Induction Machine Based Flywheel Energy Storage (FES) System Fed From a 20 khz AC Link

Transcription

1 nduction Machin Basd Flywhl Engy Stoag (FES) Systm Fd Fom a 0 khz AC Link 1 fan Alan, Mmb EEE Eg Univsity Bonova, zmi, 35100, TURKEY ifanalan@i.og Abstact - This study intoducs a fild ointd contolld (FOC) induction machin basd flywhl ngy stoag (FES) systm fd fom a 0kHz ac link and Puls Dnsity Modulatd (PDM) Convt. Th fasibilty of FES systm is invstigatd both in softwa and hadwa and is dmonstatd succsfully in both cass. Th invstigatd systm offs a good potntial as a tmpoay ngy stoag systm fo vaious applications fom automobil industy to aospac applications.. NTRODUCTON Dspit xtnsiv sach ffots on nw battis ov th past two dcads, availabl battis a limitd in thi usfulnss as a tmpoay ngy stoag dvic. Rsach xpts hav cognizd that th flywhl offs impotant advantags fo ducing pak pow dmands togth with a long svic lif. Th nd fo a cost ffctiv, long lif cycl, small siz and high pow dnsity ngy stoag systms has mad th tmpoay FES systms a viabl solution to th poblm. Pow quality suvys hav shown that th majoity of voltag sags and momntay intuptions last lss than 3 sconds, thfo th ngy stoag systms a quid to ffctivly povid a shot bust of pow [1]. Advantags offd by this mging tchnology in aospac applications a dscibd and th cunt NASA appoach towad dvloping th tchnology is psntd [,3]. Th FES Systm is intndd to b utilizd in a low-ath obit sattlit applications and flight tst dmonstation of th intnational spac station to ovcom th limitations psntd by th battis [4-8]. Fo spac vhicls, two count-otating whls a usd to poduc a FES systm [9]. Fo achiving matchd flow conditions in a natual gas pocssing plant, it is shown that th toqu distubanc jction in a obust spd contoll fo a compsso divn fild ointd contolld induction moto can bst b handld by th incopoation of a massiv flywhl [10]. Th possibilty of application of FES systm fo flywhl taction lctic tansf of whld tanspot facilitis was invstigatd in [11]. Th pak ngy quimnts of an lctic vhicl duing both acclation and gnativ baking was mt by a sconday ngy stoag unit (SESU) [1]. A FES dvic was intoducd as capabl of nhancing th ful conomy of a hybid typ oad vhicl [13]. Vaiabl spd flywhl gnatos hav also bn considd fo th stabilization of lctic pow systm tansints and faults [14-18]. This study intoducs a fild ointd contolld (FOC) induction machin basd FES systm fd fom a 0kHz High Thomas A. Lipo, Fllow EEE Univsity of Wisconsin Madison W 53706, USA lipo@c.wisc.du Fquncy (HF) ac link and Puls Dnsity Modulatd (PDM) Convt. Th 0kHz HF ac link and PDM tchnology povids convnint mans fo pow managmnt in a multi-tminal convt distibution systm and offs flxibility in voltag lvl changs, njoying fast systm spons and fdom fom acoustic nois. Such a HF ac link distibution systm is spcially attactiv fo isolation and pow dnsity snsitiv applications. Th doubl bidg ac link systm intoducd [19-3] pmits th induction machin to opat at vaiabl fquncy with full bidictional pow flow in ith otational diction. On impotant application of this ac link and PDM convt tchnology is in situations wh th chaactistics of th pow souc a constaind such that th pow must b managd so as to maintain th flow of pow to th link constant. n most cass, howv, th loads on th link a vaiabl such that th pow dmand and supply can not b matchd without additional load/soucs. Sinc th pow diffnc must b absobd within th ac link, lag fluctuations can b poducd on th link causing, phaps, failu of th tansistos in th pow convt du to an ovvoltag condition. n such situations an additional load/souc can b convnintly implmntd by mans of a FES systm connctd to th link via a pow convt and vaiabl fquncy induction machin as shown in Fig. 1. Th flywhl is contolld to opat as a load lvling dvic though th contol of th FOC induction machin. Hnc, only th avag load now nd b supplid by th batty souc whil th vaiations in pow dmand fom th moto can b absobd by th flywhl/moto by ith spding up o dclating th flywhl. n th wok achivd, th xisting HF link and doubl bidg is usd to study th ffctivnss of th FES systm. n paticula, th study dmonstats, in hadwa as wll as in softwa, th fasibility of maintaining lativly constant ac sonant link voltag amplitud by apidly xtacting o absobing xcss link pow fom/to an induction machin connctd to th link. A dtaild valuation of th contol quimnts fo such a contol statgy is dvlopd and implmntd in hadwa. On of th impotant contibution of this wok is th dmonstation of application of 0kHz ac link and PDM convt tchnology to FES systms. Espcially aospac applications may vy wll njoy th advantags povidd by th tchnology.

