ABSTRACT
Every electrical and electronic appliance is designed to work perfectly at a certain input voltage. In Nigeria, household electrical and electronic appliances are designed to work properly at 220VAC, 50Hz and most of the times the voltage supplied from distribution companies are as low as 80VAC making this appliances to work under threat of low voltage supply. This low supply voltage causes these appliances to malfunction and in most cases damage them. Since the electric power supply/distribution companies are unable to provide the consistent adequate voltage level (220VAC) demanded by these sensitive appliances, therefore there is need for consumers to protect the appliances from damage and ensure their safe operation, hence the use of automatic voltage stabilizers to improve the situation. In this research work, an Atmega 328p microcontroller was programmed to monitor the input voltage from distribution companies and if voltage level is between 80 VAC and 250VAC, it gives a constant output voltage of 220VAC (±6%) required by the appliance. In doing this, it constantly varies the turn's ratio of the Auto-transformer, initiating a step-up or step-down operation of the transformer so that a regulated voltage of 220 VAC (±6%) is obtained at the stabilizer output. The system also constitutes of a 16 by 2 liquid crystal display for the display of both the input and output voltage range.
TABLE OF CONTENTS
Title page i
Declaration ii
Certification iii
Dedication iv
Acknowledgement vi
Table of contents v
List of tables vii
List of figures viii
Abstract ix
CHAPTER 1: INTRODUCTION
1.1 Background of the Study 1
1.2 Problem Statement 4
1.3 Objectives of the Study 4
1.3.1 The specific objective of this project includes 4
1.4 Justification of the Study 4
1.5 The Scope of the Study 5
CHAPTER 2: LITERATURE REVIEW
2.1 History of Voltage Stabilizer 6
2.2 Review of Related Works 7
2.2.1 500KVA generator with automatic voltage regulator (AV0R) 7
2.2.2 A 220 volts voltage regulator 8
2.2.3 Micro-controller based automatic voltage stabilizer/corrector 8
2.2.4 A low cost servo controlled voltage stabilizer 9
2.2.5 Voltage stabilizers can increase power and torque 10
2.2.6 Digital AC power controller 11
2.3 Summary of the Related Literature 12
2.3.1 Summary of review of related works
CHAPTER 3: MATERIALS AND METHODS
3.1 Materials 13
3.2 Hardware Components 13
3.2.1 Power supply unit 13
3.2.2 Transformer 14
3.2.3 Rectifier 15
3.2.4 Smoothing or filtering 16
3.2.5 220v-12v step-down transformer 17
3.2.6 Microcontroller 18
3.2.7 The atmel atmega family (atmel atmega328p – AU) 19
3.2.8 Specification of atmega328p 20
3.2.9 Programming mode of the controller 21
3.2.10 7805 voltage regulator 25
3.2.11 Auto-transformer 25
3.2.12 Stabilizer operating current calculation 27
3.2.13 Voltage operating range of the stabilizer 28
3.2.14 Stabilizer delay calculations 29
3.2.15 UNL2803 darlington pair transistor (IC) 29
3.3 Software Components 30
3.4 Methods 31
3.4.1 Choice of method 31
3.4.2 Prototyping 31
3.4.3 Reason use prototyping method 31
3.4.4 Regulated power supply 32
3.4.5 Bridge rectifier 33
3.4.6 Filtering capacitors 34
3.4.7 Zener regulator design 35
3.4.8 Calculating current 36
3.4.9 Switching circuit 36
3.4.10 Referencing voltage 37
3.5 Flow Chart Diagram 39
3.6 System Block Diagram 40
3.7 System Circuit Diagram 41
3.7.1 Full-bridge rectification process 42
3.7.2 Referencing, supply and circuit breaking unit 42
3.8 Description of Developed System 43
CHAPTER 4: RESULTS AND DISCUSSIONS
4.1 Results 46
4.1.1 Low voltage test 46
4.1.2 High voltage test 46
4.1.3 Over voltage test 46
4.1.4 Continuity test 46
4.1.5 Open circuit test 47
4.1.6 Short circuit test 47
4.2 Discussion 49
CHAPTER 5: CONCLUSION AND RECOMMENDATION
5.1 Conclusion 50
5.2 Recommendation 50
References 51
Appendix I 53
Appendix II 56
LIST OF TABLES
2.1 Summary of Review of Related Works 12
3.1 Key Features of the Microcontroller 20
3.2 Programming Mode of the Controller 21
3.3 Serial Programming of the Microcontroller 22
4.1 Input/output Voltage Table 48
LIST OF FIGURES
3.1: Block diagram of a regulated power supply system 14
3.2: Output waveform of transformer 14
3.3 (A): Rectifier circuit 15
3.3 (B): Output of the rectifier 15
3.4: Smoothing action of capacitor 16
3.5: Waveform of the rectified output smoothing 17
3.6: Step-down transformer 17
3.7: Pin diagram of atmega328p. 19
3.8: Internal architecture of aver microcontroller 24
3.9: Regulator 25
3.10: Auto Transformer 26
3.11: UNL2803 darlington pair transistor (ICE) 29
3.12: NPN transistors in darlington pair 30
3.13: Regulated power circuit 31
3.14: Zener regulator circuit 36
3.15: Switching circuit. 37
3.16: Referencing voltage circuit. 38
3.17: System flow chart 39
3.18: Block diagram of a micro-controller based power protection system. 40
3.19: Proteus simulation of the system. 41
3.20: picture of the developed system on startup 43
3.21: picture of the system displaying the name of the designer 44
3.22: picture of the developed system displaying the output voltage 44
3.23: picture of the designed system showing the output socket 45
3.24: picture showing the top and side view of the developed system 45
4.1 Input/output characteristic graph of the power protector 53
4.2 Oscilloscopic view of the stabilizer output 53
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
In Nigeria and some other parts of the world today, the power supplied to consumers (at homes and industries) from the national grid is not maintained at a stipulated voltage say 240 volts. But the electronic gadgets and some other power operated machines that we use in our homes, offices and industries require power with constant or nearly constant voltage for their efficiency, and to avoid damage.
