Automatic Power Factor Corrector Using Capacitive Load Bank2

8/13/2019 Automatic Power Factor Corrector Using Capacitive Load Bank2

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R.V.R Institute of Engg. & Tech.

AUTOMATIC POWER FACTOR CORRECTOR

USING CAPACITIVE LOAD BANK

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1. INTRODUCTION

1.1 INTRODUCTION:

An embedded system is a combination of software and hardware to perform a

dedicated task. Some of the main devices used in embedded products are

Microprocessors and Microcontrollers. Microprocessors are commonly referred to as

general purpose processors as they simply accept the inputs, process it and give the

output. In contrast, a microcontroller not only accepts the data as inputs but also

manipulates it, interfaces the data with various devices, controls the data and thus finally

gives the result.

1.2 PROBLEM FORMULATION:

All these tasks are possible with the microcontroller because the microcontroller

has a CP in addition to a fi!ed amount of "AM, "#M, I$# ports and timer all on a

single chip. %his fi!ed amount of "AM, "#M and number of I$# ports in microcontroller

makes them ideal for many applications where cost and space are critical.

1.3. LITERATURE SURVEY:

%he automated power factor corrector using capacitive load banks is helpful in

providing the power factor correction without manual capacitive bank loading. &arlier the

power factor correction is done by manually ad'usting the capacitive bank manually.

(ow the automated pro'ect we have done helps us to decrease the manpower and thus

helps to decrease the time taken to correct the power factor which helps to increase the

efficiency.

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1.4OBJECTIVE OF THESIS:

%his pro'ect provides continuous power factor correction without manualcapacitive bank loading. A P)C controller provides power factor correction and peak

current limiting for a Switch*mode power converter of any topology +buck, boost or

buck*boost, without having to directly sense inductor current.

1.4 ORGANIZATION OF THESIS:

In this paper we are discussed about some of the important issues in different chapters

like-

Chapter 2: In this chapter we discussed about the &mbedded Systems.

Chapter 3: In this rd chapter functions have been discussed in detail about Micro

controllers .

Chapter 4: In this chapter we are going to discuss about Programming the )lash.

Chapter 5: In this chapter we are going to discuss about Automatic Power factor

Controller.

Chapter 6: In this chapter we discussed about the Component Specifications.

Chapter 7: In this chapter we discussed about the /oad 0anks.

Chapter 8: Conclusion and future scope utilities have been mentioned in this final

chapter proceeded with re1uired references.

2. EMBEDDED SYSTEMS

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2.1 INTRODUCTION TO EMBEDDED SYSTEMS:

An embedded system can be defined as a computing device that does a specificfocused 'ob. Appliances such as the air*conditioner, 2C3 player, 323 player, printer,

fa! machine, mobile phone etc. are e!amples of embedded systems. &ach of these

appliances will have a processor and special hardware to meet the specific re1uirement of

the application along with the embedded software that is e!ecuted by the processor for

meeting that specific re1uirement. %he embedded software is also called 4firm ware5.

%he desktop$laptop computer is a general purpose computer. 6ou can use it for a variety

of applications such as playing games, word processing, accounting, software

development and so on. In contrast, the software in the embedded systems is always fi!ed

listed below-

• &mbedded systems do a very specific task, they cannot be programmed to do

different things. &mbedded systems have very limited resources, particularly the

memory. 7enerally, they do not have secondary storage devices such as the

C3"#M or the floppy disk. &mbedded systems have to work against some

deadlines. A specific 'ob has to be completed within a specific time. In some

embedded systems, called real*time systems, the deadlines are stringent. Missing

a deadline may cause a catastrophe*loss of life or damage to property. &mbedded

systems are constrained for power. As many embedded systems operate through a

battery, the power consumption has to be very low.

• Some embedded systems have to operate in e!treme environmental conditions

such as very high temperatures and humidity.

2.2 APPLICATION AREAS:

(early 88 per cent of the processors manufactured end up in embedded systems.

%he embedded system market is one of the highest growth areas as these systems are

used in very market segment* consumer electronics, office automation, industrial

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automation, biomedical engineering, wireless communication, data communication,

telecommunications, transportation, military and so on.

2.2.1 C!"#$%& A''()*!+%":

At home we use a number of embedded systems which include digital camera,

digital diary, 323 player, electronic toys, microwave oven, remote controls for %2 and

air*conditioner, 2C# player, video game consoles, video recorders etc. %oday9s high*

tech car has about :; embedded systems for transmission control, engine spark control,

air*conditioning, navigation etc. &ven wristwatches are now becoming embedded

systems. %he palmtops are powerful embedded systems using which we can carry out

many general*purpose tasks such as playing games and word processing.

2.2.2 O,,)+% A#-$*-)!:

%he office automation products using embedded systems are copying machine,

fa! machine, key telephone, modem, printer, scanner etc.

2.2.3 I!#"-&)*( A#-$*-)!:

%oday a lot of industries use embedded systems for process control. %hese include

pharmaceutical, cement, sugar, oil e!ploration, nuclear energy, electricity generation and

transmission. %he embedded systems for industrial use are designed to carry out specific

tasks such as monitoring the temperature, pressure, humidity, voltage, current etc., and

then take appropriate action based on the monitored levels to control other devices or to

send information to a centrali<ed monitoring station. In ha<ardous industrial environment,

where human presence has to be avoided, robots are used, which are programmed to do

specific 'obs. %he robots are now becoming very powerful and carry out many interesting

and complicated tasks such as hardware assembly.

2.2.4 M%)+*( E(%+-&!)+":

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Almost every medical e1uipment in the hospital is an embedded system. %hese

e1uipments include diagnostic aids such as &C7, &&7, blood pressure measuring

devices, =*ray scanners> e1uipment used in blood analysis, radiation, colonoscopy,

endoscope etc. 3evelopments in medical electronics have paved way for more accurate

diagnosis of diseases.

