report on the Techno india network

PT&IV at TECHNO INDIA NETWORK GCT DEE
Session 2014-18 Page 1
Chapter 1
Introduction
1.1 Introduction
UPS stands for Uninterruptible Power Supply. It is an instrument connected between the
electric grid and the consumer, comprising of electric hardware and rechargeable batteries.
The aim of the instrument is to supply continuous undisturbed and conditioned power to the
critical load. The energy for powering the load comes from the utility, or from the battery
upon mains outage.
At times, power from a wall socket is neither clean nor uninterruptible. Many abnormalities
such as blackouts, brownouts, spikes, surges, and noise can occur. Under the best conditions,
power interruptions can be an inconvenience. At their worst, they can cause loss of data in
computer systems or damage to electronic equipment. It is the function of an Uninterruptible
Power Supply (UPS) to act as a buffer and provide clean, reliable power to vulnerable
electronic equipment. The basic concept of a UPS is to store energy during normal operation
(through battery charging) and release energy (through DC to AC conversion) during a power
failure. UPS systems are traditionally designed using analog components. Today these
systems can integrate a microcontroller with AC sine wave generation, offering the many
benefits.
As the general population continues to grow, there is an ever-increasing demand for
electricity placed on the world’s power -generation and distribution facilities.
Although significant measures are taken to ensure a reliable supply of electric power, the
significant demand for power increases the likelihood that power outages and other electrical
disruptions such as brownouts will occur. UPS that currently existed offer users extended
periods of backup power during which they can continue to use electronic equipment such as
a personal computer. However, this UPS only provide a minimal voltage regulation and

filtering for disturbance occurred. Further, most UPS equipped with microcontroller for
monitoring and display are much expensive than the standard available UPS in the market as
the application of microcontroller will provide a wide range of application in term of
programming and hardware controls. The purpose of this project is to design a UPS
that manages to act as an emergency power supply to critical load and also equipped with
microcontroller programming for UPS monitoring system.
Mobility and versatility have become a must for the fast-paced society today. People can no
longer afford to be tied down to a fixed power source location when using their equipment’s.
Overcoming the obstacle of fixed power has led to the invention of DC/AC power inverters.
While the position of power inverter in the market is relatively well established, there are
several features that can be improved upon. A comparison analysis of the different power
inverterhas been compiled. Aside from the differences in power wattage, cost per wattage, effi
ciency andharmonic contend, power inverters can be categorized into three groups square
wave, modified sine wave, and pure sine wave. A cost analysis of the different types of
inverter shows that sine wave power inverter, though has the best power quality
performance. Another feature which can be improved is the efficiency of the inverter. Thestan
dard sine wave in the market has an average efficiency of 85-90%. Power dissipated due to
efficiency flaws will be dissipated as heat and the 10-15% power lost in the will shorten
operational life span of inverters. The quality of the output power could also be improved. It
is imperative that the output signal be as clean as possible. Distortion in the output signal
leads to a less efficient output and in the case of a square wave, which has a lot of unwanted
harmonics; it will damage some sensitive equipment’s.
In designing any type of power supply, it is important to examine the intended market and
place the product in a particular market. Our market will be to design a 300 watts power
inverter that will provide optimum pure sine wave performance with minimal cost. In meeting
the design requirements, there are several technical challenges that must be overcome. Our
single, most difficult constraint will be to produce power at a lower power per unit cost than
exists in the market. Our efficiency will be greater than 90 percent. This insures that, with a

maximum load, less than 10% of power will be dissipated as heat. The total harmonic
distortion will be less than5 percent.
Generally, an ideal UPS should be able to deliver uninterrupted power while
simultaneously providing the necessary power conditioning for the particular power applicatio
n. Therefore, anideal UPS should have the following features
 Regulated sinusoidal output voltage with low total harmonic distortion (THD)
independent of the changes in the input voltage or in the load, linear or
nonlinear, balanced or unbalanced.
 On-line operation, which means zero switching time from normal to backup mode and
vice versa.
 Low THD sinusoidal input current and unity power factor.
 High reliability.
 Bypass as a redundant source of power in the case of internal failure.
 High efficiency.
 Low electromagnetic interference (EMI) and acoustic noise.
 Electric isolation of the battery, output, and input.
 Low maintenance.
 Low cost, weight, and size.
The need for standby generation arises if the consequences of a failure or disruption of the
normal supply are not acceptable. The types of installation in which the need arises seem to be
limit less. There are basically four reasons for installing standby generation safety, security,
financial loss and data loss.
 Safety Where there is a risk to life or health such as in air traffic control, aviation
ground lighting, medical equipment in hospitals, nuclear installations, oil
refineries.

 Security against vandalism, espionage, or attack Area lighting, communication
systems, military installations, etc.
 Data loss Situations in which the loss of data may be catastrophic and irretrievable
such as data processing and long-term laboratory type of testing or experiment.
 FinanciallossCritical industrial processes, large financial institutions, etc.
The advances in power electronics during the past three decades have resulted in a great
variety of new topologies and control strategies for UPS systems. The research has been
focused mainly on improving performance and expanding application areas of UPS systems.
The issue of reducing the cost of converters has recently attracted the attention of researcher.
Reducing the number of switches provides the most significant cost reduction. Another form
of cost reduction is to replace active switches such as IGBTs, MOSFETs, and thyristors with
diodes. Not only are diodes more reasonable than the controlled switches, but there is also a
cost reduction from eliminating gate drivers for active switches and power supplies for gate
drivers. Another way of reducing cost is to develop topologies that employ switches with
lower reverse voltage stresses and lower current ratings, which means less silicon and smaller
switching losses resulting in lower cost and higher efficiency.
1.2 Classification
UPS systems are classified into three general types static, rotary, and hybrid static/rotary. In
this section, we explain these three categories of the UPS systems.
1.3 Basic steps in simple UPS
 Dc to Ac converter
 Ac to Dc converter

