Automatic Power Factor Control Using Pic Microcontroller

Transcription

1 IDL - Inernaional Digial Library Of Available a: 8 h Naional Conference on Advanced Techniques in Elecrical and Elecronics Engineering Inernaional e-journal For Technology And Research-2017 Auomaic Power Facor Conrol Using Pic Microconroller Auhors Name- NASIM ALI KHAN Assisan Professor Dep.of ELECTRICAL ENGG. ALIAH UNIVERSITY KOLKATA, INDIA -kinasim@gmail.com Coauhors Name- SABBIR AZAD, PG Suden Dep.of ELECTRICAL ENGG. ALIAH UNIVERSITY KOLKATA, INDIA -sabbir.azad32@gmail.com Absrac In presen day of Technological revoluion i has been observed ha he power is very precious. In indusry or domesic load secors mos of he load are inducive in naure. For indusrializaion, he inducive loads are increasing day by day, which affec he power facor, power sysem losses and is efficiency. This paper represens he mos effecive auomaic power facor improvemen by using saic capaciors which will be conrolled by a Microconroller wih very low cos. Alhough many exising sysems are presen which are expensive and difficul o manufacure. In his sudy, many small raing capaciors are conneced in parallel and a reference power facor is se as sandard value ino he microconroller IC. Suiable number of saic capaciors is auomaically conneced according o he insrucion of he microconroller o improve he power facor close o uniy. Some ricks such as using resisors insead of poenial ransformer and using one of he lower cos microconroller IC (PIC16F877A) which also reduce programming complexiy ha make i mos economical sysem han any oher conrolling sysem. Keywords Microconroller,(PIC16F877A),Curren ransformer, Poenial ransformer, zero crossing deecor, Relay, Capacior, Proeus8, Micro C. I. INTRODUCTION TO AUTOMATIC PF CONTROL Power facor is he raion beween he KW and he KVA drawn by an elecrical load where he KW is he acual load power and he KVA is he apparen load power. I is a measure of how effecively he curren is being convered ino useful work oupu and more paricularly is a good indicaor of he effec of load curren on he efficiency of he supply sysem. Low power facor causes large copper losses, poor volage regulaion and reduce handling capaciy of he sysem. A low power facor KVA raing of he equipmen has o be made more, making he equipmen larger and expensive [ ]. For he low power qualiy, high economic loss per inciden occurs ha are given below. This paper focuses on he design and implemenaion of power facor correcion using PIC microconroller chip, deermine he power facor of he loaded power sysem, and generae proper acion o calculae and o add sufficien capacior. II. LITERATURE SURVEY: The paper eniled Developmen of power facor conroller using PIC Microconroller, inroduce abou power facor and he design o monior phase angle coninuously and in he even of phase and also inroduce o he micro-c programming for he auomaic power facor conrol (APFC) sysem. In he paper A Concepual Design of Microconroller Based Power Facor Correcor Circui shows he block diagram and he signal flow char of he sysem. Shuffling presens an inelligen power facor compensaion conroller ha can perform power facor correcion wihou exciing harmonic resonance under varying demand condiions. Pracical and robus conrol algorihms are proposed for he purpose of easy implemenaion in a microconroller. In addiion, he conroller relies on common low cos sensing devices and does no require addiional measuremens. As a resul, he proposed conroller can be consruced as a rerofiing device o replace exising power facor correcion conrollers wih lile effor. (Shuffling 2012) angle deviaion, a correcion acion is iniialized o compensae for his difference by coninuous changing variable capaciors value via swiching process. The overall 1 8h Naional Conference onadvanced Techniques in Elecrical and Elecronics Engineering, SJBIT, Bangalore (TTMT-2017) Copyrigh@IDL-

