An improved nested 3-phase 5-level MLI design with optimized output voltage and total harmonic distortion

Abstract

Multilevel Inverters (MLIs) have advanced progressively and demonstrated enormous capacity in power electronics. To provide a 5-level voltage output with a 3-phase full-bridge arrangement and an additional bi-directional switch, a dc voltage input was split by two capacitors. This setup has two issues namely the output voltage limiting the magnitude of the input supply voltage and the voltage disparity between the isolating capacitors. This study suggests an improved nested 3-phase 5-level MLI design with a voltage level and total harmonic distortion (THD) that are both optimized. The suggested arrangement has the features of a lower proportion of passive elements and separated DC sources as it is constructed with a cascade linking of nested two-level cells (NTCs). The suggested unit cell was found to produce a 9-level output voltage (line) by producing a 5-level output voltage (phase) with a peak value that is double the level of the input voltage. The output voltage increasing the capacity of the suggested circuit is its prominent advantage, and the efficacy of the suggested design is 95% and validated by the simulated resultsKeywords: Multilevel Inverters (MLIs), Total harmonic distortion (THD), Voltage level.