Study of a novel STATCOM based on modular multilevel inverter

A new shunt STATCOM based on modular multilevel converter (MMC) is researched in this paper. The circuit topology, sub-module mathematical model and working principle are analyzed in detail. A dynamic reactive current detection method based on the trigonometric function is applied to the compensation of MMC inverter. Attention is paid on the control to keep voltage stable of the capacitor with combining the regulating error signals to the CPS-SPWM waves, which has overcome the shortcoming that dc-link capacitor voltage is influenced by load interference when tracking the reactive current. The feasibility and effectiveness of the MMC-based STATCOM is validated by test results.