The Control of Electromagnetic Filter by Using FPGA Based PI Type Fuzzy Controller

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1 Th Control of Elctromagntic Filtr by Using FPGA Basd PI Typ Fuzzy Controllr Ilkr Ali OZKAN a, Ismail SARITAS b, Saadtdin HERDEM b a Dpartmnt of Computr Enginring, b Dpartmnt of Elctrical and Elctronics Enginring Slcuk Univrsity AlaaddinKykubad Campus, Slcuklu, Konya TURKEY ilkrozkan@slcuk.du.tr, isaritas@slcuk.du.tr, shrdm@slcuk.du.tr Abstract: - Thr ar a lot of factors lik particl siz, concntration and flow rat which affct th prformanc of th Elctromagntic Filtr () usd for claning of industrial filtrs. In this study, an FPGA basd PI typ fuzzy control systm is dsignd and ralizd considring th all paramtrs affcting th prformanc. Ralizd controllr has bn intgratd in kit and usd for claning of industrial liquids. Rsults of th prformd xprimnts and prvious litratur rsults ar givn with thir diffrncs in structurs. Ky-Words: Elctromagntic filtr, PI typ fuzzy controllr, FPGA basd controllr, Fuzzy controllr 1 Introduction Th high quality of industrial liquids and gass is first dtrmind by th clannss of contnt aftr thy hav usd in tchnological procsss, and scondly, invariability of physical and chmical charactristics during thir usag in th cours of production [1]. Aftr prforming many xprimnts, it is rportd that industrial liquids and gass mostly contains iron compound contaminants [2, 3] Bcaus th contaminants hav granular structur and basically shows magntic proprtis, it is advantagous to us lctromagntic mthods. Filtrs utilizing th particls magntic proprtis and using diffrnt typs and structurs of filtr matrics and prforming claning procss ar calld [1]. Claning with can b prformd ithr in th bginning phas, during or at th nd of th tchnologic procss [4]. Th diffrnc of s from classic filtrs is that thir filtr lmnts consist of frromagntic matrials. A basic principal schma is givn in Fig. 1 [5]. Th industrial liquid which is supposd to b filtrd by th is first pass through th input pip (4) and thn filtring procss is prformd. Th liquid consquntly rturnd to th systm through th output pip (5). To crat magntic fild around th filtr matrix (3) lmnts xtrnal systm (1) consists of magnts and lctromagnts. body (2) is non-magntic stainlss matrial. Filtr matrix lmnts can asily b magntizd by an applid xtrnal homognous magntic fild dnsity of approximatly B=0.05 to 1.5 T and crat high gradint multi-fild around thmslvs. Th magntic fild dnsity of th local bcoms much gratr than th applid xtrnal magntic fild dnsity. Th rgions of th cratd filds ar calld "activ rgion" or "holding rgion" [4, 6]. 5- Output 1- Th systm crating th xtrnal magntic fild 2- non-magntic body 3- Filtr matrix 4- Input Fig. 1. principl schma Th prformanc of th magntic filtrs dcras as thy oprat, th prformanc may dgrad to nothing for long duration of filtr opration. Th situation changs dpnding on many paramtrs and ths paramtrs can b dfind as tchnological paramtrs. Paramtrs may b dtrmind by filtr lngth, th siz and typ of th filtr lmnts, flow rat of th liquid, applid magntic flux dnsity tc. Th control systms dsign which considrs all th paramtrs changs ar rquird to hold th prformanc of th filtr ISBN:

2 high [1]. A prformanc of th (ψ) is dtrmind by using th quation (1). 1 In litratur, input particl concntration (IPC) and flow rat (FR) of cland liquid ar rportd to affct th prformanc [7]. In th studis to control th, thr ar rports about fuzzy controllrs adjusting th PWM rfrnc voltag which dtrmins th magntic flux of th dpnding on IPC and FR changs [5, 7, 8]. In this study, th output particl concntration (OPC) is also givn and th ffct of OPC on th prformanc ar xamind. Studis in th litratur, it is rportd that fuzzy controllr rgulats th prformanc succssfully for th cass of changing IPC and FR. Additionally, controllr dsign which considrs prformanc is rportd but thr is no rportd xprimntal study to clan th industrial liquids by using mntiond dsign [9]. In this study, a PI typ fuzzy controllr which considrs all th factors affcting th prformanc has bn dsignd and an FPGA on th controllr kit has bn programmd accordingly. An xprimnt has bn prformd to clan th industrial liquids with th dvlopd controllr on kit and rsults hav bn rportd. 2 Exprimnt Kit In this study, kit ralizd by th projct "Adaptiv Control of Elctromagntic Filtrs Usd in Claning of Industrial Liquids by Using Artificial Intllignc and Kit Dsign (109E037)" which is supportd by "Th Scintific and Tchnological Rsarch Projcts Support Program" of Th Scintific and Tchnological Rsarch Council of Turky (TUBITAK) [10]. This kit usd for claning industrial liquids houss wast dpot, powr unit, coil and matrics, particl snsors and control units. Th kit's units which ar usd in this study and control systm's working principls ar givn in Figur 2. Th physical structur sn in th figur can b summarizd as th passing th liquid which is supposd to b cland to xit aftr cland by th. Signals gathrd from IPC snsor (S1) and OPC snsor (S2) ar passd to snsor circuits which thn can b applid to instrumntation amplifirs. Analog data gathrd from th snsor circuits is snt to FPGA through a paralll output ADC intrfac card. Th control of th magntic flux is don by th output of th control systm running on FPGA. (1) Analog PWM rfrnc voltag which is an output of th controllr programmd on FPGA is passd to PWM by using a DAC card. Voltag applid to coil is controlld by th PWM which is controlld by th rfrnc voltag. By changing th coil voltag, magntic flux is controlld [10]. Powr Unit S 1 PWM Industrial Liquid DAC FPGA Systm to Filtr th Liquid ADC Snsor Circuits Cland liquid Fig. 2. Structur of Magntic Filtr Control Systm. 3 PI Typ Fuzzy Controllr A fuzzy controllr consists of fuzzifir, xtraction mchanism and dfuzzifir phass. Control input valus gathrd from th systm ar convrtd into symbolic valus which ar linguistic xprssions in fuzzification phas. Infrnc mchanism producs linguistic xprssions of control progrsss as xpctd from an xprt on subjct according to stat of input variabls by using ruls and concpts dfind in th ruls bas. At th output, fuzzy numbrs spcifid by linguistic variabls and mmbrship function ar obtaind. Crisp control valus ar acquird from fuzzy numbrs blonging to output valus producd by infrnc mchanism in dfuzzification phas [7, 8]. A PI typ fuzzy controllr (PI Typ FC) structur dsignd to apply th is givn in th Figur 3. As sn in th Figur 3 prformanc rror and rror chang ar th input variabls of th fuzzy controllr. Error and rror chang xprssions ar givn in quation (1) and (2) rspctivly. (1) 1 (2) Hr k is sampling tim, P rf is rfrnc prformanc valu, P is 's prformanc. Th output of th controllr is givn as th quation (3). S 2 ISBN:

3 P rf P - Z -1 - ψ -1 GPK Fuzzifica tion Rul Bas Infrn c Dfuzzi fication u u -1 PowrUnit Z -1 u In this study, w hav chosn MAX-MIN infrnc mthod and wightd avrag dfuzzification mthod bcaus of its rquirmnt of lss calculation powr and bing a mor FPGA frindly mthod considring th "mpty aras". ÇPK S 2 S 1 Fig. 3. Blok Diagram of Control Systm. (3) Hr u(k) is th output of th PI typ FC and shows th chang in control valu. Mmbrship functions usd in fuzzification of input and output variabls ar givn in th Figur 4. Usd mmbrship function ar NB (Ngativ Big), NM (Ngativ Mdium), NS (Ngativ Small), Z (Zro), PS (Positiv Small), PM (Positiv Mdium), PB (Positiv Big). Fig. 5. Gnral diagram of PI typ FC. Fig. 4. Mmbrship functions for,, u. Mmbrship function valus ar dfind in th rang of [-1,1] and scaling cofficints ar usd for input and output valus. Suitabl slction of scaling cofficints valus ar mad basd on proficint opinion of th fild xprts of control and trial and rror mthods. Fuzzy rul bas usd for typ-pi fuzzy controllr is givn in Tabl 1. Tabl 1. Fuzzy rul bas for u \ NB NM NS Z PS NB NB NB NB NM NS NS Z NM NB NM NM NM NS Z PS NS NB NM NS NS Z PS PM Z NB NM NS K PS PS NM NS K PS PS PM NS K PS PM PM PB K PS PS PB PB Blok diagram of th alll lmnts of th PI typ FC systm ralizd on an FPGA is givn in Figur 5. Ralizd controllr softwar is adaptd to Cyclon II FPGA. According to synthsis rsults lmnts of th logic lmnts ar usd. For th procsss rquird for th control occupis th 29% of th usd FPGA. Bsids all collctd data is transfrrd and savd to a computr via an RS-232 port during th xprimnt. 4 Control Exprimnt An xprimnt has bn prformd by using dsignd PI typ FC on kit. Magntic balls having 14mm radius hav bn usd for th xprimnt. Industrial liquid usd in th xprimnts has bn prpard by adding 4-10x10-4 mm siz iron powdr Exprimnts hav bn to 200lt liquid dpot. compltd around 14 minuts. Th incoming valus of IPC (S1), OPC (S2) and FR of industrial liquid to FPGA ar transfrrd and savd to computr by using an RS-232 intrfac during th xprimnts. Th currnt apply to coil is dtrmind by th FPGA basd fuzzy controllr by valuating th valus incoming from IPC and OPC snsors. Exprimnt is ralizd whn th prformanc is not stabl, in othr words it is prformd in th phas whn th holding rgions ISBN:

4 cannot hold particls compltly. P rf valu is dfind as 95% during th xprimnt. Chang of IPC and OPC vrsus tim during th xprimnt is givn in Figur 6. 4 Rsults and Suggstions Chang in prformanc along with th chang in PWM rfrnc voltag in th xprimnt using FPGA basd PI typ fuzzy controllr vrsus tim is givn in th Figur 9. Fig. 6. IPC and OPC Th chang in flow rat of industrial liquid is givn in Figur 7. Fig. 7.Flow rat Chang in PWM rfrnc voltag by using PI FC is givn in Figur 8. Fig. 9. PWM rfrnc voltag and prformanc with PI typ FC. Whn th control xprimnt rsults ar xamind whil th IPC and FR allowd to b variabl, it is sn that applid currnt to filtr coil is changd by FPGA basd FC, consquntly rsulting a chang in th magntic flux. If th Fig. 9 is invstigatd, it can b sn that in th rgions prformanc drops blow 95% th applid currnt to filtr coil is changd to forc th incras in magntic flux in th holding rgions rsulting a dcrasing ffct on OPC. Morovr, bcaus diffrnt from th litratur studis, dirctly prformanc valu is accptd as th bas valu, PWM rfrnc voltag dos not chang during th changs of FR as in th minuts 7 and 9. It is known that factors affcting th prformanc ar not limitd by IPC and FR, many tchnological factors can chang th prformanc. Dvlopd controllr can produc rspons changs in all factors. Th invstigatd kit controlld by th FPGA basd FC can b dvlopd furthr as an adaptiv systm changing itslf according to diffrnt paramtrs by utilizing th calculation powr and paralll procssing ability of FPGA. Fig. 8. PWM rfrnc voltag Acknowldgmnts This study is supportd by Slcuk Univrsity Scintific Rsarch Projct Coordinat (BAP) and TUBITAK (Projct 109E037). ISBN:

5 Rfrncs: [1] T. Abbasov, Elctromagntic Filtration Procss, SckinPrss, 2002 (in Turkish). [2] J.H.P. Watson, Magntic filtration, J. Appl. Phys., 44(9), 1973, pp [3] T. Abbasov, Magntic filtration with magntizd granular bds: Basic principls and filtr prformanc, China Particuology, 5, 2007, pp [4] S. Hrdm, T. Abbasov and M. Koksal, Modlling of Buildup Procss of Particls in Pors of High Gradint Magntic Filtrs by Using Fokkr-Planck Equation, J. Phys. D: Appl. Phys., 32(24), 1999, pp [5] I. Sarıtas, I.A. Ozkan, S. Hrdm,, Th ffcts of fuzzy control of magntic flux on magntic filtr prformanc and nrgy consumption, Exprt Systms with Applications, Vol.37(12), 2010, pp [6] P. Alizad, T. Abbasov, A. Nayi, AkışkanOrtamlarınElktromanytikFiltrlrlT mizlnmsi, Çv-Kor, 7(25), 1997, pp (in Turkish). [7] I. Saritas, ElktromanytikFiltrTasarımıvYapayZkaYö ntmlriyladaptifkontrolü,slcuk Univrsity Graduat School of Natural Scincs PhD Thsis, 2008 (In Turkish). [8] I.A. Ozkan, I. Saritas, S. Hrdm, Th control of magntic filtrs by FPGA basd fuzzy controllr, Enrgy Education Scinc and Tchnology Part A, 29(2), 2012, pp [9] I.A. Ozkanv S. Hrdm, FPGA TabanlıKndiniAyarlayabilnBulanıkKontrolör ilmanytikfiltrninkontrolü, OtomatikKontrolUlusalToplantısı TOK, 2012 (in Turkish). [10] S. Hrdm, I. Sarıtaş, I.A. Ozkan, Endüstriylsıvılarıntmizlnmsindkullanılan lktromanytikfiltrlrinyapayzkayöntmlriyl adaptifkontrolüv kit tasarımı, TUBITAK Projct 109E037, 2011 (in Turkish). ISBN: