Advanced pulse width modulation techniques for cascaded multilevel inverters

This Paper proposes several carrier based modulation techniques for Cascaded multilevel inverters. Multilevel power conversion technology is a very rapidly growing area of power electronics with good potential for further development. Today, it is hard to connect a single power semiconductor switch directly to medium voltage grids. For these reasons, a new family of multilevel inverters has emerged as the solution for working with higher voltage levels. In this paper, various novel pulse width modulation techniques are implemented, which can minimize the total harmonic distortion and enhances the output voltages from five level inverter to multilevel topologies. Three methodologies adopting the constant switching frequency, variable switching frequency multicarrier, phase shifted carrier pulse width modulation concepts are implemented in this paper. The above methodologies divided in to two techniques. The sub harmonic pulse width modulation cascaded multilevel inverter strategy, minimized total harmonic distortion and switching frequency optimal pulsewidth modulation cascaded multilevel inverters strategy, enhances the output voltages.