2 Fig. 1. Pow and Contol Block Diagam of th Softwa Simulatd Flywhl Engy Stoag and Load Lvling Systm. BACKROUND Som backgound on th Fild Ointd Contolld (FOC) nduction Machin and Puls Dnsity Modulation (PDM) Concpt is sn appopiat considing th scop of th publication. Th is a clos paalll btwn th physical toqu contol pincipls in a dc machin and a fild ointd contolld induction machin. Du to th commutato action in a dc machin, th fild flux and th amatu mmf (magnto motiv foc) a maintaind in a mutually ppndicula ointation indpndnt of th oto spd. As a sult of this othogonality th fild flux is unaffactd by th amatu cunt, and an lctomagntic toqu popotional to th amatu cunt is gnatd. Th gnatd toqu in a dc machin is givn by Eq. 1. T = KΦ (1) f a H, K is a toqu constant, f is fild flux, and a is th amatu cunt. f th othogonality btwn th flux and th amatu mmf w distubd (by shifting th bush positions intntionally fo xmapl), th fild flux would no long b indpndnt of th amatu cunt and th toqu quation should b modifid to includ an angl dpndnt function. Th toqu xpssion fo th induction machin basd on th classical p phas quivalnt cicuit shown in Fig. is givn in Eq..

3 T P P E = q = q s ω ω () + s s s wh q is th numb of phass, P is th numb of pols, is th stato fd oto sistanc, is th stato fd oto cunt, s is th slip, ω is th lctical angula supply fquncy, and E is th stato fd oto inducd voltag. V s jx sl m jx m jω (L s L m/l ) Sφ jx m (L m /L ) + - E m jx l Fig.. Classical P Phas Equivalnt Cicuit of an nduction Machin. By th utilization of an quivalnt cicuit modl fo th induction machin pop fo th fild ointation contol as shown in Fig. 3 a simila toqu and flux contol can b achivd fo a fild ointd contolld induction machin. Lin cunt of th induction machin is spatd into two componnts, namly th flux and th toqu componnt cunts, which a kpt othogonal to ach oth by th pop slip fquncy slction so that a simila toqu contol is obtaind as in th dc machin cas. Whn this is V s + E - ST = (- L /L m ) + E (L m /L ) /s (L - m/l ) - - Fig. 3. P Phas Equivalnt Cicuit of a Fild Ointd Contolld (FOC) nduction Machin. achivd th gnatd toqu in a fild ointd contolld induction machin can b dscibd by Eq. 3. T s s P L = q L m SΦ ST H, L m is th magntazing inductanc, L is th stato fd oto slf indcutanc, S is th flux componnt cunt, and th ST is th toqu componnt cunt of th induction machin considd. n a fild ointd contolld machin th flux componnt cunt in tms of classical quivalnt cicuit quantitis is psntd as givn in Eq. 4. (3) s S E = jω L Φ (4) m Similaly, th toqu componnt cunt in tms of classical quivalnt cicuit quantitis is psntd as givn in Eq. 5. L ST = (5) Lm Th slip fquncy in a fild ointd contolld machin is givn by Eq. 6. = L ST sω (6) SΦ Th lin cunt in a fild ointd contolld machin is givn by Eq s = Φ (7) S ST Fo futh infomation on FOC nduction Machin on is fd to Rfncs [4, 5]. Th puls Dnsity Modulation (PDM) concpt mntiond in this aticl is oftn usd with high fquncy (HF) sonant pow convts. Th dc o low fquncy ac voltag o cunt quantitis a synthsizd fom th half cycls of sonating voltag o cunt links so that both th fnc and th synthsizd actual quantitis a matchd and thy hav th sam volt-scond aa. n ssnc pics of sonating high fquncy link voltags/cunts a slctd in such a polaity and dnsity that th dc o low fquncy ac fnc and th synthsizd voltag o cunt wavfoms cov th sam avag volt-scond o cunt-scond aa within thi spcific tim intvals o piods. Pincipls of this Aa Compaison Puls Dnsity Modulation concpt is givn in dtail in Rf. [6-7]. Sval cucial advantags of PDM tchnology ov th PWM can b idntifid as mntiond in th 3 d paagaph of Sction.. SOFTWARE SMULATON OF THE SYSTEM A pow and contol block diagam of th systm which has bn simulatd in softwa is shown in Figu 1. Th systm studid in softwa compiss th complt convt bidgs fo vaious intfacs to th 0kHz ac link, on fo th initial chaging cicuit and constant pow souc intfac, on fo th induction moto load intfac, and on fo th flywhl induction machin intfac. Howv, th systm invstigatd in hadwa has only two availabl convt bidgs quiing thfo ctain aangmnts as will b mntiond in th xpimntal alization sction. Opation of th load machin in fou diffnt quadants fom th link via its associatd 3Ø-PDM convt mans vaying pow dmands fom th systm. Sinc th souc is a constant pow souc duing th flywhl mod of opation, th pow balanc in th ac link should b lvlld by th 3