2 IDL - Inernaional Digial Library Of Available a: 8 h Naional Conference on Advanced Techniques in Elecrical and Elecronics Engineering sysem requires only one PIC chip, a few power elecronic componens and a bank of capaciors. In his paper we are using PROTEUS8 where PIC16f877A microconroller as programmed ha swich on or off he capacior as per requiremen o improve he power facor close o uniy. III. PROPOSED TECHNIQUE In his projec, we are using PIC16f877A as conrolling device, PROTEUS o design he circui and MICRO C for programming MC. A. Comparaor secion The 230 V, 50 Hz is sep downed using volage ransformer and curren ransformer is used o exrac he waveforms of curren. The oupu of hevolage ransformer is proporional o he volage across he load and oupu of curren ransformer is proporional o he curren hrough he load. These waveforms are fed o Volage Comparaorconsruced using LM358 op-amp. Since i is a zero-crossing deecor, is oupu changes during zero crossing of he curren and volage waveforms. These oupus are fed o he PIC which does he furher power facor calculaions. B. Microconroller Secion PIC 16F877A microconroller is he hear of his Auomaic Power Facor Conroller, i find, displays and conrols he Power Facor.. To correc power facor, firs we need o find he curren power facor. I can be find by aking angen of raio of ime beween zero crossing of curren and volage wave forms and wo successive zero crossing of volage waveform. Then i displays he calculaed power facor in he 16 2 LCD Display and swiches ON he capaciors if required. C. Zero crossing deecor Inernaional e-journal For Technology And Research-2017 deecor circui which conver he sinusoidal waveform in o square waveform o be used by microconroller. D. Correcion Secion When load is conneced he power facor is calculaed by he PIC microconroller. If he calculaed power facor is less han 0.95 hen he relay swiches on he capacior. The relays are swiched using ULN2003 which is basically a driver IC.ULN2003 consiss of seven DARLINGTON PAIRS.Thecurren lead in capacior compensaes he correspondingcurren lag which is usually presen in loads. Hence he phase difference beween he curren and volage will be reduced. Power Facor Correcing capacior conneced parallel o load hrough relay, if he relay is energized by microconroller i will connec he capacior parallel wih load, if relay de-energized i will remove he capacior from he load. When he resisive load is on he power facor will be near o uniy so he microconroller doesn energize he relay coil. When he inducive load is on he power facor decrease now he microconroller energize he relay coil in order o compensae he excessive reacive power. Hence according o he load he power facor is correced. E. Operaional principal The oupu from he zero crossing deecors are now fed o he pins of PIC of microconroller separaely which uses is inernal imers o measure he ime duraion of signals in which heir value is high or 1. When he volage signal crosses zero he imer will sar and when he curren signal crosses zero he imer sops couning. Microconrollers coun he ime difference and convered ino corresponding phase difference as followingequaion- Phasediff= ( T / T) * where T= imer coun, T= oal coun in one full cycle. Inernal program of microconrollercheck he power qualiy and urned on he capacior hrough swiching uni as per requiremen. As he name indicaes he zero-crossing deecor is adevice for deecing he poin where he volage crosseszero or curren crosses zero in eiher direcion. As shown in he circui diagram 4, here are wo ZCD are used. The inpu secion is conneced o ransformer secondary, which provides sinusoidal inpu o he ZCD. Zero crossing of wo waves mus be deeced o measure he phase difference beween wo waves. Zero crossing deecor circui basically convers he sinusoidal wave o square wave. The oupus from sep down curren and volage ransformers are fed in o zero crossing F. On/off capacior For he uilizaion of capacior, we have chosen a mehod where he capacior will urn on or off as per requiremen in ascending order. For example, when he power facor is less han predeermined value hen he firs capacior will urn on. Then he microconroller will again check he power facor in second ieraion. And will urned on or off he capacior as requiremen as shone bellow. 2 8h Naional Conference onadvanced Techniques in Elecrical and Elecronics Engineering, SJBIT, Bangalore (TTMT-2017) Copyrigh@IDL-

3 IDL - Inernaional Digial Library Of Available a: 8 h Naional Conference on Advanced Techniques in Elecrical and Elecronics Engineering Le iniially one capacior will urned on Then in second ieraion for lower power facor And will increases as per heir limi as follows- Inernaional e-journal For Technology And Research-2017 sysem is PIC microconroller. The curren and volage single are feed from he main AC line by using Curren Transformer and Poenial Transformer hrough zero crossing deecors. Boh he volage and curren signal are fed ino a CRO o display he behavior of he signal and o he microconroller for furher operaion. Inernal program of microconrollerselec he demand of capacior and give signal o he driver circui o urn on he capacior. In case of low power facor Microconroller send ou he signal o swiching uni ha will swich on he in-demand value of capacior. The asks execued by he microconroller for correcing he low power facor by selecing he in-demand value of capacior and load monioring are shown in LCD. A. Block diagram If he power facor crosses he upper power limi, hen urned off he firs urned on capacior And his process will coninue up o he power facor become less han upper power facor limi. Figure 1: Overview of he block diagram for he microconroller based power facor correcor. B. Conroller circui diagram I is clear from he figure ha he capacior raing will increase in each sage. IV. BLOCK DIAGRAM AND DESCRIPTION The block diagram of he microconroller based power facor conroller is shown in Figure 1. The principal elemen of he Figure 2: circui diagram using PROTEUS h Naional Conference onadvanced Techniques in Elecrical and Elecronics Engineering, SJBIT, Bangalore (TTMT-2017) Copyrigh@IDL-