2.2./ C$'#-%& N%-0&)!:

Computer networking products such as bridges, routers, Integrated Services

3igital (etworks +IS3(, Asynchronous %ransfer Mode +A%M, =.:? and frame relay

switches are embedded systems which implement the necessary data communication

protocols. )or e!ample, a router interconnects two networks. %he two networks may be

running different protocol stacks. %he router9s function is to obtain the data packets from

incoming pores, analy<e the packets and send them towards the destination after doing

necessary protocol conversion. Most networking e1uipments, other than the end systems

+desktop computers we use to access the networks, are embedded systems.

2.2. T%(%+$$#!)+*-)!":

In the field of telecommunications, the embedded systems can be categori<ed as

subscriber terminals and network e1uipment. %he subscriber terminals such as key

telephones, IS3( phones, terminal adapters, web cameras are embedded systems. %he

network e1uipment includes multiple!ers, multiple access systems, Packet Assemblers

3issemblers +PA3s, sate@@ite modems etc. IP phone, IP gateway, IP gatekeeper etc. are

the latest embedded systems that provide very low*cost voice communication over the

Internet.

2.2. W)&%(%"" T%+5!()%":

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using fingerprint and face recognition are now being e!tensively used for user

authentication in banking applications as well as for access control in high security

buildings.

2.2.19 F)!*!+%-

)inancial dealing through cash and che1ues are now slowly paving way for

transactions using smart cards and A%M +Automatic %eller Machine, also e!panded as

Any %ime Money machines. Smart card, of the si<e of a credit card, has a small micro*

controller and memory> and it interacts with the smart card reader. A%M machine and

acts as an electronic wallet. Smart card technology has the capability of ushering in a

cashless society. ell, the list goes on. It is no e!aggeration to say that eyes wherever

you go, you can see, or at least feel, the work of an embedded system.

2.3 OVER VIEW OF EMBEDDED SYSTEM ARCHITECTURE:

&very embedded system consists of custom*built hardware built around a Central

Processing nit +CP. %his hardware also contains memory chips onto which the

software is

)ig- :.@ Architecture can be represented as a layered architecture

loaded. %he software residing on the memory chip is also called the firmware9. %he

operating system runs above the hardware, and the application software runs above the

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operating system. %he same architecture is applicable to any computer including a

desktop computer. Dowever, there are significant differences. It is not compulsory to

have an operating system in every embedded system. )or small appliances such as remote

control units, air conditioners, toys etc., there is no need for an operating system and you

can write only the software specific to that application. )or applications involving

comple! processing, it is advisable to have an operating system. In such a case, you need

to integrate the application software with the operating system and then transfer the entire

software on to the memory chip. #nce the software is transferred to the memory chip, the

software will continue to run for a long time you don9t need to reload new software.

now, let us see the details of the various building blocks of the hardware of an embedded

system. As shown in )ig. the building blocks are-

• Central Processing nit +CP

• Memory +"ead*only Memory and "andom Access Memory

• Input 3evices

• #utput devices

• Communication interfaces

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)ig- :.: Dardware of an embedded system

2.3.1 C%!-&*( P&+%"")! U!)- CPU;:

%he Central Processing nit +processor, in short can be any of the following-

microcontroller, microprocessor or 3igital Signal Processor +3SP. A micro*controller is

a low*cost processor. Its main attraction is that on the chip itself, there will be many other

components such as memory, serial communication interface, analog*to digital converter

etc. So, for small applications, a micro*controller is the best choice as the number of

e!ternal components re1uired will be very less. #n the other hand, microprocessors are

more powerful, but you need to use many e!ternal components with them. 3?P is used

mainly for applications in which signal processing is involved such as audio and video

processing.

2.3.2 M%$&8:

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%he memory is categori<ed as "andom Access @@emory +"AM and "ead #nly

Memory +"#M. %he contents of the "AM will be erased if power is switched off to the

chip, whereas "#M retains the contents even if the power is switched off. So, the

firmware is stored in the "#M. hen power is switched on, the processor reads the

"#M> the program is program is e!ecuted.

2.3.3 I!'#- D%<)+%":

nlike the desktops, the input devices to an embedded system have very limited

capability. %here will be no keyboard or a mouse, and hence interacting with the

embedded system is no easy task. Many embedded systems will have a small keypad*you

press one key to give a specific command. A keypad may be used to input only the digits.

Many embedded systems used in process control do not have any input device for user

interaction> they take inputs from sensors or transducers @9fnd produce electrical signals

that are in turn fed to other systems.

2.3.4 O#-'#- D%<)+%":

%he output devices of the embedded systems also have very limited capability.

Some embedded systems will have a few /ight &mitting 3iodes +/&3s to indicate the

health status of the system modules, or for visual indication of alarms. A small /i1uid

Crystal 3isplay +/C3 may also be used to display some important parameters.

2.3./ C$$#!)+*-)! I!-%&,*+%":

%he embedded systems may need to, interact with other embedded systems at

they may have to transmit data to a desktop. %o facilitate this, the embedded systems are

provided with one or a few communication interfaces such as "S::, "SE::, "SEF?,

niversal Serial 0us +S0, and I&&& @8E, &thernet etc.

2.3. A''()+*-)!=S'%+),)+ C)&+#)-&8-





Sensors, transducers, special processing and control circuitry may be re1uired fat an

embedded system, depending on its application. %his circuitry interacts with the

processor to carry out the necessary work. %he entire hardware has to be given power

supply either through the :; volts main supply or through a battery. %he hardware has to

design in such a way that the power consumption is minimi<ed.

2.4 S#$$*&8:

0y close observation about this chapter we have discussed about the &mbedded

Systems and their application in this pro'ect.





3. MICRO CONTROLLERS

3.1 INTRODUCTION:

Microprocessors and microcontrollers are widely used in embedded systems

products. Microcontroller is a programmable device. A microcontroller has a CP in

addition to a fi!ed amount of "AM, "#M, I$# ports and a timer embedded all on a single

chip. %he fi!ed amount of on*chip "#M, "AM and number of I$# ports in

microcontrollers makes them ideal for many applications in which cost and space are

critical.

%he Intel F;?@ is a Darvard architecture, single chip microcontroller +GC which

was developed by Intel in @8F; for use in embedded systems. It was popular in the @8F;s

and early @88;s, but today it has largely been superseded by a vast range of enhanced

devices with F;?@*compatible processor cores that are manufactured by more than :;

independent manufacturers including Atmel, Infineon %echnologies and Ma!im

Integrated Products.

