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Electrical & Computer Engineering: An International Journal (ECIJ) Volume4. Number 3. September 2015

COMPREHENSIVE ANALYSIS AND SlMULATION OF Multilevel Power Converters To Curtail Total Harmonio Distortion

PriyaTyagi¹ and Rakeshwri Agrawal²

'Department of Electrical and Electronics Engineering,

Trinity Institute of Technology & Research. Bhopal. India "Assistant Professorat department of Electrical and Electronics Engineering. Trinity Institute of Technology & Research. Bhopal. India

Abstract

Presem day industrial applicalions reąuire higher fmwer apparatus for /wwer conversxon. At medium voltage grid. to connect onty one power semiconduetor switch directly is a not practically successfid concept. To overeome this multilevel power converter struciure has been intmduced and studied as an alternati\e in high [>ower and medium voltage applicalions. Renewable energy sources like photovoltaic. wind. fuel cells can be conveniently interfaced to a multilevel converter system for high power applicalions. In this study it is discussed in detail for different levels of the multilevel converters using pulse width modulation technique (PWM) the harmonics contents decreases gradually. The simulated results are presented and com/tared thereafter. Total harmonie distortion decreases as the number of levels inereased are tabulatedaccordingly. Ali the simulation results are carriedout under MATLAB/Simulink environment.

Keywords

Multile\el converter. Neutral Point Clam[>ed. Cascade H Bridge. PWM

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INTRODUCTION

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The concept of multilevel convcrtcrs has bccn inlroduccd sinec 1975. The term mullilevel slarled with the lhree-level converler which was Ihe first basie upgrade from the conventional Iwo level eonvcrlcrs. Subscqucnlly, numerous mullilevel convcrtcr lopologies have been developed sińce then. However. the elemenlary concept of a mullilcvcl convertcr to achieve higher power uses serics of power semiconduetor swilches with ihe scvcral lowcr vollage DC sources to perform power conversion by synlhesizing a siaircase vollage waveform. Renewable energy vollage sources, Capacitors, balleries can be uscd as mulliple DC vollage sources. The commulalion of Ihe power swilches aggregales these mulliple DC sources in order lo achieve high voltage al the oulpul. However. Ihe raled vollage of Ihe power semiconduclor swilches depends only upon Ihe raling of Ihe DC voltage sources lo which Ihey are connected 11-51. The numerous advanlages of mullilevel convcrter over conventional iwo levels can be summarised as siaircase waveform qualily generaled by mullilevel converter itself provcs lo be a new achievemenl in Ihe field of converlcrs [2|. The mullilevel convcrtcrs are gradually being used in induslrial applicalions in DOI : 10.14810/ecij.2015.4302    15