Investigation of pwm techniques for Multilevel inverters

Abstract

Multilevel inverters MLI have drawn immense interest in power newlineindustry as they provide a cost effective solution for medium voltage high newlineand low power applications High power applications include motor drives newlineelectric traction High Voltage DC HVDC transmission Unified Power newlineFlow Controller UPFC Flexible AC Transmission Systems FACTS and newlinestatic compensators Few low power applications include photo voltaic newlinesystems active power filters voltage sag compensation and hybrid electric newlinevehicles The lower voltage stress produced on power switches reduced newlineharmonic content in output voltage and current lower dv/dt and hence newlinenegligible electromagnetic interference mark the distinct features of MLI The newlinepractical difficulties encountered in cascaded Multilevel VSI and CSMLI newlinesuch as requirement of separate DC sources and its fluctuation DC source newlinefailure and the resulting common mode effects are discussed This justifies the newlinerequirement of a generalised control to mitigate the effects of the above said newlineissues and it forms the core objective of the proposed work. newline newline