a benchmark for an HVDC link, based on a real project, and investigates the impact of six different switching methods on the converter loss, utilizing a commercial semiconductor device. The evaluation indicates that switching methods which consider the current level at switching instants are more efficient in comparison with the other methods which only consider the number of switching events. The result of this study is essential for more efficient converter stations.