F;?@ is an F*bit processor, meaning that the CP can work on only F bits of data

at a time. 3ata larger than F bits has to be broken into F*bit pieces to be processed by the

CP. F;?@ is available in different memory types such as 2*&P"#M, )lash and (2*

"AM.

%he microcontroller used in this pro'ect is A%F8C?@. Atmel Corporation

introduced this F8C?@ microcontroller. %his microcontroller belongs to F;?@ family. %his

microcontroller had @:F bytes of "AM, EH bytes of on*chip "#M, two timers, one serial

port and four ports +each F*bits wide all on a single chip. A%F8C?@ is )lash type F;?@.

%he present pro'ect is implemented on Heil vision. In order to program the

device, Proload tool has been used to burn the program onto the microcontroller.





%he features, pin description of the microcontroller and the software tools used are

discussed in the following sections.

3.2 FEATURES OF AT67C/1:

EH 0ytes of "e*programmable )lash Memory.

"AM is @:F bytes.

:.2 to J2 #perating "ange.

)ully Static #peration- ; D< to :E MD<.

%wo*level Program Memory /ock.

@:F ! F*bit Internal "AM.

: Programmable I$# /ines.

%wo @J*bit %imer$Counters.

Si! Interrupt Sources.

Programmable Serial A"% Channel.

/ow*power Idle and Power*down Modes.

3.3 DESCRIPTION:

%he A%F8C?@ is a low*voltage, high*performance CM#S F*bit microcomputer

with EH bytes of )lash programmable memory. %he device is manufactured using

Atmel9s high*density nonvolatile memory technology and is compatible with the

industry*standard MCS*?@ instruction set. 0y combining a versatile F*bit CP with )lash





on a monolithic chip, the Atmel A%F8C?@ is a powerful microcomputer, which provides

a highly fle!ible and cost*effective solution to many embedded control applications.

In addition, the A%F8C?@ is designed with static logic for operation down to <ero

fre1uency and supports two software selectable power saving modes. %he Idle Mode

stops the CP while allowing the "AM, timer$counters, serial port and interrupt system

to continue functioning. %he power*down mode saves the "AM contents but free<es the

oscillator disabling all other chip functions until the ne!t hardware reset.

)ig .@ Pin diagram





PIN DESCRIPTION:

3.3.1 S#''(8 V++:

Pin E; provides supply voltage to the chip. %he voltage source is K?2.

3.3.2 GND:

Pin :; is the ground.

3.3.3 >TAL1 *! >TAL2:

=%A/@ and =%A/: are the input and output, respectively, of an inverting

amplifier that can be configured for use as an on*chip oscillator, as shown in )igure @@.

&ither a 1uart< crystal or ceramic resonator may be used. %o drive the device from an

e!ternal clock source, =%A/: should be left unconnected while =%A/@ is driven, as

shown in the below figure. %here are no re1uirements on the duty cycle of the e!ternal

clock signal, since the input to the internal clocking circuitry is through a divide*by*two

flip*flop, but minimum and ma!imum voltage high and low time specifications must be

observed.

)ig- .: #scillator Connections





C@, C: L ; p) @; p) for Crystals

L E; p) @; p) for Ceramic "esonators

)ig- . &!ternal Clock 3rive Configuration

3.3.4 RESET:

Pin8 is the reset pin. It is an input and is active high. pon applying a high pulse

to this pin, the microcontroller will reset and terminate all the activities. %his is often

referred to as a power*on reset.

3.3./ EA E?-%&!*( *++%"";:

Pin @ is &A. It is an active low signal. It is an input pin and must be connected to

either 2cc or 7(3 but it cannot be left unconnected.

%he F;?@ family members all come with on*chip "#M to store programs. In

such cases, the &A pin is connected to 2cc. If the code is stored on an e!ternal "#M, the

&A pin must be connected to 7(3 to indicate that the code is stored e!ternally.





3.3. PSEN P&&*$ "-&% %!*@(%;:

%his is an output pin.

3.3. ALE A&%"" (*-+5 %!*@(%;:

%his is an output pin and is active high.

3.3.6 P&-" 9 1 2 *! 3:

%he four ports P;, P@, P: and P each use F pins, making them F*bit ports. All

the ports upon "&S&% are configured as input, since P;*P have value ))D on them.

3.3.7 P&- 9P9;:

Port ; is also designated as A3;*A3, allowing it to be used for both address and

data. A/& indicates if P; has address or data. hen A/&L;, it provides data 3;*3, but

when A/&L@, it has address A;*A. %herefore, A/& is used for demultiple!ing address

and data with the help of an internal latch.

hen there is no e!ternal memory connection, the pins of P; must be connected

to a @;H*ohm pull*up resistor. %his is due to the fact that P; is an open drain. ith

e!ternal pull*up resistors connected to P;, it can be used as a simple I$#, 'ust like P@ and

P:. 0ut the ports P@, P: and P do not need any pull*up resistors since they already have

pull*up resistors internally. pon reset, ports P@, P: and P are configured as input ports.

3.3.19 P&- 1 *! P&- 2:

ith no e!ternal memory connection, both P@ and P: are used as simple I$#.

ith e!ternal memory connections, port : must be used along with P; to provide the @J*

bit address for the e!ternal memory. Port : is designated as AF*A@? indicating its dual





function. hile P; provides the lower F bits via A;*A, it is the 'ob of P: to provide bits

AF*A@? of the address.

3.3.11 P&- 3:

Port occupies a total of F pins, pins @; through @. It can be used as input or

output. P does not need any pull*up resistors, the same as port @ and port :. Port has an

additional function of providing some e!tremely important signals such as interrupts.

T*@(%: P&- 3 A(-%&!*-% F#!+-)!"

3.3.12 M*+5)!% +8+(% ,& -5% 69/1:

%he CP takes a certain number of clock cycles to e!ecute an instruction. In the

F;?@ family, these clock cycles are referred to as machine cycles. %he length of the

machine cycle depends on the fre1uency of the crystal oscillator. %he crystal oscillator,





along with on*chip circuitry, provides the clock source for the F;?@ CP. %he fre1uency

can vary from E MD< to ; MD<, depending upon the chip rating and manufacturer. 0ut

the e!act fre1uency of @@.;?8: MD< crystal oscillator is used to make the F;?@ based

system compatible with the serial port of the I0M PC.