1.3.1 On-Line UPS
On-line UPS systems appeared during the 1970s. They consist of a rectifier/ charger, a battery
set, an inverter, and a static switch (bypass). Other names for this configuration are inverter-
preferred UPS and double-conversion UPS Figure 1.1 shows the block diagram of
a typical on-line UPS. The rectifier/charger continuously supplies the DC bus with power. Its
power rating is required to meet 100% of the power demanded by the load as well as the
power demanded for charging the battery bank. The batteries are usually sealed lead acid
type. They are rated in order to supply power during the backup time, when the AC line is not
available. The duration of this time varies in different applications. The inverter is rated at
100% of the load power since it must supply the load during the normal mode of operation as
well as during the backup time. It is always on; hence, there is no transfer time associated
with the transition from normal mode to stored energy mode. The AC line and load voltage
must be in phase in order to use the static switch. This can be achieved easily by locked-phase
control loop
Fig 1.1

The main important component is inverter, which converts the Dc stored in Battery back into
Ac. So by improving the inverter we can improve the efficiency of UPS. There are few
problems in inverters available in market, so we will try to overcome these problems, to
increase the efficiency of ups.
1.4 Design Background
When designing a UPS system, there are three items that must be considered cost
vs. performance, output waveform and topology.
1.4.1 Cost vs. Performance
A UPS system has to be reliable. Money saved on features or performance can be
overshadowed by the cost associated with data loss or component failure. So it is important to
develop a costeffective solution which satisfies both end user price sensitivity and design
robustness.
1.4.2OutputWaveform
Some UPS designs use a square wave output instead of a sine wave. This makes the system
cheaper to produce. But is this type of waveform really acceptable?
Electrical equipment uses power delivered in the form of a sine wave from local utility
Companies. When considering alternative waveforms, how differing loads rely on different
parts of the standard power company waveform must be examined. Electrical equipment uses
power delivered in the form of a sine wave from local utility companies. When considering
alternative waveforms, how differing loads rely on different parts of the standard power
company wave form must be examined.
For instance, most appliances are always on, thus the power used by the appliance is the RMS
value of the sine wave, which is approximately 120 volts. However, equipment such as
computers use peak voltage values, which are approximately 170 volts. When a square wave

output is used to supply power to computer equipment, the RMS and peak values are
equivalent, thus stressing some loads and under-supplying others. So the best output to
provide electrical equipment is the output that they are designed to operate with - a sine wave.
1.5 Application Markets for UPS Systems
UPS systems provide for a large number of applications in a variety of industries. Their
common applications range from small power rating for personal computer systems to
medium power rating for medical facilities, life-support systems, data storage, and emergency
equipment, and high power rating for telecommunications, industrial processing, and online
management systems. Different considerations should be taken into account for these
applications. As an example, a UPS for emergency systems and lighting may support the
system for 90-120 minutes. For other applications like computer backup power, a UPS may
typically support the system for 15-20 minutes. If power is not restored during that time, the
system will be gracefully shut down.
If a longer backup period is considered, a larger battery is required. For process equipment
and high power applications, some UPS systems are designed to provide enough time for the
secondary power sources, such as diesel generators, to start up.
1.6ComponentsofUPS
Mainly UPS consists of
 DC/DC CONVERTER
 VOLTAGE SOURCE INVERTER (VSI)
 BATTERY CHARGER

1.6.1 DC/DC Converters
Most UPS designs contain a transformer-type DC/DC converter. The transformer provides
electrical isolation between the input and output of the converter. The transformer also
provides the option to produce multiple voltage levels by changing the turns ratio, or provide
multiple voltages by using multiple secondary windings. Transformer-type DC/DC converters
are divided into five basic topologies
 Forward Converter
 Push-Pull Converter
 Half-Bridge Converter
 Full-Bridge Converter
 Flyback Converter
1.6.2 Voltage Source Inverter (VSI)
A single-phase Voltage Source Inverter (VSI) can be defined as a half-bridge and a full-
bridge topology. Both topologies are widely used in power supplies and single-phase
UPS systems.
 Half-Bridge VSI
 Full-Bridge VSI
1.6.3 Battery Charger
When the AC mains voltage is present, the Offline UPS charges the batteries, and therefore,
a battery charger circuit is implemented. Most battery chargers can be divided into four basic
design types, or topologies

 Linear Chargers
 Switch Mode Chargers
 Ferroresonant Chargers
 SCR Chargers

Chapter 2
Intelligence - UPS
2.1 Introduction of i-UPS
We implement intelligent uninterrupted power supply (i-UPS) for multipurpose. It consists
of microcontroller based circuit. Mainly four feature of our i-UPS. First, it is safe and
Improves battery life by using temperature sensor. When battery is fully charged and compara
tor do nottrip battery charging then microcontroller will come into work trip the battery
charging by temperature sensing because heating hardens the battery and it loses its efficiency
and life. Second, we provide two outputs from i-UPS, Load-1 and Load-2, Load-1 controls
lights, chargers and low power electronics appliances. On the other hand, Load-2 controls the
fans and inductor type loads. Third is Energy saving works in the form of battery status.
When battery is at its critical situation it switches off Load-2 and lets the Load-1 on. So we
can get lights at low battery status.
When main supply is on, automatically Load-1 and Load-2 are connected to main supply.
Fourth, we have provided two main energy sources Line-1 and Line-2 from different feeders.
Microcontroller automatically checks and selects the active Line. If both lines are active then
microcontroller will select Line-1 by default setting.
This Intelligent Uninterruptible Power Supply (i-UPS) will enable the users to monitor
different status of i-UPS on LCD. One of the advantage applying microcontroller for the
Intelligent Uninterruptible Power Supply (i-UPS) is that the system is more reliable and user
friendly in functions as compare to the conventional Uninterruptible Power Supply available
in the market. At the competition of our project we will be hopefully able to save energy and
utilization of energy due to intelligent uninterruptible power supply because of our country
facing a large amount of electricity crises so people wants such type of ups like i-UPS.

