Kulaj Kau, SSSR Saathbabu Duvvu and Shakt Sngh 1 Elctcal and Elctoncs Engnng Dptt., LPU, Jallandha, Punjab, Inda 2 Elctcal and Inst. Engnng Dptt., Thapa Unvsty, Patala, Punjab, Inda 3 Elctcal and Inst. Engnng, Thapa Unvsty, Patala, Punjab, Inda E-mal: kulaj.1572@lpu.co.n, saath.duvvu@thapa.du, shakt.sngh@thapa.du Abstact Th pap mphass a soluton fo nducton moto spd contol. In ths pap w psnt th smulaton sults of vcto spd contol of an nducton moto. In ths cas, ndct mthods w smulatd usng MATLAB (SIMULINK). A squl cag nducton moto modl was usd takng th fnc coodnats as th oto magntc fld. Th accuacy of sults s gvn by th pcson of moto modl usd. Ths pap dscbs th us of th MATLAB smulaton toolbox SIMULINK fo dynamc modlng of vcto contolld moto dv systm. Th dynamc and tansnt pfomanc s studd though smulaton and th sults a psntd. Th pncpl of vcto contol of AC machn nabls th dynamc contol of AC motos, and nducton motos n patcula to a pfomanc lvl compaabl to that of a DC machn. Th basc quatons dscbng th dynamc bhavo of an nducton machn n otatng fnc fam a dsgnd. Basd on ths quatons th stuctu of th vcto contolld nducton moto dv s dsgnd. Th pocdu s valuatd though xtnsv comput smulaton. Th complx natu of th vcto contolld schm placs a havy computatonal budn on th contoll. Th pow ccut s dvlopd usng Insulatd Gat Bpola Tansstos (IGBTs). Ths stuctu gnats th dsd fnc voltag by actng on both th ampltud and th angl of ts componnts. Th moto achs th fnc spd apdly and wthout ovshoot, load dstubancs a apdly jctd and vaatons of som of th moto paamts a faly wll dalt wth. Kywods: vcto contol, nducton moto, scala contol, oto quatons, fnc fam Intoducton Modn ndustal pocsss plac stngnt qumnts on ndustal dvs by way of ffcncy, dynamc pfomanc, flxbl opatng chaactstcs, as of dagnostcs and communcaton wth a cntal comput. Ths coupld wth th dvlopmnts n mco-lctoncs and pow dvcs hav ld to a fm tnd towads dgtal contol of dvs. Th s a wd vaty of applcatons such as machn tools, lvatos; mll dvs tc., wh quck contol ov th toqu of th moto s ssntal. Such applcatons a domnatd by DC dvs and cannot b satsfactoly opatd by an nducton moto dv wth constant Volt-Htz (V/f) schm. Ov th last two dcads th pncpl of vcto contol of AC machns has volvd, by mans of whch AC motos and nducton motos n patcula, can b contolld to gv dynamc pfomanc compaabl to what s achvabl n a spaatly xctd DC dv. In cnt dcads, many nvstgatons hav bn don by sachs to contol ac motos smla to that of spaatly-xctd dc machns that lad thm to vcto contol thoy [1]. Vcto contol mad th ac dvs quvalnt to dc dvs n th ndpndnt contol of flux and toqu. Th majo dsadvantag of th ndct vcto contol schm s that t s machn paamt dpndant, snc th modl of th moto s usd fo flux stmaton. Th machn paamts a affctd by vaatons n th tmpatu and th satuaton lvls of th machn. Any msmatch btwn th paamts n th moto and that nstumntd n th vcto contoll wll sult n th dtoaton of pfomanc n tms of stady stat o and tansnt oscllatons of oto flux and toqu. Ths typs of oscllatons a not dsd fo som xact uss. Rgadng th mpotanc of snstvty of vcto contol dv to th moto paamts, many