A Novel Cascaded H-Bridge Multilevel Converter with Reduced Number of Switches

A Novel Cascaded H-Bridge Multilevel Converter with Reduced Number of Switches
Authors:M.VIJAYA, M.REDDY PRASANNA, C.SUBBA RAMI REDDY

Abstract: In this paper mainly focused on the design and implementation of new topology in a single phase five level cascaded H-bridge multilevel inverter by using only a five switches and two DC power source. The main objective of this paper is to increase number of levels with a low number of switches and sources at the output without adding any complexity to the power circuit.. The optimal structures of this topology are investigated for various objectives, such as minimum number of switches and capacitors, and minimum standing voltage on switches for producing maximum output voltage steps. A new algorithm for determination of dc voltage sources’ magnitudes has also been presented. The proposed topology results in reduction of the number of switches, losses, installation area, and converter cost. The operation and performance of the proposed multilevel converter has been verified by the simulation and experimental results of a single-phase 53-level multilevel converter. 

Keywords: Bidirectional Switch, Full-Bridge Topology, Multilevel Converter, Sub Multilevel Converter. 

INTRODUCTION 

         The Concept of multilevel converters was introduced in 1975 [2]. The term multilevel began with the three level converters [3]. A multilevel converter is a power electronic system that synthesizes a desired output voltage from several levels of dc voltages as inputs. With an increasing number of dc voltage sources, the converter output voltage waveform approaches a nearly sinusoidal waveform while using a fundamental frequency-switching scheme. Compared with the traditional two-level voltage converter, the primary advantage of multilevel converters is their smaller output voltage step, which results in high power quality, lower harmonic components, better electromagnetic compatibility, and lower switching losses. Numerous industrial applications have begun to require high power apparatus in recent years. Power electronic inverter become popular for various industrial drives applications. Recently, multilevel power conversion technology has been developing the area of power electronics very rapidly with good potential for further developments. As a result the most attractive applications of this technology are in the medium to high voltage ranges. A multilevel converter not only achieves high power rating, but also enables the use of renewable energy sources. Renewable energy sources such as photovoltaic, wind, and fuel cells can be easily interfaced to a multilevel converter system for a high power application proposed topology has less switches than that of [2] in symmetric topology. The H-bridge topology was followed by the diode-clamped converter that utilized a bank of series capacitors.

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