Modeling and control of three-phase multilevel inverter-based STATCOM

This paper investigates the detailed model, control and simulation of a multilevel inverter-based STATCOM. Nine-level STATCOM is selected as a demonstration. Basic structure and operation principle of the cascade multilevel inverter are explored, firstly. The cascade multilevel inverter consists of four single-phase full bridges in which each bridge has its own dc source, respectively. The phase-shifted SPWM is used for eliminating the lower-order harmonics of the output voltage, and the d-q axis transform is employed to decouple the active and reactive power components for regulating the compensation power. Finally, ATPDraw is used to build the model of power circuit and controller of the three-phase nine-level STATCOM. The results of simulation are analyzed and discussed.