A Comparative Study of Various Multi-Level Inverter Based on Multi-Cell

Multilevel inverters provide a staircase output voltage from DC voltage sources. Demanding large number of semiconductor power switches is main disadvantage of multilevel inverters. The multilevel inverters can be divided in two groups: symmetric and asymmetric inverter. The asymmetric multilevel inverters produce a great number of output steps without increased the number of DC voltage sources and components. In this thesis, a novel technique for multilevel inverter is proposed used cascaded sub-multilevel Cells. This sub-multilevel inverter can provide five levels of voltage. Here a level shifted Pulse Width Modulation (PWM) technique is applied to control the power devices. This modulation technique uses a sine wave and a repeating wave, these waves are combined and a complete reference wave is generated. Four Comparative study (5, 7, 9 & 11 level inverter) and algorithms for determining the DC voltage sources magnitudes have been presented. Finally, in order to verify the theoretical issues, simulation is presented in MATLAB/SIMULINK Software.