A DER Based Single - Phase Asymmetrical 27 Level Inverter Topology

This paper deals single phase 27-level multilevel inverter topology for DER’s-based DC/AC conversion system. This work mainly focuses on cascaded MLI using three unequal dc sources in order to produce twenty seven-level output. In this study, a high step-up converter is introduced as a front-end stage to improve the conversion efficiency of conventional boost converters and to stabilize the output dc voltage of DERs such as photovoltaic modules for use with the simplified MLI. A conventional 27-level cascade multilevel inverter requires a combination of 13 H-bridge (single-phase full-bridge) inverter modules but the present topology, 27 level multilevel inverter is obtained by using only 3 H-bridge inverter modules with different dc voltage sources This MLI offers strong advances such as improved output waveforms, smaller filter size, low THD, reduced volume and cost, and lower electromagnetic interference. The need of several sources on the DC side of the converter makes multilevel technology attractive for many photovoltaic applications. This paper provides an overview of DER based 27-level multilevel inverter topology and investigates their suitability for single-phase. A simulation model based on MATLAB/SIMULINK(version 7.12) is developed.