In the original version of F;?@, one machine cycle lasts @: oscillator periods.

%herefore, to calculate the machine cycle for the F;?@, the calculation is made as @$@: of

the crystal fre1uency and its inverse is taken .%he assembly language program is written

and this program has to be dumped into the microcontroller for the hardware kit to

function according to the software. %he program dumped in the microcontroller is stored

in the )lash memory in the microcontroller. 0efore that, this )lash memory has to be

programmed.

3.4 BLOCK DIAGRAM:







4. PROGRAMMING THE FLASH

4.1 INTRODUCTION:

%he A%F8C?@ is normally shipped with the on*chip )lash memory array in the

erased state +that is, contents L ))D and ready to be programmed. %he programming





interface accepts either a high*voltage +@:*volt or a low*voltage +2CC program enable

signal. %he low*voltage programming mode provides a convenient way to program the

A%F8C?@ inside the user9s system, while the high*voltage programming mode is

compatible with conventional third party )lash or &P"#M programmers. %he A%F8C?@

is shipped with either the high*voltage or low*voltage programming mode enabled. %he

respective top*side marking and device signature codes are listed in the following table.

%able E.@ %op side marking and device signature

%he A%F8C?@ code memory array is programmed byte*byte in either programming

mode. %o program any nonblank byte in the on*chip )lash Memory, the entire memory

must be erased using the Chip &rase Mode.

4.2 PROGRAMMING ALGORITHM:





0efore programming the A%F8C?@, the address, data and control signals should

be set up according to the )lash programming mode table. %o program the A%F8C?@, the

following steps should be considered-

@. Input the desired memory location on the address lines.

:. Input the appropriate data byte on the data lines.

. Activate the correct combination of control signals.

E. "aise &A$2PP to @:2 for the high*voltage programming mode.

?. Pulse A/&$P"#7 once to program a byte in the )lash array or the lock bits. %he byte*

write cycle is self*timed and typically takes no more than @.? ms.

"epeat steps @ through ?, changing the address and data for the entire array or until the

end of the ob'ect file is reached.

4.2.1D*-* P(()!:

%he A%F8C?@ features 3ata Polling to indicate the end of a write cycle. 3uring a

write cycle, an attempted read of the last byte written will result in the complement of the

written datum on P#.. #nce the write cycle has been completed, true data are valid on





all outputs, and the ne!t cycle may begin. 3ata Polling may begin any time after a write

cycle has been initiated.

4.2.2 R%*8B#"8:

%he progress of byte programming can also be monitored by the "36$0S6

output signal. P.E is pulled low after A/& goes high during programming to indicate

0S6. P.E is pulled high again when programming is done to indicate "&A36.

4.2.3 C5)' E&*"%:

%he entire )lash array is erased electrically by using the proper combination of

control signals and by holding A/&$P"#7 low for @; ms. %he code array is written with

all 4@5s. %he chip erase operation must be e!ecuted before the code memory can be re*

programmed.

4.2.4 R%*)! -5% S)!*-#&% B8-%":

%he signature bytes are read by the same procedure as a normal verification of locations

;;D, ;@D, and ;:D, e!cept that P.J and P. must be pulled to a logic low. %he

values returned are as follows.





+;;D L @&D indicates manufactured by Atmel

+;@D L ?@D indicates F8C?@

+;:D L ))D indicates @:2 programming

+;:D L ;?D indicates ?2 programming

4.2./ P&&*$$)! I!-%&,*+%:

&very code byte in the )lash array can be written and the entire array can be

erased by using the appropriate combination of control signals. %he write operation cycle

is self timed and once initiated, will automatically time itself to completion. All ma'or

programming vendors offer worldwide support for the Atmel microcontroller series.





)ig- E.@ )lash Programming Modes





)ig-E.: Programming the )lash )ig-E. 2erifying the )lash

4.3 SOFTWARES USED:

4.3.1 KEIL COMPILER:

Heil compiler is software used where the machine language code is written and

compiled. After compilation, the machine source code is converted into he! code which

is to be dumped into the microcontroller for further processing. Heil compiler also

supports C language code.

4.3.2 PROLOAD:





Proload is software which accepts only he! files. #nce the machine code is

converted into he! code, that he! code has to be dumped into the microcontroller and this

is done by the Proload. Proload is a programmer which itself contains a microcontroller

in it other than the one which is to be programmed. %his microcontroller has a program in

it written in such a way that it accepts the he! file from the keil compiler and dumps this

he! file into the microcontroller which is to be programmed. As the proload programmer

kit re1uires power supply to be operated, this power supply is given from the power

supply circuit designed above. It should be noted that this programmer kit contains a

power supply section in the board itself but in order to switch on that power supply, a

source is re1uired. %hus this is accomplished from the power supply board with an output

of @:volts.

4.4 LIUID CRYSTAL DISPLAY:

/C3 stands for Li1uid Crystal Display. /C3 is finding wide spread use replacing

/&3s +seven segment /&3s or other multi segment /&3s because of the following

reasons-

@. %he declining prices of /C3s.

:. %he ability to display numbers, characters and graphics. %his is in contrast to

/&3s, which are limited to numbers and a few characters.

. Incorporation of a refreshing controller into the /C3, thereby relieving the CPof the task of refreshing the /C3. In contrast, the /&3 must be refreshed by the

CP to keep displaying the data.

E. &ase of programming for characters and graphics.





%hese components are 4speciali<ed5 for being used with the microcontrollers, which

means that they cannot be activated by standard IC circuits. %hey are used for writing

different messages on a miniature /C3.

)ig E.E /C3 3isplay

A model described here is for its low price and great possibilities most fre1uently

used in practice. It is based on the D3EEF; microcontroller + Hitachi and can display

messages in two lines with @J characters each . It displays all the alphabets, 7reek letters,

punctuation marks, mathematical symbols etc. In addition, it is possible to display

symbols that user makes up on its own. Automatic shifting message on display +shift left

and right, appearance of the pointer, backlight etc. are considered as useful

characteristics.

