Asymmetrical Multilevel Hybrid Inverter - Analysis and Experimentation

Abstract

This paper describes a voltage-fed asymmetrical hybrid inverter based on a symmetrical hybrid multilevel DC-AC converter for high voltage/high power applications. The proposed inverter is controlled by two types of modulation patterns: low frequency (single pulse) and high frequency (sinusoidal PWM), responsible for obtaining a reduced harmonic distortion in the output voltage. Furthermore, the converter is asymmetrically powered, being fed by two sources with distinct values, obtaining seven levels phase voltage output. The results are presented with two pulse width modulation strategies, aimed at reducing the harmonic distortion in the voltage output. The operation of single-phase and three-phase circuits was verified by means of simulations and results obtained with an experimental prototype operating at a frequency switching of 1.5 kHz with a fundamental frequency of 50 Hz.