Reliability analysis of modular multilevel converter system under different submodule topologies

Modular multilevel converter (MMC) has gradually become the preferred converter topology for high voltage direct current (HVDC) technology due to its clear advantages of low power consumption and modularity, its safe and reliable operation is of great significance to grid safety and energy utilization. Therefore, it is very important to model and analyze the system reliability of MMC. This paper firstly describes the commonly used system-level reliability modeling methods. Then on this basis, under the premise of considering the correlation between sub-modules, reliability analysis and modeling of several common sub-module topologies in modular multilevel converters are carried out. Finally, use actual engineering data as a reference to calculate the reliability of different topology systems and draw the three-dimensional curves of system reliability changes by using software programming. By comparing the results, the influence of the sub-module topology on the system reliability is analyzed, which provides a theoretical basis for the planning and design of actual projects.