nvstgatons hav bn cad out n ths fld. In [2] th ffcts of oto sstanc and mutual nductanc vaatons on output toqu and oto flux hav bn dscussd qualtatvly. In th oth wok th ffct of th machn paamts vaatons on ts outputs, fng to smulaton sults has bn nvstgatd and two tchnqus fo oto sstanc stmaton hav bn dscbd [3]. Kshnan n [4] has dvd appoxmat quatons fo paamt snstvty of ndct vcto contol; and fnally n som fncs, moto paamt stmaton and compnsaton tchnqus and th ffct on machn outputs hav bn dscbd [5]-[9]. In ths pap xact quatons of paamt snstvty hav bn dvd. Usng dvd quatons, th ffct of paamt vaatons on th outputs of th machn can b dtmnd. In th nxt sctons, fst th basc quatons of ndct vcto contol a psntd, and thn snstvty analyss of ths typ of contol cad out and analytcal functons fo output toqu and oto flux snstvty a dvd. Indct vcto contol oto fld ontd nducton machn Th analyss of vcto contol stuctus hghlghts sval possblts to contol th nstantanous valus of th lctomagntc toqu of th nducton machn. Th poston of oto flux can b stmatd dctly o ndctly. Th [Pag No. 373]
5 th IEEE Intnatonal Confnc on Advancd Computng & Communcaton Tchnologs [ICACCT-211] ISBN 81-87885-3-3 ndct stmaton schms of th oto flux poston nsu a good bhavou n all spd ang, and thy a th common soluton n pactc. In th ndct mthod [4], t s ncssay to dtmn th oto tm constant n od to alz ffctvly th ontaton of th oto flux spac vcto. Ths can b sn fom th followng quatons [7]: dm τ + [1 jωmτ] m = s (1) L R τ = s th oto tm constant L, R s th oto nductanc and sstanc spctvly m Roto magntzaton cunt spac s - Stato cunt spac vcto ω - Elctc oto spd. m Equaton (1) s dtmnd takng nto consdaton th coodnats of th stato, tansfomng t to th oto flux j coodnats by multplyng wth th unt vcto ρ and spaatng th sult nto al and magnay pats, w gt d m τ + m = ds (2) d ρ qs = ωm = ωm + τ (3) m Fgu 1 shows th cunt phaso dagam n th otatoy fnc fam. Th synchonous spd of th stato cunt spac vctos s: dδ ω1 = ωm + (4) δ s th toqu angl uncouplng th magntc oto flux fom th toqu, a smla bhavou as a spaatly xctd dc moto. Ths s th basc pncpl of fld ontaton contol (FOC). Th ndct vcto spd contol wth oto tm constant (z,) stmaton s shown n fgu 2 [6]. In th dct mthod [5], a oto flux obsv (oto flux modl) s ndd n od to mplmnt closd loop flux contol such that a fnc flux valu s st and th stmatd flux s th fdback sgnal. Th basc quatons dscbng th dynamc bhavou of an nduton machn n a otatng fnc fam algnd to th oto flux axs [1, 2] can b gvn as T( dm)/ + m = sd (5) d( ρ)/ = ω1 = ω1+ ω2 = ω + sq / T m (6) Jd( ω )/ = 2/3 P[ L /(1 + σ) m ] ( 7) m m sq load As vdnt n th abov quatons, th lctomagntc toqu s dctly popotonal to sd componnt of th stato cunt, f m s kpt constant. Th dal mthod of vcto contol mplmntaton s to contol th stato cunt by contollng sq and sd componnts spaatly. Whl a cunt contolld nvt usng hystss contoll s asy to als, t has th Kt = followng dsadvantags: 1. Th swtchng fquncy dpnds on th natu of th load. 2. Th cunt ppl s hgh. 3. Pfomanc at hgh spds s unsatsfactoy. Ths dsadvantags can b ovcom by usng a constant swtchng fquncy Puls Wh Modulatd (PWM) nvt