MULTIMODULAR MULTILEVEL CONVERTERS WITH INPUT OUTPUT LINEARITY/

Multilevel converters constitute the keg technology of power electroni cs to reach the high power ratings required by controllers of flexible at transmission systems (FACTS), This paper shows that the sinusoidal pulsewidth modulation (SPWM) technique, as applied to multilevel conv erters, inherently requires a high switching rate, The paper then pres ents a strategy based on multiple modules of multilevel converters whi ch operate with the lowest possible switching loss (each gate-turn-off thyristor (GTO) switches ON and OFF only once during the modulation p eriod), while maintaining the high gain-bandwidth product of linear am plifiers to handle fast feedbacks, which FACTS controllers must be cap able of, in order to carry out dynamic performance enhancement.