2.1.1 Objective or Features of our Project
The main objective of our project is handling and utilization of power with Intelligence.
Features and Applications of our work include.
 Improvement of battery life.
 Automatic load control using relays.
 Energy saving in critical battery status.
 Multi input ports for different sources.
 Over Voltage Protection.
2.1.2 i-UPSBlockDiagram
Fig 2.1

2.1.3 Project Applications
 Auto selection of sources
 Auto stop of battery charging
 Continuous Temperature sensing of battery
 Level (status) of Battery
 Automatic load control
 Display different status by LCD
 Continuity of backup in critical battery
2.2 Methodology
2.2.1 Project implementation Steps
 AC/DC conversion
 DC/AC Inversion
 Intelligent circuitry
 LCD interfacing
2.2.2 Implementation Tools
 Pic-16F877A microcontroller for intelligent circuitry
 Pic-16F628A microcontroller for inversion
 Proton Basic for coding
 Simulation Tool used is Proteous
 LCD 4*20 for i-UPS status
 LM-35

Chapter 3
RESULTS AND DISCUSSION
3.1 Principles And Configurations
An UPS system is an alternate or backup source of power with the electric utility company
being the primary source. The UPS provides protection of load against line frequency
variations, elimination of power line noise and voltage transients, voltage regulation, and
uninterruptible power for critical loads during failures of normal utility source. An UPS can b
e considered asource of standby power or emergency power depending on the nature of the
critical loads. The amount of power that the UPS must supply also depends on these specific
needs. These need scan include emergency lighting for evacuation, emergency perimeter
lighting for security, orderly shutdown of manufacturing or computer operations, continued
operation of life support or critical medical equipment, safe operation of equipment during
sags and brownouts, and a combination of the preceding needs.
3.2 Dc-Ac Conversion
After converting 12VDC-220VDC, now we have toconvert it into 220VAC at 50Hzfor deriving home
appliances.
3.2.1 Inverter
The method, in which the low voltage DC power is inverted, is completed in two steps. The
first being the conversion of the low voltage DC power to a high voltage DC source, and the
second step being the conversion of the high DC source to an AC waveform using pulse width
modulation. Another method to complete the desired outcome would be to first convert the
low voltage DC power to AC, and then use a transformer to boost the voltage to 120 volts.
This project focused on the first method described and specifically the transformation of a hig
hvoltage DC source into an AC output. Of the different DCAC inverters on the market today

there are essentially two different forms of AC output generated modified sine wave, and pure
sine wave.
Power inverters were first invented using a square wave as the output form. This led to many
different problems involving the functionality of devices that were being powered because
they were designed to work with a sine wave instead of a square wave. There were some
changes made to the hardware to eliminate the harsh corners from the square wave to
transform it to a modified sine wave. It was mainly marketers who coined the term modified
sine wave which in all reality is nothing more than a modified square wave. Power inverters
that used a modified sine wave eliminate the problems associated with square wave inverters.
Although most people without a background in electronics do not know the difference, a
modified square wave can have detrimental effects on electrical loads. In square wave
inverters abnormal heat will be produced, causing a reduction in product reliability,
efficiency, and useful life. Another disadvantage of a square wave inverter is that its choppy
waveform can confuse the operation of some digital timing devices. Undesirable or abnormal
functions this can cause a device to perform.
A modified sine wave can be seen as more of a square wave than a sine wave; it passes the
high DC voltage for specified amounts of time so that the average power and RMS voltage
are the same as if it were a sine wave. These types of inverters are much cheaper than pure
sine wave inverters and therefore are attractive alternatives. Pure sine wave inverters, on the
otherhand, produce a sine wave output identical to the power coming out of an electrical outle
t. These devices are able to run more sensitive devices that a modified sine wave may cause
damage to such as laser printers, laptop computers, power tools, digital clocks and medical
equipment. This form of AC power also reduces audible noise in devices such as fluorescent
lights and runs inductive loads, like motors, faster and quieter due to the low harmonic
distortion.

3.2.2 Problems in Typical Inverter
Mobility and versatility have become a must for the fast-paced society today. People can no
longer afford to be tied down to a fixed power source location when using their equipment’s.
Overcoming the obstacle of fixed power has led to the invention of DC/AC power inverters.
While the position of power inverter in the market is relatively well established, there are
several features that can be improved upon. A comparison analysis of the different power
inverterhas been compiled. Aside from the differences in power wattage, cost per wattage, effi
ciency andharmonic contend, power inverters can be categorized into three groups square
wave, modified sine wave, and pure sine wave. A cost analysis of the different types of
inverter shows that sine wave power inverter, though has the best power quality
performance. Another feature which can be improved is the efficiency of the inverter. Thestan
dard sine wave in the market has an average efficiency of 85-90%. Power dissipated due to
efficiency flaws will be dissipated as heat and the 10-15% power lost in the will shorten
operational life span of inverters. The quality of the output power could also be improved. It
is imperative that the output signal be as clean as possible. Distortion in the output signal
leads to a less efficient output and in the case of a square wave, which has a lot of unwanted
harmonics; It will damage some sensitive equipment.
In designing any type of power supply, it is important to examine the intended market and
place the product in a particular market. Our market will be to design a power inverter that
will provide optimum pure sine wave performance with minimal cost. In meeting the design
requirements, there are several technical challenges that must be overcome. Our single, most
difficult constraint will be to produce power at a lower power per unit cost than exists in the
market. Our efficiency will be greater than 90 percent. This insures that, with a maximum
load, less than 10%of power will be dissipated as heat. The total harmonic distortion will be
less than 5 percent. With a total harmonic distortion this low and a pure sine wave output, we
will be able to power even the most sensitive loads. . The DC/AC inverter circuit will use a
microprocessor to digitally pulse the transistors. This will allow us to produce a pure sine
wave output. This feature will also allow us to enter other markets more easily. For instance,
in Pakistan the fundamental frequency is 50 Hz. The feedback control system will be used to

