Microcontroller based control


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Microcontroller based control

  1. 1. ]OJ J International Conference 011 Electrical Energy and NeT11orksr7CEEN ]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 ofby various methods. The stator frequency control is one of the motor is controlled by sensing the rprn and current valvesimplest methods to control the speed of the Induction motor. of the rpm. The current value of rpm i 5 sensed by inductiveThe 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 rprnto operate the motor according to the desired speed. This iscompletely dosed loop system and the speed of the motor will with set values and adjusts the rime period ef the pulsesbe 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 industrialThe inductive magnetic sensor can be interfaced .with micro applications to control the speed of the 3 phase inductioncontroller easily and can sense rp m of the motor and give 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 Frommotor, an energy- transmining device and L1eworking (or h1t,~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:: )--1electric motor to the driven machine (or the load); it usually ~ :,uP!<" r-~iconsists 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:;ud1 D.CMotorSeveral industrial applications need adjustable speeds for Fig.l.Block Diagram of Comrollcr cardtheir efficient operation. The various methods of speedControl 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 and2. 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. The4. 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 this6. 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 itwhereas method 5 and 6 can be used for only WRl!·1s. Out increases the frequency of the pulses applied to the stator ofof above listed methods. Here stator frequency control the induction motor. It does so by decreasing the lime periodmethod to control the speed of the 3 phase induction motor of these pulses. When the frequency of the pulses appl ied tois 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 thesystem 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. 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,------ ald , 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:Slf.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 prclgl!11 ,.2b) 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 otherand other external peripherals such as the magnetic switch, fixed devices that are connected to the system. The designOpto isolators. 110SFETs. 110SFET driver IC etc. This of the microprocessor is driven by the desire to make it assection focuses on the: features and brief introduction of expandable and flexible as possible, in the expectation ofthese ICs 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 microsame basic idea. are made b). the same people, and are sold controller which is a true computer on a chip. The designto the same types of sysr m designers and programmers. incorporates all of the features found in a micro processorWhat 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 aenerala 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: ironmentchip", the microprocesso: is in no S=Il~ a complete digital based on the those calculations. The prime use of acomputer. Figure h:I(). sho« S 2 block diagram a ;r microcontrollcr is to cor-trot the operation of a machin;
  3. 3. 2011lnternafional Conference on Electrical Energy and J.:erl1vrks(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 iCs is discussed. Tha: is it explains I ! ~~ i I connection of the each pin of micro- vnuoller ":ith the other lCs 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 PGfn9r-.-::..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 ..-,,.-;,-,--. _:"1instructions that are used in microprocessors to move code f ! T Fad data from internal memory to the ALU. Manyinstructions are coupled with pins on the integrated packagethe pins are "Programmable" that is capable of havingseveral di fferern functions depending on the wishes of ther;()grammer, The microconrroller is concerned with ceninz data fromand to it" own pins: the archite ture and I~struc~ion .et areopurmzed to handle data in bit and byte size,Comparison between Microprocessors and-,f icrocontrollers The ontrast between a microcontrolier and a croprocessorI~;: is best explained by the fact that mostrr.icroprocessors have many operational codes Cop codes) formoving data from external memory to the CPU;microcontrollers mav have one or two, Microprocessorsmay hav e one or rwo types of bit handling instructions; D) PULSE WIDTH, TODlLI:"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. arapid 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. Outputmovement of bits within the chip, The microcontroller can frequency and voltage is controlled electronically byfunction 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 inverterpans 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 programmableand erasable read only memory (PEROM), The dev ice is ~=~_=_~~_=J:manufactured using Armels high density nonvolatilememory 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 -Lulemcmor. programmer. B~ cornl-imng a cr s.nile ; bit LPLJIlth Hash on a monolithic chip. the .vtmel AT. -IL:,2 I a
  4. 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, :~nC5t:1 1 r-------~ FloW Ch~rt> ( --_/ 51 ;.1{1 J L ~I .......···-jr-.n"j1 ALSoL -,:: .,. ,.11.: -I. Fig.7.PWM Generator TI~r 10,: .••••.• •• 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 111.I "1 ~ It, H •.•. 10" 1 ",""",,> ( ,....,," ••.,<1 Ij,.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-, ". Il I •.; .•.•torque control. at a re:i~ vnable cost. Sensor less VectorControl provides better s;,,eo regulation. and the ability toproduce high starring W·_.i,~. Flux Vector control providesmore precise speed Cl:c- torque control, with dynamic r rresponse. Field Orieme.t ~ornrol drives provide the best ., I /d Hspeed and torque CO!J1r,; available for AC motors, It , I ..••• ;.1 HI.:.J !".I Iprovides DC performance tor AC motors. and is well suitedfor typical DC applications. I". 5-0r-; ,RC 0 :ERlE - ---,--- Softw arc ,.: "":;:1-: . ~!I~_j~~ ~:-o~;-:.·~.. ·,T:~i..?n f();- theinterfacing of tile ~k controller Ilil LCD display,keyboard. DC (;,( liJ:!; ci"cui,1d the mobileinterface lhe c ,~: , . i , ,j, _ ltr,)ller arc best Fig. 9.FJo chart
  5. 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 CEIvIE1T 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 phasevariable frequency drive model. COICLUSIU:" 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:TJ) L(lW voltage testing lamp load: Bharati Vidyapeeth Deemer .: <::<lY, Pune. To observe the proper functioning of drive circuit, lowvoltage testing is carried out. A 12V DC supply coming outfrom the transformer and bridge rectifier circuit is given toinput 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.nVariable fr quency drive problem faced was: heaung and 3] wwwdalias scnn.cc.nl-urning of 10SFET bridge circuit.The reason IS that. the -t} y., ,f;L·(l=lc.c-lllbridge circuit it is required thr.t two IU F[T should be