4./ PIN FUNCTIONS:





%here are pins along one side of the small printed board used for connection to the

microcontroller. %here are total of @E pins marked with numbers +@J in case the

background light is built in. %heir function is described in the table below-

E.?.@ /C3 screen-





/C3 screen consists of two lines with @J characters each. &ach character consists

of ?! dot matri!. Contrast on display depends on the power supply voltage and whether

messages are displayed in one or two lines. )or that reason, variable voltage ;*2dd is

applied on pin marked as 2ee. %rimmer potentiometer is usually used for that purpose.

Some versions of displays have built in backlight +blue or green diodes. hen used

during operating, a resistor for current limitation should be used +like with any /& diode.

)ig E.? /C3 display panel

4. LCD BASIC COMMANDS:

All data transferred to /C3 through outputs 3;*3 will be interpreted as

commands or as data, which depends on logic state on pin "S-

"S L @ * 0its 3; * 3 are addresses of characters that should be displayed. 0uilt in

processor addresses built in 4map of characters5 and displays corresponding symbols.

3isplaying position is determined by 33"AM address. %his address is either previously

defined or the address of previously transferred character is automatically incremented.





"S L ; * 0its 3; * 3 are commands which determine display mode. /ist of commands for lcd:


C$$*! RS RW D D D/ D4 D3 D2 D1 D9E?%+#-)!

T)$%

Clear display ; ; ; ; ; ; ; ; ; @ @.JEmS

Cursor home ; ; ; ; ; ; ; ; @ ! @.JEmS

&ntry mode set ; ; ; ; ; ; ; @I$

3S E;uS

3isplay on$off control ; ; ; ; ; ; @ 3 0 E;uS

Cursor$3isplay Shift ; ; ; ; ; @ 3$C "$/ ! ! E;uS

)unction set ; ; ; ; @ 3/ ( ) ! ! E;uS

Set C7"AM address ; ; ; @ C7"AM address E;uS

Set 33"AM address ; ; @ 33"AM address E;uS

"ead 40S65 flag +0) ; @ 0) 33"AM address *

rite to C7"AM or

33"AM@ ; 3 3J 3? 3E 3 3: 3@ 3; E;uS

"ead from C7"AM or

33"AM@ @ 3 3J 3? 3E 3 3: 3@ 3; E;uS




Increment +by @ "$/ @ L Shift right

; L 3ecrement +by @ ; L Shift left

S @ L 3isplay shift on 3/ @ L F*bit interface

; L 3isplay shift off ; L E*bit interface

3 @ L 3isplay on ( @ L 3isplay in two lines

; L 3isplay off ; L 3isplay in one line

@ L Cursor on ) @ L Character format ?!@; dots

; L Cursor off ; L Character format ?! dots

0 @ L Cursor blink on 3$C @ L 3isplay shift

; L Cursor blink off ; L Cursor shift





4..1 LCD C!!%+-)!-

3epending on how many lines are used for connection to the microcontroller,

there are F* bit and E*bit /C3 modes. %he appropriate mode is determined at the

beginning of the process in a phase called 4initiali<ation5. In the first case, the data are

transferred through outputs 3;*3 as it has been already e!plained. In case of E*bit /&3

mode, for the sake of saving valuable I$# pins of the microcontroller, there are only E

higher bits +3E*3 used for communication, while other may be left unconnected.

Conse1uently, each data is sent to /C3 in two steps- four higher bits are sent first

+that normally would be sent through lines 3E*3, four lower bits are sent afterwards.

ith the help of initiali<ation, /C3 will correctly connect and interpret each data

received. 0esides, with regards to the fact that data are rarely read from /C3 +data

mainly are transferred from microcontroller to /C3 one more I$# pin may be saved by

simple connecting "$ pin to the 7round. Such saving has its price. &ven though

message displaying will be normally performed, it will not be possible to read from busy

flag since it is not possible to read from display.

4..2 LCD I!)-)*()*-)!:

#nce the power supply is turned on, /C3 is automatically cleared. %his process

lasts for appro!imately @?mS. After that, display is ready to operate. %he mode of

operating is set by default. %his means that-

@. 3isplay is cleared

:. Mode





3/ L @ Communication through F*bit interface

( L ; Messages are displayed in one line

) L ; Character font ? ! F dots

. 3isplay$Cursor on$off

3 L ; 3isplay off

L ; Cursor off

0 L ; Cursor blink off

E. Character entry

I3 L @ Addresses on display are automatically incremented by @

S L ; 3isplay shift off

Automatic reset is mainly performed without any problems. Mainly but not

alwaysN If for any reason power supply voltage does not reach full value in the course of

@;mS, display will start perform completely unpredictablyO If voltage supply unit can not

meet this condition or if it is needed to provide completely safe operating, the process of

initiali<ation by which a new reset enabling display to operate normally must be

applied.Algorithm according to the initiali<ation is being performed depends on whether





connection to the microcontroller is through E* or F*bit interface. All left over to be done

after that is to give basic commands and of course* to display messages.

)ig- E.J Procedure on F*bit initiali<ation.





)ig E. /C3 interfacing with microcontroller





4.6 CONTRAST CONTROL:

%o have a clear view of the characters on the /C3, contrast should be ad'usted.%o ad'ust the contrast, the voltage should be varied. )or this, a preset is used which can

behave like a variable voltage device. As the voltage of this preset is varied, the contrast

of the /C3 can be ad'usted.

)ig- E.F 2ariable resistor

4.6.1 P-%!-)$%-%&:

2ariable resistors used as potentiometers have all -5&%% -%&$)!*(" connected.

%his arrangement is normally used to <*&8 <(-*%, for e!ample to set the

switching point of a circuit with a sensor, or control the volume +loudness in an amplifier

circuit. If the terminals at the ends of the track are connected across the power supply,

then the wiper terminal will provide a voltage which can be varied from <ero up to the

ma!imum of the supply.





Fig.:5.8 Potentiometer Symbol

4.6.2 P&%"%-":

%hese are miniature versions of the standard variable resistor. %hey are designed

to be mounted directly onto the circuit board and ad'usted only when the circuit is built.

