Enhanced modulation strategy for 7-level voltage waveform in asymmetrical 5-level Cascaded H-Bridge Inverters

Abstract

The CHBMI performance optimization can be reached both with hardware and software solutions. Generally, asymmetrical configurations allow the extension of the voltage levels number and the implementation of an innovative modulation strategy allows for improving the performance in terms of harmonic distortion and conversion efficiency. This work is devoted to the development of a modulation strategy that allows improving the performance of an asymmetrical single-phase five-level Cascaded H-Bridge Inverter generating a 7-level voltage waveform. Thus, a digital approach and corresponding digital functions are presented. Subsequently, the impact of the dead time and the influence on the voltage harmonic distortion have been discussed. Through simulation analysis, in the Matlab environment, the main benefits and drawbacks of the proposed approach have been discussed.