SOFT SWITCHING OF 5 LEVEL INVERTER

Outer Ring Road, Bellandur, Bengaluru – 560103

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

EEE84 Project - Phase II

Report on

SOFT SWITCHING OF 5 LEVEL INVERTER

Submitted in the partial fulfilment of the Final Year Project - Phase II

Submitted by

HARSHA T 1NH15EE024

SHARATH M 1NH15EE051

SUHAS N J 1NH15EE056

SWAROOP H J 1NH15EE060

2018-19

VISVESVARAYA TECHNOLOGICAL UNIVERSITY

“JnanaSangama”, Belgaum: 590018

Outer Ring Road, Bellandur, Bengaluru - 560103

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

CERTIFICATE

Certified that the Project work entitled “SOFT SWITCHING OF 5 LEVEL

INVERTER” carried out by HARSHA T (1NH15EE024), SHARATH M

(1NH15EE051), SUHAS N J (1NH15EE056), SWAROOP H J (1NH15EE060)

bonafide Student(s) of New Horizon College of Engineering submitted report in

the partial fulfilment for the award of Bachelor of Engineering in Department of

Electrical and Electronics Engineering, New Horizon College of Engineering

of Visvesvaraya Technological University, Belgaum during the Year 2018-19.

It is certified that all the corrections / suggestions indicated for Internal

Assessment have been incorporated in the report deposited in the department

library. The project report has been approved as it satisfies the academic

requirements in respect of project work prescribed for said Degree.

SEMESTER END EXAMINATION

Internal Examiner External Examiner

Name & Signature of the Project Guide

Name & Signature of Head of the Department

Signature of Principal

Prof. S Inbasakaran Dr.S.RAMKUMAR Dr.MANJUNATHA

DECLARATION

We HARSHA T, SHARATH M, SUHAS N J, SWAROOP H J students of New Horizon College of Engineering hereby declare that, this project work entitled “SOFT SWITCHING OF 5 LEVEL INVERTER” is an original and bonafide work carried out by me at New Horizon College of Engineering in partial fulfillment of Bachelor of Engineering in Electrical and Electronics Engineering of Visvesvaraya Technological University, Belgaum. I also declare that, to the best of my knowledge and belief, the work reported here in does not form part of any other thesis or dissertation on the basis of which a degree or award was conferred on an earlier occasion by any student.

Harsha T

1NH15EE024

Sharath M

1NH15EE051

Suhas N J

1NH15EE056

Swaroop H J

1NH15EE060

ACKNOWLEDGEMENT

The satisfaction and euphoria that accompany the successful completion of any task would be incomplete without the mention of the people who made it possible and whose constant encouragement and guidance crowned our efforts with success. I am highly indebted to the Management and the Principal of New Horizon College of Engineering for the facilities provided to accomplish this project. I would like to thank the Head of the Department Dr. S. Ramkumar for his constructive appreciation throughout my project. I would like to thank faculty supervisor Prof. S Inbasakaran for the support and advices to get and complete project. I am extremely grateful to my department staff members and friends who helped me in successful completion of this project. Last but not the least I would like to thank all my friends without whose support and co-operation the completion of project would not have been possible.

STUDENT NAME– Harsha T

USN – 1NH15EE024

STUDENT NAME– Sharath M USN – 1NH15EE051

STUDENT NAME– Suhas N J USN – 1NH15EE056

STUDENT NAME– Swaroop H J USN – 1NH15EE060

ABSTRACT

An inverter is utilized to transform a direct current (DC) source into an alternating current

(AC) source using electronic component like switch. While converting DC to AC, it is

conceivable to acquire the preferred output voltage and frequency by two types of

inverters, one is two level and another one is multi-level inverter (MLI).

The multilevel inverter has been implemented in various applications, such as motor

drives, power conditioning devices, renewable energy generation and distribution. PWM

inverters can simultaneously control output voltage, frequency and it can reduce the

amount of harmonics in output current which results in better THD content.

Cascaded H-Bridge type of Multi-level inverter is more efficient compare to the other

topologies of Multi-level inverter. Minimum total harmonic distortion, reduced EMI are

the advantages of MLI, and it can be operated on different voltage levels. Here MOSFETs

are used as switches. In this Paper, Simulation and hardware implementation of single

phase 5- level cascaded Multi-level inverter with separate DC sources are presented.

A microcontroller design was chosen to implement a 5-level pulse-width modulation

technique for greater efficiency. Standard high voltage components were chosen for

MOSFET drivers. Several multilevel topologies have been developed, but as the output

voltage levels increases, it also increases the number of switches, number of independent

dc sources, switching stresses, losses, voltage unbalancing across capacitors etc.

SOFT SWITCHINING OF 5 LEVEL INVERTER 2018-19

Department of Electrical and Electronics Engineering, NHCE, Bangalore Page 1

Contents CHAPTER 1 .............................................................................................................................................. 3

INTRODUCTION .................................................................................................................................. 4

1.1 OVERVIEW .................................................................................................................................... 4

1.1.1 DIODE CLAMPED INVETRER ................................................................................................... 4

1.1.2 FLYING CAPACITOR INVETER ................................................................................................. 5

1.1.3 CASCADED H-BRIDGE INVERTER ............................................................................................ 6

CHAPTER 2 .............................................................................................................................................. 7

LITERATURE SURVEY .......................................................................................................................... 7

2.1 Recent Advances and Industrial Applications of Multilevel Converters ...................................... 9

CHAPTER 3 ............................................................................................................................................ 12

BLOCK DIAGRAM ............................................................................................................................. 12

CHAPTER 4 ............................................................................................................................................ 13

METHODOLOGY ............................................................................................................................... 13

4.1 Soft switching of DC-AC inverter ................................................................................................ 13

4.2 Full bridge voltage source inverter ............................................................................................. 14

4.3 Usage of Cascaded H-Bridge ....................................................................................................... 15

CHAPTER 5 ............................................................................................................................................ 16

HARDWARE REQUIREMENT ............................................................................................................ 16

CHAPTER 6 ............................................................................................................................................ 17

SOFTWARE USED.............................................................................................................................. 17

CHAPTER 7 ............................................................................................................................................ 19

CIRCUIT DIAGRAM ........................................................................................................................... 19

7.1 CASCADED H-BRIDGE .................................................................................................................. 19

7.2 ISOLATION CIRCUIT OR DRIVER CIRCUIT .................................................................................... 20

CHAPTER 8 ............................................................................................................................................ 21

SIMULATION .................................................................................................................................... 21

8.1 MODE OF OPERATION AND BLOCKS USED ................................................................................. 22