regulate the output voltage of the DC/DC converter. This is necessary since the current will
vary will the load. The feedback control system will be accomplished using by sampling
the output with an integrated circuit.
3.2.3 Modified sine wave
Fig 3.1
A modified sine wave is similar to a square wave but instead has a stepping look to it that
Relates more in shape to a sine wave. This can be seen in Figure 2.1, which displays how a
modified sine wave tries to emulate the sine wave itself. The waveform is easy to
produce because it is just the product of switching between 3 values at set frequencies, thereb
y leavingout the more complicated circuitry needed for a pure sine wave. The modified sine
wave inverter provides a cheap and easy solution to powering devices that need AC power. It
does have some drawbacks as not all devices work properly on a modified sine wave,
products such as computers and medical equipment are not resistant to the distortion of the
signal and must be run off of a pure sine wave power source.

3.2.4 Sinusoidal PWM Generation
In electronic power converters and motors, PWM is used extensively as a means of powering
alternating current (AC) devices with an available direct current (DC) source or for advanced
DC/AC conversion. Variation of duty cycle in the PWM signal to provide a DC voltage
across the load in a specific pattern will appear to the load as an AC signal, or can control the
speed of motors that would otherwise run only at full speed or off. This is further explained in
this section. The pattern at which the duty cycle of a PWM signal varies can be created
through simple analog components, a digital microcontroller, or specific PWM integrated
circuits. Analog PWM control requires the generation of both reference and carrier signals
that feed into a comparator which creates output signals based on the difference between the
signals10. The reference signal is sinusoidal and at the frequency of the desired output signal,
while the carrier signal is often either a saw tooth or triangular wave at a frequency
significantly greater than the reference. When the carrier signal exceeds the reference, the
comparator output signal is at one state, and when the reference is at a higher voltage, the
output is at its second state. This process is shown in Figure 3 with the triangular carrier wave
in red, sinusoidal reference wave in blue, and modulated and unmodulated sine pulses.
The average value of voltage (and current) fed to the load is controlled by turning the
switch between supply and load on and off at a fast pace. The longer the switch is on
compared to the off periods, the higher the power supplied to the load is.
The PWM switching frequency has to be much faster than what would affect the load, which
is to say the device that uses the power. Typically switching’s have to be done several times a
Minute in an electric stove, 120 Hz in a lamp dimmer, from few kilohertz (kHz) to tens of
kHz for a motor drive and well into the tens or hundreds of kHz in audio amplifiers and
computer power supplies.
The term duty cycle describes the proportion of 'on' time to the regular interval or 'period'
of time; a low duty cycle corresponds to low power, because the power is off for most of the
time. Duty cycle is expressed in percent, 100% being fully on.
The main advantage of PWM is that power loss in the switching devices is very low. When as
witch is off there is practically no current, and when it is on, there is almost no voltage drop

across the switch. Power loss, being the product of voltage and current, is thus in both cases
close to zero. PWM also works well with digital controls, which, because of their on/off
nature, can easily set the needed duty cycle.
Various PWM techniques have been used to create transistor drive circuits. Before
microcontrollers became popular, varying PWM circuits usually consisted of analogue-to-
digital comparator circuits. These circuits compared a small voltage sinusoidal wave
(reference signal)t o a small voltage saw-tooth wave (control frequency signal). At each point
where the sinusoidal and saw-tooth signals intersect, the output of the comparator toggles
from a high state to a low state.
Today the sinusoidal PWM is generated using Microcontrollers. It is the most economical
solution to get pure sinusoidal output up to tens of kilowatts power rating inverters. The
pulses are not clear due to the high modulation ratio (requirement for pure sinusoidal output).
For small filet at the output, modulation ratio should be greater than 200.

Fig 3.2
In order to source an output with a PWM signal, transistor or other switching technologies are
used to connect the source to the load when the signal is high or low. Full or half bridge
configurations are common switching schemes used in power electronics. Full bridge
configurations require the use of four switching devices and are often referred to as H
Bridges ‘due to their orientation with respect to a load.

3.2.5 Inverter Module
DC/AC conversion is done by inverter module An inverter converts direct current (DC) to
alternating current (AC).The basic components of Inverter module are
 Pic16F628 microcontroller
 Centre-taped Transformer
 D1047 Transistors
 TIP 31 Transistors
3.2.6 Inverter Schematic
Fig 3.3

3.2.7 Sinusoidal PWM Generation
 Various PWM techniques have been used to create transistor drive circuits, Before
microcontrollers became popular.
 Today the sinusoidal PWM is generated using Microcontrollers.
 It is the most economical solution to get pure sinusoidal output up to tens of
kilowatts power rating inverters.
3.2.8. Power Amplification
3.2.8.1. Introduction
Power inverter is a device which converts 12 volts to 150 volts of D.C into 220 volt to 110
volt. Power inverter is commonly known as UPS. UPS stands for uninterruptible power
supply which is the modified form of inverter. Due to the lack of electricity the importance of
inverter increases day by day. The substitute of load shedding is generator or UPS.
Few advantages and disadvantages of generator are as follows
Its first advantage is, it can run many electronic devices and it can supply electricity for the
long duration of load shedding. The disadvantages are noise pollution, usage of fossil fuel
cost it too high. The alternate of generator is UPS, it has also some advantages and
disadvantages.
The supply of electricity goes uninterrupted, it do not require much effort. Its backup depends
on battery, as many amperes of the battery it has, that much it backup it would provide.
Its disadvantages are, recharging takes a lot of time and in the long duration of load
shedding battery cannot be recharged so that it stops working. By putting excessive load the d
uration of backup reduces. Its performance is about 60% to 90%.