4 flywhl. n oth wods, whn xta pow is pumpd into th link, th flywhl should absob th xta pow and whn th load and losss dmand mo pow than th constant pow souc can dliv, th flywhl should dliv th diffnc to maintain a pop link voltag in th link. As a sult th pow diffnc btwn th constant pow souc and vaying dmands of th load and losss is lvlld out by th flywhl on an avag basis. Th softwa simulation of this typ of opation is psntd in this sction. Th constant pow souc is psntd only by th amount of constant pow it dlivs to th high fquncy ac link without simulating any typ of dc o ac souc and associatd convts. n th simulations diffnt constant pow lvls such as of.5, 3.0 and 3.5kW a usd. Th namplat atings and p phas quivalnt cicuit paamts of th induction machin opatd as a flywhl is givn in Appndix-1. Simila atings and paamts fo th induction machin usd as load is givn in Appndix-. Both of ths machins a assumd to b indict FOC via cunt gulatd PDM convts..a. Ovall Opating Pincipl of th Systm Th induction machin usd as flywhl, shown in Fig. 1, must b xcitd and opatd at som sufficint spd bfo it can b usd as a load lvling dvic. Thfo, an initial chaging cicuit and an associatd convt is usd to stablish th pak link voltag, to xcit and bing th machin to a pdtmind sufficint spd. Onc th spd and xcitation quimnt is mt fo th flywhl, th flywhl mod of opation is statd and th initial chaging cicuit is switchd to opat as a constant pow souc duing th nw mod of opation. Th contol of th avag activ pow balanc in th link quis a good stimation of th toqu componnt cunt command fo th flywhl machin to lvl th load vaiations, to mt th vaying dmand of opating losss and maintain a pop link voltag in th link. Sinc pow matching on an instantanous basis is not possibl, an avag pow matching tchniqu which maks us of pow stimation fo both induction machins is usd. Th convt and sonant tank cicuit losss hav also bn incopoatd into th stimation pocdu. Th diffnc btwn th instantanous pow and avag pow is lft to th ngy stoag capacity of th sonant tank cicuit and a popotional-intgal (P) pak link voltag gulato..b. Toqu Componnt Cunt Command Estimation nitially, th avag activ pow quid fom th flywhl is stimatd by a simpl summation of incoming and outgoing avag activ pows to and fom th link. A positiv sign convntion fo th losss and outgoing pow, and a ngativ sign convntion fo th incoming pow is usd fo this pupos. Onc th total avag activ pow quid fom th flywhl is dtmind, th toqu componnt cunt command of th flywhl machin is stimatd by mans of quations 8 though 10 to mt th quid pow dmand. 4 H, th spd of th machin is masud, th flux componnt cunt command and th p phas quivalnt cicuit paamts of th flywhl machin a known in advanc. P = ω (8) q T Fo a th phas and two pols induction machin th toqu xpssion in Eq. 3 bcoms as follows. 1 L m * ss * T = 3 ids iqs (9) L * i qs Pq * ss 3 Lm ωids L = (10) H in ths quations, P q is th stimatd avag activ pow quid fom th flywhl induction machin, T is th gnatd lctical toqu of th flywhl induction machin, ω is th oto lctical angula fquncy, L m is th p phas magntizing inductanc, L is th p phas total stato fd *ss oto inductanc, i ds is th stady stat stato flux componnt cunt command in synchonous fnc fam, and i * qs is th stato toqu componnt cunt command in synchonous fnc fam. Bfo th stimatd toqu componnt cunt command is applid to th flywhl induction machin, a mino contibution fom th P pak link voltag gulato is addd to th stimation to pvnt xcssiv pak link voltag vaiations as a sult of instantanous mismatchs btwn th incoming and outgoing avag activ pows, stimation os, and paamt vaiations. Th systm is snsitiv to th oto tim constant to a ctain xtnt sinc this constant is dtmind at th bginning and assumd as such thoughout th opation. Th only gulation that taks masu against th vaiations of th paamts is th abov mntiond P pak link voltag gulato. Th systm pfomanc, howv, could b impovd by vy caful dsign of a paamt insnsisitv systm..c. Softwa Simulation Rsults Th load machin and flywhl intia w chosn to b 0.07 and 0. kgm spctivly and th