8.1.1 REPEATING SEQUENCE BLOCK ............................................................................................ 22

8.1.2 NOT GATE ............................................................................................................................ 23

8.1.3 MOSFET ............................................................................................................................... 23



CHAPTER 9 ............................................................................................................................................ 24

SIMULATION RESULT ....................................................................................................................... 24

CHAPTER 10 .......................................................................................................................................... 25

HARDWARE ...................................................................................................................................... 25

10.1 Step down transformer ............................................................................................................ 25

10.2 Power MOSFET IRFZ44 ............................................................................................................. 26

10.2.1 IRFZ44 Features ................................................................................................................. 26

10.2.2 Ratings of IRFZ44 MOSFET ................................................................................................. 27

10.3 ARDUINO UNO .......................................................................................................................... 27

10.3.1 SPECIFICATIONS ................................................................................................................. 28

10.4 Bridge rectifier .......................................................................................................................... 33

10.4.1 Controlled bridge rectifier ................................................................................................. 33

10.4.2 Bridge Rectifier Operation ................................................................................................. 34

10.5 Filter capacitor .......................................................................................................................... 34

10.6 Isolation circuit or Driver circuit ............................................................................................... 35

10.6.1 LED ..................................................................................................................................... 35

10.6.2 Opto isolator TLP250 ......................................................................................................... 36

10.6.3 Diode FR107....................................................................................................................... 37

10.6.4 Zener diode ........................................................................................................................ 38

10.6.5 Transistors ......................................................................................................................... 38

10.6.6 RESISTOR ........................................................................................................................... 39

10.7 PICTURE OF HARDWARE........................................................................................................... 40

10.8 OUTPUT .................................................................................................................................... 41

CHAPTER 11 .......................................................................................................................................... 42

WORKING ......................................................................................................................................... 42

CHAPTER 12 .......................................................................................................................................... 43

CONCLUSION .................................................................................................................................... 43

CHAPTER 13 .......................................................................................................................................... 44

REFERENCES ..................................................................................................................................... 44



LIST OF FIGURES

1. Fig. 3 Block Diagram

2. Fig. 4.2 full bridge voltage source inverter

3. Fig. 7.1 Cascaded H-bridge inverter

4. Fig. 7.2 Isolation circuit or Driver circuit

5. Fig. 8 Cascaded H-bridge model for simulation

6. Fig. 9 Simulation output

7. Fig. 10.1 Step down transformer

8. Fig. 10.2.1 MOSFET pin diagram

9. Fig. 10.3.1 pin diagram of microcontroller

10. Fig. 10.4.1 Controlled bridge rectifier

11. Fig. 10.6.1 LED

12. Fig. 10.6.2 TLP250

13. Fig. 10.6.3 symbol of diode

14. Fig. 10.6.4 symbol of Zener diode

15. Fig. 10.6.5.1 2N2222 transistor

16. Fig. 10.6.5.2 CK100 transistor

17. Fig 10.6.6 resistor

18. Fig. 10.7 Picture of hardware

19. Fig. 10.8 Output as seen in CRO

APPENDIX

1. Microcontroller Program



CHAPTER 1

INTRODUCTION

This chapter will focus on the brief of the project to be carried out. The important overview

or description including the problem statement, project objectives, and project scopes are

well emphasized in this part.

1.1 OVERVIEW

Inverter is a key system element that is used for power conditioning. Almost any solar systems

of any scale include inverter of some type to allow the power to be used on site for AC-

powered appliances or on grid. The available inverter models are now very efficient (over

95% power conversion efficiency), reliable, and economical. On the utility scale, the main

challenges are related to system configuration in order to achieve safe operation and to

reduce conversion losses to a minimum.

The inverter topologies are classified into three categories up to now: Diode Clamped

inverters, Flying Capacitor inverters, and Cascaded H Bridge inverters. The first topology

introduced was the series H-bridge design.

1.1.1 DIODE CLAMPED INVETRER

This topology was first proposed in 1981. They are also known as neutral point inverters. In

1992 a lot of research work was published on Diode Clamped Multilevel Inverters. They have

their fair share of advantages and disadvantages tied to them but then again, our firm faith

in scientists and researchers has kept us calmly waiting for the better version of what we see

today.



Features

• As the name suggests, and unlike Cascaded H-Bridge Inverters, they need clamping

devices.

• Diodes are used as clamping devices.

• Three phase diode clamped multilevel inverters have three legs with a common DC

bus.

• This DC voltage is subdivided into switches via capacitors.

• For n-levels, n-1 switch pairs are required.

• One of the switches from each pair should be turned on.

• If one switch is turned on, the other one from the pair should be necessarily off.

• For n-levels, n-1 capacitors are required for clamping DC voltage.

• Switching devices (e.g. transistors) need to block only the supplied DC voltage;

however the clamping diodes have a whole different story.

• Each diode has to block the voltage equal to number of switches above it times the

supplied DC voltage.

1.1.2 FLYING CAPACITOR INVETER

Flying capacitor multilevel inverters are increasingly used in industrial applications because it

is easier to be extended to multilevel inverter than diode clamped inverter [1][2][3]. For flying

capacitor multilevel inverters, the most common PWM method is the phase-shifted carrier

PWM (PSPWM), which can keep the capacitor voltage being balanced by applying the same

time of the charging and the discharging switch states [4]. But the harmonic performance of

output voltage with PSPWM is poor, especially under low modulation index region. For many

of these applications, flying capacitor multilevel inverters will operate in the low amplitude

modulation index region, such as static var compensation, motor drives, and active power

filters.



Many large variable speed drives operate the majority of the time at just a fraction of their

rated loads. Static var generators and active filters may also operate for long durations well

below their rated capabilities, such as at night when the production has stopped at a

commercial or industrial facility [5].

The multilevel inverters that are the backbone of these products have to be sized for the

largest rated loads that will be demanded of them; however, they also should be optimized

to operate proficiently over most of their operating regions including at low amplitude

modulation index.

1.1.3 CASCADED H-BRIDGE INVERTER

There are so many types of H-Bridge inverter like two level, three level and five level etc.

Comparing with the two or three level inverter multilevel inverter has the more harmonics

reduction capability. Here five level inverter has discussed and its results. Five level inverter

has made up of D.C. source, 8 power electronic devices (ideal switches), star connected

resistive load, (with 180 deg. conduction mode).

Therefore, the multilevel inverters also have lower dv/dt ratios to prevent induction or

discharge failures on the loads. Sinusoidal Pulse Width Modulation (SPWM) technique is used

to generate the gate pulses. SPWM technique is widely used in industries. In five level power

electronic converters, the desired output can be synthesized by combining several DC

sources. These converters are having single phase and three phase applications.



CHAPTER 2

LITERATURE SURVEY

Power Electronics is the art of converting electrical energy from one form to another in an

efficient, clean, compact, and robust manner for convenient utilization. For getting controlled

A.C output an inverter to be used. Inverter is converting uncontrolled D.C. in to controlled

A.C. It has found an important place in modern technology being core of power and energy

control[1].

A multilevel inverter is a power electronics converter is recently applicable for high voltage

and high power application such as flexible AC transmission system and AC motor drives. Also,

power electronics technologies have provided an important improvement in the renewable

energy application.

Numerous industrial applications have begun to require higher power apparatus in recent

years. Some medium voltage motor drives and utility applications require medium voltage

and megawatt power level. For a medium voltage grid, it is troublesome to connect only one

power semiconductor switch directly. As a result, a multilevel power converter structure has

been introduced as an alternative in high power and medium voltage situations. A multilevel

converter not only achieves high power ratings, 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[1].

The aim of this project is to group and review these recent contributions, in order to establish

the current state of the art and trends of the technology, to provide readers with a

comprehensive and insightful review of where multilevel converter technology stands and is

heading.



The term multilevel began with the three-level converter. Subsequently, several multilevel

converter topologies have been developed. However, the elementary concept of a multilevel

converter to achieve higher power is to use a series of power semiconductor switches with

several lower voltage dc sources to perform the power conversion by synthesizing a staircase

voltage waveform[2].

Multilevel inverters have been attracting industry in the recent decade for high - power and

medium - voltage energy control. In addition, they can synthesize switched waveforms with

lower levels of harmonic distortion than an equivalently rated two - level converter. The

multilevel concept is used to decrease the harmonic distortion in the output waveform

without decreasing the inverter power output[2].

This paper presents the model of H-Bridge for different levels and analysis of the THD with

the resistive load with hardware waveform results. The THD of five-level MLI can be reduced

up to 16.91% by using the various control strategies which is introduced in this paper[2].

Large electrical drives and utility application require advanced power electronics converter

to meet the high power demands. As a result, multilevel power converter structure has been

introduced as an alternative in high power and medium voltage situations.

A multilevel converter not only achieves high power rating but also improves the

performance of the whole system in terms of harmonics. The proposed inverter can output

more numbers of voltage levels with reduced number of switches as compared to cascade H-

bridge inverter, which results in reduction of installation cost and have simplicity of control

system.

Multilevel converters have been under research and development for more than three

decades and have found successful industrial application. However, this is still a technology

under development, and many new contributions and new commercial topologies have been

reported in the last few years.



2.1 Recent Advances and Industrial Applications of Multilevel Converters

Research try to enhance the efficiency and quality of the output power of multilevel inverters

by use of new topologies or enhanced switching algorithms. But it should be noted that, it is

not easy to change the inverter switching algorithm and doing this will increases the costs.

Also, these algorithms are not usually extensible to all inverter types[1].

Now, with the use of genetic algorithm which is one of the strongest optimization tools, the

voltage THD is minimized and the optimized switching angles are obtained. The method used

in this paper is simpler than the switching algorithm changing method and can be generalized

to different types of multilevel inverters. Also the use of fundamental switching frequency,

will reduce switching losses. The simulation results obtained by MATLAB/SIMULINK software,

confirm the performance accuracy of the proposed method[4].

In this project many topologies and control techniques have been reviewed, which helps the

researchers to use proper techniques to control multilevel converters for renewable energy

sources grid integration.

Also, the use of fundamental switching frequency, will reduce switching losses. The

simulation results obtained by MATLAB/SIMULINK software, confirm the performance

accuracy of the proposed method. Large electrical drives and utility application require

advanced power electronics converter to meet the high power demands. As a result,

multilevel power converter structure has been introduced as an alternative in high power and

medium voltage situations. A multilevel converter not only achieves high power rating but

also improves the performance of the whole system in terms of harmonics[3].

These designs can create higher power quality for a given number of semiconductor devices

than the fundamental topologies alone due to a multiplying effect of the number of levels.



Recent advances in power electronics have made the multilevel concept practical. In fact, the

concept is so advantageous that several major drives manufacturers have obtained recent

patents on multilevel power converters and associated switching techniques.

The cascaded H-Bridge multilevel inverter are the most advanced and important method of

power electronic converters that analyses output voltage with number of dc sources as

inputs. As compared to neutral point clamped multilevel inverter and flying capacitor

multilevel inverter, the cascaded H-Bridge multilevel inverters requires less number of

components and it reaches high quality output voltage which is close to sinewave[4].

By increasing the number of output levels the total harmonic distortion in output voltage can

be reduced. In cascaded H-Bridge multilevel inverter required AC output voltage is obtain by

synthesizing number of DC sources. The number of H-Bridge units with different DC sources

is connected in series or cascade to produce cascaded H-Bridge multilevel inverter.

In recent year’s cascaded configuration have become popular in speed drive applications and

high power AC supplies. In case of cascaded configuration, each of the H-bridge (single phase

full bridge) inverter consists of separate DC source. Cascaded configuration is formed by

cascading the series H-bridges. The general configuration of single phase cascaded H-bridge

inverter with separate DC sources for each H-bridge (single phase full bridge)[3].

Demand for high power converters along with high voltage, which are capable of producing

quality waveforms that utilizes low voltage devices with reduced switching frequency has led

to the development of multilevel inverters. Multilevel inverters include an array of voltage

source, capacitors and power semiconductors, the generated output voltage is a stepped

waveform[5].

In addition, many multilevel converter applications focus on industrial medium-voltage motor

drives, utility interface for renewable energy systems, Universal Power Conditioner and

traction drive systems.



Finally, some future trends and challenges in the further development of this technology are

discussed to motivate future contributions that address open problems and explore new

possibilities.



CHAPTER 3

BLOCK DIAGRAM

Fig. 3 Block diagram

The block diagram in this figure shows the steps that we need to generate the output signal.

A 230 V AC supply is taken and voltage is step down to 12V AC using a step down transformer.

A rectifier is used to convert the 12 AC to 12 DC and it acts as a DC source to the MOSFET

Bridge. The signal is generated within the microcontroller. Then, it is input to the MOSFET

drivers to provide a safety catch as well as the ability to keep the MOSFETS active when they

are high. Finally, it passes into the MOSFETS of the H-bridge and draws power from the high

voltage supply through the filter to generate the appropriate output signal.