3.2.8.2. Components
 Transformer 40 amps (500 W), 220 V, 12X12 V
 Transistor (10) 1047
 Resistor (1) 500 ohms
 Battery 40 Ampere
 Capacitor 250 V, 0.5 uf
3.2.8.3. Method
First of all you have to make some changes in transformer. If u are using 500 V transformer
then take 18 to 22 gauge copper wire and on the one side of transformer’s core make five turn
and put a point on it, and turn this point, and again turn the wire five times on the same
direction. In this way u get three terminals. If u r connect the transformer to 220 V power
supply then it gives1.5 V on both terminals. Now put transformer D1047 on the palm of your
hand and turn it such a way that number appears your way. Now you will see three points.
The point on your left side is known as (B) Base, middle one is collector(C) and the right one
is (E) emitter. (These are the information only for D1047.
Now first of all tight the 5 transistor in heat sink in series with the help of nut bolt.
Connect the base of all five transistors altogether and then join the points of
collector together.

Fig 3.4
In the same way arrange the other five transistors individually and connect the collector(C) of
both sides of transistors with the outer terminal of secondary coil, after that connect the botho
uter terminals of the third coil with the base of the both heat sinks of transistor. Then connect
the (E) emitter of both side by wires n then connect the 500 ohm resistor on emitter and
resistor on either side. Now connect the middle terminal of primary coil by one to two ft long
wire and clip (crocodile) it and attach this terminal always by the positive terminal, and with
the negative terminal of battery connect the both (E) emitter of transistor.
After that the central point of the third coil and a wire attach it with emitter to connect using a
heavy ampere switch between both terminals of the Inverter primary coil to apply a capacitor
This will prevent the current from the sparking. Inverter will switch on as soon as starting to
work.

3.2.8.4 Working
With both the terminals of battery connect the positive and negative wires to its
terminals positive to positive and negative to negative and then open the switch, slightly
vibration starts in the inverter as switch is open. Now you can run it into 1 to 500 watt load.
2.2.8.5 i-UPS Power Amplification
2.2.8.6 i-UPS Power control Circuit
Fig 3.5

3.3 AC to DC Conversion
A rectifier is an electrical device that converts alternating current (AC), which periodicallyrev
erses direction, to direct current (DC), which flows in only one direction. The process is
known as rectification. Physically, rectifiers take a number of forms, including vacuumtube
diodes, mercury-arc valves, solid-state diodes, silicon-controlled rectifiers and other silicon-
based semiconductor switches. Historically, even synchronous electromechanical switches an
dmotors have been used. Early radio receivers, called crystal radios, used a "cat's whisker" of
fine wire pressing on a crystal of galena (lead sulfide) to serve as a point-contact rectifier or
"crystal detector".
Rectifiers have many uses, but are often found serving as components of DC power supplies
and high-voltage direct current power transmission systems. Rectification may serve insoles
other than to generate direct current for use as a source of power. As noted, detectors of radio
signals serve as rectifiers. In gas heating systems flame rectification is used to detect presence
of flame. The simple process of rectification produces a type of DC characterized by pulsating
voltages and currents (although still unidirectional). Depending upon the type of end-use, this
type of DC current may then be further modified into the type of relatively constant voltage
DC characteristically produced by such sources as batteries and solar cells.
3.3.1 Centre-Tap Full-Wave Rectifier
In such a rectifier, the ac input is applied through a transformer, the anodes of the two diodes
D1 and D2 (having similar characteristics) are connected to the opposite ends of the centre
tapped secondary winding and two cathodes are connected to each other and are connected
also through the load resistance RL and back to the centre of the transformer, as shown in

Fig 3.6
When the top of the transformer secondary winding is positive, say during the first half-cycle
of the supply, the anode of diode D1 is positive w.r.t. cathode, and anode of diode D2 is
negative w.r.t. cathode. Thus only diode D1 conducts, being forward biased and current flows
from cathode to anode of diode D1 through load resistance RL and top half the transformer
secondary making cathode end of load resistance RL positive. During the second half-cycle of
the input voltage the polarity is reversed, making the bottom of the secondary winding
positive w.r.t. centre tap and thus diode D2 is forward biased and diode D1 is reverse biased.
Consequently during this half-cycle of the input only the diode D2 conducts and current flows
through the load resistance RL and bottom of the transformer secondary make the cathode end
of the load resistance RL positive. Thus the direction of flow of current through the load
resistance RL remains the same during both halves of the input/supply voltage. Thus the
circuit showed acts as a full-wave rectifier.

