Analysis of Most Optimal Multi-unit Multi-level Inverter Having Minimum Components and Lower Standing Voltage

Abstract

Most of the asymmetrical reduced-component multi-level inverters (MLIs) can generate their maximum possible voltage levels; however, their total standing voltage (TSV) is comparatively higher. Here, a single-phase, multi-unit MLI configuration is proposed that can generate a maximum number of output voltage levels using minimum components and achieve lower TSV. Here, a single-phase generalized MLI unit is proposed to generate a more number of output voltage levels using lesser components and to achieve lower TSV. The inverter is further extended to a cascaded multi-unit MLI for high power applications. Further, a most optimal generalized multi-unit MLI is derived from the generalized topology that has designed with a minimum component and TSV for maximum voltage levels. The performance of the proposed MLI is compared with other similar existing MLIs in terms of the number of switches, the number of DC sources and TSV with an increase in voltage levels to prove its superiority. Further, a comparative study of voltage stress experienced on the highest voltage rated switches of the proposed most optimal MLI and the most popular CHB trinary is done for an increasing number of levels. The TSV of the proposed 11-level inverter is calculated as 21V DC, which is much smaller as compared to the similar existing topologies. A MATLAB/Simulink based simulation and corresponding experimental results of the 11-level and 47-level inverters are presented at different modulation indices as well as under load variations to verify their effectiveness.