)or e!ample to set the fre1uency of an alarm tone or the sensitivity of a light*sensitive

circuit. A small screwdriver or similar tool is re1uired to ad'ust presets.

Presets are much cheaper than standard variable resistors so they are sometimes

used in pro'ects where a standard variable resistor would normally be used.

Multiturn presets are used where very precise ad'ustments must be made. %he

screw must be turned many times +@;K to move the slider from one end of the track to

the other, giving very fine control.

)ig-?.@; Preset

4.7 S#$$*&8:


Fig:5.9 Preset Symbol




So by close observation of this chapter we understood about Programming the

)lash.





/. AUTOMATIC POWER FACTOR CONTROLLER

)ig ?.@ 0lock 3iagram of AP)C

/.1 POWER SUPPLY





%he input to the circuit is applied from the regulated power supply. %he a.c. input

i.e., :;2 from the mains supply is step down by the transformer to @:2 and is fed to a

rectifier. %he output obtained from the rectifier is a pulsating d.c voltage. So in order to

get a pure d.c voltage, the output voltage from the rectifier is fed to a filter to remove any

a.c components present even after rectification. (ow, this voltage is given to a voltage

regulator to obtain a pure constant dc voltage.

)ig- ?.: Power supply

/.1.1 T&*!",&$%&:

sually, 3C voltages are re1uired to operate various electronic e1uipment and

these voltages are ?2, 82 or @:2. 0ut these voltages cannot be obtained directly. %hus

the a.c input available at the mains supply i.e., :;2 is to be brought down to the

re1uired voltage level. %his is done by a transformer. %hus, a step down transformer is

employed to decrease the voltage to a re1uired level.

/.1.2 R%+-),)%&:


R% #(*-&F)(-%&

0ridge

"ectifier

Step down

transformer

230V

AC

3.C#utput




%he output from the transformer is fed to the rectifier. It converts A.C. into

pulsating 3.C. %he rectifier may be a half wave or a full wave rectifier. In this pro'ect, a

bridge rectifier is used because of its merits like good stability and full wave rectification.

/.1.3 F)(-%&:

Capacitive filter is used in this pro'ect. It removes the ripples from the output of

rectifier and smoothens the 3.C. #utput received from this filter is constant until the

mains voltage and load is maintained constant. Dowever, if either of the two is varied,

3.C. voltage received at this point changes. %herefore a regulator is applied at the output

stage.

/.1.4 V(-*% &%#(*-&:

As the name itself implies, it regulates the input applied to it. A voltage regulator

is an electrical regulator designed to automatically maintain a constant voltage level. In

this pro'ect, power supply of ?2 and @:2 are re1uired. In order to obtain these voltage

levels, F;? and F@: voltage regulators are to be used. %he first number F represents

positive supply and the numbers ;?, @: represent the re1uired output voltage levels.

/.2 RELAYS:

A relay is an electrically controllable switch widely used in industrial controls,

automobiles and appliances.%he relay allows the isolation of two separate sections of a





system with two different voltage sources i.e., a small amount of voltage$current on one

side can handle a large amount of voltage$current on the other side but there is no chance

that these two voltages mi! up.

)ig-?. Circuit symbol of a relay

/.2.1 OPERATION:

hen current flows through the coil, a magnetic field are created around the coil

i.e., the coil is energi<ed. %his causes the armature to be attracted to the coil. %he

armature9s contact acts like a switch and closes or opens the circuit. hen the coil is not

energi<ed, a spring pulls the armature to its normal state of open or closed. %here are all

types of relays for all kinds of applications.





)ig-?.E "elay #peration and use of protection diodes

%ransistors and ICs must be protected from the brief high voltage spike produced

when the relay coil is switched off. %he above diagram shows how a signal diode +eg

@(E@EF is connected across the relay coil to provide this protection. %he diode is

connected backwards so that it will normally not conduct. Conduction occurs only when

the relay coil is switched off, at this moment the current tries to flow continuously

through the coil and it is safely diverted through the diode. ithout the diode no current

could flow and the coil would produce a damaging high voltage spike in its attempt to

keep the current flowing.

In choosing a relay, the following characteristics need to be considered-

@. %he contacts can be normally open +(# or normally closed +(C. In the (C type, the

contacts are closed when the coil is not energi<ed. In the (# type, the contacts are closed

when the coil is energi<ed.

:. %here can be one or more contacts. i.e., different types like SPS% +single pole single

throw, SP3% +single pole double throw and 3P3% +double pole double throw relay.





. %he voltage and current re1uired to energi<e the coil. %he voltage can vary from a few

volts to ?; volts, while the current can be from a few milliamps to :;milliamps. %he relay

has a minimum voltage, below which the coil will not be energi<ed. %his minimum

voltage is called the 4pull*in5 voltage.

E. %he minimum 3C$AC voltage and current that can be handled by the contacts. %his is

in the range of a few volts to hundreds of volts, while the current can be from a few amps

to E;A or more, depending on the relay.

/.2.2 HOW TO CONTROL THE RELAY:

)or the relay to be operated, coil should be energi<ed i.e., current should flow

through the coil. %hus, a voltage difference should e!ist between the terminals for the

current to flow through the coil. #ne terminal of the coil will be connected to the power

supply +?2 and the other terminal is connected to the microcontroller. %hus when a ;

+<ero is applied to the other terminal of the relay, voltage difference e!ists and the

current flows and thus the coil will be energi<ed. %herefore, the relay will be operated

and the load will be applied.

0ut, the microcontroller cannot provide the sufficient current re1uired for the

relay coil to be energi<ed. %herefore, a power transistor or an /( driver should be

connected between the microcontroller and the relay. Power transistor can be connected

as the current driver but if more number of relays are re1uired to operate the loads, /(

driver is the best choice.