Chapter 4
Microcontroller
4.1 Introduction
A microcontroller is a small computer on a single circuit containing a processor core,
memory, and programmable input/output peripherals. Neither program memory in the form
of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount
of RAM. Microcontrollers are designed for embedded applications, in contrast to the
microprocessors used in personal computers or other general purpose applications.
Microcontrollers are used in automatically controlled products and devices, such as
automobile engine control systems, implantable medical devices, remote controls, office
machines, appliances, power tools, toys and other embedded systems. By reducing the size
and cost compared to a design that uses a separate microprocessor, memory, and input/output
devices, microcontrollers make it economical to digitally control even more devices and
processes. Mixed signal microcontrollers are common, integrating analog components
needed to control non-digital electronic systems.
Some microcontrollers may use four-bit words and operate at clock rate frequencies as low
as4 kHz, for low power consumption (mill watts or microwatts). They will generally have the
ability to retain functionality while waiting for an event such as a button press or other
interrupt; power consumption while sleeping (CPU clock and most peripherals off) may be
just nana watts, making many of them well suited for long lasting battery applications.
Other microcontrollers may serve performance-critical roles, where they may need to
act more like a digital signal processor (DSP), with higher clock speeds and power
consumption. Microcontrollers and microprocessors are integrated circuits, but they differ
fundamentally from other ICs. They are a class in themselves, that the designers have not
made them to do a particular job. As such when you buy them from the market, you can not

specify what function it will do. In order to get some useful function, these ICs have to be
configured. Thus a microprocessor or microcontroller can be configured to check the status of
a button, and then turn a motor ON or OFF. While the same IC can be configured later, to
read the status of an infra-red sensor, decode the signal and turn another device ON or OFF.
If these two types of circuitries were to be made using conventional digital ICs, it would have
required a large number of components. Moreover any change in the specification, like
change of Infra-Red codes would result in total change in design! Using a configurable IC is a
great idea. Not only the same IC, can be configured to do different tasks, but a change in
specifications can easily be implemented by just changing the device configuration.
4.1.1 PIC16F877A
In our project we are using the PIC16F877A microcontroller for intelligent circuitry. We have
chosen this controller due to its
 Cost effectiveness.
 High-performance
 Built-in clock
 low-voltage
 Flexibility
4.1.1.1 Peripheral Features
 Timer0 8-bit timer/counter
 Operating speed DC – 20 MHz clock input
 Up to 8K x 14 words of Flash Program Memory
 Up to 368 x 8 bytes of Data Memory (RAM),
 Up to 256 x 8 bytes of EEPROM Data Memory
 Universal Synchronous Asynchronous Receiver Transmitter (USART/SCI)

 Parallel Slave Port (PSP)– 8 bits wide with external RD, WR and CS controls
4.1.1.2 Analog Features
 10-bit, up to 8-channel Analog-to-Digital Converter (A/D)
4.1.1.3 Special Microcontroller Features
 Self-reprogrammable under software control
 In-Circuit Serial Programming™ (ICSP™) via two pins
 Single-supply 5V In-Circuit Serial Programming
 Watchdog Timer (WDT) with its own on-chip RC oscillator for reliable operation
 Programmable code protection
 Power saving Sleep mode
 Selectable oscillator options
 In-Circuit Debug (ICD) via two pins
 Enables you to view variable values, Special Function Register and EEPORM while
the program is running.

4.1.2 Pin Configuration
Fig 4.1

4.1.3 I/O Ports of PIC16F877A
Some pins for these I/O ports are multiplexed with an alternate function for the peripheral
features on the device.
I/ O pins there are 40 pins on PIC16F877A. Most of them can be used as an IO pin. Others are
already for specific functions. These are the pin functions.
1. MCLR – to reset the PIC
2. RA0 -port A pin 0
8. RE0 -port E pin 0
9. RE1 -port E pin 1
10. RE2-port E pin 2
11. VDD- power supply
12. VSS- ground
13. OSC1- connect to oscillator
14. OSC2- connect to oscillator
15. RC0 - port C pin 0
19. RD0 - port D pin 0

31. VSS – ground
32. VDD- power supply
33. RB0 - port B pin 0
2.4.3.1 There are five ports on PIC16F877A
 Port A
 Port B
 Port C
 Port D
 Port E
PORTA
 6-bit wide, bidirectional port.
 Data direction register is TRISA.
 If TRISA=1 then PORTA input port vice versa.
 Pin PA4 is multiplexed with Timer0 module clock input to become the PA4/TOCK1
pin.
 Other PORTA pins are multiplexed with Analog input.

 On power reset these pins are analog input.
PORTB
 8-bit wide, bidirectional port.
 Data direction register is TRISB.
 If TRISB=1, then PORTB is input else output.
 Three pins RB3/PGM, RB6/PGC and RB7/PGD are multiplexed with in circuit
debugging and low voltage programming function.
 RB0/INT is an external interrupt pin and is configured using then INTEDG bit
OPTION_REG<6>.
PORTC
 PORTC is 8-bit wide, bidirectional port.
 Data direction register is TRISC.
 RC0/T1OSO/T1CKI
 Input/output port pin
 Timer1 oscillator output
 Timer1 clock input.
 RC1/T1OSI/CCP2
 Timer1 oscillator input
 PWM2 output.
 RC2/CCP1
 PWM1 output.
 RC3/SCK/SCL
 RC3 can also be the synchronous serial clock for SPI mode.
 RC4/SDI
 RC4 can also be the SPI data in (SPI mode)

 RC5/SDO
 Synchronous Serial Port data output.
 RC6/TX/CK
 USART asynchronous transmit
 Synchronous clock.
 RC7/RX/DT
 USART asynchronous receive
 Synchronous data.
PORTD
 8-bit wide port.
 This port can be I/O or Parallel Slave Port
PORTE
 Three pins port.
 The PORTE pins become the I/O control inputs for the microprocessor port when bit
PSPMODE (TRISE<4>) is set.
 RE0/RD/AN5
 I/O port pin
 read control input in Parallel Slave Port mode
 analog input

