A Sub-Module Topology of MMC With DC Fault Ride-Through Capability

Modular Multilevel Converter(MMC) is widely used in high voltage DC transmission(HVDC) for its advantages such as high modularity, low switching frequency, low content of harmonics, etc. DC fault is an main issue that MMC must deal with. In this paper, an improved MMC sub-module topology was proposed based on analyzing existing sub-module topology. This topology can block DC fault current without changing original control and modulation strategy. The simulation is realized in PSCAD/EMTDC, and the DC fault ride-through capability of the proposed sub-module topology is verified by simulation results.