Four and five level hybrid inverters with reduced number of components and low harmonic content

The reduction of harmonic content generated is one of the advantages associated to the use of multilevel converters in distributed systems of electric power conversion. In this work, we present some four and five level multilevel converters with a reduced number of components and with reduced harmonic content when compared to traditional four and five level converters. These converters are based on Neutral-Point Clamped - NPC and Flying Capacitors - FC structures with inductive coupling between the arms. Considerations are made on the operation/modulation of the converters and, finally, a comparative study of the harmonic content generated by these converters with respect to the traditional converters is made from Weighted Total Harmonic Distortion index (WTHD) performance graphs versus the amplitude modulation index (ma).