Performance Enhancement of Reduced Component Multilevel Inverter with Optimal Placement of Level Shifter

Abstract

Multi-Level Inverter (MLI) structures with and without cross-connecting switches are constructed using bidirectional and uni-directional switches and their performances are verified via real-time experimentation. Initially a cross connecting switch inverter (CCSI) is constructed and then modified multilevel inverter (MMLI) is derived from it by removing the cross connecting switches. Two basic units are used in constructing the above converters. Further, the CCSI and MMLI configurations are studied with the identification of optimal placement of the level shifter circuit in the basic unit. In order to enhance the performance of the inverter, different types of procedures for the design of voltage sources are proposed. With the best method of defining the value of voltage sources among the proposed nine different algorithms and with optimal placement of level shifter in the MLI circuit, a 31-level CCSI, a 49 level and 71 level MMLI are designed and tested experimentally. Efficiency, total blocking voltage, harmonic presence, real and reactive powers are obtained for the proposed converters to study their performance. Finally, a comparative analysis is made for the proposed structure against the other MLIs in-terms of switch count, 'ON' state switches, voltage sources and efficiency. Link to graphical and video abstracts, and to code: https://latamt.ieeer9.org/index.php/transactions/article/view/8526