CONSTRUCTION OF UNTERRUPTIBLE POWER SUPPLY

ABSTRACT

Uninterruptible power supplies UPS are used to provide power when regular utility power is unavailable. Although they are commonly used for providing power in remote locations or emergencies, this is not because they are the same as auxiliary power units, emergency power units or standby generators.

Unlike the aforementioned power sources, UPS provides an immediate and continuous supply of power to a device, hence protecting it from power interruption and allowing time for auxiliary or emergency powers, to kick in equipment to be safely shut down or utility power restored.

The major aim of this was to design a system which will be able to convert battery voltage12v to 220v, which is equivalent to wall outlet and secondly able to charge the battery.

The chapter one of this work, gives the overview of UPS, its importance, uses, and application and some of its special features like its ability to correct frequency instability and many more.

Secondly, this work dealt with all components used in the construction of the device, there working condition and uses. Some basic abstract phenomenon were also treated like wave forms and electronic switching.

The chapter three, basically dealt on all electrical measuring instrument used in and on the device, how they are used, why and where.

The fourth chapter explains how the components where assembled into section and the sectional connection used to form the device.

The last chapter is a simple conclusion with honest recommendation.

TABLE OF CONTENT

CERTIFICATION i

DEDICATION ii

ACKNOWLEDGEMENT iii

ABSTRACT iv

TABLE OF CONTENT v

CHAPTER ONE

1.1 INTRODUCTION 1

1.1 AIMS AND OBJECTIVES 8

1.2 SCOPE OF THIS PROJECT 8

1.3 AVAILABILITY OF DESIGN MATERIALS 8

CHAPTER TWO

2.1 LITERATURE REVIEW 9

2.1 WHAT IS A UPS 9

2.2 WAVEFORMS 9

2.2.1 SQUAREWAVE 9

2.2.2 MODIFIED SINE WAVE 10

2.2.4 TRUE SNE WAVE 10

2.3 RESISTORS 11

2.4 CAPACITORS 12

1.4.1 CAPACITANCE 13

2.4.2 ELECTROLYTIC CAPACITOR 14

2.4.3 PLASTIC FILM, CERAMIC NAD MONOLITHIC

CAPACTOR 14

2.5 DIODE 16

2.5.1 MOUNTING A DIODE 18

2.5.2 CHARACTERISTICS CURVES OF A DIODE 18

2.5.3 IDEAL DIODE 19

2.5.4 LIGHT EMITTING DIODE 19

2.5.5 DIODES AS RECTIFIERS 21

2.5.5.1 HALFWAVE RECTIFIER 22

2.5.5.2 FULLWAVE, CENTERTAP RECTIFIE 23

2.5.6 FILTERS 24

2.6 TRANSISTORS 26

2.6.1 TRANSISTOR AS A SWIRCH 26

2.6.2 MOSFETS 28

2.6.2.1 SUPERHIGH INPUT IMPEDANCE 29

2.6.2.2. SETBACKS IN MOSFETS 29

2.6.2.3 ITS FLEXIBILITY 30

2.7 OPTOCOUPLER 30

2.7.1 OPTOCOUPLER CHARACTERISTICS 31

2.7.2 ITS INPUT 32

2.7.3 ITS OUTPUT 32

2.7.4 ITS OPERATING MODE 33

2.8 THE SG3524 INTEGRATED CIRCUIT 33

2.8.1 OPERATING PRINCIPLE OF SG3524 34

CHAPTER THREE

3.0 METHODOLOGY 36

3.1 ELECTRONIC WORKBENCH 37

3.2 GALVANOMETER 37

3.3 OSCILLOSCOPE 38

3.4 VOLTMETER 39

3.5 AMPMETER 41

3.6 WATTMETER 43

3.7 MULTIMETERS 44

CHAPTER FOUR

4.0 DESIGN AND CONSTRUCTION METHODS 46

4.1 COMPLETE CIRCUIT DIAGRAM OF A UPS 47

4.2 STAGE BY STAGE DESIGN 47

4.2.1 OSCILLATOR SECTION 50

4.2.2 DRIVER/SWITCHING SECTION 51

4.2.3 THE OUTPUT SECTION 52

4.2.4 THE CHANGEOVER SECTION 53

4.2.5 THE LOW BATTERY CUTOFF SECTION 54

4.3 COMPONENT JUSTIFICATION 55

4.3.1 MOSFETS 55

4.3.2 SG3524 OSCILLATOR 55

4.3.3 OPTOCOUPLER 56

4.3.4 RESISTORS 56

4.4 TEST AND ANALYSIS 56

4.4.1 TESTING AND SETTING THE INVERTER 57

4.5 BILL OF ENGINEERING CONSTRUCTION 60

CHAPTER FIVE

5.0 CONCLUSION 62

5.1 RECOMMENDATION 62

REFERENCES 63