CMLI Based Statcom Employing Single DC Input Source

This paper proposes an isolated cascaded multilevel inverter employing low-frequency three-phase transformers and a single dc input power source. The proposed circuit configuration can reduce a number of transformers compared with traditional three-phase multilevel inverters using single-phase transformers. It controls switching phase angles to obtain an optimal switching pattern identified with the fundamental frequency of the output voltage. The major problem in the electrical power quality is the harmonic content. There are several methods indicating the quantity of harmonic content and the most widely used measure is the Total Harmonic Distortion (THD). Owing to this control strategy, harmonic components of the output voltage and switching losses can be diminished considerably.This technique is applied for any number of levels of multilevel inverter. A 7 level cascaded multilevel inverter power circuit is simulated in MATLAB 7.8 simulink with sinusoidal PWM technique. To verify the performance of the proposed approach, we implemented experiments using a prototype.