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 voltage(12v) to 220v, which is equivalent
to wall outlet and secondly able to charge the battery.
The chapter one of this work, gives the
over-view of UPS, it’s 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 HALF-WAVE RECTIFIER - - - - - 22
2.5.5.2 FULL-WAVE,
CENTER-TAP 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 SUPER-HIGH INPUT IMPEDANCE - - - - 29
2.6.2.2. SETBACKS IN MOSFETS - - - - - 29
2.6.2.3 ITS FLEXIBILITY - - - - - - 30
2.7 OPTO-COUPLER - - - - - - 30
2.7.1 OPTO-COUPLER
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
4.3 COMPONENT
JUSTIFICATION - - - - 55
4.3.1 MOSFETS - - - - - - - - 55
4.3.2 SG3524 OSCILLATOR - - - - - - 55
4.3.3 OPTO-COUPLER - - - - - - - 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
LIST
OF FIGURES
Fig 1. Offline/ standby diagram - - - 5
Fig 2. A capacitor - - - - - 12
Fig 3. Capacitors - - - - - - 15
Fig 4. Circuit Symbol of a diode - - - - 17
Fig 5. A Led - - - - - - 20
Fig 6. Half-wave rectifier - - - - 21
Fig 7. Half wave Rectifier - - - - 22
Fig 8. A full-wave centre tap
rectifier - - 24
Fig 9. A Simple filter - - - - - 25
Fig 10. Transistor as a Switch - - - - 27
Fig 11. A Transistor as a Switch - - - 27
Fig 12. A Mosfet - - - - - - 28
Fig 13 Opto-Coupler’s Input - - - - 32
Fig 14. Inputs and output circuit of an
opto-coupler - 32
Fig 15. A Digram of a Voltmeter - - - 41
Fig 16. Diagram of Amp meter - - - - 42
Fig 17 Diagram of a Wattmeter arrangement - 43
Fig 18 Oscillator Circuit - - - - - 49
Fig 19 Pre-Driver Section - - - - 51
Fig 20 Change over circuit of the UPS - - 53
Fig 21 Low battery cut-off circuit - - - 54
CHAPTER ONE
1.10 INTRODUCTION
As
blackouts roll through power-starved communities, the threat to you and your
computer is not the lack of electricity, but the change in power. When the
lights are off and you are about to start any industrial or computer-based projects, all your efforts will be wasted. Even when
your system acts as a server, a sudden shutdown could disrupt the processing of
many others. You can make your work immune to the intransigence of rolling
blackouts and protect against many other types of unexpected power
disturbances. Your secret weapon is the uninterruptible power supply or
uninterruptible power source. Commonly called the UPS, this devices is
a cleaver threefold package-a set of battery, an inverter that transforms the
low-voltage direct current of the batteries into the standard alternating
current equivalent to your wall outlet, and a battery changer that assures that
reserve power storage system (the batteries) with interfaces to mach it to
utility power and your computer system. A UPS differs from an auxiliary emergency power system or standby generator in that it will provide instantaneous
or near-instantaneous protection from input power interruptions by means of one
or more attached batteries and associated electronic circuitry for low power
users, and or by means of diesel generators and flywheels for high power users. While not limited to protecting any particular type of equipment, a UPS is
typically used to protect computers, data centers, telecommunication equipment
or other electrical equipment where an unexpected power disruption could cause
injuries, fatalities, serious business disruption and/or data loss. UPS units
range in size from units designed to protect a single computer without a video
monitor (around 200 VA rating) to large units powering entire data centers,
buildings, or even cities. The UPS is designed to project against
changes, specifically a temporary loss of electrical supply.
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