simulation tim intval to b 6.5 sc. A.5 kw avag pow was assumd to b dlivd to th systm by th constant pow souc. Th initial spd of th flywhl was assumd to b 4000 pm. A paalll quivalnt loss sisto of 0.03? fo th sonant tank cicuit was assumd. Figu 4 shows basically what happns to th spd of th flywhl and th pak link voltag duing th flywhl mod of opation und th spcifid opating conditions. H th load machin opats in fou diffnt quadants of opation. Th figu shows th stat of flywhl mod of opation at tim t=0.35 sc with th stat of toqu componnt cunt command application to th flywhl machin. Pio to th flywhl mod of opation, th ncssay pow balanc in

5 th systm is maintaind by th initial chaging cicuit. Duing th flywhl mod of opation 5 phas vsal na th middl of th tac bcaus of th spd vsal and consqunt chang in th quadant of opation. Fig. 4. Dynamic Rspons of th Flywhl to Vaying Pow Dmands of th Load and Losss with th Opating Conditions Statd in Sction.C. Fom th Top: PEAK: HF Pak Link Voltag [ 0, 500, 1000] V. QSREF: Estimatd Toqu Componnt Cunt Command fo th Flywhl [ -40, 0, +40] A. SPEED: Spd of th Flywhl [ 3500, 4000, 4500] pm. SPEED: Spd of th Flywhl [ 0, 3000, 6000] pm. POUT: Avag Ral Load Machin Pow [ -5000, 0, 5000] W. PN: Avag Activ Pow of th Flywhl Machin [ , 0, 10000] W. Tim/div: 54 ms. th load machin has a vy dynamic and vaying pow dmand fom th systm as can b obsvd fom th fifth tac fom th top. Th flywhl machin thfo should b givn a pop toqu componnt cunt command to maintain th nti pow balanc in th systm and achiv a pop pak link voltag. Th scond tac fom th top shows such toqu componnt cunt command fnc fo th flywhl machin. Th fist tac shows a wll gulatd pak link voltag thoughout th nti opation. Th thid and fouth tacs fom th top show th spd of th flywhl in vaious spd angs. Th thid tac, bing th mo pcis, claly shows that th spd of th flywhl is initially 4000 pm and lat on it gos though som vaiations dpnding on th load lvlling quimnts. Figu 5 shows diffnt tacs of th sam opation in Fig. 4., namly, flywhl and load machin toqu componnt cunt commands, lin cunt fncs and actual lin cunts. Both machins a givn full atd flux commands and thfo fully xcitd duing th flywhl mod of opation. Thfo, whnv th is a chang in th toqu componnt cunt command th is also a cosponding chang in th lin cunts of th latd machin. Sinc th flywhl machin is opating at aound 00 Hz whil th load machin is opating at lss than 60 Hz th load sid machin lin cunts a asi to follow with spct to flywhl machin lin cunts. Load machin lin cunts also show a Fig. 5. Rspons of th Machin Lin Cunts to thi Vaying Toqu Commands with Ratd Excitation and Sam Opating Conditions of Fig. 4. Fom th Top Rspctivly: QSREF: Estimatd Toqu Componnt Cunt Command fo th Flywhl [ -40, 0, +40] A. AREF: Flywhl Machin Phas-A Lin Cunt Rfnc [ -60, 0, +60] A. AS: Flywhl Machin Phas-A Lin Cunt[ -60, 0, +60] A. MQREF: Toqu Componnt Cunt Command of th Load Machin[ - 0, 0, +0] A. MAREF: Load Machin Phas-A Lin Cunt Rfnc [ -30, 0, +30] A. MAS: Load Machin Phas-A Lin Cunt [ -30, 0, +30] A. Tim/div: 54 msc..d. Limits of th Flywhl Machin Figu 6 is intndd to show th limits of th flywhl machin by intntionally stting ctain initial conditions and flywhl machin intia to citical valus. H, a load machin intia of 0.01 kgm, a constant souc pow dlivy of 3.0 kw, a 0.1 kgm flywhl intia, 3000 pm initial flywhl spd, and a.5 sc simulation tim intval is assumd. As th tacs shown in Fig. 6 val, ducing th initial flywhl spd and th intia, and th constant pow dlivy to th systm whil incasing th applid load lvl sults in a high amplitud of toqu componnt cunt commands fo th flywhl. Futhmo, whn th load machin nts th scond quadant of opation which cosponds to th gnating gion, th toqu componnt cunt command fo th flywhl achs its limit valu and dos not bcom sufficintly lag to absob th xta pow pumpd to th link. As a sult, th pak link voltag gos out of contol and continus to incas bcaus of this unabsobd xta pow dumpd onto th link until th gnatd load-machin pow ducs in amplitud to a valu that flywhl can absob o handl with its cunt spd and intia. This figu thus claly convys mssags as to what should b th minimum spd and intia of th flywhl, and how much pow can b xtactd o absobd and how long.

