Design and development of Non modular multilevel inverter Topologies for device count waning

Abstract

Recent developments in the field of power electronics supported by newlinethe structural inovations in power conversion circuits and their operational newlineflexibility motivate to develop various multilevel inverter (MLI) topologies newlinecompatible for various applications like renewable energy systems, electric newlinedrives and other low/medium power applications. Inherently the MLI can newlinesynthesize a high quality ac output voltage of required frequency from multiple newlineseparate/isolated dc sources (SDCs) with merits such as lower dv/dt and device newlinestresses, a diminsihed output voltage distortion, minimal switching losses, and newlinehaving ability to operate at higher voltages. newlineThe main objective of this thesis is to propose three different novel newlineMLI structures to mitigate the issues like the objectionable component count, newlinehigher number of active devices in the conduction path and more conduction newlinelosses. First, a flexible rung ladder structured MLI (FRLSMLI) structure is newlineproposed with the dual mode capability (both symmetrical and asymmetrical newlinemodes), which paves the solution to the above mentioned problems. A tapped newlinesource stack succored modified HX bridge MLI (TSSSMHXBMLI) to trim the newlinetotal count of power components is proposed secondly. Finally, a matrix newlinestructure, involving switches in columns and SDCs in the row links, to wane newlinethe total component count is developed, by introducing the cross switching in newlinethe structure to curtail the number of switching devices in the current newlineconduction path in all output voltage levels. newline