 RE1/WR/AN6
 I/O port pin
 write control input in Parallel Slave Port mode
 analog input
 RE2/CS/AN7
 I/O port pin
 chip select control input in Parallel Slave Port mode
 analog input
 PORTE pins are multiplexed with analog inputs.
4.1.4 PIC16F628
4.1.4.1 High-Performance RISC CPU
Operating speeds from DC – 20 MHz
 Interrupt capability
 8-level deep hardware stack
 Direct, Indirect and Relative Addressing modes
 35 single-word instructions- All instructions single cycle except branches
4.1.4.2 Special Microcontroller Features
Internal and external oscillator options
 Precision internal 4 MHz oscillator factory calibrated to ±1%
- Low-power internal 48 kHz oscillator
- External Oscillator support for crystals and resonators
 Power-saving Sleep mode
 Programmable weak pull-ups on PORTB
 Multiplexed Master Clear/Input-pin
 Watchdog Timer with independent oscillator for reliable operation
 Low-voltage programming

 In-Circuit Serial Programming™ (via two pins)
 Programmable code protection
 Brown-out Reset
 Power-on Reset
 Power-up Timer and Oscillator Start-up Timer
 Wide operating voltage range (2.0-5.5V)
 Industrial and extended temperature range
 High-Endurance Flash/EEPROM cell
 100,000 write Flash endurance
 1,000,000 write EEPROM endurance
 40 year data retention+
4.1.4.3 Low-Power Features
Standby Current- 100 nA @ 2.0V, typical
 Operating Current
 12μA @ 32 kHz, 2.0V, typical
 120μA @ 1 MHz, 2.0V, typical
 Watchdog Timer Current
 1μA @ 2.0V, typical
 Timer1 Oscillator Current
 1.2μA @ 32 kHz, 2.0V,typical
 Dual-speed Internal Oscillator
 Run-time selectable between 4 MHz and48 kHz
 4μs wake-up from Sleep, 3.0V, typical
4.1.4.4 Peripheral Features
 16 I/O pins with individual direction control
 High current sink/source for direct LED drive
 Analog comparator module with

 Two analog comparators
 Programmable on-chip voltage reference
 (VREF) module
 Selectable internal or external reference
 Comparator outputs are externally accessible
 Timer0 8-bit timer/counter with 8-bit
 programmable prescaler
 Timer1 16-bit timer/counter with external crystal/
 clock capability
 Timer2 8-bit timer/counter with 8-bit period
 register, prescaler and postscaler
 Capture, Compare, PWM module
 16-bit Capture/Compare
 10-bit PWM
 Addressable Universal Synchronous/Asynchronous
 Receiver/Transmitter USART/SCI

2.4.5 Pin Configuration
Fig 4.2

4.2 Microprocessor Oscillator
Most microprocessors, micro-controllers and PICs have two oscillator pins labeled OSC1
andOSC2 to connect to an external quartz crystal, RC network or even a ceramic resonator. In
this application the Quartz Crystal Oscillator produces a train of continuous square wave
pulses whose frequency is controlled by the crystal which intern regulates the instructions that
controls the device.
Fig 4.3
4.3 Software
 Proton Basic
 Proteous

4.3.1 Proton Basic
 For coding we have used proton Basic. Compiler based on BASIC Language
 Designed for PIC microcontrollers ONLY
4.3.2 BASIC Language
 Very easy to learn and use.
 A BASIC compiler will produce code that runs fast as a C compiler.
 Many in built functions (depending on compiler).
 Very popular, large user base with many example programs.
 Major advantages and why Basic is popular for hardware & Software designing
 100 % High-level programming languages
 Easy for beginners to use
 Allow advanced features to be added for experts
 Provide clear and friendly error messages and correction
Today’s market is demanding to solve their hardware & software problems, which is easily
done through
 Proton Basic Plus (PIC Microcontroller)
 Microsoft Visual Basic (PC to Hardware Communication, Database, etc )
 Visual Basic .NET (.NET Framework)
 & many more……

4.3.3 Proteous
The Proteus Design Suite is wholly unique in offering the ability to co-simulate both high and
low-level micro-controller code in the context of a mixed-mode SPICE circuit simulation.
With this Virtual System Modeling facility, you can transform your product design cycle,
reaping huge rewards in terms of reduced time to market and lower costs of development. If
one person designs both the hardware and the software then that person benefits as the
hardware design may be changed just as easily as the software design. In larger organizations
where the two roles are separated, the software designers can begin work as soon as the
schematic is completed; there is no need for them to wait until a physical prototype exists. In
short, Proteus VSM improves efficiency, quality and flexibility throughout the design process.
4.4 Transformer
A transformer is a power converter that transfers electrical energy from one circuit to
another through inductively coupled conductors the transformer's coils. A varying current in
thefirstor primary winding creates a varying magnetic flux in the transformer's core and thus a
varyingmagnetic field through the secondary winding. This varying magnetic field induces a
varying electromotive force (EMF), or "voltage", in the secondary winding. This effect is
called inductive coupling.
If a load is connected to the secondary winding, current will flow in this winding, and
electrical energy will be transferred from the primary circuit through the transformer to the
load. In an ideal transformer, the induced voltage in the secondary winding (Vs) is in
proportion to the primary voltage (Vp) and is given by the ratio of the number of turns in the
secondary (Ns) to the number of turns in the primary (Np) as follows
Vs/Vp = Ns/Np

4.4.1 Basic Principle
The transformer is based on two principles first, that an electric current can produce a
magnetic field (electromagnetism) and second that a changing magnetic field within a coil of
wire inducesa voltage across the ends of the coil (electromagnetic induction). Changing the
current in the primary coil changes the magnetic flux that is developed. The changing
magnetic flux induces a voltage in the secondary coil.
Fig 4.4
An ideal transformer is shown in the adjacent figure. Current passing through the primary coil
creates a magnetic field. The primary and secondary coils are wrapped around a core of very
high magnetic permeability, such as iron, so that most of the magnetic flux passes through
both the primary and secondary coils.

