A NEW FOUR-LEVEL CONVERTER CELL TOPOLOGY FOR CASCADED MODULAR MULTILEVEL CONVERTERS

摘要

A cascaded modular multilevel converter has a plurality of 4-level converters, each ac phase generates the multilevel voltage waveforms composed of different outputs of the modules in the same phase. Each module is a controlled voltage source. The number of voltage levels in the cascaded converter is determined by the number of modules in each phase and the voltage levels generated by each module. N cascaded 4-level converters generate 4N+1 phase-to-neutral voltage levels and 8N+1 phase-to-phase voltage levels.