/.3 RELAY INTERFACING WITH THE MICROCONTROLLER:

Fig 5.5 Relay interfacing with microcontroller

/.4 TRANSISTOR DRIVER CIRCUIT:

An SP3% relay consists of five pins, two for the magnetic coil, one as the

common terminal and the last pins as normally connected pin and normally closed pin.

hen the current flows through this coil, the coil gets energi<ed. Initially when the coil is

not energi<ed, there will be a connection between the common terminal and normally

closed pin. 0ut when the coil is energi<ed, this connection breaks and a new connection

between the common terminal and normally open pin will be established. %hus when

there is an input from the microcontroller to the relay, the relay will be switched on. %hus

when the relay is on, it can drive the loads connected between the common terminal and

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normally open pin. %herefore, the relay takes ?2 from the microcontroller and drives the

loads which consume high currents. %hus the relay acts as an isolation device.

3igital systems and microcontroller pins lack sufficient current to drive the

circuits like relays and bu<<er which consume high powers. hile the relay9s coil needs

around @;milli amps to be energi<ed, the microcontroller9s pin can provide a ma!imum

of @*:milli amps current. )or this reason, a driver such as a power transistor is placed in

between the microcontroller and the relay.

/./ TRANSISTOR DRIVER INTERFACING WITH MICROCONTROLLER:





)ig ?.J 3river circuit interfacing with microcontroller

%he operation of this circuit is as follows-

%he input to the base of the transistor is applied from the microcontroller port pin

P@.;. %he transistor will be switched on when the base to emitter voltage is greater than

;.2 +cut*in voltage. %hus when the voltage applied to the pin P@.; is high i.e., P@.;L@

+Q;.2, the transistor will be switched on and thus the relay will be #( and the load will

be operated.

hen the voltage at the pin P@.; is low i.e., P@.;L; +R;.2 the transistor will be

in off state and the relay will be #)). %hus the transistor acts like a current driver to

operate the relay accordingly

/. BUZZER INTERFACING WITH THE MICROCONTROLLER:

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?. 0u<<er interfacing with Microcontroller

?.. S#$$*&8:

In this chapter we have discussed about the Automatic Power )actor

Controller+AP)C and AP)C block diagram.

. COMPONENT SPECIFICATIONS

Department of EEE

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.1 PNP GENERAL PURPOSE TRANSISTORS BC/4 ///

.1.2 FEATURES:

/ow current +ma!. @;; mA

/ow voltage +ma!. J? 2.

.1.3 APPLICATIONS:

7eneral purpose switching and amplification.

.1.4 DESCRIPTION:

PNP -&*!")"-& )! * TO=72 SOT/4 '(*"-)+ '*+*%.

)ig J.@ P(P transistor

.1./ LIMITING VALUES:





In accordance with the Absolute Ma!imum "ating System +I&C @E.

S6M0#/ PA"AM&%&" C#(3I%I#(S MI(. MA=. (I%

2C0# collector*base voltage open emitter

0C??J * *F; 2

0C?? * *?; 2

2C&# collector*emitter voltage open base

0C??J * *J? 2

0C?? * *E? 2

2&0# emitter*base voltage open collector * *? 2

IC collector current +3C * *@;; mA

ICM peak collector current * *:;; mA

I0M peak base current * *:;; mA

Ptot total power dissipation %amb T :? UC * ?;; m

%stg storage temperature *J? K@?; UC

%' 'unction temperature * @?; UC

%amb operating ambient temperature *J? K@?; UC

.2 NPN GENERAL PURPOSE TRANSISTORS BC/4 BC/4

.2.1 FEATURES:





/ow current +ma!. @;; mA

/ow voltage +ma!. J? 2.

.2.2 APPLICATIONS:

7eneral purpose switching and amplification.

.2.3 DESCRIPTION:

(P( transistor in a %#*8:> S#%?E plastic package

)ig J.: (P( %ransistor

.2.4 LIMITING VALUES:

In accordance with the Absolute Ma!imum "ating System +I&C @E.

@. %ransistor mounted on an )"E printed*circuit board.





S6M0#/ PA"AM&%&" C#(3I%I#(S MI(. MA=. (I%

2C0# collector*base voltage open emitter

0C?EJ * F; 2

0C?E * ?; 2

2C&# collector*emitter voltage open base

0C?EJ * J? 2

0C?E * E? 2

2&0# emitter*base voltage open collector

0C?EJ * J 2

0C?E * J 2

IC collector current +3C * @;; mA

ICM peak collector current * :;; mA

I0M peak base current * :;; mA

Ptot total power dissipation %amb T :? UC> note @ * ?;; m

%stg storage temperature *J? K@?; UC

%' 'unction temperature * @?; UC

%amb operating ambient temperature *J? K@?; UC

.3 IN 499 D)% :

.3.1 F%*-#&%":

• 3iffused Vunction





• Digh Current Capability and /ow )orward

• 2oltage 3rop

• Surge #verload "ating to ;A Peak

• /ow "everse /eakage Current

• Plastic Material- / )lammability

• Classification "ating 8E2*;

.3.2 APPLICATION:

• Single phase, half wave, ?;D<, and resistive or inductive load.

• )or capacitive load, derate current by :;W.

.3.3 F&0*& V(-*% D&' V,:

(otice that the diode conducts a small current in the forward direction up to a

threshold voltage, ;. for germanium and ;. for silicon ,after that it conducts as we

might e!pect. %he forward voltage drop, 2f, is specified at a forward current, If.

.3.4 L%**% +#&&%!-:

In the reverse direction there is a small leakage current up until the reverse breakdown

voltage is reached. %his leakage is undesirable, obviously the lower the better, and is

specified at a voltage less the than breakdown> diodes are intended to operate below their

breakdown voltage.

.3./ C#&&%!- R*-)!:

%he current rating of a diode is determined primarily by the si<e of the diode chip, and

both the material and configuration of the package, Average Current is used, not "MS





current. A larger chip and package of high thermal conductivity are both conducive to a

higher current rating.

.3. S0)-+5)!:

%he switching speed of a diode depends upon its construction and fabrication. In

general the smaller the chip the faster it switches, other things being e1ual. %he reverse

recovery time, %rr, is usually the limiting parameter , %rr is the time it takes a diode to

switch from on to off.

)ig J. Characteristics9 of diode

.4 69/612 V(-*% R%#(*-&:

F;? X F@: is an integrated three*terminal positive fi!ed linear voltage

regulator. It supports an input voltage of @; volts to ? volts and output voltage of ?

volts. It has a current rating of @ amp although lower current models are available. Its





output voltage is fi!ed at ?.;2. %he F;? also has a built*in current limiter as a safety

feature. F;? is manufactured by many companies, including (ational Semiconductors

and )airchild Semiconductors.