Load

Micro

controller

Step down

transformer

Rectifier

Driver

Circuit

5 Level

Inverter

DC Source

230V AC



CHAPTER 4

METHODOLOGY

This system presents Soft switching of 5 level inverter using MOSFET as switches. This system

describes the design and simulation of 5 level inverter using Arduino UNO controller.

Producing the quasi square wave from the topology used the same can be used for loads for

different application. According to program the isolation circuit is managed and through the

switching sequence MOSFET are triggered and output voltage is produced.

4.1 Soft switching of DC-AC inverter

Soft-switching technique not only offers a reduction in switching loss and thermal

requirement, but also allows the possibility of high frequency and snubberless operation.

Improved circuit performance and efficiency, and reduction of EMI emission can be achieved.

For zero-voltage switching (ZVS) inverter applications, two major approaches which enable

inverters to be soft-switched have been proposed.

The first approach pulls the dc link voltage to zero momentarily so that the inverter’s switches

can be turned on and off with ZVS. Resonant dc link and quasi-resonant inverters belong to

this category. The second approach uses the resonant pole idea. By incorporating the filter

components into the inverter operation, resonance condition and thus zero voltage/current

conditions can be created for the inverter switches.

For a resonant dc link inverter with low voltage stress . It consists of a front-end resonant

converter that can pull the dc link voltage down just before any inverter switching. This

resonant dc circuit serves as an interface between the dc power supply and the inverter. It

essentially retains all the advantages of the resonant (pulsating) dc link inverters. But it offers

extra advantages such as



• No increase in the dc link voltage when compared with conventional hard-switched

inverter. That is, the dc link voltage is 1.0 per unit.

• The zero voltage condition can be created at any time. The ZVS is not restricted to the

periodic zero-voltage instants as in resonant dc link inverter.

• Well-established PWM techniques can be employed.

• Power devices of standard voltage ratings can be used.

4.2 Full bridge voltage source inverter

This inverter is similar to the half-bridge inverter; however, a second leg provides the neutral

point to the load. As expected, both switches S1+ and S1− (or S2+ and S2−) cannot be on

simultaneously because a short circuit across the dc link voltage source vi would be produced.

There are four defined (states 1, 2, 3, and 4) and one undefined (state 5) switch state.

Fig. 4.2 Full bridge voltage source inverter

The undefined condition should be avoided so as to be always capable of defining the ac

output voltage always. In order to avoid the short circuit across the dc bus and the undefined

ac output voltage condition, the modulating technique should ensure that either the top or

the bottom switch of each leg is on at any instant. It can be observed that the ac output

voltage can take values up to the dc link value which is twice that obtained with half-bridge

VSI topologies. Several modulating techniques have been developed that are applicable to

full-bridge VSIs. Among them are the PWM (bipolar and unipolar) techniques.



4.3 Usage of Cascaded H-Bridge

The cascaded H-Bridge multilevel inverter are the most advanced and important method of

power electronic converters that analyses output voltage with number of dc sources as

inputs. As compared to neutral point clamped multilevel inverter and flying capacitor

multilevel inverter, the cascaded H-Bridge multilevel inverters requires less number of

components and it reaches high quality output voltage which is close to sinewave. By

increasing the number of output levels the total harmonic distortion in output voltage can be

reduced. In cascaded H-Bridge multilevel inverter required AC output voltage is obtain by

synthesizing number of DC sources. The number of H-Bridge units with different DC sources

is connected in series or cascade to produce cascaded H-Bridge multilevel inverter.

Conventional cascaded multilevel inverters are one of the most important topologies in the

family of multilevel and multi-pulse inverters. The cascade topology allows the use of several

levels of DC voltages to synthesize a desired AC voltage. The DC levels are considered to be

identical since all of them are fuel cells or photovoltaics, batteries, etc. It requires least

number of components compared to diode-clamped and flying capacitors type multilevel

inverters and no specially designed transformer is needed as compared to multi pulse

inverter. Since this topology consist of series power conversion cells, the voltage and power

level may be easily scaled.

The concept of this inverter is based on connecting H-bridge inverters in series to get a

sinusoidal voltage output. The output voltage is the sum of the voltage that is generated by

each cell. It also uses a combination of fundamental frequency switching for some of the

levels and PWM switching for part of the levels to achieve the output voltage waveform. This

approach enables a wider diversity of output voltage magnitudes; however, it also results in

unequal voltage and current ratings for each of the levels and loses the advantage of being

able to use identical, modular units for each level.



CHAPTER 5

HARDWARE REQUIREMENT

• Microcontroller

Arduino UNO SMD R3 based on ATmega328

• Diodes

FR 107

15V Zener diode

• Resistors

500K, 1k, 100K, 220K

• Transformer

Step down transformer 230V to 12V

• Capacitor

0.1uf

Filter capacitor

• Opto isolator

TLP250

• MOSFET

IRFZ44

• Bridge rectifier



CHAPTER 6

SOFTWARE USED

MATLAB SIMULINK

Simulink, developed by Math Works, is a graphical programming environment for modeling,

simulating and analyzing multi-domain dynamical systems. Its primary interface is a graphical

block diagramming tool and a customizable set of block libraries. It offers tight integration

with the rest of the MATLAB environment and can either drive MATLAB or be scripted from

it. Simulink is widely used in automatic control and digital signal processing for multidomain

simulation and model-based design.

Math Works and other third-party hardware and software products can be used with

Simulink. For example, State flow extends Simulink with a design environment for

developing state machines and flow charts.

Math Works claims that, coupled with another of their products, Simulink can automatically

generate C source code for real-time implementation of systems. As the efficiency and

flexibility of the code improves, this is becoming more widely adopted for production

systems, in addition to being a tool for embedded system design work because of its flexibility

and capacity for quick iteration. Embedded Coder creates code efficient enough for use in

embedded systems.

