DESIGN AND CONSTRUCTION OF MICROCONTROLLER BASED AUTOMATIC THREE PHASE

SELECTOR BY

ORISANAIYE IFEDA YO OLUWASEYI

2004/18754EE ..

A THESIS SUBMITED TO DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING SCHOOL OF ENGINEERING AND

ENGINEERING TECHNOLOGY FEDERAL UNIVERSITY OF TECHNOLOGY MINNA NIGER STATE NIGERIA

IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF BACHELOR IN ENGINEERING

DECEMBER, 2009.

DEDICATION

This project work is dedicated to JEHOVAH GOD who served as the spinal cord of my

success in the university.

This project is also dedicated to my beloved brother who served as my stepping stone

ENGR' ORISANA YE T JOSEPH.

ii

,

DECLARATION

I, ORISANAIYE IFEDA YO OLUWASEYI, declare that this work was done by me and has

never been presented elsewhere for the award of a degree. I also hereby relinquish the

copyright to the Federal University of Technology, Minna.

ORISANAIYE I OLUWASEYI. ENGN lG.KOLO

Name of Student Name of Supervisor

-~1.3.t.~.t'rb Signature and Date Signature and Date

Dr y.A. ADEDlRAN ........ . . .. . .. .. ..... . .......

Name of H.O.D Name of External Examiner

Signature and Date Signature and date

iii

ACKNOWLEDGEMENT

To my father in heaven, the creator of Heaven and Earth, JEHOVAH. It is you that

deserve all the praise and glory, for the favor, protection and honor you have bestowed

upon me at this point in my life.

My parents; Mr. Simon Orisanaiye & Mrs. Janet Orisanaiye, words are definitely not

enough to appreciate and thank you for your prayers, support and the trust you both have

given to me. I look at both of you and you give me every reason to want to excel in life,

you both undoubtedly are the best. I love you both. My prayer is that I continue to be a

source of joy to you.

To my amiable, principled and incorruptible Head of Department, Dr. Yunusa Adediran,

you are one in a million, I thank you sir for the discipline and sense of responsibility you

have instilled in my colleagues and I. God bless you and your family sir.

My project supervisor, engr J.G.KOLO, meeting you has taken me step closer to my

success; you are an uncle, a friend and a brother. I thank you for your assistance, support

and encouragement throughout the course of executing this project. God bless you sir.

To the class of 2009 graduates of Electrical and Computer Engineering; the top is where

all of us belong; I will definitely miss you all.

IV

ABSTRACT.

The mains supply in Nigeria fluctuates widely due to overloading, ageing and improper

distribution ofloads among the three phases of the consumers'! substation transformer.

Appliances such as video cassette player, television as well as those containing compressors like

air conditioners, refrigerators, etc could be damaged due to this variation and fluctuation in

voltage mains.

The automatic three-phase selector is an electronic circuit that is capable of detecting voltage

levels by means of a micro-controller that does some level of comparison before initializing a

logic combinational circuit that does some logic combination before initializing an electronic

relay switch action. The relay is energize only when the mains voltage is within an accepted pre­

determined limit, outside of which relay remains dormant .voltage levels below the desired range

is ignored. This device is designed to work with a 3-phase input signal. The device functions in

the form of an automatic electronic switch, switching between three potentials, with the aim of

supplying the highest potential to the load and supplying one out of either of phases with the

same potential.

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Table of Contents

Title Page ............ .. . .... . ... . ...................... .. ................................ . ............. I

Dedication .. .. ........................ ....... . .... : .................. . ...................... . ..... .. '" ii

Declaration ............ . ... .... . .. ............ . ...... . . .. . ....... . ..... . .. ... ... . ...... .... .... ... .. .. iii

Acknowledgement .. ............. . ..... ............................................................. iv

Abstract . .. .... . ...... .. .............. . ... ... .. .. . ..... ..... ... ... . .. ... . ........... ......... . . .. .... ... V

Table of Contents .... . ........ . . ... ............... .. . .. .. .. ..... ... ............... . .. .. . ........ vi-viii

Lists of Figures ................... ........... . . .. . . ...... .. ........... . ... . .. , ........ ... . ...... . .. ix-x

List of Tables ............ . ...... ............. . ........ . . . . .. ............. . .... .............. .. . . ....... xi

Chapter One: Introduction ........... .. . . ............ .. ..... .................... .......... .. .. ... ... 1

Project aim and Objective ..... . . ...... ...... ......................... . ................. . .... 3

Methodology . . . ...... .. . ... . .... . ........ .......... . . . ...... .. .. . ..... ... ........... ..... . ... ...... 3

Scope of Study ... .. .. ..... .................. ...... .. . .. .... . .... . ...... . .. . . .... ... ... ... ... . . .. . 3

Relevant of project .. .. ......... ... ..... . .. . .. . ......... .. .. ..... . . .. ..... .............. . .. . ..... 4

Project layout ......... . .. . .. ... ..... . ... .... .. ........................... ... ... ....... . .. . . . . .... .4

Chapter Two: Literature Review! Theoretical background ... .... .. ..... . ............... . ..... 5

Theoretical Background ... . . . .......... .... . ..... . ....... . ... .. ........ ................. . ...... 5-10

Block diagram ........ . .. . ....... ... . ... ... ......... .. ............................ . ... . ... . . . ..... 11

apter Three: Design and Implementation ........... .. ......... ... ...... ... ...... ............... .. .............. ... . 12

