A COMPARISON STUDY BETWEEN STEREOTYPICAL MULTILEVEL-INVERTERS WITH MULTISTRING INVERTER IN THREE-PHASE LOADED CONDITION

摘要

This paper presents a recently developed, popular and efficient Multi-level Inverter (MLI) known as Multistring-MLI (MMLI). This topology not only demands lesser switches but also provide superior quality of output waveform with lesser THD and good fundamental RMS value than that of conventional converters. So for the very first time it has been compared with all stereotypical MLIs in three-phase loaded condition. For five level output, MMLI needs two numbers of lesser switches in each phase than conventional MLIs. Although with increase with levels no of switches increases, but at the same time the difference of no of required switches among the conventional converters and MMLI also increases. This is the best advantage of MMLI. In the study all the simulation has been carried out for five-levels only in three phase loaded condition. From the study it has been demonstrated that how it maintains more and equal quality of output waveform irrespective of switching frequencies. All the output voltage levels also have been mathematically derived.