%he F;? will automatically reduce output current if it gets too hot.%he last two

digits represent the voltage> for instance, the F@: is a @:*volt regulator. %he F!! series

of regulators is designed to work in complement with the 8!! series of negative voltage

regulators in systems that provide both positive and negative regulated voltages, since the

F!! series cant regulate negative voltages in such a system.

%he F;? X F@: is one of the most common and well*known of the F!! series

regulators, as its small component count and medium*power regulated ?2 make it useful

for powering %%/ devices.

%able J.@ Specifications of various voltage regulators

./ S#$$*&8:

In this chapter we have discussed about the different components used and their

specifications.


SPECIFICATIONS IC 69/ IC 612

2out ?2 @:2

2in * 2out 3ifference ?2 * :;2 ?2 * :;2#peration Ambient %mp ; * @:?UC ; * @:?UC

#utput Ima! @A @A




. LOAD BANKS

.1 I!-&#+-)!

A load bank is a device which develops an electric load, applies the load to

an electrical power source and converts or dissipates the resultant power output of the

source.





%he purpose of a load bank is to accurately mimic the operational or 4real5 load

that a power source will see in actual application. Dowever, unlike the 4real5 load, which

is likely to be dispersed, unpredictable and random in value, a load bank provides a

contained, organi<ed and fully controllable load.

Conse1uently, a load bank can be further defined as a self*contained, uniti<ed,

systematic device that includes load elements with control and accessory devices re1uired

for operation.

hereas the 4real5 load is served by the power source and uses the energy output

of the source for some productive purpose, the load bank serves the power source, using

its energy output to test, support or protect the power source.

7.2 Applications:

/oad banks are used in a variety of applications, including-

• )actory testing of engine ie/el generator sets

• %o reduce wet /tacing problems

• Periodic e!ercising of stand*by engine generator sets

• #) /y/tem testing

• ,attery system testing

• 7round power testing

• /oad optimi<ation in prime power applications

• )actory testing of trine

• "emove carbon build*up on the piston heads

.3 Types of load bank:





%he three most common types of load banks are resistive load banks, reactive

load banks, and capacitive load banks.

.3.1 R%")"-)<% (* @*!:

A resistive load bank, the most common type, provides e1uivalent loading of

both generor and primemover. %hat is, for each kilowatt load applied to the generator by

the load bank, an e1ual amount of load is applied to the prime mover by the generator. A

resistive load bank, therefore, removes energy from the complete system- load bank from

generatorYgenerator from prime moverYprime mover from fuel. Additional energy is

removed as a conse1uence of resistive load bank operation- waste heat from coolant,

e!haust and generator losses and energy consumed by accessory devices. A resistive load

bank impacts upon all aspects of a generating system.

%he 4load5 of a resistive load bank is created by the conversion of electrical

energy to heat via high*current resistors such as grid resistors. %his heat must be

dissipated from the load bank, either by air or by water, by forced means or convection.

In a testing system, a resistive load simulates real*life resistive loads, such as

incandescent and heating loads as well as the resistive or unity power factor component

of magnetic +motors, transformers loads.

.3.2 R%*+-)<% (* @*!:

A 4reactive5 load includes inductive +lagging power factor and$or capacitive

+leading power factor loads.

Inductive loads, the more common type, consist of iron*core reactive elements

which, when used in con'unction with a resistive load bank, create a lagging power factor

load. %ypically, the inductive load will be rated at a numeric value ?W that of the

corresponding resistive load such that when applied together a resultant ;.F power factor

load is provided. %hat is to say, for each @;; k of resistive load, ? H2A" of inductive

load is provided.





#ther ratios are possible to obtain other power factor ratings. Inductive loads are

used to simulate real*life mi!ed commercial loads consisting of lighting, heating, motors,

transformers, etc. ith a resistive$inductive load bank, full power system testing is

possible, given the impact of reactive currents on generator$voltage regulator

performance as well as effects on conductors and switchgear.

.3.3 C*'*+)-)<% (* @*!

A capacitive load bank is similar to a reactive load bank in rating and purpose,

e!cept leading power factor loads are created. %hese loads simulate certain electronic or

non*linear loads typical of telecommunications, computer or PS industries

.4 A''()+*-)!" , APFC:

AP)C are used in industrial applications such as induction motors , transformers

etc

%his is also used in air conditioners , fans

It is also applicable in industrial heating furnaces, arc lamps

./ A<*!-*%" , APFC:

%he H capacity of the prime movers is better utili<ed

%his increases the kilowatt capacity of the alternators

%he efficiency of plant is increased

%he overall cost per unit decreases

%he regulation of the lines is increased

. S#$$*&8-

In this chapter we have discussed about the /oad 0anks and the Applications and

Advantages of AP)C.





APPENDI>=A





6. CONCLUSIONS

6.1. CONCLUSIONS:

0y observing all aspects of the power factor it is clear that power factor is

the most significant part for the utility Company as well as for the consumer. tility





company rid of from the power losses while the consumer free from low power factor

penalty charges.

0y installing suitably si<ed power capacitors into the circuit the Power )actor is

improved and the value becomes nearer to ;.8 to ;.8? thus minimising line losses and

improving the efficiency of a plan.

0y using this AP)C system the efficiency of the system is highly increased.

6.2. FUTURE SCOPE OF THE WORK:

%he automotive power factor correction using capacitive load banks is very

efficient as it reduces the cost by decreasing the power drawn from the supply and as it

operates automatically men are not re1uired to operate this ,so this Automated Power

factor Correction using capacitive load banks must be used for the industries purpose in

the future.

REFERENCES

1. I&&& PAP&"S

2. ZPower Supply 3esign Principles by 40en Schramm5.

[\. www.pscpower.com


http://www.pscpower.com/

http://www.pscpower.com/




[4]. http-$$www.onsemi.com

[?\. http-$$electrical*engineering*portal.com

l


http://www.onsemi.com/

http://www.onsemi.com/




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