1. ]OJ J International Conference 011 Electrical Energy and NeT11'orksr7CEEN ]OJ I!
Micro controller Based Control of Three Phase Induction Motor Using PVl1
Technique
S.M.Wank..hede, R.M.Holmukhe, Miss.A.M.Kadam,
Electrical Engineering Department
Miss.P.R shinde, *p.s.Chaudhari
I
Bharati Vidyapeeth Deemed University College of Engineering, Pune, India
"Scientist, DRDO, Pune, India.
Email ID: rajeshmholmukhergjhotmail.com
Abstract-The speed of the induction motor can be controlled using pulse width modulation technique. Here the speed of
by various methods. The stator frequency control is one of the motor is controlled by sensing the rprn and current valve
simplest methods to control the speed of the Induction motor. of the rpm. The current value of rpm i 5 sensed by inductive
The micro controller based speed controlling system can be
magnetic switch and its output is fed :0 the micro controller.
used in various industries such as chemical, textile and cement
The micro controller compares the current value of the rprn
to operate the motor according to the desired speed. This is
completely dosed loop system and the speed of the motor will
with set values and adjusts the rime period ef the pulses
be controlled automaucally by use. of feed back from motor in applied to the stator to control the frequency of the stator.
term of rpm , This system can be used effectively in the industrial
The inductive magnetic sensor can be interfaced .with micro applications to control the speed of the 3 phase induction
controller easily and can sense rp m of the motor and giv'e it to motor.
micro controller in digital form as a feed back from motor.
II. BLOCK DIAGRAM A~D WO~Ki:-G
Keywords- microcontroller, induction motor, PHiM
.cchnicue
,
i
1. INTRODUCT10N __ ._. i
1;-.;;]3!-;Y of the industrial applications, an electric motor is
l~;)[!~
tile most imporrant component. A complete production unit S:j~p~~!
C,l;1SiSt5 primarily of three basic components; an electric From
motor, an energy- transmining device and L'1eworking (or h'1t,~0r ; i 1 Cor.:.r~·.i:::
driven) machine.An electric motor is the source of motive ----. ,
power. An energy- transmitting device delivers power from i ~r .';vc:: )--1
electric motor to the driven machine (or the load); it usually ~ :,uP!'<" r-~i
consists of shaft, belt, chain rope etc. .------ -~~~,~~---
The electric motor is widely classified as ! ,;(~~ R::);-:.r..::i /--'
I. A.C Motor ---c....oil:'r(Jlicr
Fi~.
--' C:;ud
'1 D.CMotor
Several industrial applications need adjustable speeds for Fig.l.Block Diagram of Comrollcr card
their efficient operation. The various methods of speed
Control semiconductor devices are as follows: Above figure shows the block diagram of the controller
I. Stator voltage control card.The controller card consists of 1 icro controller and
2. Stator frequency control related circuitry to it such as oscillator circuit tIC. The rpm
, Stator voltage and frequency control of the motor is sensed by inductive magnetic switch. The
4. Stator current control output of the magnetic switch is fed to the micro controller.
-. Static rotor- resistance control The micro controller performs the controlling action in this
6. Slip-energy recovery control system. It monitors the status of .he magnetic i.litch
continuously to measure the current :Vi11 of the motor. Then
Methods I to 4 are applicable to both (SelM and WRJM) it compares the read value (current value) of rprn with the
set value. If the set value is less than the set value then it
whereas method 5 and 6 can be used for only WRl!·1s. Out
increases the frequency of the pulses applied to the stator of
of above listed methods. Here stator frequency control
the induction motor. It does so by decreasing the lime period
method to control the speed of the 3 phase induction motor
of these pulses. When the frequency of the pulses appl ied to
is used.
the stator increases the speed of the induction motor
In this research project paper a micro controller based increases. The exact reverse action will be taken if the
system to control the speed of the 3 phase LM.is developed current rpm value of motor is greater than the set value.