Simulink Real-Time (formerly known as xPC Target), together with x86-based real-time

systems, is an environment for simulating and testing Simulink and State flow models in real-

time on the physical system. Another Math Works product also supports specific embedded

targets. When used with other generic products, Simulink and State flow can automatically

generate synthesizable VHDL and Verilog.

https://en.wikipedia.org/wiki/Dynamical_systems

https://en.wikipedia.org/wiki/Visual_modeling

https://en.wikipedia.org/wiki/Visual_modeling

https://en.wikipedia.org/wiki/Library_(computer_science)

https://en.wikipedia.org/wiki/MATLAB

https://en.wikipedia.org/wiki/Automatic_control

https://en.wikipedia.org/wiki/Digital_signal_processing

https://en.wikipedia.org/wiki/Model-based_design

https://en.wikipedia.org/wiki/Stateflow

https://en.wikipedia.org/wiki/State_machines

https://en.wikipedia.org/wiki/Flowchart

https://en.wikipedia.org/wiki/MathWorks

https://en.wikipedia.org/wiki/Automatic_code_generation

https://en.wikipedia.org/wiki/Automatic_code_generation

https://en.wikipedia.org/wiki/C_(programming_language)

https://en.wikipedia.org/wiki/Source_code

https://en.wikipedia.org/wiki/Real-time_computing

https://en.wikipedia.org/wiki/Embedded_system

https://en.wikipedia.org/wiki/Stateflow

https://en.wikipedia.org/wiki/Logic_synthesis

https://en.wikipedia.org/wiki/VHDL

https://en.wikipedia.org/wiki/Verilog



Simulink Verification and Validation enables systematic verification and validation of models

through modeling style checking, requirements traceability and model coverage analysis.

Simulink Design Verifier uses formal methods to identify design errors like integer

overflow, division by zero and dead logic, and generates test case scenarios for model

checking within the Simulink environment.

SimEvents is used to add a library of graphical building blocks for modeling queuing systems

to the Simulink environment, and to add an event-based simulation engine to the time-based

simulation engine in Simulink. Therefore in Simulink any type of simulation can be done and

the model can be simulated at any point in this environment. Different type of blocks can be

accessed using the Simulink library browser. And therefore, the benefit could be taken out

from this environment efficiently.

https://en.wikipedia.org/wiki/Requirements_traceability

https://en.wikipedia.org/wiki/Formal_methods

https://en.wikipedia.org/wiki/Integer_overflow

https://en.wikipedia.org/wiki/Integer_overflow

https://en.wikipedia.org/wiki/Division_by_zero

https://en.wikipedia.org/wiki/Model_checking

https://en.wikipedia.org/wiki/Model_checking

https://en.wikipedia.org/wiki/SimEvents



CHAPTER 7

CIRCUIT DIAGRAM

7.1 CASCADED H-BRIDGE

Fig. 7.1 Cascaded H-Bridge inverter



7.2 ISOLATION CIRCUIT OR DRIVER CIRCUIT

Fig. 7.2 Isolation circuit or Driver circuit

The fundamental motivation behind driver circuit is to improve the switching voltage for the

MOSFET or any switching device. And also it gives the isolation between the power circuit

and the microcontroller circuit. In this project TLP250 opto-coupler is used, which isolates the

power circuit with the microcontroller circuit. Signal from microcontroller is given to the

driver circuit.



CHAPTER 8

SIMULATION

The Simulink model for 5 level H-bridge inverter is developed using MATLAB is as shown in

figure. The subsystem pulse generator consists of 8 pulse generators in order to generate the

gate pulses for each MOSFET’s. The delays and pulse widths in each pulse generator are

calculated according to the switching pulses.

Fig. 8 cascaded H-bridge model for simulation



8.1 MODE OF OPERATION AND BLOCKS USED

In MATLAB/SIMULINK the sine wave and repeating sequence are available directly and a NOT

gate is used in this to differentiate between switches.

In simulation for switches to get on and it is done on based on relational operator which

compares the pulse that are generated from sine wave and the repeating sequence.

The multilevel output voltage can be obtained by closing the appropriate switches mentioned

in the switching sequence. Example: by opening all the switches, we get zero output voltage

across the load. To get Vdc across the load, close the switches S1, S4, S7, S8.

Mode Switch 1 Switch 2 Switch 3 Switch 4 Switch 5 Switch 6 Switch 7 Switch 8

1 1 0 1 0 1 0 1 0

2 1 0 1 0 1 0 0 1

3 1 0 0 1 1 0 0 1

4 0 1 0 1 0 1 1 0

5 0 1 0 1 0 1 0 1

6 0 1 1 0 0 1 1 0

8.1.1 REPEATING SEQUENCE BLOCK

The Repeating Sequence block outputs a periodic scalar signal having a waveform that you

specify using the Time values and Output values parameters. The Time values parameter

specifies a vector of output times. The Output values parameter specifies a vector of signal

amplitudes at the corresponding output times. Together, the two parameters specify a

sampling of the output waveform at points measured from the beginning of the interval over

which the waveform repeats (the period of the signal).



8.1.2 NOT GATE

A simple 2-input logic NOT gate can be constructed using a RTL Resistor-transistor switches

as shown below with the input connected directly to the transistor base. The transistor must

be saturated “ON” for an inverted output “OFF” at Q.

8.1.3 MOSFET

The metal-oxide-semiconductor field-effect transistor , most commonly fabricated by

the controlled oxidation of silicon. It has an insulated gate; whose voltage determines the

conductivity of the device. This ability to change conductivity with the amount of applied

voltage can be used for amplifying or switching electronic signals.

The main advantage of a MOSFET is that it requires almost no input current to control the

load current, when compared with bipolar transistors. In an enhancement mode MOSFET,

voltage applied to the gate terminal increases the conductivity of the device. In depletion

mode transistors, voltage applied at the gate reduces the conductivity.

https://en.wikipedia.org/wiki/Thermal_oxidation

https://en.wikipedia.org/wiki/Silicon

https://en.wikipedia.org/wiki/Signal_(electrical_engineering)



CHAPTER 9

SIMULATION RESULT

To display the generated signals during simulation. The SCOPE block in MATLAB displays its

input with respect to simulation time.

Fig. 9. Simulation output as seen in simulink



CHAPTER 10

HARDWARE

10.1 Step down transformer

A Transformer is a static apparatus, with no moving parts, which transforms electrical power

from one circuit to another with changes in voltage and current and no change in frequency.

There are two types of transformers classified by their function: Step up Transformer and

Step down Transformer.

Fig.10.1 step down transformer

A Step up Transformer is a device which converts the low primary voltage to a high secondary

voltage i.e. it steps up the input voltage. A Step down Transformer on the other hand, steps

down the input voltage i.e. the secondary voltage is less than the primary voltage.

A Step down Transformer is a type of transformer, which converts a high voltage at the

primary side to a low voltage at the secondary side. in terms of the coil windings, the primary

winding of a Step down Transformer has more turns than the secondary winding.

In our project 230V single phase supply is step down to 12V for the cascaded H-bridge in

hardware. The following image shows a typical step down transformer.



10.2 Power MOSFET IRFZ44

The MOSFET (Metal Oxide Semiconductor Field Effect Transistor) transistor is a

semiconductor device which is widely used for switching and amplifying electronic signals in

the electronic devices. The MOSFET is a core of integrated circuit and it can be designed and

fabricated in a single chip because of these very small sizes.

