Modeling and analysis of modular multilevel converter based static synchronous compensator

This thesis is concentrated on the modeling and analysis of the modular multilevel converter based on static synchronous compensator (MMC-STATCOM). In order to obtain the most suitable switching method for MMC-STATCOM, Scalar PWM methods such as level-shifted carrier based PWM methods and phase-shifted carrier based PWM method are compared considering equivalent switching count in a phase leg without any control structures. Moreover, Nearest Level Control method is also implemented to the MMC and that of performance analysis is discussed. Taking into account overall control parts of the MMC; active and reactive power control, DC-link voltage control, output current control and also submodule capacitor voltage balancing methods are concerned. Finally, submodule capacitor voltage balancing methods such as; sort and selection method related to direct modulation and Phase-shifted PWM based control method are implemented to the MMC-STATCOM and also compared to each other considering static mode and dynamic mode of the MMC-STATCOM having both inductive and capacitive mode ranges.