978-1-4244-9567-2/11/$26_00 ©2011 JEEE 26

2. :;011 international Conference on Electrical Energy and NelWorks(lCEEN 20J 1)
Also the set value and the current value of the rprn is microprocessor CPU, which contains ap' Arithmetic and
displayed by using LCD display. Logic (ALU) a program Counter (PC), a Stack Pointer (SP),
some working registers, clock timing circuit and interrupt
circuits. To make a complete microcomputer, one must data
I . I i /'--..........., memory (RAM), memory decoders, an oscillator and a
, Pulses I I number of input / output (I/O) devices, such as parallel and
from ~/ '- serial data ports. In addition, special purpose devices, such
.--, H"<: ';
, ,.,.uJL I !
r ·Micro I D .• I i Induction as interrupt handlers and counters. may be added to relieve
I·,.... ~ iJn(!g~ the CPU from time consuming counting or timing chores.
I
I. Controller , I f-+ Motor ,
I .I
Equipping the microcomputer with mass storage devices.
1_'_-
I I
<c.> commonly a floppy and hard dist drives, and I/O peripherals,
--.1
such as a keyboard and a CRT display. yields a small
computer that can be applied to a range of general purpose
Fig.:!. Block Diagram of Dr inn Circuit software application.
I,------ a'ld ,
The driver circuit consists of MOSFET driver IC lR ,----.J ,A.:i(t;metic
Logic U!'li~ j-.
2110 and other additional components as diodes, capacitors
etc. The driver circuit is used to drive the induction 1110tor,
which is connected as load to the VFD. The Speed of the
1 '.'Vorklrtg ~~g:S'l'f.rs
induction motor, is controlled by varying the frequency of L .. .
the pulses applied to the stator of the motor .These pulses
coming from the microconrroller are fed to the MOSFET
driver IC IR 211a.TIle IlUII 0 is high voltage. high- speed
---'---'--~
_______
.
.L . _
power MOSFET and [GBT driver with independent high . C!():k (;i~o:ui';
and low side referenced output channels. The output of the
IR 2110 is given to tile 10SFET JRF 540.lt is used for Fig.3.Block Diagram of Microprocessor CPU
switching purpose because of tile its high current rating .The
pulses coming from the frequency of the stator and in tUi11to The key term in describing the design of the
control the speed of the induction motor. microprocessor is general purpose. The hardware design O!'
a microprocessor CPU is arranged so that a small or 'ei
ur. HA~DWARE OVERVIEW large system can be configured around the CPLJ 2S the
application demands. The internal CPU architecture as -:1 i
1I) DESIGN CO.NSIDERA TIOSS:- as the resultant machine level code that operates rne
The most important and basic aspect of the any system is architecture is comprehensive but as flexible as possible.
to design the circuit (t.c. hardware design) for the specific The prime use of a microprocessor is to read dn~.
application. This inv ohes deciding which component to use. perform extensive calculations on that data, and store those
specifications of different components. mathematical calculations in a mass storage device or display the resi.lts
calculations, components selection and other related issues. for human use. The programs used by the microprocessor
The detailed information of the hardware desizn of the our are stored in the mass storage device and loaded into R.' j
system is an follows. - as the user directs. A few microprocessor prclg'l!'11' ,.'2
b) IC FEATCRES AM) BRItJS:- srored in ROM. The ROM based programs are prirnarilv
In our system we hav e used micro controller AT89C51 small fixed programs that operate peripherals and other
and other external peripherals such as the magnetic switch, fixed devices that are connected to the system. The design
Opto isolators. 110SFETs. 110SFET driver IC etc. This of the microprocessor is driven by the desire to make it as
section focuses on the: features and brief introduction of expandable and flexible as possible, in the expectation of
these IC's peripherals, their significance etc. commercial success in the marketplace.
1) Micro Controller AT .'9C51 Micro Controllers
Microprocessors and micro controllers stem from the Figure shows the block diagram of a typical micro
same basic idea. are made b). the same people, and are sold controller which is a true computer on a chip. The design
to the same types of sysr m designers and programmers. incorporates all of the features found in a micro processor
What is the difference between the -0" CPU: ALU, PC, SP. and registers. It ;,150 has added the
other features needed to make a complete computer: RO. 1.