The MOSFET is a four terminal device with source(S), gate (G), drain (D) and body (B)

terminals. The body of the MOSFET is frequently connected to the source terminal so making

it a three terminal device like field effect transistor. The MOSFET is very far the most common

transistor and can be used in both analog and digital circuits.

Power MOSFET is a type of MOSFET which is specially meant to handle high levels of power.

These exhibit high switching speed and can work much better in comparison with other

normal MOSFETs in the case of low voltage levels. However its operating principle is similar

to that of any other general MOSFET. Power MOSFETs which are most widely used are n-

channel Enhancement-mode or p-channel Enhancement-mode or n-channel Depletion-mode

in nature.

According to the IRFZ44 datasheet this is a third generation Power MOSFET that provide the

best combination of fast switching, ruggedized device design, low on-resistance and cost-

effectiveness. The TO-220AB package is universally preferred for commercial-industrial

applications at power dissipation levels to approximately 50 W. The low thermal resistance

and low package cost of the TO-220AB contribute to its wide acceptance throughout the

industry.

10.2.1 IRFZ44 Features

• Dynamic dV/dt Rating

• 175 °C Operating Temperature

https://www.electrical4u.com/mosfet-working-principle-of-p-channel-n-channel-mosfet/



• Fast Switching

• Ease of Paralleling

• Simple Drive Requirements

• Lower Leakage Current: 10µA (Max.) @ VDS = 60V

• Lower RDS(ON): 0.020Ω

• Lower Input Capacitance

• Improved Gate Charge

Fig. 10.2.1 MOSFET pin diagram

10.2.2 Ratings of IRFZ44 MOSFET

VDSS Drain to source voltage 60V

VGS Gate to source voltage ±20V

ID Continuous drain current at Tc=25⁰C 50A

and at Tc=100⁰C 35A

10.3 ARDUINO UNO

The Arduino Uno is a microcontroller board based on the ATmega328. It has 14 digital

input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz crystal

oscillator, a USB connection, a power jack, an ICSP header, and a reset button. It contains

everything needed to support the microcontroller; simply connect it to a computer with a

USB cable or power it with a AC-to-DC adapter or battery to get started.



10.3.1 SPECIFICATIONS

Microcontroller ATmega328P

Operating Voltage 5V

Input voltage (recommended) 7 – 12 V

Input voltage (limit) 6 – 20 V

Digital I/O Pins 14

PWM Digital I/O Pins 6

Analog input Pins 6

DC current per I/O Pin 20mA

DC current for 3.3V pin 50mA

Flash memory 32KB

SRAM 2 KB

EEPROM 1 KB

Features

• High performance, low power AVR 8-bit microcontroller

• Advanced RISC architecture

• 131 powerful instructions – most single clock cycle execution

• 32 8 general purpose working registers

• Fully static operation

• Up to 16MIPS throughput at 16MHz

• On-chip 2-cycle multiplier

• High endurance non-volatile memory segments

• 32K bytes of in-system self-programmable flash program memory

• 1Kbytes EEPROM

• 2Kbytes internal SRAM

• Write/erase cycles: 10,000 flash/100,000 EEPROM



• Optional boot code section with independent lock bits

• In-system programming by on-chip boot program

• True read-while-write operation

• Programming lock for software security

• Peripheral features

• Two 8-bit Timer/Counters with separate prescaler and compare mode

• One 16-bit Timer/Counter with separate prescaler, compare mode, and

capture mode

• Real time counter with separate oscillator

• Six PWM channels

• 8-channel 10-bit ADC in TQFP and QFN/MLF package

• Temperature measurement

• Programmable serial USART

• Master/slave SPI serial interface

• Byte-oriented 2-wire serial interface (Phillips I2 C compatible)

• Programmable watchdog timer with separate on-chip oscillator

• On-chip analog comparator

• Interrupt and wake-up on pin change

• Special microcontroller features

• Power-on reset and programmable brown-out detection

• Internal calibrated oscillator

• External and internal interrupt sources

• Six sleep modes: Idle, ADC noise reduction, power-save, power-down,

standby, and extended standby

The ATmega328 on the Arduino Uno comes preprogramed with a bootloader that allows

you to upload new code to it without the use of an external hardware programmer. The

Arduino Uno board can be powered via the USB connection or with an external power supply.

The power source is selected automatically.

https://www.arduino.cc/en/Hacking/Bootloader?from=Tutorial.Bootloader



External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery.

The adapter can be connected by plugging a 2.1mm centre-positive plug into the board's

power jack. Leads from a battery can be inserted in the GND and Vin pin headers of the

POWER connector.

The board can operate on an external supply from 6 to 20 volts. If supplied with less than 7V,

however, the 5V pin may supply less than five volts and the board may become unstable. If

using more than 12V, the voltage regulator may overheat and damage the board. The

recommended range is 7 to 12 volts.

Pin configuration and description[5]

1. VCC

Digital supply voltage.

2. GND

Ground.

3. Port B (PB7:0) XTAL1/XTAL2/TOSC1/TOSC2

Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit).

The Port B output buffers have symmetrical drive characteristics with both high sink and

source capability. As inputs, port B pins that are externally pulled low will source current if

the pull-up resistors are activated. The Port B pins are tri-stated when a reset condition

becomes active, even if the clock is not running. Depending on the clock selection fuse

settings, PB6 can be used as input to the inverting oscillator amplifier and input to the internal

clock operating circuit. Depending on the clock selection fuse settings, PB7 can be used as

output from the inverting oscillator amplifier. If the internal calibrated RC oscillator is used as

chip clock source, PB7..6 is used as TOSC2..1 input for the asynchronous Timer/Counter2 if

the AS2 bit in ASSR is set.



4. Port C

Port C is a 7-bit bi-directional I/O port with internal pull-up resistors (selected for each bit).

The PC5..0 output buffers have symmetrical drive characteristics with both high sink and

source capability. As inputs, Port C pins that are externally pulled low will source current if

the pull-up resistors are activated. The port C pins are tri-stated when a reset condition

becomes active, even if the clock is not running.

Fig. 10.3.1 pin diagram of microcontroller



5. PC6/RESET

If the RSTDISBL fuse is programmed, PC6 is used as an input pin. If the RSTDISBL fuse is

unprogrammed, PC6 is used as a reset input. A low level on this pin for longer than the

minimum pulse length will generate a reset, even if the clock is not running. Shorter pulses

are not guaranteed to generate a reset.

6. Port D (PD7:0)

Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit).