6 V. EXPERMENTAL REALZATON A pow cicuit and contol block diagam of th xpimntal systm is shown in Fig. 7. On of th xisting two convt bidgs in hadwa is usd fo th initial chaging cicuit and constant pow souc, and th oth is usd fo th flywhl induction machin intfac. Th batty and its souc sid convt of th softwa simulatd systm is placd by a th phas (3Ø), 60 Hz utility souc and an associatd 3Ø-PDM convt. Th constant pow souc chaactistic of th batty is convnintly modlld by tight contol of th souc sid convt pow. A 3Ø, 300 Hz, 10 Hp induction machin with a dc dynamomt and two flywhl intia discs coupld to th sam shaft is usd as flywhl fo th systm. This machin is connctd to th ac link via anoth 3Ø-PDM convt. Th induction machin load of th softwa simulatd systm is placd by manually switchd sisto blocks acoss th ac link in th hadwa pototyp. Thfo, th nd fo a thid convt intfac to th link is liminatd. Tuning on and off diffnt lvls of activ pow by conncting/disconncting pow sistos acoss th link sults in vaying pow dmands fom th systm and th pow balanc in th ac link is maintaind by th flywhl machin. n oth wods, whn xta pow is pumpd into th link, th flywhl absobs th xta pow and spds up, and whn load and losss dmand mo pow than th systm can dliv, th flywhl dlivs that quid pow to th Fig. 6. Softwa Simulation Rsults Showing th Limits of th Flywhl Machin with ntntionally St nitial Conditions and Small Flywhl ntia. Fom th Top Rspctivly: PEAK: HF Pak Link Voltag [ 0, 500, 1000] V. POUT: Avag Ral Load Machin Pow [ -5000, 0, 5000] W. MSPEED: Spd of th Load Machin [ -000, 0, 000] pm. MTL: Load Toqu Applid to th Load Machin [ -30, 0, +30] Nm. SPEED: Spd of th Flywhl [ 0, 1500, 3000] pm. QSREF: Estimatd Toqu Componnt Cunt Command fo th Flywhl [ -40, 0, +40] A. Tim/div: 08 msc. 6

7 7 Fig. 7. Pow and Contol Block Diagam of th Hadwa Pototyp Flywhl Engy Stoag and Load Lvling Systm link and spds down. Th xpimntal sults of this typ of opation is psntd in this sction. V.A. Spcifications of th Souc, Load and th Flywhl Th 3Ø, 60Hz utility gid opating via 3Ø-PDM convt fom 0kHz ac link is usd as constant pow souc fo th systm. Th lin to lin voltag of th souc is st to 150V ms. A sinusoidal cunt fnc having a 13.6A pak valu is usd. Ths givn spcifications imply a constant pow dlivy of about.5kw fom th souc to th systm. Th namplat atings and p phas quivalnt cicuit paamts of th induction machin usd in th xpimnt as flywhl a givn in Appndix 1. Sval 1kW pow sistos opating fom 500V pak ac link a usd as load units. Ths 1-kW load units a connctd/disconnctd acoss th 0kHz ac link using manual switchs. V.B. Pincipl of Opation of th Expimntal Systm n od to ngiz th systm, th fnc pak link voltag is stablishd acoss th paalll sonant 0kHz ac link. Th induction machin is xcitd and bought up to som sufficint spd bfo it is opatd as a flywhl. Sinc no xta xcitation capacitos is usd, th xcitation of th induction machin is achivd via opation of th associatd 3Ø-PDM convt fom th 0kHz ac link. As is appant, this initial stating pocss can not b achivd by simply utilizing a constant pow dlivy/flywhl mod of opation. Thfo, initially, th 3Ø, 60 Hz utility gid is not usd as a constant pow souc ath it is usd as a pow balancing souc in th pocss of stablishing th fnc pak link voltag, xciting th flywhl machin and binging it to its dsid spd in spd gulation mod bfo it is usd as flywhl. Aft ths initial quimnts a mt, a manual contoll switch is usd to initiat th flywhl mod of opation along with 3Ø, 60 Hz utility gid contol to pfom a constant pow dlivy mod of opation. Aft th nw stting, th induction machin is opatd so as to balanc th pow in th link and maintain a pop link voltag by a pop stimation of th toqu componnt cunt command of th flywhl induction machin as dscibd in th pcding sction. Pow consumption of th load sistos a masud and includd in th quid pow and toqu command stimation fo th flywhl machin. Th contol of th avag activ pow balanc in th link is achivd in th sam mann as dscibd in Sction.A. Th only changs concn th spcifications of th

