New Frequency Modulation Strategy with SHE for H-bridge Multilevel Inverters

Abstract

This paper presents the selective harmonic elimination (SHE) of cascade H-bridge multilevel inverters using a new fundamental frequency modulation strategy. Compared to the conventional switching scheme, in this new method stepped waveforms with more than N possible kind could be synthesized. As a result, it is more achievable to compute the proper set of switching angles, especially at the low-modulation index to gain SHE for multilevel inverters. The controlling purpose is to eliminate selective harmonics and also fundamental output voltage control for a cascade LI-Ievel inverter. Finding an optimal set of switching angles for above objective function requires solving a nonlinear equation that is solved by the use of shuffled frog leaping algorithm in this paper. Simulation results are presented using Matlab environment to verify the suggested technique.