Microprocessors RA11, parallel 10, serial I '0. counters. and a clock circuit
A microprocess, r. ~" iItc term has come w be known. is Like the microprocessor. :1 microcontroller is a aeneral
a general purpose digital computer central processing unit purpose device, but one that is meant ro read data, pe-rforms
(CPU). Although ;->opula;ly know n 2, <I "Computer on a limited calculated on the data. and control its e: ironment
chip", the microprocesso: is in no S=Il'~ a complete digital based on the those calculations. The prime use of a
computer. Figure h:I()'. sho« S 2 block diagram a ;r microcontrollcr is to cor-trot the operation of a machin;

3. 2011lnternafional Conference on Electrical Energy and J.:erl1'vrks(1CEE" 201 J)
using a fixed program that is stored in ROM and that does powerful microcomputer which provides a highly flexible
not change over the lifetime of the system, and cost effective solution to many embedded control
I A:"w 1 Ttrrrer/Courner IIG Port applications,
,
C) INTERFACING DETAILS j
Aceumutetor
nternal ROt.."
~
..
In this chapter the interfacing of the micro
Registers
.•. ! controller with other iC's is discussed. Tha: is it explains
I
!
~~
i
I
connection of the each pin of micro- vnuoller ":ith the other
lC's and external peripherals used in '1-' -vsrern.
I I The Controller Card
'__ ..__ --1
I
I The controller card .s the .: .- :'IC:, the Micro
, controller AT 89(51 is placed.
'---'-.--~
L_:«cI' PGfn'9r-.-::..r.- ,__ ~ __ --'
I
r
>l
Ctcc«
Circuits
The other objects 011 the C llj(, .iner card are power
1L ;;:
I
supply and the connectors for display. tvlOSFET driver
L ~P~roo~~~~~'~C~,n~u~n~t~~-' ~ Circuit etc. The interfacing of the master micro conrroller
with all these components is listed in .he following table,
Fig_4, Block Diagram ofT) pical Microcontroller $'",,, (,), "".0"',. •.'
C on , t""C'; I I•..•.
,
The design approach of the micro controller mirrors that ~ .-:
,r
r
-,'--
--,
A:-h-
, , "":_'(
of the microprocessor. The microcontroller design uses a .. I·'
~., .
1-:·
..: •.. ·.....•
Cu·
.;J'" i,i:' ••
.
similar. much more limited set of single and do~ble byte I :-,. ,- .•... :-.,:.
t' ~, , l ..-,,.-;,'-,--.
_:"1
instructions that are used in microprocessors to move code f '!' T
'
F'
ad data from internal memory to the ALU. Many
instructions are coupled with pins on the integrated package
the pins are "Programmable" that is capable of having
several di fferern functions depending on the wishes of the
r;'()grammer,
The microconrroller is concerned with ceninz data from
and to it" own pins: the archite ture and I~struc~ion .et are
opurmzed to handle data in bit and byte size,
Comparison between Microprocessors and
-',f icrocontrollers
The ontrast
between a microcontrolier and a
croprocessor
I~';: is best explained by the fact that most
rr.icroprocessors have many operational codes Cop codes) for
moving data from external memory to the CPU;
microcontrollers mav have one or two, Microprocessors
may hav e one or rwo types of bit handling instructions; D) PULSE WIDTH, TODl'LI:"
mici ocomrollers will have many, Figure shows a bl.vck ',,1:;1" ," .he power
surnmarize: the microprocessor is concerned with onversion unit in a P ' dr:v <: I ;, i~ "l of dnve. a
rapid mov ernent of code and data from external addresses to diode bndge recutier PI'" 11..1.:, t,;~ Iku; .,.: Ul c irc n:
the chip; the microcontrcller is concerned with rapid the DC voltage is filtered in a LC 1,' pass filter. Output
movement of bits within the chip, The microcontroller can frequency and voltage is controlled electronically by
function as a computer with the addition of no external controlling the width of the pulses ,1' voltage to the motor.
digital parts; the microprocessor must have many additional Essentially, there techniques reqi.u , ,', ilchi:ig the inverter
pans to be operational. power devices (Transistor or ICBT<oj t':l and air many times
in order to generate the proper R;"1S .•l,;t;Jg:: levels,
ATli9CS2 It1/CROCO_!'TROLLER HARDWARE
The AT8,-,C52 is a low power, high performance (MO
t-.----~Y'"'.