8 souc and th load and th mann fo dtmining how much pow th load is dawing. V.C. Expimntal Opation Rsults Bfo th flywhl mod of opation is st, th induction machin usd as flywhl is xcitd with atd flux command and th machin is bought up to a spd of appoximatly,700pm. n th flywhl mod of opation.5kw constant pow is dlivd fom th 3Ø, 60Hz utility souc to th systm via associatd 3Ø-PDM convt. Th pictus psntd h a takn fo a flywhl mod of opation psisting long than 10 sc which claly dmonstats th fasibility of opation of th ovall systm. Figu 8 shows th xpimntal pfomanc of th flywhl mod of opation of th systm und load vaiations. Not that th pak of th 0kHz high fquncy link voltag is wll gulatd duing th nti mod of opation. Th fist tac fom th top shows th load cunt. nitially, until th fist lvl of load is applid th is a small positiv toqu componnt cunt duing which th flywhl machin opats as a moto and absobs a cosponding pow. Whn th fist lvl of load, appoximatly 1-kW, is applid, a ngativ 10A toqu componnt cunt command is gnatd by th flywhl moto contoll to mt this load dmand in which th flywhl machin opats as a gnato and dlivs a cosponding pow. n th motoing mod flywhl tnds to spd up and in th gnating mod it tnds to spd down. As th lvl of pow absobd/dlivd incass, th pocss of spding up/down gts fast. n th gnating mod of opation, th toqu componnt cunt command has a tndncy to incas in amplitud fo th sam pow dlivy lvl to mt th sam activ pow dmand of th systm as th flywhl spd ducs. Whn anoth 1-kW load is addd to th pvious load th contoll immdiatly sponds to th chang by incasing th toqu componnt cunt command fom aound 10A lvls to 30A lvls dpnding of cous on th spd of th flywhl at that instant. Sinc mo ngy is xtactd fom th flywhl duing this tim, th spd of th flywhl ducs mo apidly. Whn on of th 1-kW load is movd fom th systm, th contoll sponds again but not so fast as whn th load is applid. Nonthlss, th pak link voltag is still gulatd within an accptabl ang. Th ason fo th slow spons Fig. 8. Pfomanc of Opation of th Expimntal Flywhl Load Lvlling Systm und.5kw Constant Pow Dlivy and Two Diffnt Lvl of Load Application and Rmoval. LOAD : Load Cunt, 5A/div. * qsfw : Toqu Componnt Cunt Command of th Flywhl nduction Machin, 10A/div. Spd : Spd of th Flywhl, 100 pm/div. V HF Link : 0kHz High Fquncy AC Link Voltag, 00V/div. Tim/div: 1 s. of th contoll is pobably du to th tim constant of th pak dtction cicuits of th masumnt systms. t is intsting to not that th toqu componnt cunt command incass to about 15A lvls vn though th maining load is 1-kW compad to th 10A lvls with 1- kw load at th bginning of opation. This sult is du to th ducd spd of th flywhl as mntiond ali. Whn all th maining load is movd fom th systm, th contoll gnats a positiv toqu command with a small amplitud and th flywhl machin tnds to absob pow and incas its spd in this mod. t is difficult to obsv th dtails of th load cunt and th 0 khz link voltag in this tac bcaus of th vy low fquncy of th data takn. Th tminal quantitis of th flywhl machin, namly th lin cunt and lin to lin voltag, a psntd in Figu 9 fo a simila opation and diffnt tim intval. Th is a lin cunt flowing and a vy littl toqu command xists duing th no load condition du to th xcitation cunt of th flywhl machin. Whnv th toqu command lvl changs a cosponding chang in th lin cunt is obsvd. This figu claly shows how th flywhl lin to lin voltag is synthsizd fom th potions of th 0 khz paalll sonant ac link and indicats how th lin cunt gulation of th flywhl machin is achivd dpnding on th toqu command applid. t is possibl to incas th opating tim intval of th flywhl mod by incasing th initial spd and intia of th flywhl. f th lab nvionmnt would allow high spd of opations, th induction machin usd as flywhl whos namplat atings and quivalnt cicuit paamts a givn in Appndix-1 would allow 6000 pm opation at atd flux and pm opation in ducd flux gion. 8