to contol th stato cunt by a voltag souc nvt. Ths calls fo th tanslaton of stato voltag quatons to th oto flux fnc fam. Th possblty to us th squl cag moto n hgh pfomanc contol systms n whch a dynamc spons smla to that gvn by dc moto opns up nw applcatons n ndusty fo ths typ of motos. Th xst two vcto contol mthods: Th dct fld ontaton mthod wh fld snsos o modls a usd to calculat th magntud and poston of th oto flux vcto subsquntly ontng t n a systm of otatoy othogonal coodnats. Th ndct mthod n whch th slp angula spd s usd to obtan th poston of th oto flux vcto hncfoth ontng t. Fgu 1 Phaso dagam psntaton In stady stat, th toqu angl s constant.. ω1 = ω m and th vctos s and m, otat n synchonsm. Th componnts qs and ds can b contolld ndpndntly thus In both mthods, t s ncssay to dtmn coctly th ontaton of th oto flux vcto, lack of whch lads to dgadaton n th spd contol of th moto. In th ndct mthod, th oto flux obtand fom an adaptabl fnc modl was compad to a oto flux obtand fom a fxd fnc modl thus stmatng th oto tm constant. Ths nw valu s substtutd n th ontd fld quatons thus [Pag No. 374]
not dsontng th magntc fld famwok that otats at th sam spd as th oto magntc flux. Th ndct vcto contoll s dvd fom th dynamc quatons of th nducton machn n th synchonously otatng fnc fams. Th oto quatons of th nducton machn a gvn by: R q+ pλq+ ωslλd= (8) R + pλ ω λ = (9) d d sl q ω = ω ω (1) λ = + (11) sl s q Lmqs L q d Lmds Ld λ = + (12) In ths quatons, th vaous symbols dnot th followng: R, th fd oto sstanc p phas; Lm, th mutual nductanc p phas; L, th stato fd oto slf nductanc p phas; d and q th fd dct and quadatu axs cunts, spctvly; p, th dffntal opato; ω sl, slp spd n ad/sc, ωs and ω a synchonous spd and lctcal oto spd both n ad/sc, and λd and λ q a oto dct and quadatu axs flux lnkags,spctvly. Th sultant oto flux s assumd to b on th dct axs, to duc th numb of vaabls n th quatons. Hnc, algnng th d axs wth oto flux phaso ylds: λ = λ (13) d λ q = (14) pλ = (15) q Substtutng quatons (6) to (8) n (1) and (2) and usng quatons (4) and (5), th followngs a obtand fo f and ω sl : 1 f = [1 + pt ] λ Lm (16) Lm T ωsl = T λ (17) f T = = ds qs L T = R Th q and d axs cunts a labld as toqu ( T ) and flux ( f ) poducng componnts of th stato cunt phaso, spctvly. T dnots th oto tm constant. Also usng quatons (6) to (8), w can summaz th nducton machn toqu quaton as: T= ( λqs ) = λt = KtλT (18) K Kt s toqu constant and s qual to: 3 p L m t = (19) Not that th toqu s popotonal to th poduct of th oto flux lnkags and th stato q axs cunt. Ths smbls th toqu xpsson of dc moto, whch s popotonal to th poduct of th fld flux lnkags and th amatu cunt. If th oto flux lnkag s kpt constant, thn th toqu s smply popotonal to th toqu poducng componnt of th stato cunt ( T ), as n th cas of th spaatly xctd dc machn, wh th toqu s popotonal to th amatu cunt whn th fld cunt s constant. Th oto flux lnkag and toqu quatons gvn n (9) and (14), spctvly, complt th tansfomaton of th nducton machn nto an quvalnt spaatly xctd dc machn fom a contol pont of vw. Fgu 2 Smulaton modl of ndct vcto contolld nducton moto dv