The component choice and description ...... ................ ...... ......... ....... . ..... .. 12

3.1.1 Capacitor .................... . ......... . ....... . .. .. . . . ...... . ..... .. .... ... . .. ... . . .. .... 12

3.1.2 Voltage Regulators IC ..... .. ............................... . .. .... ... . . .... .. ..... . 13-14

3.1.3 Diodes ..... .. .. .. . . . . ...... : .... . ........ . .... ............ ........... . .... .... . .. .. .. .. ... 14

VI

3.1.4 Transistors . .................... . . . ......... . .. . ........ . .. . .......... .. ... . ..... . ...... 15-16

3.2 Power supply unit. ................ . .............................. .. ............................. 16-18

3.2.1 Transformer ... . .... . . ... .. ........... .. .... . ... .. ...... . ... .......... ...... .. . ..... . 18-20

3.2.2 Bridge rectifier , ......... . ............ .. . . .. .. ........................... . .... . ........ . .... 20

3.2.3 Filtering ... . .. .... ... ...... . . .. .. . ......... . .. . ..... . ...... . ... . . . .. . ......... . . . ...... .. . 20-21

3.2.3.1

3.2.3.2

Mathematical reasons .. .. .. . .. . . . . . ... ... . ......... . ....... ..... . .. .. . .. 21-22

Low voltage cut off .. ........ ...................... .............. .... .. .. 22

3.2.3.2.1 Mathematical reasons .. . ........ .. .... . ...... . ........... ... ... 22-23

3.2.4 Choice of voltage regulator .................. .. ............... . . .. ......... .. ... ...... . 23

3.3 Control unit. ... .. .. ... . ... ... . ... . ..... . .... . .. . . . .. ...... . ..... . .... . ... . ....... ... . . . . . . ... . 24-25

3.2.1 8051 Microcontroller. .. ... .. .... . . .. .. . . . ...... . ...... ... ......... . .... . ... .. .... . .... . 26-27

3.4 switch circuit. ... . ...... ....... . ..... . .... . . .. ....... ..... ... . ... . .......... . ......... . . .. ........ 28-30

3.5 Relay unit. . .... . ... . ........ . ... .. . .. . .. .. . ... . . .. . . .. .. ........ .. ..... ... . . .... . . . . . ...... . .. 30-31

3.5.1 Calculations involve . .. . .. . .. . ... . ..... .. . . .......... . ... . ........... . .. . .. .. . . . .. . .. 31

3.6 Display unit. . ... . ............................ . .. . .. . .. . .. . .... . ............ . .... . ... . . .. .... . 32-33

3.6.1 Programs .. . .. . ..... .. . . .... . .. . .. . ... . .. . .. . ... .. ........ .. . . . . ... .. . ... .. . . . . . .... . . .. 34-36

3.7 circuit diagram . ....... . .... ... ........ . ..... . .... .. ........ . .................. . .. . ... . . . .......... 36

Chapter Four: Construction, Testing and Result .................... .. ............................ .. .... .. ...... .. .. 37

4.1 Testing .. .. . .......... . ... . ............ . .. . .. . ......... . . . .. . ........... . .. . .... . .... . . ... .... . .. 37-38

4.2 Result and discussion of result .............. . .. . .. . .. . ...... . ..... .. ............. ..... .. .. 38-40

4.3 casing .. . . ....... . ........ .' . . ....... . . .. ................ . ......... . .... .. ..... . ........ . ..... . . ... 40

4.4 Circuit Construction ...................... .. . ................ ......................... .. .40-41

4.5 List of components ............................ . . . . . ... . ...... . ......... . .... . . .. ... ... .. . ... 41

Vll

Chapter Five: Conclusion and Recommendation

5.1 conclusion . .................................................................................... 43

5.2 IZeCOlTIlTIendation .... . ... . .. ... .. .. . ... .. . .. .... .. . · .......... ... ... . ... ....... . ..... ... .. ... 44

Reference ......... . ....... ... ..... . .......... . ...... . ............ .. . .... . ..... ... . ................ . ..... ... . 45

Appendix . .... ... . ...... . . .. ... .. . ... .. ... . .. ... ............ ... ........ ... ........ ......... . ... . .. 46-48

Vlll

LIST OF FIGURES

FIG.2.1 Motorized voltage control system 6

FIG.2.2 Block diagram of a resonant circuit voltage regulator 7

FIG.2.3 Block diagram of the automated voltage regulator 8

FIG.2.4 Block diagram of an A.C inversion system 9

FIG.2.S Phase controlled automatic voltage regulator 10

FIG.2.6 Circuit block diagram 11

FIG.3.1 Capacitor circuit symbol 13

FIG.3.2 Schematic symbol and pin out of a 78xx series regulator 14

FIG.3.3 Diode circuit symbol 14 I

FIG.3.4 A circuit symbol of BJT transistor 15

FIG.3.S Block diagram of a regulated power unit 17

fIG.3.6 Power unit 18

FIG.3.7 The circuit symbol of a transformer 19

FIG.3.8 Pin layout of 8051 microcontroller 24

The program flow chart 25

BJT when reverse biased 28

ix

FIG 3.11 BJT when forward biased 29

FIG.3.12 Driver circuit 30

FIG.3.13 Relay circuit 30

FIG.3.14 Seven segment display 33

FIG.3.15 Program codes 34-36

FIG.3.16 Circuit diagram 37

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