8-bit microcomputer with 8K bytes of Flash programmable
and erasable read only memory (PEROM), The dev ice is ~=~_=_~~_=J:
manufactured using Armel's high density nonvolatile
memory technology and is compatible ith the industry :'"
';cdHL;-J :--'OC.'i I and 80C52 instruction ".'t an i i~::llll1. The
(':1 UHf rla~h allow s the pru~raI" mcm. r, l~
reprogr mined 111 5) stem or b) a COI1 enuonal 11)i1 -Lule
mcmor. programmer. B~ cornl-imng a cr s.nile ; bit L'PLJ
Ilth Hash on a monolithic chip. the .vtmel AT. -IL:,2 I' a

4. ::C11 International Conference 011 Electrical Energy and Networks(ICEEN 2011)
explained with the help of the flow charts includes in this
This switching scheme requires a more complex chapter. .
regulator than the VVI. With the use of a microprocessor, 1_ The next step is to understand the software
these complex, regulator functions are effectively handled. programming incorporated in the microcontroller to achieve
Combining a triangle ave and a sine wave produces the the given task.While performing its calculations and control,
output voltage waveform. the rnicrocontroller need to be human friendly both in terms
of data input and display, .
Irlan;;l: 2. The software has been written instructured manner
Sens:at:1 ~----'~'~--~ in which all the subroutines are linked to a single main
'-------, PNr.~
program, Each subroutine is further divided ir .o sub sub
routine as per the requiremen_t. _
i
ii Med.-al c,'
':'~nC'5t:1
1
r-------~ Flo'W Ch~rt> (
'--_/
51 ;.1{1 'J
L ~I
.......···-jr-.n"j1 ALSoL -,::
.,. ,.11.: '-I.
Fig.7.PWM Generator TI'~'r 1'0,: .••••.• •• n •...
,....•
------
.The triangular _izual is the carrier or switching r---- - .--.'!..--:---- ------
I '1: FuR Si Tn {J
v"", J ••.£ Y H(.l/d~
frequency of the in;;:'rter. The modulation generator . (1- R "IV· FR~ I)
produces a sinewave signal the determines the width of tile ••• :J ..••
pulses, and therefore the RMS voltage output of the inverter. ,· ,..~·I;.·-:-r: (;
( )".1f':...Lfi
-;:';'----- ~ /',
. 'I ' r">:
i
/ ' " ,-~ 1/ "-
'J I
I
I '-' '
,
"1-·
I I "
'
f I I I
_ ---- 1------4' ~_
T_
,
I:.· •...•
•• .•..••.
:-1 "•.•• :1 I 'H
K~··.1 • .)r ..• ,,('!" i),~ P! A'
..._:r _
._:. , :",,'-' f"'. .••• f' -i. "',
r
HI'''") ...•
t••...•. !~ , ..••.
:'
J I, (~, 1, • I , ., '-
<I : ..Ii
• ~I R i·~.1
( .';' I !~
I ;t;.~. aveforrns
___ <r:::. • __ ~. •
f .>I•..•
I'~ ,,' cl 11'1.'I "1 ' ~' It, H •.•. '10"
1
",""",,> '( ,....,," ••.,<1 I'j',.I. ,-!')! 'Iii •., 1 •••..• " t I
AC drives that use :1 PWM type schemes have varying
levels of performance based on control algorithms. There "
•..• I'
, ',ll I
are 4 basis rypes of con n I for AC drives t~day. There are • l. '
'olts per Hertz. Sensor e s Vector Control. Flux Vector
Control and field Oriented Control. V/Hz control is a basic
control method. providing a variable frequency drive for
:)i ( I~ ,,~: '.'
I . Ii! I: '.""".
applications like fan <InJ "lump. It provides fair speed and (~i 1'-, ". I'l I •.; .•.•
torque control. at a re:i~ vnable cost. Sensor less Vector
Control provides better s;,,'eo regulation. and the ability to
produce high starring W'·_'.i,~. Flux Vector control provides
more precise speed Cl':c- torque control, with dynamic
r r
response. Field Orieme.t ~'ornrol drives provide the best ., I '/d H
speed and torque CO!J1r,; available for AC motors, It , I
' ..•••
;.1
HI.:.J !".I
I
provides DC performance tor AC motors. and is well suited
for typical DC applications.