systm smulaton and xpmntaton Comput modllng and smulaton s wdly usd to study th bhavou of vaous complx systms. Wth pop smulaton tchnqus, a sgnfcant amount of xpmntal cost could b savd n th pototyp dvlopmnt. Among sval smulaton softwa packags, SIMULINK [7] s on of th most powful tchnqus fo smulatng dynamc systms du to t s gaphcal ntfac and hachcal stuctu and n addton SIMULINK uss MATLAB as a Tool fo mathmatcal puposs whch futh nhancs th modllng pocss. Ths softwa pmts th dsgn of spcal us blocks, whch can b addd to th man lbay. Fgu 3 shows th block dagam n th d-q synchonous fnc fam of th luctanc synchonous machn wthout damp wndngs, by consdng a two pol machn. Th vcto contol aspcts a studd usng synchonously otatng [Pag No. 375]
5 th IEEE Intnatonal Confnc on Advancd Computng & Communcaton Tchnologs [ICACCT-211] ISBN 81-87885-3-3 fnc fam. Th man pat of th dynamc vcto contolld luctanc synchonous moto modl s th two-axs moto modl block whch conssts of lctcal toqu, machn voltags and mchancal quatons. Th (3-2) phas tansfomaton block convts th 3 phas supply to 2-phas but th vs tansfomaton block convts th 2-phas otatng fnc fam nto 3-phas statonay quvalnt Th load toqu T s smply psntd as a constant valu, though t can b psntd as a vaabl quantty. In old to stat snulatng th systm, th paamts must b known Thy can b th calculatd o masud as n ths nvstgaton.th paamts of th moto, usd fo smulaton a as shown n Tabl. Tabl I nducton machn paamts. S.no. Paamts Valu 1 Voltag(V) 22 2 Fquncy (Hz) 6 3 Inta.89 Fgu 2 Moto spcfcatons. Tabl II: Spd Contoll S.no Paamts Valu 1 Popotonal gan (Kp).5 2 Intgal gan (K) 3 3 Dvatv gan (Kd) Fgu 3 Contoll paamts. Rsults and Dscussons Vcto contolld moto (kw) has bn smulatd and th dynamc sponss hav bn obtand.. Th smulaton sults fo spd-tm, toqu-tm and cunt-tm a as shown n fgus 3-5 spctvly. Fgu 3 shows th spd spons fo th moto wth dffnt load toqu (T,) whn th fnc spd s 2 (ad sc) whl kpng th voltagfquncy ato (v/f) constant. Fgu 6 shows th statng toqu poducd by th moto whn th moto statd fom st, and fgu 5 shows th spd /toqu chaactstcs of th dv. cunt 8 6 4 2-2 -4-6 -8-1.5 1 1.5 tm Fgu 5 Cunt Rsponss wth Tm Vaaton spd -1.5 1 1.5 tm c u n t 7 6 5 4 3 2 1 8 6 4 2-2 -4-6 -8 Fgu 6 Spd Rspons wth Tm Vaaton -1.5 1 1.5 tm Fgu 7 Toqu Vaaton wth tm. To valdat th smulaton sults, th pototyp of th poposd schm s wokd upon n th laboatoy and tsts a conductd on t. Th moto s un at spd of 1425 pm n both smulatons as wll as n xpmntaton. It can b obsvd that th smulaton sults match asonably wth th xpmntal sults. It has bn obsvd that th dsgn of poposd mthod s flxbl fo makng t sutabl fo toft applcatons. 1% 8% 6% 4% 2% % voltag vs spd 1 3 5 7 9 11 13 spd voltag Fgu 8 Expmntal Spd and voltag spons [Pag No. 376]
