An Efficient method for Voltage Quality improvement in Asymmetrical Multilevel Inverter

Multilevel inverter are becoming more and more popular as they have advantages of modularity, less harmonic contents and can withstand higher voltages. However, conventional multilevel inverter topology like cascaded H-bridge inverter, required a large number of DC sources, switches and driver circuit as number of level in output voltage increases. To address this issue, numerous asymmetrical topologies have been invented with less count of components. But, total harmonic distortion specially low order harmonics are still an issue that has not been addressed. In this paper a new idea employing selective harmonic elimination (SHE) technique has been exhibited to diminish the low order harmonics and maintain the fundamental output voltage at desired level. Switching angles for controlling the power electronic switches has been calculated using particle swarm optimization (PSO) technique. The proposed method has been verified by simulation of 15-level asymmetrical inverter. Analytical and simulation results gave a promising nature for the performance ofproposed method.