9 M 60Hz and 50 V L 1l = L l '=1.4345mH with Masumnt at 60Hz L M =37.577mH at 60Hz and 30V L M =38.598mH at 60Hz and 115V L M =35.448mH at 60Hz and 50V S R 30V ll /60Hz and Ratd Toqu 9 Fig. 9. Pfomanc of Opation of th Flywhl Machin Concning ts Elctical Quantitis. AFW : Phas-A Flywhl nduction Machin Cunt, 0A/div. * qsfw : Toqu Componnt Cunt Command of th Flywhl nduction Machin, 10A/div. Spd : Spd of th Flywhl, 100 pm/div. V ACFW : Phas-AC Lin to Lin Voltag of th Flywhl, 00V/div. Tim/div: 1 ms. V. CONCLUSONS n this study, th fasibility of induction machin basd flywhl load lvlling systm fd fom a 0kHz ac link and Puls Dnsity Modulatd (PDM) convt has bn dmonstatd both in softwa and hadwa. Th fasibility of maintaining a lativly constant ac pak link voltag by apidly xtacting o absobing xcss link pow fom/to a flywhl induction machin connctd to th link was dmonstatd as wll. A dtaild valuation of th contol quimnts fo such a contol statgy has bn dvlopd, implmntd and dmonstatd. An impotant contibution of this wok has bn to dmonstat th application of 0kHz ac link and PDM convt tchnology to FES systms. n paticula, aospac applications a wll suitd to bnfit fom th advantags povidd by this tchnology. APPENDX 1 3-Phas (3Ø), 10Hp, 30V, 3A, 300Hz, 6-pols No Load, Ratd Toqu?-Connctd Stato Winding, Squil Cag Roto Dsignd to Opat at 900Hz (18,000pm) with Fild Wakning, 1dc =0.195? ' =0.1048? M 300Hz and 60Hz L 1l = L l '=0.6796mH at 60Hz L M =11.149mH at 300Hz and mH at 60Hz S R 30V ll /300Hz and Ratd Toqu S R 46V ll /60Hz and Ratd Toqu APPENDX 3-Phas (3Ø), 10Hp, 30V/460V, 4.A/1.1A, 60-Hz, 4-pols, No Load, 1750 Ratd Toqu Sta-Connctd Stato Winding, Squil Cag Roto 1dc =0.1844? ' =0.009? M 60Hz and 30 V M 60Hz and 115 V V. REFERENCES [1] Van Zyl A.; Sp, R.; Shot Tm Engy Stoag fo ASD Rid-Though, EEE ndusty Applications Confnc, Th 33d AS Annual Mting Confnc Rcods, Vol., pp [] Chistoph, D.A.; Bach, R.; Flywhl Tchnology Dvlopmnt Pogam fo Aospac Applications, EEE Aospac and Elctonics Systms Magazin, Jun 1998, pp [3] Chistoph, D.A.; Dont, C.; Flywhl Tchnology and Potntial Bnfitsfo Aospac Applications, EEE 1998 Aospac Confnc, Confnc Rcods, Vol. 1, pp [4] Kik. J.A.; Walsh, G.C.; Homada, L.P.; Zmood, R.P.; Sullivan, G.E.; Th Opn Co Composit Flywhl, Pocdings of th 3nd ntsocity Engy Convsion Engining Confnc, ECEC-97, Vol. 3, pp [5] Edwads, J.; Aldich, J.W.;Chistoph, D.A.; Bach, R.F.; Baton. J.R.; Flight Tst Dmonstation of a Flywhl Engy Stoag Systm on th ntnational Spac Station, Pocdings of th EEE 1997 NationalAospac and Elctonics Confnc, NAECON-97, Vol., pp [6] Chistoph, D.A.; Bach, R.F.; Baton. J.R.; Flywhl Engy Stoag Systm Tst on th ntnational Spac Station, Pocdings of th 3nd ntsocity Engy Convsion Engining Confnc, ECEC-97, Vol. 3, pp [7] Robinson, W.; Hanks, J.; Gisl, O.; Spina, L.; Gint, D.S.; Spaccaft Engy Stoag Systms, Pocdings of th EEE 1997 NationalAospac and Elctonics Confnc, NAECON-97, Vol., pp [8] Pionk, T.J.; Dck, D.K.; Spcto, V.A.; Spaccaft Flywhl Systms-Bnfits, and ssus, Pocdings of th EEE 1997 NationalAospac and Elctonics Confnc, NAECON-97, Vol., pp [9] Baman, B.G.; Rao, G.M.; Hybid Batty and Flywhl Engy Stoag Systm fo LEO Spaccaft, Th Thitnth Annual Batty Confnc on Applications and Advancs, Confnc Rcods, pp [10] Chu, A.; Nowicki, E. P.; Chn, T.; Dsign of a Robust Spd Contoll fo a Compsso Divn by a Fild Ointd Contolld nduction Moto, EEE Canadian Confnc on Elctical and Comput Engining, 1998, Confnc Rcods, Vol., pp [11] Rutbg, P.; vanov, V.; Kashkasky, E.; Kustov, N.; Rovinsky, P.; Elctotansmission of Altnating Cunt with Flywhl fo Whl Tanspot Facility, MELECON 98, 9th Mditanian Elctotchnical Confnc, 1998, Confnc Rcods, Vol., pp [1] Szabodos, B.; Schaibl, U.; Pak Pow Bi-Dictional Tansf fom High Spd Flywhl to Elctical Rgulatd Bus Voltag Systm: A Pactical Poposal fo Vhicula Tchnology, EEE Tansactions on Engy Convsion, Mach 1998, Vol. 13, ssu 1, pp [13] Acanly, P.P.; Mcow, B.C.; Budss, J.S.; Fawctt, J.N.; Klly, J.G.; Dickinson, P.G.; Dsign Pincipls fo a Flywhl Engy Sto fo Road Vhicls, EEE Tansactions on ndusty Applications, Nov.-Dc. 1996, Vol. 3, ssu 6, pp