The port D output buffers have symmetrical drive characteristics with both high sink and

source capability. As inputs, port D pins that are externally pulled low will source current if

the pull-up resistors are activated. The port D pins are tri-stated when a reset condition

becomes active, even if the clock is not running.

7. AVCC

AVCC is the supply voltage pin for the A/D converter, PC3:0, and ADC7:6. It should be

externally connected to VCC, even if the ADC is not used. If the ADC is used, it should be

connected to VCC through a low-pass filter.

8. AREF

AREF is the analog reference pin for the A/D converter.

9. ADC7:6 (TQFP and QFN/MLF Package Only)

In the TQFP and QFN/MLF package, ADC7:6 serve as analog inputs to the A/D converter.

These pins are powered from the analog supply and serve as 10-bit ADC channels.



10.4 Bridge rectifier

A Bridge rectifier is an Alternating Current (AC) to Direct Current (DC) converter that rectifies

mains AC input to DC output. Bridge Rectifiers are widely used in power supplies that provide

necessary DC voltage for the electronic components or devices. They can be constructed with

four or more diodes or any other controlled solid state switches. Depending on the load

current requirements, a proper bridge rectifier is selected.

Components ratings and specifications, breakdown voltage, temperature ranges, transient

current rating, forward current rating, mounting requirements and other considerations are

taken into account while selecting a rectifier power supply for an appropriate electronic

circuit’s application.

Bridge rectifiers are classified into several types based on these factors: type of supply,

controlling capability, bride circuit’s configurations, etc. Bridge rectifiers are mainly classified

into single and three phase rectifiers. Both these types are further classified into

uncontrolled, half controlled and full controlled rectifiers.

10.4.1 Controlled bridge rectifier

In this type of rectifier, AC/DC converter or rectifier – instead of uncontrolled diodes,

controlled solid state devices like SCR’s, MOSFET’s, IGBT’s, etc. are used to vary the output

power at different voltages. By triggering these devices at various instants, the output power

at the load is appropriately changed.

https://www.elprocus.com/bridge-rectifier-basics-application/

https://www.elprocus.com/power-electronic-converters/



Fig. 10.4.1 Controlled bridge rectifier

10.4.2 Bridge Rectifier Operation

As we discussed above, a single-phase bridge rectifier consists of four diodes and this

configuration is connected across the load. For understanding the bridge rectifier’s working

principle, we have to consider the below circuit for demonstration purpose.

During the Positive half cycle of the input AC waveform diodes D1 and D2 are forward biased

and D3 and D4 are reverse biased. When the voltage, more than the threshold level of the

diodes D1 and D2, starts conducting – the load current starts flowing through it,

10.5 Filter capacitor

A capacitor is included in the circuit to act as a filter to reduce ripple voltage. Make sure that

you connect the capacitor properly across the DC output terminals of the rectifier so that the

polarities match.

https://www.elprocus.com/3-different-types-diodes/

https://www.elprocus.com/3-different-types-diodes/



10.6 Isolation circuit or Driver circuit

10.6.1 LED

Light emitting diodes (LEDs) are semiconductor light sources. The light emitted from LEDs

varies from visible to infrared and ultraviolet regions. They operate on low voltage and power.

LEDs are one of the most common electronic components and are mostly used as indicators

in circuits. They are also used for luminance and optoelectronic applications.

Based on semiconductor diode, LEDs emit photons when electrons recombine with holes on

forward biasing. The two terminals of LEDs are anode (+) and cathode (-) and can be identified

by their size. The longer leg is the positive terminal or anode and shorter one is negative

terminal.

The forward voltage of LED (1.7V-2.2V) is lower than the voltage supplied (5V) to drive it in a

circuit. Using an LED as such would burn it because a high current would destroy its p-n gate.

Therefore, a current limiting resistor is used in series with LED. Without this resistor, either

low input voltage (equal to forward voltage) or PWM (pulse width modulation) is used to

drive the LED. Get details about internal structure of a LED.

Fig. 10.6.1 Light Emitting Diode

http://www.engineersgarage.com/insight/how-led-works



10.6.2 Opto isolator TLP250

TLP250 is more suitable for MOSFET and IGBT. The main difference between TLP250 and

other MOSFET drivers is that TLP250 MOSFET driver is optically isolated. Its mean input and

output of TLP250 MOSFET driver is isolated from each other. Its works like a optocoupler.

Input stage have a light emitting diode and output stage have photo diode. Whenever input

stage LED light falls on output stage photo detector diode, output becomes high.

Pin configuration isolated MOSFET driver TL250

Pin layout of TLP250 is given below. It is clearly shown in figure that led at input stage and

photo detector diode at output stage is used to provide isolation between input and output.

Pin number 1 and 4 are not connected to any point. Hence they are not in use. Pin 2 is anode

point of input stage light emitting diode and pin 3 is cathode point of input stage. Input is

provided to pin number 2 and 3. Pin number 8 is for supply connection. Pin number 5 is for

ground of power supply.

Fig. 10.6.2 TLP250

https://i0.wp.com/microcontrollerslab.com/wp-content/uploads/2015/04/pin-configuation-of-isolated-MOSFET-driver-TLP250.jpg?ssl=1



10.6.3 Diode FR107

Characteristics FR107 diode

• Maximum Recurrent Peak Reverse Voltage – 1000 V

• Maximum Average Forward Output Current – 1 A

• Maximum Forward Voltage Drop per element at 1.0A DC – 1.3 V

• Maximum reverse recovery time – 500 ns

• Typical Junction Capacitance 15 pF

• Package – DO-41

• Weight 0.33 grams

• Operating and Storage Temperature Range -65…+150 °C

Polarity and pinout

FR107 diode has a cathode (-) and anode (+). In the schematic symbol, the tip of the triangle

with the line on top of it is the cathode. The cathode is marked on the body of a diode by a

band as shown below.

Fig. 10.6.3 symbol of a diode

Diode polarity Current can flow from the anode to the cathode only and never from the

cathode to the anode - FR107 diode is like a one way valve.



10.6.4 Zener diode

Fig. 10.6.4 Symbol of diode

A Zener diode is a type of diode that allows current to flow not only from its anode to its

cathode, but also in the reverse direction, when the Zener voltage is reached.

A conventional solid-state diode allows significant current if it is reverse-biased above its

reverse breakdown voltage. When the reverse bias breakdown voltage is exceeded, a

conventional diode is subject to high current due to avalanche breakdown. Unless this

current is limited by circuitry, the diode may be permanently damaged due to overheating. A

Zener diode exhibits almost the same properties, except the device is specially designed so

as to have a reduced breakdown voltage, the so-called Zener voltage. By contrast with the

conventional device, a reverse-biased Zener diode exhibits a controlled breakdown and

allows the current to keep the voltage across the Zener diode close to the Zener breakdown

voltage.

