A Variable Frequency Switching Scheme for THD Reduction with 13-level Symmetrical Inverter under Test

To reduce distortion from the fundamental sinusoidal waveform, inverters were extended to more than two layers, which gave rise to the concept of a multilayer inverter. The need for extra switches, which increases system bulk and cost and decreases system reliability because of the higher component count, is a disadvantage of multiple-level inverters. The distortion in the result is lessened by the increase in inverter levels. In this study, a variety of switching approaches have been tried using a symmetrical 13 level inverter (13-LI) and their results are compared with 180 degree shifted adjacent level pulse span modulation. This is because efficient switching techniques may help minimize distortion. The model and variable switching strategy are constructed using the MATLAB software.