10 [14] Wissbach, R.S.; Kaady, G.G.; Fam, R.G; Dynamic Voltag Compnsation on Distibution Fds Using Flywhl Engy Stoag, EEE Tansactions on Pow Dlivy, Apil 1999, Vol. 14, ssu, pp [15] Umua, S.; Nomua, S.; Shimada, R.; Stabilization of Elctic Pow Systm Using th Vaiabl Spd Flywhl Gnato, Pocdings of th Pow Convsion Confnc, Nagaoka 1997, Vol.1, pp [16] Nishio, T.; Minoguti, K; Uno, S.; Futami, M.; Hombu, M; chinos, M.; Maoka, A.; Continuous Opation Contol Duing Elctic Pow Ntwok Faults in an Adjustabl Spd Gnation Systm with a Flywhl Excitd by a DC Link Convt, Pocdings of th Pow Convsion Confnc, Nagaoka 1997, Vol.1, pp [17] Schonung, S.M.; Buns, C.; Utility Engy Stoag Applications Studis, EEE Tansactions on Engy Convsion, Sp. 1996, Vol. 11, ssu 3, pp [18] Bonmann, H.J.; Sand, M.; Concptual Systm Dsign of a 5 MWh/100MW Supconducting Flywhl Engy Stoag Plant fo PowUtility Applications, EEE Tansactions on Aplid Supconductivity, Jun 1997, Vol. 7, ssu, Pat-1, pp [19] Sul, S.K.; Alan,.; Lipo T.A.; "Pfomanc Tsting of a High Fquncy Link Convt fo Spac Station Pow Distibution Systm", 1989 ntsocity Engy Convsion Engining Confnc, Washington DC, August 1989, Vol. 1, Aospac Pow Systms and Pow Conditioning, pp [0] Lipo, T.A.; Alan,.; Systm and Componnt Dsign and Tst of a 10 HP, 18,000 RPM AC Dynamomt Utilizing a High Fquncy AC Voltag Link, Final Rpot, Contact No. NAG3-940, Jun [1] Alan,.; A Compltly solatd 3-Phas to 3-Phas nduction Moto/nduction Gnato Pow Convsion Systm, Ph.D. Thsis, Dcmb [] Alan,.; Lipo, T.A.; Contol of Polyphas nduction Gnato/nduction Moto Pow Convsion Systm Compltly solatd fom th Utlity, EEE Tansactions on ndusty Applications, Vol. 30, No.3, May-Jun 1994, pp [3] Alan,.; Lipo, T.A.; Fasibility Study of a Batty Statd nduction Gnato Maintaind 3-Phas/400Hz Voltag Rgulatd Bus Utilizing High Fquncy AC Link, Final Rpot, Contact No. NAG3-1447, May [4] Novotny D.W.; Lipo, T.A.; Vcto Contol and Dynamics of AC Divs, NwYok: Oxfod Univ. Pss, [5] Divan D.M.; Lontz R.D.; Lipo T.A.; Novotny D.W.; Fild Ointation and High Pfomanc Motion Contol, UW-Madison, WEMPEC, Summay of Publications [6] Sood P.K.; Lipo T.A.; Pow Convsion Distibution Systm Using a Rsonant High Fquncy AC Link, EEE Tansactions on ndusty Applications, Mach-Apil 1988, Vol. 4, pp [7] Divan D.M.; Lasst R.H.; Lontz R.D.; Lipo T.A.; Novotny D.W.; Soft Switching Convts: Topologis, Dsign and Contol, UW-Madison, WEMPEC, Summay of Publications fan Alan (S 91-M 94) was bon in stanbul, Tuky. H civd th B.E.E. and M.S.E.E. dgs fom stanbul Tchnical Univsity (TU), in 1983 and 1986, and th Ph.D. dg in E.E. fom th Univsity of Wiscconsin-Madison, in H was appointd a Rsach Assistant duing his M.S. studis at TU. n 1986 h was awadd a loan scholaship by th Tukish Ministy of Education to pusu a Ph.D. dg aboad. Duing most of his Ph.D. studis h has bn a sach assistant at UW-Madison, woking on vaious NASA pojtcs. H wokd as a sach associat at UW-Madison in anoth NASA pojct duing his post doctoat studis. H has submittd a total of fou contacto pots to NASA. H is cuntly an Associat Pofsso taching vaious undgad and gad lvl Elctical-Elctonics and in paticula Elctical Machins and Pow Elctonics couss at th Dpatmnt of Elctical and Elctonics Engining of Eg Univsity in zmi, Tuky. His sach intsts a in solid stat pow convsion systms and ac machin divs in gnal, and sonant and matix pow convts and divs in paticula. Thomas A. Lipo (M 64-SM 71-F 8) was bon in Milwauk, W. H civd th B.E.E. and M.S.E.E. dgs fom Maqutt Univsity Milwauk, W. in 196 and 1964, and th Ph.D. dg in lctical ngining fom th Univsity of Wisconsin in Fom 1969 to 1979, h was an Elctical Engin in th Pow Elctonics Laboatoy of Coopat Rsach and Dvlopmnt of th Gnal Elctic Company, Schnctady, NY. H bcam Pofsso of Elctical Engining at Pudu Univsity, Wst Lafaytt, N, in 1979, and in 1981 h joind th Univsity of Wisconsin, Madison, in th sam capacity, wh h is psntly th W. W: Gaing Pofsso fo Pow Elctonics and Elctical Machins. D. Lipo civd th Outstanding Achivmnt Awad fom th EEE ndusty Applications Socity, William E. Nwll Awad of th EEE Pow Elctonics, and th 1995 Nicola Tsla EEE Fild Awad fom th Pow Engining Socity fo his wok. H has svd EEE in vaious capacitis, including Psidnt of ndustial Applications Socity.