Overview Of Multilevel Inverter, Types And Advantages

Inverter is a power electronic device that converts DC power into AC power at desired output voltage and frequency. Multilevel inverters nowadays have become an interesting area in the field of industrial applications. Conventional power electronic converters are able to produce an output voltage that switches between two voltage levels only. Multilevel Inverter generates a desired output voltage from several DC voltage levels at its input. The input side voltage levels are usually obtained from renewable energy sources, capacitor voltage sources, fuel cells etc.

ACRONYM AND MEANING

MLI – multilevel inverters

EMI- electromagnetic interference

NPC- neutral point clamped

FC – flying capacitor

CHB cascaded H-bridge

SDCSs – separate DC sources

SHE-PWM selective harmonic elimination PWM

SPWM – sinusoidal PWM

f sw – The switching frequency

IGBT – insulated gate bipolar transistors

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

1.0      INTRODUCTION

1.1      BACKGROUND OF THE STUDY

• AIM OF THE PROJECT
• OBJECTIVE OF THE PROJECT
• PURPOSE OF THE PROJECT

CHAPTER TWO

LITERATURE REVIEW

• OVERVIEW OF THE STUDY
• REVIEW OF INVERTERS CLASSIFICATION
• REVIEW OF MULTILEVEL INVERTER
• CONTROL STRATEGIES

CHAPTER THREE

METHODOLOGY

• SYSTEM BLOCK DIAGRAM
• WORKING PRINCIPLE OF A MULTILEVEL INVERTER
• TYPES OF MULTILEVEL INVERTERS AND ADVANTAGES

CHAPTER FOUR

• CONCEPT OF MULTILEVEL INVERTER
• FEATURES OF MULTILEVEL INVERTER
• THE NEED FOR MULTILEVEL CONVERTER
• GENERAL APPLICATIONS OF MULTILEVEL INVERTER
• GENERAL ADVANTAGES OF MULTILEVEL INVERTER

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION
• REFERENCES

CHAPTER ONE

1.0                                                        INTRODUCTION

Power Electronics is a branch of electronics that deals with conversion and control of Electric power is called power electronics. Many of our appliances are designed to work with AC, but a power generator normally generates DC. So, if we want to run something like an AC-powered gadget from a DC car battery in a mobile home, we need a device that will convert DC to AC. Here comes the concept of Inverters.

Inverters converts DC voltage to AC voltage. Output voltage should ideally be sinusoidal wave of variable magnitude and variable frequency. An inverter does the opposite job of Rectifier. Electronic inverters can be used to produce smoothly varying AC output from a DC input. Inverters are made up of capacitors and inductors which make the output current smooth as compared to switching square wave output you get with a basic inverter.

A multilevel inverter is a power electronic device which is capable of providing desired alternating voltage level at the output using multiple lower level DC voltages as an input. Mostly a two-level inverter is used in order to generate the AC voltage from DC voltage.

Multilevel inverters are the preferred choice of industry for the application in high voltage and for high power application. Multilevel inverter technology has emerged recently as a very important alternative in the area of high-power medium-voltage energy control. This work presents the concept behind multi-level inverters, their types, pros and cons and the area of their practical applications.

1.1                                              BACKGROUND OF THE STUDY

The Inverter is an electrical device which converts direct current (DC) to alternate current (AC). The inverter is used for emergency backup power in a home. The inverter is used in some aircraft systems to convert a portion of the aircraft DC power to AC. The AC power is used mainly for electrical devices like lights, radar, radio, motor, and other devices.

Now a day’s many industrial applications have begun to require high power. Some appliances in the industries however require medium or low power for their operation. Using a high power source for all industrial loads may prove beneficial to some motors requiring high power, while it may damage the other loads. Some medium voltage motor drives and utility applications require medium voltage. The multi level inverter has been introduced since 1975 as alternative in high power and medium voltage situations. The Multi level inverter is like an inverter and it is used for industrial applications as alternative in high power and medium voltage situations.

1.2                                                        AIM OF THE STUDY

The main aim of a multilevel inverter is to provide sinusoidal waveforms with low-level harmonic content to reduce distortion in a grid and maximize power efficiency.

• OBJECTIVE OF THE STUDY

1. To discuss about the diode-clamped multilevel converter, types and advantages.
2. To learn more about power electronics
3. To discuss about low cost converters suitable for high power applications

1.4                                                 PURPOSE OF THE PROJECT

A multilevel inverter is a power electronic device which is capable of providing desired alternating voltage level at the output using multiple lower level DC voltages as an input. Mostly a two-level inverter is used in order to generate the AC voltage from DC voltage.