10.6.5 Transistors

10.6.5.1 2N2222

The 2N2222 is a common NPN bipolar junction transistor used for general purpose low-power

amplifying or switching applications. It is designed for low to medium current, low power,

medium voltage, and can operate at moderately high speeds.

https://en.wikipedia.org/wiki/Diode

https://en.wikipedia.org/wiki/Reverse-biased

https://en.wikipedia.org/wiki/Breakdown_voltage

https://en.wikipedia.org/wiki/Avalanche_breakdown



Fig. 10.6.5.1 2N2222 transistor

10.6.5.2 CK100

Fig. 10.6.5.2 CK100

The CK100 is general purpose silicon, PNP, bipolar junction transistor. It has maximum VCE

rated at 50V and can sink maximum current of -500mA. It has typical power dissipation of

4W. It offers gain between 100 to 400.

10.6.6 RESISTOR

500K, 1k, 100K, 220K

Fig. 10.6.6 resistor



10.7 PICTURE OF HARDWARE

Fig 10.7 Picture of hardware



10.8 OUTPUT

Fig. 10.8 output as seen in CRO



CHAPTER 11

WORKING

1. A 230 V single phase supply is taken and then voltage is stepped down to 12V using

a step-down transformer.

2. The 12V AC the transformer is converted to 12V DC using a full bridge rectifier a filter is

used

to remove the surges or harmonics produced.

3. The DC voltage as a source is given to cascaded H-bridge inverter

4. From Arduino UNO’s ATmega328 microcontroller the High and Low signals are

generated and given to the isolation circuit or driver circuit’s opto isolator.

4. The capacitor’s in the driver circuit get charge and discharge on basis of the pulse

generated. Each MOSFET is having its own isolation circuit.

5. Then, it is input to the MOSFET drivers to provide a safety catch as well as the ability to

keep

the MOSFETS active when they are high

6. Through the driver circuit the gate voltage is given to MOSFET at different sequence of time

into the MOSFETS of the H-bridge and draws power from the high voltage supply through

the filter to generate the appropriate output signal.

7. The same can be seen in CRO and voltage approximately of 24V can be measured and

a simple load can be connected such as bulb.



CHAPTER 12

CONCLUSION

Simulation was conducted with the help of MATLAB Simulink, the 5-level inverter circuit was

designed and with the help of simple control strategy the simulation was conducted.

With the help of Microcontroller and driver circuit we could easily implement the cascaded 5

level inverter using MOSFET IRFZ44. A simple program is uploaded to the microcontroller and

was used to trigger the switches (MOSFET) as per different switching sequence at different

switching frequency.

As the levels of output increases, nearly sinusoidal waveform will be obtained, this results in

reduced THD. Load which are rated as per inverter output can be used for various application.

In future 7 level inverter or 9 level inverter or so on can be used this results in reduced Third

Harmonic distortion, increased efficiency with less losses. So, the benefits of multilevel

inverter include, lower transient power loss due to low-frequency switching, less THD,

reduced ac filters, and possibility to replace MOSFETs with IGBTs, and thereby providing

compact power conversion. It can be concluded that, in order to maintain the good quality of

power, it is necessary to replace the conventional drives with 2 level inverters by multilevel

inverters.



CHAPTER 13

REFERENCES

[1]. Vinayaka B C, S Nagendra Prasad, M.Tech Student Scholar, Associate professor

Department of EEE, The National institute of Engineering Mysore, Karnataka India

Modeling and Design of Five Level Cascaded H-Bridge Multilevel Inverter with

DC/DC Boost Converter

[2]. Pallavi Appaso Arbune, PG Scholar, Dept. of EE, G.H.Raisoni Institute of Engineering and

Technology, Wagholi, Pune, India

Dr. Asha Gaikwad, Professor, Dept. of EE, G.H.Raisoni Institute of Engineering & Technology,

Wagholi, Pune, India

Comparative Study of Three level and Five level Inverter

[3]. Suman Ghosh, Student, Department Of Electronics and Communication Engineering,

RVSCET, Jamshedpur, Jharkhand, India.

Sushanta Mahanty, Assistant Professor, Department Of Electronics and Communication

Engineering, RVSCET, Jamshedpur, Jharkhand, India.

Single Phase Multilevel Inverters with Simple Control Strategy Using MATLAB

[4]. Veena B M 1, Assistant Professor, Dept. of EEE, Bapuji Institute of Engineering

&Technology, Davangere, Karnataka, India1

Triveni M T, Assistant Professor, Dept. of EEE, Bapuji Institute of Engineering &Technology,

Davangere, Karnataka, India2

Hardware Implementation of 5 Level Inverter Using Microcontroller

[5]. V. Mahananda Reddy, PG student, Electrical Engineering, VNIT Nagpur, India

K. Raghavendra Reddy, Research Scholar, Electrical Engineering, VNIT Nagpur, India

A Comprehensive Review on Single-Phase Five-level Inverter Topologies, VNIT-

Nagpur, India.



Appendix 1 : Program used in microcontroller

const int pulse1=3;

const int pulse2=4;

const int pulse3=5;

const int pulse4=6;

const int pulse5=7;

const int pulse6=8;

const int pulse7=9;

const int pulse8=10;

void setup()

// put your setup code here, to run once:

Serial.begin(9600);

pinMode(pulse1,OUTPUT);








void zero()

digitalWrite(pulse1,HIGH);


digitalWrite(pulse3,LOW);








void first()









void second()









void third()











void fourth()









void fifth()









void sixth()











void seventh()









void eight()











void nine()









void ten()









void eleven()











void multi_20hz()

zero(); delayMicroseconds(6200);

first(); delayMicroseconds(6200);

second(); delayMicroseconds(6200);

third(); delayMicroseconds(6200);

fourth(); delayMicroseconds(6200);

fifth(); delayMicroseconds(6200);

sixth(); delayMicroseconds(6200);

seventh();delayMicroseconds(6200);

void multi_50hz()









eight(); delayMicroseconds(2500);

nine(); delayMicroseconds(2500);

ten(); delayMicroseconds(2500);

eleven(); delayMicroseconds(2500);

void multi_80hz()











eight();delayMicroseconds(1500);

nine();delayMicroseconds(1500);

ten();delayMicroseconds(1500);

eleven();delayMicroseconds(1500);

void loop()

//Serial.available()>0

multi_50hz();

SOFT SWITCHING OF 5 LEVEL INVERTER

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