I"'. 5-0r-; ,RC 0 ':ER'lE' - ---,---
Softw arc ,'.: "":';:1-: . ~'!I~_j~~ ~:-o~;-:.·~.. ·,T:~i..?n f();- the
interfacing of tile' ~k' controller 'Ilil LCD display,
keyboard. DC (;,(' liJ:!; ci"cui','1d the mobile
interface lhe c ,~: , . i' , ',j, _ 'ltr,)ller arc best Fig. 9.FJo chart

5. 2011 International Conference on Electrical Energy and Networks (JCEE.'" ]011)
V. PULSE WIDTH MODULA TION TECHNIQUES 'ON' at a time and at that instant other MOSFET should be
turned 'OFF' but while testing it is observed that turning
PWM l-ridges the. gap between the digital and analog 'ON' and turning 'OFF' both these two pair were overlapping.
regimes allowing one to exchange tone for voltage. Most Following may be the reason behind this:
people use hardware to generate PWW waveforms. There • Mismatching of actual delay time of MOSFET bridge
art! few different techniques for generating pulse width ckt. with programmed delay time.
Modulated square waves using software. It 'turns out that • Due to failure oflR21 10 Ie
many of techniques described here mav also be Following are the remedies Taken TO overcome the problems:
implemented in VijDL. I) Modification of the program in the microcontroller
2) Application of heat sink for the ;,10SFET bridge circuit
VI. COMPONE IT LIST 3) Addition ofTC MCT 2E for isolation purpose.
m:f,' UI,IT 3) High Voltage Testing 011 Moto>.
::JESCRfPTION PRICE
-:----, -fiansform-&----~·-·----l-- ---1~{j -- By providing the above modif.cauon. we proceeded for
- --- II/lIem ccntrcllep -- --;r,- '"- 55
230 volt motor testing. In this no
volt testing we observed
AT 89C52 -- the proper functioning of micro controller circuit as well as
- .--- ~~Fs~E;-----;r-1
-------.- .. - so"'-
-
of the drive circuit. Also by varying the load the variation in
Mos=n - ..- -- ----.---- - Frequency according to load current Ie observed.
vm. FUTURE E, 'H.'.J 'CEI'vIE1T
There are certain features thai can be added in this
system. Some of the fearures ar ii. ed below.
::'ooo;anr:
~.::J·lr.'2~' • Incorporate RTC chip DS I '(j- which can be used
::;.~ u::.35 J
--~--
l to how the time. and w e can soft different
'L _~""2 ':
~~;r.I= !
(,2 __ __2.~ readings ofrpm in timely manner.
~'(~I::' • Use serial memory hip. T 2·kO.:l and can store
the e records il the system.
• Upload this data to the PC by serial communication
using MAX 232 IC
• Efficiency of motor can b controlled using this
system.
• Instead of a liLw-:Oilti', I,: .v e can use? CPLD
chip since the CPLD I"','q~,)]'aie~ mall) more
features than a Microcor.rroiler. 'LSI VHDL can
VIi. TESTTI G AND TROUBLE SHOOTING
be used for CPLD programming.
Following testing are carried out in the three phase
variable frequency drive model. COI'CLUSIU:"
I) Low voltage with lamp load Micro controller based system cun be effectively used
2) High voltage (230V) testing with lamp load. for speed control of the 3phase induction motor along with
PWM techniques,
3) High voltage (230V) testing with motor load.
ACKNOWLL"GHE:T
J) L(lW voltage testing lamp load:
Bharati Vidyapeeth Deemer' '.': '<::<lY, Pune.
To observe the proper functioning of drive circuit, low
voltage testing is carried out. A 12V DC supply coming out
from the transformer and bridge rectifier circuit is given to
input of drive circuit and following observation are made [1] The S05~ . licro Controller •-·~iJ!;cclUrc. programming &
Applications pen ram inrernationa. - "...."lIh.'ih I. -:- •.• 3
1
• Square waves across the s itching transistors
[~] The SC5~ t-licro controller anJ J -nbeddcc Svstcms Pearson
6 Square waves acres load i.e. in bridge inverter Education-M, A .. tazio:
circuit. [3] Power Electronics - P. S. Birnbhra
• Similarly desired waveforms across the [4] Power Electronics - :-'1 Rashid
rnicrocontroller circuit. [5] Electrical Technology . B. L Thera;" '. rnSITES:
2) High voltage (230 V) Testing will! Lamp Load: I] www.nationalseruicondiciors.c .. TI
H
1 ile Joing this 230 V testing with sing!.: phase =J .•.lmci.co.n
Variable fr quency drive problem faced was: heaung and 3] wwwdalias scnn.cc.n
l-urning of 10SFET bridge circuit.The reason IS that. the -t} y., ,f;L·(l=lc.c'-'lll
bridge circuit it is required thr.t two IU F[T should be