A survey on modeling, control, and dc-fault protection of modular multilevel converters for HVDC systems

The modular multilevel converter (MMC) is becoming one of the most promising topology in multilevel converter series especially for high-voltage and high-power applications. This valuable features, nominates MMCs to interface high-voltage and high-power renewable energy resources into modern HVDC electric grids for more penetration of renewable energy. This paper investigates recent modelling, control, and dc-fault protection techniques that have been applied to MMCs.