Voltage stabilizer is an electronic control circuit or device that is capable of providing a constant or nearly constant output voltage even when there is variation in load or input voltage as low as 90 volt can be boost up to 240 volt by 40stabilizer at output stage without any voltage fluctuation.
Voltage Regulators owe their existence to over 200 years of discovery and inventions – from the development of the 1st electric battery by Alessandro Volta (Italy) in 1800 to the latest solid state computerized systems of the present day.
The current development of 3rd Generation Voltage Regulator was only possible following the inventions of transformers; programmable digital computers and Silicon Controlled Rectifiers (SCR).
3rd Generation Systems uses transformers to change the voltage from one value to another. The computers carry out complex and lightning fast calculations, and the SCR’s switch on and off smaller transformers to change the voltage as and when needed. (Mohammad, 2015).
The earliest discovery that paved the way for the development of the transformer was the discovery of electromagnetic induction which is the relationship between electromotive force (EMF) or “voltage” and magnetic flux. This was independently discovered by Michael Faraday (English) and Joseph Henry (American) in 1831. Faraday was the first to publish the results of his experiments and thus receive credit for the discovery. This discovery provided the basis of Faraday Law – still used today as a basic law of electromagnetism relating to the operating principles of transformers, inductors, and many types of electrical motors and generators.
The second important development toward the design of a transformer occurred in 1836; and is credited to the Rev. Nicholas Callan of Maynooth College, Ireland.
Callan designed the first induction coil and was one of the first researchers to realize that the more turns the secondary winding has in relation to the primary winding – the larger is the increase in EMF (Volts). At this time the only power being generated was Direct Current (DC). Induction coils were needed to get higher voltages from batteries. Before the development of transformers, the first electric power generators used DC at low voltages to power a small customer base using electric lights and small motors. As use of electricity grew and transmission distances increased, DC became unreliable and costly.
A change from DC to Alternating Current (AC) was required. AC could be generated at higher voltages and at lower amperages. The lower current meant that thinner and cheaper wires could be used in transmission and the higher voltage overcame the losses of transmission to the end user. However, this much higher AC voltage then had to be reduced at the end of the transmission line so that it could be used by the consumer hence the need for efficient and cost effective Transformers. (Mohammad, 2015)
In 1882, Lucien Gaulard (French) and John Dixon Gibbs (English) first build what they term as a “secondary generator” or in today’s terminology a step down transformer which they designed with open iron core.
Then in 1885, William Stanley (American) of Westinghouse (USA) makes the Lucien Gaulard and Gibbs transformer more practical due to some design changes. Mikhail Dolivo-Dobrovolsky (Russian-born engineer) in 1889, developed the first three-phase transformer at the Allgemeine Elektricitäts-Gesellschaft (“General Electricity Company”) in Germany.
Automation was the only solution for effective stabilizing and with the invention of the semi-conductors this was achieved. These semi-conductors (like the transistors, diodes, TTL-IC’s etc.) are also employed in the construction of the micro-controller based power protector, which compensate for voltage fluctuations.
The early days voltage stabilizers consists of series of low voltage comparators like the LM239 op Amp to determine the variation in the supplied voltage furthermore its takes action based of the differential feedback, based on the action taken the supply output is maintained at a steady 220V thus reducing risk of hazardous effects on our domestic equipment. (Mohammad, 2015).
1.3 PROBLEM STATEMENT
Over the years the industrial sector has faced power issues of various types, either of power not being available in the national grid or the voltage of the supplied power not being efficient enough to operate their machines. This results to them running the factory on an alternative power supply system, thus leading to high cost of products because of high production cost.
The system proposed in this report is designed to solve the problem of fluctuation in voltage used to power the heavy machines, hence eliminating the need to power the factory on alternative power source like generators.
To achieve the result stated above, a micro-controller based voltage stabilizer is proposed because it is cost effective when compared to the early day voltage stabilizers which make use of series of IC’s for their operation.
1.3 OBJECTIVES OF THE STUDY
The aim of this project is design and implementation of a micro-controller based power protection and control system for industrial machines.
1.3.1 The specific objective of this project includes:
1. To design a microcontroller based voltage stabilizer system.
2. To develop an algorithm for programming of the project designed above.
3. To Program the microcontroller of the system using Arduino IDE with C programming language.
4. To simulate the designed system in 1 above using Proteus professional
5. To construct the designed system in 1 above.
6. To interface the software developed above to the developed system.
7. To test and implement the system designed above.
1.4 JUSTIFICATION OF THE STUDY
The Power Protection system maintains the terminal voltage of the electrical /electronic devices and components within 160V to 260V giving a regulated output voltage of 230V ± 10V despite variation in input voltage or load.
This device maintains a load voltage nearly constant over a range of variation of input voltages
The device has a circuit breaker which is triggered when the supply voltage is below operational level.
1.5 THE SCOPE OF THE STUDY
This project shall cover the design, implementation and testing of a voltage protector for an industrial load.
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