4.5 i-UPSTransformer
Fig 4.5

4.6 Intelligent circuitry & LCD interfacing
We implement intelligent uninterrupted power supply (i-UPS) for multipurpose. It consists
of microcontroller based circuit. Mainly four feature of our i-UPS.
4.6.1 First
It is safe and Improves battery life by using temperature sensor. When battery is fully charged
and comparator do not trip battery charging then microcontroller will come into work trip
the battery charging by temperature sensing because heating hardens the battery and it loses
its efficiency and life.
4.6.2 Second
We provide two outputs from i-UPS, Load-1 and Load-2, Load-1 controls lights, chargers and
low power electronics appliances. On the other hand, Load-2 controls the fans and inductor
type loads.
4.6.3 Third
Is Energy saving works in the form of battery status. When battery is at its critical situation it
switches off Load-2 and lets the Load-1 on. So we can get lights at low battery status. When
main supply is on, automatically Load-1 and Load-2 are connected to main supply.
4.6.4 Fourth
We have provided two main energy sources Line-1 and Line-2 from different feeders.
Microcontroller automatically checks and selects the active Line. If both lines are active then
microcontroller will select Line-1 by default setting.

4.6.5 Intelligent circuitry & LCD interfacing
Fig 4.6

4.7 Final Hardware Implementation
Fig 4.7

Chapter 5
SUMMARY AND CONCLUSION
5.1 Summary and Conclusion
During the last decades UPS system had undergone several major changes due to benefits
from the developments in power semiconductor devices, microprocessors, maintenance free
sealed lea. acid, and improvements in control techniques. Thus, it has become one of the
fastest growing fields of power electronics. UPS provides emergency power to critical loads
in case of utility mains failure, and as such constitutes an essential element in providing back-
up power [1]for computer networks, communication links, biomedical equipment, and
industrial processes, among others. Full hardware-based UPS are gradually being replaced by
microprocessor or microcontroller-based counterparts, with significant improvement in ease
of design, flexibility of the control software and overall reduction in development cost. Since
a UPS incorporates a relatively large number of detection, protection and control functions,
[2] it is important to develop an organized approach to the identification and implementation
of these requirements.
5.2 Comparison with simple UPS
In simple ups the output waveform is rectangular. Distortion in the output signal leads to a
less efficient output and in the case of a square wave, which has a lot of unwanted harmonics;
it will damage some sensitive equipment
.
The quality of the output power could also be improved. It is imperative that the output signal
be as clean as possible. About 20 -30 % power is being dissipated as heat. A cost analysis of
the different types of inverter shows that sine wave power inverter, though has the best power
quality performance, and has a big spike in cost per unit power.

Another feature which can be improved is the efficiency of the inverter. The standard sine
wave in the market has an average efficiency of 85-90%. Power dissipated due to efficiency
flaws will be dissipated as heat and the 10-15% power lost in the will shorten operational
lifespan of inverters. The quality of the output power could also be improved. It is imperative
that the output signal be as clean as possible.
5.3 Conclusion with Future Work
This Intelligent Uninterruptible Power Supply (i-UPS) will enable the users to monitor
different status of i-UPS on LCD. One of the advantage applying microcontroller for the
Intelligent Uninterruptible Power Supply (i-UPS) is that the system is more reliable and user
friendly in functions as compare to the conventional Uninterruptible Power Supply available
in the market. At the competition of our project we will be hopefully able to save energy and
utilization of energy due to intelligent uninterruptible power supply because of our country
facing a large amount of electricity crises so people wants such type of ups like i-UPS.
We are also plane to launch i-UPS in market and plane to make a transformer lees i-UPS in
Future work.

References
6.1. References
6.1.1. Book
 UNINTERRUPTIBLE POWER SUPPLIES AND ACTIVE FILTERS
 By Ali Emadi, Abdolhosein Nasiri
 Uninterruptible power supplies
 By William Knight
 Uninterruptible power systems (UPS)
 ByIEC
 IEEE 446
 Orange Book, Emergency and Standby Power Systems for Industrial and Commercial
Applications, (1996) (cited in paragraph 2-3, Table 3-1)
 IEEE 450
 Recommended Practice for Maintenance, Testing, and Replacement of Vented Lead-
Acid Batteries for Stationary Applications, (1995) [cited in paragraphs 3-2b (2), 5-2c,
and 5-2c5- 2c (2) (k), 5-2f (4), 5-2f (5) (6)]
 ANSI/IEEE 519
 Recommended Practices and Requirements for Harmonic Control in Electrical
Power Systems, (1992) (cited in table 2-2)

6.1.2. Journal Articles
 Farrukh, K. and T.G. Habetler, 1998. A novel online UPS with universal filtering
capabilities. IEEE Trans. on Power Electronics, 13 3.
 Matthew, S.R., J.D. Parham and M.H. Rashid, An Overview of Uninterruptible
Power Supplies. IEEE Proc., pp 159-164.
 S.A.Z. Murad "Monitoring system for uninterruptible power supply". American
Journalof Applied Sciences. FindArticles.com. 09 Aug, 2011.
 Tanvir Singh Mundra "Microcontroller based power supply". Journal of
Computer Science. FindArticles.com. 09 Aug, 2011.

report on the Techno india network

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Ähnlich wie report on the Techno india network

Ähnlich wie report on the Techno india network (20)

Mehr von Yuvraj Singh

Mehr von Yuvraj Singh (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

report on the Techno india network