Abstract: Voltage boosting is very essential issue in renewable-energy fed applications. The classical two-stage power conversion process is typically used to interface the renewable energy sources to the grid. For better efficiency, singlestage inverters are recommended In this paper we make MATLAB-Simulink models of the three types of multilevel inverters: Cascaded type, Diode clamped and Capacitor clamped. A relative study of the carrier frequency modulation techniques is also presented on the basis of THD under various modulating indices. Graphs have been plotted based on these results.

Keywords:Pulse width modulation converters, Multilevel Inverters, Total Harmonic Distortio.