4 IDL - Inernaional Digial Library Of Available a: 8 h Naional Conference on Advanced Techniques in Elecrical and Elecronics Engineering In his circui wo zero crossing are used which conneced o wo differen ransformers (CT & PT) secondary. ZCD oupu hen fed ino conroller pin RA0 & RA1. Microconroller gives oupu o he LCD Display hrough RB pors and also o he driver circui o urned on he capacior uni hrough RD pors as per requiremen. The ULN2003A driver gives signal o he relay o urned on or off he capacior hrough relay. C. Volage and curren signals Sysem curren and volage wave-forms for (3.1) leading power facor, (3.2) lagging power facor. where Vs and Is is ransformer oupu volage and curren respecively and V s & I s is he oupu of ZCD Inernaional e-journal For Technology And Research-2017 Vs Is Figure V s Vs I s Is Figure3.2: Lagging power facor. V s I s Figure3.1: Leading power facor Figure3.3 Signals ge from sysems CRO. 4 8h Naional Conference onadvanced Techniques in Elecrical and Elecronics Engineering, SJBIT, Bangalore (TTMT-2017) Copyrigh@IDL-

5 IDL - Inernaional Digial Library Of Available a: 8 h Naional Conference on Advanced Techniques in Elecrical and Elecronics Engineering V. ALGORITHM FOR DETERMINING THE POWER FACTOR Sep 1- Check for volage cross zero from negaive o posiive. Sep 2- Timer T sars (T). Sep 3- Timer T sars ( T). Sep 4- Check for curren cross zero from negaive o posiive. Sep 5- Timer T sops. Sep 6- Check again for volage cross zero from negaive o posiive. Sep 7- Timer T sops. Sep 8- Phase difference= ( T / T) * Sep 9- Ge cosφfrom look up able. Sep 10- If T > T/4 repor power facor is leading. Curren and volage waveform wih ime period (T) are shown in figure 5 and 6 and combined waveform wih ime gap ( T) is shown in figure 7. Inernaional e-journal For Technology And Research-2017 Sep 3- Deermine power facor. Sep 4- deermine value of curren. Sep 5- if value of curren is less han TUC, ake no acion and go o sep 3. Sep 6- if he value of power facor is beween LPF and UPF ake no acion and go o sep 3. Sep 7- if he value of power facor is less han LPF swich on he nex off capacior and wai for 1.0 seconds. Go o sep 3. Sep 8- If he value of power facor is more han UPF or as leading, swich off he firs on capacior and wai for 1.0 second. Go o sep 3. VII. CONCLUSION This work is an aemp o design and implemen he power facor conroller using PIC microconroller. In his work here is a predefined own curren minimum range and power facor minimum and maximum range. PIC moniors boh coninuously and hen according o he lagging or leading power facor i akes he conrol acion. This hesis gives more reliable and user friendly power facor conroller. This hesis makes possible o sore he real ime acion aken by he PIC microconroller. This hesis also faciliaes o monior he power facor changes on LCD in real ime. Figure 4: Curren wih ime period References Volage Curren Figure 5: Curren and volage wih ime gap VI. ALGORITHM FOR CONTROL SCHEME Sep 1- Se he user define lower and upper power facor (LPF & UPF). Sep 2- Se he user define hreshold value of curren (TUC). [1] Mr. Akash Sakpal, Mr. Shubham Salunkhe, Mr.SubodhSonawane, Prof.Mrs.A.A.Rane. auomaic power facor by using conroller Vol-2 Issue [2] Md. Shohel Rana, Md. Naim Miah &Habibur RahmanEason, Auomaic Power Facor Improvemen by using Microconroller. Volume 13 Issue 6 Version 1.0 Year [3] Parveen kumar, developmen of power facor conroller using PIC Microconroller july [4] B.C. Kok, C. Uraphan, and H.H. Goh, A Concepual Design of Microconroller-Based Power Facor Correcor Circui. june h Naional Conference onadvanced Techniques in Elecrical and Elecronics Engineering, SJBIT, Bangalore (TTMT-2017) Copyrigh@IDL-

6 IDL - Inernaional Digial Library Of Available a: 8 h Naional Conference on Advanced Techniques in Elecrical and Elecronics Engineering [5] Bryan Underwood, Alernaing Curren Power Facor Monioring and Correcion may [6] PranjaliSonje, Power Facor Correcion Using PIC Microconroller volume 3, ocober [7] Murad Ali, Design and Implemenaion of Microconroller-Based Conrolling of Power Facor Using Capacior Banks wih Load Monioring. Volume 13 Issue 2 Version 1.0 Year Inernaional e-journal For Technology And Research-2017 [8] Priya S. Devkar, Microconroller Based Power Facor CorrecionUsing IC L [9] hp://documenslide.com/documens/pic54769f12b4af9f6f518b4595.h ml. [10] hps://en.wikipedia.org/wiki/power_facor. [11] hp://microconrollerslab.com/auomaic-power-facor-conroller-usingpic-microconroller/. 6 8h Naional Conference onadvanced Techniques in Elecrical and Elecronics Engineering, SJBIT, Bangalore (TTMT-2017) Copyrigh@IDL-