Th xpmntal st up s shown as und: Conclusons A dsgn pocdu has bn gvn fo vaous contol loops of a vcto contolld dv. Th dsgn pocdu s vfd usng comput smulaton. Th smulaton sults hlps to dcd th hadwa and softwa stuctu fo th vcto contolld nducton moto dv. Th total systm ncluds an lctonc contoll fo th sgnal pocssng nvolvd n vcto contol, PWM nvt, moto and th load. Although th hadwa and softwa hav bn dalt wth n th contxt of a vcto contolld nducton moto dv, thy a gnal pupos n natu. Ths can b usd fo contol of oth machn typs such as wound fld as wll as pmannt magnt synchonous motos. It s also possbl to us th sam hadwa and softwa fo th mplmntaton of oth contol schms lk dct slf- contol of nducton machns. Th opaton of 3.75 KW dv was also nvstgatd xpmntally. Th smulaton has bn valdatd usng th actual contol of nducton moto. Th smulaton sults hav bn shown a asonably clos agmnt wth xpmntal sults. Th sults dmonstat that th dv can b opatd n a wd spd and load ang. Rfncs [1] Blaschk F., Th Pncpl of Fld Ontaton as Appld to th Nw Tansvkto Closd-Loop Contol Systm fo Rotatng -Fld Machns. Smns Rv., 39, 5, May 1972, pp. 2 17-22. [2] Blaschk F., Das Vfahn d Fldontung zu Rglung d Dhfldmaschn Tchn. Unv. Baunschwg, Dsstaton, 1973. [3] Hass K., Zu Dynamk dhzahlgglt Antb mt stomchtgspstn Asynchon Kuzschlusslaufmaschnn.Tchn. Hochsch. Damsta, Dsstaton, 1969. [4] Pdo Ponc & Jam Rodguz Rvas., Smulaton dl Contol po Campo Ontado d Motos d Induccon. IEEE RVP 97. [5] Bmal K. Bos Pow Elctoncs and Vaabl Fquncy Dvs, IEEE Pss [6] Pdo Ponc & Jam Rodguz Rvas., Estmacon d la Constant d Tmpo dl Roto dl Moto d Induccon Mdant un Modlo d Flujo Adaptabl dl Sstma. IEEE RVP 98, pp. 373-379, Tomo I. [7] Muphy J.M.D. & Tunbull F.G. Pow Elctonc Contol of A.C. Motos, Pgamon also stmats th oto flux satsfactoly. Pss, 1988. [8] Bn-Bahm L., Gastl A., Al-Hamad M., Auto- Tunng fo Snsolss AC Moto Dv Systms. IEEE Int. Symp. on Ind. Elctoncs, Bld, Slovna, 367-372, 1999. [9] Ona A, Hoga V., Educatonal Softwa Envonmnt fo Moton Contol. Poc. of th IASTED 5th Int. Conf. on Comp. and Adv. Tchn. n Educaton, 334-339, 22. [1] Bhm Sngh, A Novl Polygon Basd 18-puls AC- DC Convt fo Vcto Contolld Inducton Moto Dv. IEEE tansactons vol.22, no.2, Mach 27. [11] J. C. Baslo, and S. R. Matos, "Dsgn of PI and PID Contolls wth Tansnt Pfomanc Spcfcaton," IEEE. Tans. Educaton, vol. 45, No.4, pp. 364-37, Novmb 22. [12] M. M. M. Ngm, J. M. Bakhashwan, and M. H. Shwhd, "Spd Contol of a Th-Phas Inducton Moto Basd on Robust Optmal Pvw Contol Thoy," IEEE Tans. On Engy Convson, vol. 21, No. I, pp. 77-84, Mach 26. [13] M. Bounadja, A. Mllakh, and B. Blmadan, "A Hgh Pfomanc PWM Invt Voltag-Fd Inducton Machns Dv wth an Altnatv Statgy fo Spd Contol," Sban jounal of lctcal ngnng, vol. 4, No. I, pp. 35-49, Jun 27. [14] L. A. Zadh,"Outln of a Nw Appoach to th Analyss of Complx Systms and Dcson Pocsss", IEEE Tans. Systms, Man, and Cybntcs, No.3, pp. 28-44. [15] B. Sngh, G. Bhuwanswa and V. Gag, "Multpuls mpovd-pow-qualty AC-DC convts fo vcto contolld nducton moto dvs", IEE Poc. Elct Pow Appl., vol. 153, no. 1, pp. 88-96, Jan. 26. [16] T. Iwakan t al., "hgh pfomanc vcto contolld AC moto dvs, vol.ia 23, no.5, Sptmb 1987. [17] J. A. Santstban, and R. M. Stphan, "Vcto contol mthods fo nducton machns: an ovvw," IEEE Tans. On Educaton, vol. 44, No.2, pp. 17-174,21. [18] V. Gag, Pow Qualty Impovmnts at ac Mans n Vaabl Fquncy Inducton Moto Dvs, Ph.D. dsstaton, Indan Inst. Tchnol. Dlh, Nw Dlsh, 26. [Pag No. 377]