Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT1Chng 1:Cc nguyn tc khng ch h thng truyn ng in. 1-1. Nhng vn chung v h thng trang b in - t ng ho cc my sn xut I-1-1.Khi qut v h thng trang b in - t ng ho cc my sn xut1. Chc nng, nhim v ca h thng TB -TH cc my sn xut a. Chc nng: * H thng TB-TH cc my sn xut l tng hp cc thit b in c lp rp theomtsphhpnhmmbochoccmysnxutthchinnhimvsn xut * H thng TB-TH cc my sn xut gip cho vic-Nng cao nng sut my-m bo chnh xc gia cng-Rt ngn thi gian my-Thchincccngongiacngkhcnhautheomttrnhtcho trc. * H thng TB-TH cn c:-Cc thit b ng lc-Cc thit b iu khin-Cc phn t t ng Nhm t ng ho mt phn hoc ton b cc qu trnh sn xut ca my, h thng TB-TH s iu khin cc b phn cng tc thc hin cc thao tc cn thit vi nhng thng s ph hp vi quy trnh sn xut. b. Nhim v ca h thng TB-TH: *Nhnvbininnglnginthnhdngnnglngkhcthchin nhim v sn xut thng qua b phn cng tc * Khng ch v iu khin b phn cng tc lm vic theo trnh t cho trc vi thng s k thut ph hp. * Gp phn nng cao nng sut, cht lng, hiu qu ca qu trnh sn xut, gim nh iu kin lao ng cho con ngi. * m bo an ton cho ngi v thit b trong qu trnh sn xut.2. Kt cu ca h thng TB-TH: Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT2a. Phn thit b ng lc:L b phn thc hin vic bin i nng lng in thnh cc dng nng lng cn thit cho qu trnh sn xut. Thit b ng lc c th l: * ng c in * Nam chm in, li hp in t trong cc truyn ng t ng c sang cc my sn xut hay ng m cc van kh nn, thu lc... * Cc phn t t nng trong cc thit b gia nhit... * Cc phn t pht quang nh cc h thng chiu sng... * Cc phn t R, L, C, thay i thng s ca mch in lm thay i ch lm vic ca phn t ng lc b. Thit b iu khin: L cc kh c ng ct, bo v, tn hiu nhm m bo cho cc thit b ng lc lm vic theo yu cu ca my cng tc. Cc trng thi lm vic ca thit b ng lc c c trng bng:-Tc lm vic ca cc ng c in hay ca my cng tc -Dng in phn ng hay dng in phn cm ca ng c in-Mmen ph ti trn trc ng c... Tu theo qu trnh cng ngh yu cu m ng c truyn ng c cc ch cng tc khc nhau. Khi ng c thay i ch lm vic, cc thng s trn c th c gi tr khc nhau. Vic chuyn ch lm vic ca ng c truyn ng c thc hin t ng nh h thng iu khin. Nhvy:Hthngkhngchtruynng inltp hpcckhc inv dy ni c lp rp theo mt s no nhm p ng vic vic iu khin, khng ch v bo v cho phn t ng lc trong qu trnh lm vic theo yu cu cng ngh t ra. I-1-2.Chc nng, yu cu ca h thng khng ch truyn ng in. 1. Cc chc nng ca h thng khng ch truyn ng in a. ng ct: L qu trnh a phn t ng lc vo hoc ra khi mchin thay i trng thi lm vic ca h thngtruyn ng Chc nng ng ct do cc kh c ng ct thc hin Cc thit b ng ct bao gm:Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT3-Cu dao, p tmt-Cngtct, khi ng t-Nt n, cng tc hnh trnh-B khng ch ch huy hay ng lc..... Kt qu hot ngca qu trnh ngctsa hthng nglc ntrngthi lm vic mi trong c t nht mt thng s c trng ca h thng ng lc nhn gi tr mi. b. Khng ch:Nhm m bo choqu trnh ng ct xy ra ng thi im, ng trnh t yu cu. Nh chc nng khng ch ca h thng m thit b ng lc s lm vic vi tc , dng in, m men,thi gian, trnh t theoyu cu ca quy trnh cng ngh i hi. Chc nng khng ch do cc kh c khng ch thc hin Cc kh c khng ch bao gm: -Cc loi rle nh rle in p, dng in, tc , thi gian-Cng tc hnh trnh-Ccphnttngnhttrchnhit,ttrchkimtrakch thc, p sut,... Cc kh c khng ch ng vai tr l cc phn t tn hiu, cn cc kh c ng ct l phn t chp hnh. c. Bo v:Nhm m bo an ton cho con ngi v thit b trong qu trnh sn xut. Chc nng bo v do cc kh c bo v thc hin. Cc kh c bo v bao gm cu ch, p tmat, r le nhit, rle dng in, in p, cng tc cc hn.... 2. Cc yu cu ca h thng khng ch truyn ng in:a. Ph hp nht vi quy trnh cng ngh: y lyu cu quan trng nht ca h thng khng ch v h thng khng ch c hnh thnh t yu cu cng ngh. Mt h thng khng ch c gi l "ph hp nht vi quy trnh cng ngh" phi c cc c im sau: - ngc intruynng phic ctnh c vctnh iuchnhtc ph hp vi c tnh c ca c cu sn xut m n dn ng -ngcphiccccchcngtccnthitpngcihicamy cng tc. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT4 Khi hthng truynngsckhaithctritnhtv mt cngsut,hiu sut, nng cao c hiu qu kinh t- k thut ca phng n la chn. b. Kt cu n gin, tc ng tin cy: Tnh n gin c th hin: - Kt cu ca thit b n gin. - S dng t chng loi thit b. S lng thit b l t nht. - S lng v chiu di dy ni l t nht. Tnh tin cy c th hin: - Thit b phicthngsvctnhlmvictbin itheothigianv iukin mi trng - Thit b co tui th v c, in, tn s ng ct ph hp vi c tnh ca my cng tc. c. Thun tin, linh hot trong iu khin: Tnhlinhhot:Mththngiukhinccoillinhhotkhinnhanh chng v d dng: - Chuyn t ch iu khin bng tay sang iu khin t ng, bn t ng v ngc li. - Chuyn t khi lm vic sang khi d phng v ngc li. - Chuyn t quy trnh lm vic ny sang quy trnh lm vic khc. Tnh thun tin:Tnh thun tin trong iu khin ngha l: - T mt ch c th iu khin c nhiu i tng. - T nhiu ch iu khin c mt i tng. d. n gin cho kim tra v pht hin s c:Qutrnhhotngcahthngkthutnichungcng nhhthngtruyn ng in ni ring c th xy ra cc ch lm vic khng mong mun hoc s c. Cc ch nythnggythithiv nhiu mt.Do khixut hinccch nycn nhanh chng loi b gim thiu nhng thit hi do chng mang li. Vic thit k v xy dng h thng phi lm sao cho cho nhn vin vn hnh c cc x l ng n trong qutrnhlmvicngthigipchonhnvinsachathuntinchovicbo dng, thay th v nhanh chng pht hin ra cc phn mch b s c Khi thit k v xy dng h thng nn b tr thit b theo cc quy tc: * B tr thit b thnh nhm theo tng cm chc nng ca s * Cc nhm khc nhau c cung cp t cu dao, cu ch ringTrng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT5 * Cc cm quan trng phi c tn hiu bo v tnh trng lm vic bnh thng hay s c ca chng bng m thanh, nh sng * Cc thit b phi thng xuyn kim tra bo dng phi c b tr ch thun tin cho xem xt, tho lp thay th, sa cha * t k hiu v s hiu u ni ca dy dn * S dng cc dy dn vi mu sc khc nhaue.Tc ng phn minh lc bnh thng cng nh khi c s c: Hotngcamchphittckhivnhnhbnhthngcngnhkhicsc. Khngctoraccmchgikhicshotngkhngbnhthngcamch. Mch phi c thit k m bo sao cho khi nhn vin vn hnh tthao tc nhm, khng gy ra s c. g. Kch thc v gi thnh nh nhtKchthcvgithnhcahthngiukhinnhhngngknkch thcvgithnhcamy.Dovictnhton,thitkhthngtruynngphi c ch trng nhng phi p ng cyu cu k thut, chc chn v tnh m thut cho c my h. An ton v cc yu cu khcAntoncho ngivthit btrong qutrnhkhaithc,vn hnhthit b lyu cu quan trng. Khi thit k v xy dng h thng cn d kin n cc ch lm vic xu v s c c cc phng n bo v cn thit, ng thi phi c cc bin php m bo an ton cho ngi vn hnh v nhng ngi lin quan. Ngoi cc bin php k thut phi c c cc bin php qun l nh h thng bin bo, bin cm i vi nhng khu vc hoc nhng thit b c nguy c gy mt an ton cho ngi v thit b Ngoi ra cn ccyu cu ph nhyu cu v mi trng lm vic (khi bi, ha chtn mn, phngchngchyn)tlachnthitb intheo ngyucu lm vic. 1.1.3. Cc loi s in: a. S khai trin: L s th hin tt c cc phn t ca mch in. Trong s ny cc my in, kh c in c th hindi dng khai trin, trong v tr ca cc chi tit, phn t ca my in, kh c in trn s khng xt n v tr tng quan thc t ca chng, m ch xt n v tr thc hin chc nng ca n.Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT6 Vd:Cngtct gmcc b phnchnhlcun dy(cun ht),cctipim chnh, cc tip im ph thng m, thng kn....Mi chi tit c mt chc nng ring. - Cun ht: quyt nh n trng thi lm vic ca cng tc t. Khi cun ht c in (v trstcng)nsmcctipimthngkn,ngcctip imthng h. Nh vy v tr ca cun ht l mch iu khin. - Cc tip im chnh: cho dng in cp cho ng c chy qua. Vy v tr ca chng l mch in cp cho ng c hay cn gi l mch ng lc. - Cc tip im ph tu thuc n iu khin i tng no th v tr ca chng s c v trong mch cp in cho i tng nh tip im t gi l tip im cp in cho cun ht ca cng tc t nn n c v trong mch cun dy cng tc t.... - Tip im thng h ca cng tc t l tip im m trng thi cun dykhng c in hoc c m khng ht mch t (trng thi thng) n trng thi ngt mch in.Khicun dycdng in(trs)chyqua,tanicun dy cin,thtip im s ng li - Tip im thng kn th ngc li, khi cun dy khng c in (hoc c nhng khng ht) n trng thi kn mch. Khi cun dy tc ng, thip im thng kn s m ra. Trn s khai trin thit b in c biu din trng thi thng, ngha l trng thi thit b khng chu tc ng v c, in, nhit, quang. Vd:-Cu dao in,cngtc,ptmtv trngthi h mchin (khngctc ng c hc - tay ngi tc ng vo ng mch in. - R le, cng tc t v trng thi cun dy khng c in, tip im thng h trng thi h mch in, tip im thng kn trng thi ng mch in. . .... S khai trin gm 2 phn mch l: Mch ng lc:cp in cho ng c qua cu dao, cu ch, tip im chnh ca cngtct... v bng nt m. Mch iu khin:gm cc nt n iu khin, cng tc hnh trnh, cun dy cc rle, cng tc t, cc tip im ph... v bng nt mnh. Tn ca cc thit b in c t theo nhim v ca n v vit tt bng cc ch ci bn cnh, pha trn bn phi.Tt c cc chi tit ca cng mt thit b u c cng tn gi. (cun dy K, tip im K. Rle RH, tip im RH...) Cc im ni phi nh s th t thun li cho vic s dng s , d lp rp...Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT7b. S nguyn l: Lmtdngcaskhaitrinnginhonhmgipngichiuc nguyn l lm vic ca s hoc ca mt khu no ca h thng t ng. Trong s nguyn l ch li cc mch chnh biu th my in, cc kh c in c th nu c nguyn l lm vic ca s . Nhng chi tit, phn t khng lin quan n nguyn l lm vi cu s th khng cn v. V d cu dao, cu ch, cun dy kch t ca my in mt chiu kch thch c lp....c. S lp rp: L s gii thiu v tr lp t thc t ca thit b in trong t iu khin v cc b phn khc ca my, ch r ng dy ni gia cc kh c, thit b, k c tit din ca dy dn v s hiu ca n. Cc thit b ca my c b tr ti 3 ni: ng c in, r le tc , p tmat, cng tc hnh trnh...c b tr ti my. Cckhctngnhrleinp,dngin,cngtct,khingt,binp chnh lu... t trong t in. Cckhccnquanstnhccloinghchth,ccntnhiu,ntn,cc kho iu khin... b tr trn bng in. Slprpphivtheomttlxchnhtnh,phighirkchthccabn in, t in, kch thc ca kh c in... Cc u dy tng khi u c nh s thng nht vi s nguyn l. Cc dy dn i theo mt chiu c b thnh mt b... S lp rp dng cho lp rp hoc sa cha khi c hng hc. 3.Bng k hiu cc chi tit, phn t ca thit b in trn s nguyn l.Khi xy dng s nguyn l mch in, cn tun th cc k hiu th hin ca cc chi tit, phn t ca thit b in trn s . Bng k hiu sau gii thiu mt s k hiu thng dng trong cc s nguyn l mch in trang b in t ng ha ccmy sn xut. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT8TTTn giK hiu 1. ng c in mt chiu a/ Kch t c lpb/ Kch t ni tip c/ Kch t song songd/ Kch t hn hp 2. ng c in xoay chiua/ Khng ng b rotor lng sc b/ Khng ng b rotor dy qun c/ ng c ng b

3. My bin p o lng 4. My bin dng 5. p t mata/ Mt cc ;b/ Hai cc;c/ Ba cc 6. Cu daoa/ Mt cc ;b/ Hai cc;c/ Ba cc 7.Cu ch8. R le, cng tc t kiu in ta/ Cun dy;b/ Tip im thng h c/ Tip im thng kn 9. R le nhit a/ Phn t pht nng;b/ Tip im 10. R le thi gian a/ Tip im thng h, ng chmb/ Tip im thng h, m chm c/ Tip im thng kn, ng chmd/ Tip im thng kn, m chm 11. Nt n a/ n, tip im thng h b/ n, tip im thng h c/ Nt n kp (1 T h, 1T kn) Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT912. Cng tc hnh trnh a/ n, tip im thng h b/ n, tip im thng h c/ Kp (1 tip im h, 1T kn) 13. B khng ch ch huy S hng biu th s tip im S ct biu thv tr ca tay gt iu khin Du chm biu th trng thi ng ca tip im v tr ca tay gt 14. Bng n tn hiu 15. Chung in 16. Ci in 17. Cu chnh lu 1 pha I-2: CC NGUYN TC KHNG CH TRUYN NG IN 1.2.1. Khi nimv khng ch truyn ng in Cc ch lm vic ca h thng truyn ng in c c trngbng cc thng s: -Tc ca ng c in truyn ng hoc tc ca c cu sn xut. -Dng in phn ng ca ng c- l thnh phn sinh m men quay ca ng c. -Mmen in t do ng c sinh ra hoc m men cn ca c cu sn xut trn trc ng c. Mi quan hgiacc ilng nyc biu din bngcc phngtrnh ctnh tc v phng trnh c tnh c. Khi ng c lm vic n nh, ng vi mt tr s ph ti trn trc ng c ta c cc cp thng s (n,M) hoc (n,I) xc nh. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT10 Khi ng c chuyn i t ch xc lp ny sang ch xc lp khc, cc thng s trn s nhn gi tr mi sau mt thi gian chuyn i ch lm vic. Thi gian c gi l thi gian qu ca h thng truyn ng. Nh vy cc thng s n, M, I s bin i theo thi gian vi quy lut c xc nh bng cc bi ton qu trnh qu . Bngcc bitontruynng in ch xclpvch qu tabit c cc quy lut bin i ca cc thng s sao cho s chuyn i ch lm vic l c li nht. Da vo cc quy lut bit trc ta c th tc ng vo h thng bng cch thay i tham s ca mch in cp cho ng c in dn n ng c s chuyn i ch lm vic vi cc quy lut nh mong mun. Nh vy, khng ch truyn ng in thc cht l vic thay i thng s ca mch incpcho ngctheo mt quylutno lmthay ichlmvicca ng c nh yu cu Qu trnh khng ch h thng truyn ng in bao gm: T ng iu khin qu trnh m myl qu trnh a tc ng c t n = 0 n tc lm vic no theo yu cu ca my sn xut sao cho dng in m mynh,mmenmmyln.Nimtcchkhcphikhngchcqu trnh m my theo quy lut c tnh sn. T ng iu khin qu trnh lm vic. Trong qu trnh lm vic ng c truyn ng phi c c cc ch lm vic theo yu cu ca c cu sn xut, c th phi duy tr mt thng s no theo mt quy lut cho trc nh duy tr tc khng i hoc bin i theo quy lut, theo trnh t tnh sn. Tng iukhin qutrnh hmv dng my.Ccqutrnh hm dng my thngnhmynhanhqutrnhdngmynngcaonngsutmy.Cc ch hm dng thng ko theo s tiu ph nng lng v lm t nng ng cin.Phiiukhinqutrnhnynhmhmdngmyhiuqunhtv tiu tn nng lng t nht. I-2-2. Khng ch truyn ng in theo thi gian. 1. Ni dung nguyn tc khng ch theo thi gian Cc thng s n;M;Ic trng cho ch cng tc ca h truyn ng. Khi ng c chuyn ch lm vic th chng thay i t gi tr ny sang gi tr khc v bin i theo thi gian vi mt quy lut no . Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT11 Davoccbitontruynngin(qutrnhqu)tnhcccgitr chuyn i n;M;I,ti qu trnh chuyn i l ti u nht. ng vi cc gi tr chuyn i ca tc , dng in, m men, c thi gianchuyn itngng.Thiimticntcngthayithamsmch incpcho ng c lm chuyn i ch lm vic c gi l thi im chuyn i. khng ch c cc ch lm vic ca h thng truyn ng in theo nguyn tcthi gian,trong hthng iukhin phi cthit btn hiu o cckhong thi gianvti ccthi imtnhtonsn,thit btn hius iukhin phntngct thchinvicavohocarakhihthng ccphntcnthit(R,L,C...) lm thay i tham s mch in dn n thay i ch lm vic ca ng c Phn t tn hiu c s dng l rle thi gian. 2. S ng dng: Ta hyxtskhngch qutrnhkhing ngc mtchiukcht clp qua 2 cp in tr ph. m bo an ton cho cun dy phn ng ca ng c khikhi ng, cn phi hn ch tr s dng in phn ng trong thi gian khi ng khng vt qu tr s ln nht cho php. Mt khc khi tc ng c tng ln, dng in phn ng gim lm gim gia tc ca qu trnh khi ng. Do ngi ta trong qu trnh khi ng cn phi loi b dn cc in tr ph cho n khi tc ng c bng vi tc lm vic. Qu trnh khi ng ca ng c qua 2 cp in tr ph c m t qua cc c tnh tnh (ch xc lp) v c tnh ng nh hnh v 1-1. Trn ng c tnh tnh (1-1a) qu trnh khi ng i theo cc on thng a-b-c-d-e-A. A l im lm vic ca ng c (kt thc qu trnh khi ng). a) c tnh tc b) c tnh ng Hnh 1-1:Cc c tnh khi ng ca ng c qua 2 cp in tr ph Trn c tnh ng, tc ca ng c bin i theo thi gian qua cc giai on: Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT12- T (0-t1)- ngckhi ngvi 2 in tr ph.Tithi imt1 intr phth nht b ngn mch. - T (t1 - t2) - ng c khi ng vi in tr ph cn li. Ti thi im t2 in tr ph th 2 b ngn mch. - Thi gian khng ch khi ng c tnh n khi in tr ph cui cng b lai b. a. Gii thiu s : Hnh 1-2: S nguyn l mch in khng ch khi ng ng c mt chiu kch thch c lp qua 2 cp in tr ph lhng ch theo thi gian. Cc phn t ca s bao gm: - Phn ng ca ng c . - Cun kch t ng c CK - Cc in tr ph khi ng 1R, 2R. - R le dng in bo v mt t thng kch t ng c. - Cc r le thi gian RTZ1, RTZ2 khng ch cc qu trnh khi ng. - Cng tc t lm vic K ni phn ng ng c vo ngun in. - Cc cng tc t khi ng K1, K2 ngn mch cc in tr 1R, 2R ti cc thi im cn thit. - Cc nt n iu khin khi ng v dng my M, D. b. Hot ng ca s khi ng ng c, ng in vo mch ng lc v iu khin. Qua cun kch t CKT v r le dng in RTT c dng in kch t cho ng c. Nu dng in kch t , RTT tc ng ng tip im ca n trong mch cun dy cng tc t K, cho php ng c khi ng. ng thi r le thi gian RTZ1 c in, tip im thng kn ca n mlmcccngtctK1,K2khngc invothiimtrckhikhi ng,cc tip im K1, K2 m lm cc in tr 1R, 2R c ni vo mch phn ng ng c. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT13 n nt khi ng M, cng tc t K c in. Tip im thng kn K m l RTZ1 mt in,ngthicctipimthngmKnglingckhingvduytr dng cp in cho ng c. Do tip im RTZ ng chm nn cc cng tc t K1, K2 vn cha c in, ng c khi ngvi 2 intrphtrong mch phn ng.Khicdng in quaintr 2R, to ra st p lm RTZ2 tc ng, m tip im ca n m bo trnh t khi ng. SauthigianchnhnhcaRTZ1(nthiimt1),tipimthngknRTZ1 ng li, cng tc t K1 c in, ng tip im K1, in tr 1R b ni ngn mch. ng c tip tc khi ng vi in tr ph 2R. Khiintr1Rbngnmch,rleRTZ2mtin,Sauthigianchnhnhca RTZ2, tip im ca n ng li, cng tc t K2 c in, in tr 2R b ngn mch, ng c tng tc n tc lm vic, kt thc qu trnh khi ng. 3. Nhn xt v nguyn tc khng ch theo thi gian: * Khi dng nguyn tc khng ch theo thi gian th c cc yu t nh MC,J,U, R, L, Cca mch phi ng vi iukintnhton.Nukhngthticcthi imchuyn igitrca n,M,Ithctca ngcskhngngvigitrtnh ton dn n vicng c chuyn ch lm vic khng ng vi yu cu. * u im:c th iu chnh c thi gian theo tnh ton c lp vi thng s ca h thng ng lc, c th iu chnh c thi gian chnh nh ca rle cho ph hp vi thng s thc t ca h. * Thit b ca s n gin, lm vic tin cy *Rlethigiancthdngchobtkloingcvicngsutnodort thun tin v c tnh kinh t cao v c s dng rt rng ri. I-2-3. Khng ch truyn ng in theo tc . 1. Ni dung nguyn tc:-Tc ng c truyn ng hoc tc ca c cu sn xut l thng s c trng quantrngxc nhtrngthica htruynng in, do davothngs ny khng chh thng truyn ng in. -Trong mch iu khin phi c phn t th cm c tc lm vic ca ng c gi l rle tc .Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT14-Khi tc t c gi tr t tnh ton trc th rle tc pht tn hiu n phntchp hnh chuyntrng thi lm vicca hthngtruyn ng in n trng thi mi yu cu. -i vi ng c ng c in mt chiu khi vn hnh v t thng l hng s, c th gin tip kim tra tc thng qua sc in ng ca ng c.-Vi ng c xoay chiu rotor dy qun c th khng ch tc thng qua s.. hoc tn s dng in rotor. 2. Cc khu khng ch theo nguyn tc tc : a. Khi ng ng c mt chiu qua 2 cp in tr ph:

Hnh 1-3: S nguyn l khu khi ng ng c mt chiu kch t c lp qua 2 cp in tr ph, khng ch theo nguyn tc tc Cc phn t ca s : Cc r le gia tc 1G, 2G va l phn t tn hiu, va l phn t chp hnh. in p t ln cc r le ny ph thuc vo tc ca phn ng ng c. Ti thi im ban u ca qu trnh khi ng, in p t ln cc r le 1G, 2G: Uht1 = Ce.u.n + I.(R +2R) = U - I.1R Uht2 = Ce.u.n + I.R = U - I.(1R+2R) Ti thi im ban u ca qu trnh khi ng, E = 0, URG ~ 0, cc in tr ph c ni vo mch phn ng ng c ng c khi ng vi 2 in tr ph. Khi tc ng c t n1 ( c chnh nh), in p t ln 1G l: hut u eU R r I n C U = + + u = ) 2 ( .2 1

1G tc ng, ngn mch 1R. ng c tip tc tng tc vi in tr 2R. Tng t, khi tc ng c l n2 cng tc t 2G tc ng ngn mch in tr 2R ng c tng tc n tc lm vic. b. Hm ngc ng c mt chiu theo nguyn tc tc : Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT15 Khi hm ngc ng c mt chiu, dng in hm rt ln do sc in ng ng c v in p phn ng cng du nn cn phi tng thm in tr ph trong mch phn ng. Yucucaslkhikhing,chc2intrc nivomch,khio chiu quay (ng c hm ngc ri khi ng theo chiu ngc li), c 3 in tr phi c ni vo mch phn ng ng c.

Hnh 1-4: S nguyn l khu hm ngc ng c mt chiu kch t c lp khng ch theo tc Cc phn t ca s : - Cc in tr khi ng Rk1, Rk2. - in tr hm RH. - Cc r le hm RH1, RH2, in p t ln cc r le ny ph thuc vo tc ng c T yu cu ca mch, cn xc nh iu kin chn ca cc r le hm. in p t ln r le khi khi ng l: rle tc ng, ngn mch in tr Rh, ng c khi ng qua 2 in tr ph. Tr s in tr Rx v in p ht ca RH c xc nh theo dng in cho php khi hm lc URH = 0 in p t ln r le khi hmng vi dng in hm khng vt qu tr s cho php l:

Xc nh tr s in tr Rx v in p ht ca r le theo tr s cho php ca dng in. URH = U - Icp.Rx = 0HayRx = U/Icp.3. nh gi nguyn tc khng ch theo tc : ( . . ). 2. 2 (1 ) 0e x x xRH xU C n R R RU U I R U U U UR R R|E += = ~ = =( . . ).. (1 )e x x xRH x hutU C n R R RU U I R U U U U UR R R|E = = = = =Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT16 * u im:s dngthit b s dng n gin, r tin, mch ng lc v iu khin u c kt cu chc chn, d lp t, kim tra, thay th sa cha. Thit b iu khin c th l cngtct mc trc tip vo phn ng m khng cn qua rle. * Nhc im:thi gian qu ph thuc vo MC, J, in p li... Cc cngtct gia tc c th khng lm vic v in p li gim, v qu ti, dn n dng in qu ln chy qua cc in tr hoc qua phn ng lu lm chy in tr, chy ng c... * Thng thng nguyn tc tc c dng khng ch qu trnh hm. I-2-4. Khng ch truyn ng in theo dng in. 1. Ni dung nguyn tc:-Dng in trong mch phn ng ng c xc nh trng thi mang ti ca ng ccng nh phn nh trng thi khi ng hay hm ca ng c.-Trong cc qu trnh khi ng hay hm dng in cn phi nh hn mt tr s cho php.-Trong qu trnh lm vic cng cn duy tr dng in mt tr s no theo yu cu ca qu trnh cng ngh Nh vy ta cn c cc rle dng in hoc cc thit b lm vic c tn hiu u vo l dng in khng ch h thng theo ccyu cu ni trn.Khi dng in phn ng tgitrngngxcnhcth iuchnhccanthnsphttnhiuiu khin h thng chuyn n trng thi lm vic yu cu.2. S ng dng:a. Khu khing ng c mt chiukch thch ni tip dng mt in tr ph trong mch phn ng: Hnh1-5:Khukhingngcmtchiukchtnitip, khng ch theo dng in R le dng in RI c chn theo cc iu kin: Dng in tc ng (dng in ht) It < I1. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT17Dng in nh Inha < I2. I1, I2 c xc nh t iu kin khi ng. R le RK c gi l r le kho, c chn theo iu kin: thi gian tc ng ringca RK ln hn thi gian tc ng ring ca RI. Kt hp cc iu kin chn ca RI, RK m bo cho in tr ph c tham gia vo qu trnh khi ng. Hotngcas:KhinntM,ngccnivomchquaintrph. Khitcngctng,dnginphnnggim.ntrsnhcaRI,tipim thng kn RI ng, cng tc t K1 c in, ngn mch in tr ph ng c tng tc n tc lm vic. b.Khu m my ng c rotor dy qun dng in tr ph mch rotor:Khingnithmintrphvomchrotorlphngphpkhingc bn i vi ng c rotor dy qun. Phng php ny c u im l m men khi ng ln, dng in khi ng nh. Khi tc ng c tng ln, dng in, m men ng c gim, do phi loi b dn in tr ph ni trong mch rotor cho n khi kt thc qu trnh khi ng.CcrlednginRI1,RI2 c chn theo cc iu kin: - Dng in tc ngIt < I1. - Dng in nh Inha < I2. -I1,I2cxcnhtiukin khi ng. R le kho RK. Hot ng ca s : Khi n nt M, cng tc t K c in, cc r le RI1, RI2 tc ng. ng c khi ng vi 2 in tr ph. Khi dng in rotor gim n tr s nh ca RI1, lm K1 c in, in tr rf1 b ngn mch. ng c tip tc khi ng vi rf2. Khi dng in rotor gim n tr s nh ca RI2, K2 tip tc tc ng loi b rf2 ng c tng tc n tc lm vic. m bo cho trnh t khi ng, thng chn dng in nh ca RI2 nh hn RI1 khong 5%. c. Khng ch qu trnh hm ngc ng c rotor dy qun: Hnh 1-6:Khukhi ng ngc rotor dy qun Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT18 Khiochiuquayngcdnginhmngcrtln,do phiaintr ph vo mch rotor vi tr s ln hn khi khi ng. Qutrnhkhing,ngckhi ng qua 2 in tr ph r1, r2, khng ch theo nguyn tc thi gian. Khi hm ngc, dng in trong mch rotorlnhntrstcngcarle dnginRI,tipimthngknRI m, mch cp in cho cc cng tc t H, K1, K2 mt. Ccintrrh,r1,r2cnivomc rotorlmgimdnginhm,ktqu dnginstatorcnggim.Khitc ngctheochiucv0,dngin rotor gim n tr s nh ca RI. R le RI ng,tip im cp ngun cho cng tc t H, in tr hm b ngn mch trckhingckhingtheochiu ngc li. 3. nh gi nguyn tc khng ch theo dng in: u im ca phng php l thit b n gin, d lp t. Nhc im ca phng php l tin cy thp, nht l khi ng c lm vic vi ti nng,dng in c th khng gim n tr s nh ca rle dng in lm b qua cc cp trung gian. Nguyn tc dng in c ng dng ch yu iu khin qu trnh khi ng ca ngcmtchiukchtnitiphocngcrotordyqun(thchhpvidng rotor ln) I-2-5. Khng ch truyn ng in theo theo hnh trnh. 1. Ni dung nguyn tc: Khi qu trnh thay i trng thi lm vic ca h c quan h cht ch vi v tr ca cc bphndichuynthsdngcngtchnhtrnhttinhngvtrthchhptrn ng i ca cc b phn ny tin hnh khng ch s di chuyn ca chnh nHnh 1-7: Khu hm ngc ngc rotor dy qun Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT19 chnh l khng ch theo nguyn tc hnh trnh. Khi cc b phn di chuyn i n cc v tr b tr cng tc hnh trnh s tc ng ln cc cng tc, cng tc hnh trnh s pht tn hiu (ng hoc m tip im ca n) iu khin h thng n trng thi lm vic mi. Khngchtheonguyntchnhtrnhthnggptrongtruynngbncamy bo, my phay, my mi cu trc... 2. S ng dng: Xt mch in o chiu hnh trnh bn ca my bo ging. o chiu hnh trnh bn, tin hnh o chiu dng phn ng ca ng c (vi my c nh v c trung) hoc o chiu dng kch t ca my pht (my pht cung cp cho mch phn ng ng c) Trong s s dng cng tc hnh trnh khng t phc hi. Khi bn my di chuyn, cnthaotc btrtrn bn mystcngvocngtc hnhtrnh thayimch in cp cho T hoc N o chiu quay ng dn n o chiu hnh trnh bn. Hnh 1-8:S nguyn l mch o chiu hnh trnh bn ca my bo gingCcrlethigian1RTZ,2RTZnhmtorakhongthigiancnthitchobnmy hmtdo(gimtcsb)trckhihmngcochiuquayhnchdng in hm. I-3.BOVVTNHIUHATRONGHTHNGTRUYNNG INI-3-1. ngha ca bo v v tn hiu ho trong h truyn ng in. Trong qu trnh lm vic ca h thng truyn ng in c th xut hin cc ch lm vic xu hoc s cTrng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT20Huquccchnyslmhhngmymc,thitb,rilonqutrnhsn xut, h hng sn phm thm ch c th gy nguy him cho tnh mng ca con ngi. Nhim v ca h thng bo v v tn hiu ho l loi tr cc s c v ch lm vic xu, mbo antonchochocon ngi vthit btrongqutrnhsn xut,gipcho vic nhanh chng khc phc cc hu qu ca cc ch ny nhm gim n mc thp nht thi gian dng my. Tc ng ca bo v v tn hiu ho tu theo mc v tnh cht s c v c im ca quy trnh cng ngh m c th l: -Ngt ng c v h thng ra khi li in khi c s c nguy him trc tip n ng c v thit b.-Khi mc nguy him cha cao phi c tn hiu bo cho nhn vin vn hnh bit theo di v c bin php x l ph hp. -Ct mt s phn t khng quan trng m bo cho cc thit b quan trng c in p khi cng sut ngun khng hoc khi c s c tm thi, in p gim thp.1.3.2. Cc dng bo v c bn trong truyn ng in: a.Bo v ngn mch: Ngn mchlsc ngimtrng nhtca mng in.Khi bngn mch, dng in trong mch tng rt ln gy hu qu v nhit v lc in ng, va t chy cch in gy ho hon va ph hng thit b v mt c hc. Dobovngnmchlnidungkhngththiuivimchinnichung cngnhhthngtrrangbinniring.Yucuquantrngnhtcabovngn mch l phict phn mch b s c cng nhanh cng tt. Bo v ngn mch c th thc hin bng cu ch, aptmat hoc rle dng in cc i tc ng nhanh. Bo v bng cu ch c cc c im:-n gin, r tin, tng i tin cy.-c tnh lm vic bin i theo thi gian-Tc ng ring r theo tng phaCuchcdnglmphngnbovchnhchoccthitbhocmchin khng quan trng v phng n bo v ph cho cc mch in khc. Bo v bng ptomat:Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT21-c tnh bo v hon thin hn-Kh nng ct dng ln-Tc ng ng thi c 3 pha-Thi gian tc ng nhanh, nht l aptomat c mc in t. - Nhc im ca n l kt cu c kh phc tp, t tin nn dng bo v cc thit b hay mch in quan trng. Bo v bng r le dng in tc ng nhanh thng l bo v gin tip. Khi c ngn mch rle dng in cp tn hiu cho cng tc t thc hin ct mch in b s c ra khi li. b. Bo v qu ti: Hai dng qu ti:di hn v ngn hn xung kch-Qu ti di hn: Qu ti xy ra khi dng in chy qua thit b ln hn tr s trong khong thi gian ln hn cho php.Qu ti di hn gy hu qu v nhit, lm thit b b pht nng, cch in b gi ha nu lu c th lm cch in b chy gy s c. Nguyn nhn xy ra qu ti di hn c th l: Do in p ngun b st di mc cho php. Do mt pha, thiu pha ngun. Do cc nguyn nhn c kh nh mn bi, cong trc, lch trc, bi trn km Do qu ti cng ngh,ng c lm vic vi dng in hoc cng sut ln hn tr s cho php Qu ti di hn c bo v bng rle nhit hoc aptomat c mc nhit.-Qutingnhnxungkch:Qutixyravitrslnnhngtntitrong khong thi gian ngn. Vi tr s ln ca dng in, lc in ng do n sinh ra s gy hu qu v lc in ng, c th ph hu thit b v mt c hc. Qu ti ngn hn xung kchthngxyrakhikhinghochmngcin,dnginkhinghoc dngin hmthngctrsln(t 5 7lndng in nh mci vi ngc xoay chiu v t 10 20 ln i vi ng c mt chiu).Qu ti ngn hn xung kch c bo v bng rle dng in cc i tc ng nhanh hoc aptomat c mc in t. c. Bo v khng v cc tiu: Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT22Trong cc h thng truyn ng dng b khng ch ch huy trng xy ra hin tng t ng khi ng ca h thng khi in p phc hi sau s c mt in. Hin tng ny c th gy ra cc hu qu nh: - Lng ph in nng. - H hng sn phm. - H hng thit b. - Mt an ton cho ngi. Trong cc h thng dng ng c xoay chiu, nu ni ng c vo li in p di mc cho php, ng c b qu ti, c th b chy. Trong thc t, thng phi hp 2 bo v trn v c gi l bo v khng v cc tiu. S ni dy ca bo v nh hnh v. BkhngchchhuyccctipimKC0, KC1, KC2 R le in p RA c tr s tc ng khng nh hn 95% in p nh mc. Tc ng ca s nh sau: Trc khi khi ng, tay gt iu khin v tr gia, tip im KC0 kn, r le RA c in. Nuinp,RAtcng,ngtipimtgivcpngunchomchiu khin. a ng c vo lm vic phi a tay gt iu khin sang phi hoc sang tri, cc tip im KC1 hoc KC2 kn, cp ngun cho mch. Nu mtin,RAmtipimtgi.Khic intrli, mun angcvo lmvicphi a tagtiukhinvgiacpnguntrlichoRA,do hthng khng th t khi ng c. Nu in p li gim qu mc, RA khng tc ng, ng c c ct ra khi ngun. d. Bo v mt t thng kch t: Vi ng c mt chiu nu t thng ng c nh qu mc cho php s gy ra cc s c sau: - Khi khi ng nu t thng u = 0, nu ni dy qun phn ng vo mch, ng c s khng khi ng c, dng in phn ng s tng ng vi dng ngn mch, dng in ny s t chy ng c. Hnh 1-9: Khu bo v khng v cc tiu Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT23- Khi ang lm vic nu v l do no , u qu nh, c dng in phn ng v c tc ng c u tng qu mc gy chy dy qun phn ng ng thi ph hng cc chi tit c kh lin quan nh c gp, chi than.. bo v mt t thng kch t, s dng r le dng in. Cun dy ca r le c ni trongmchcundykchtngc,cntipdimcancnitrongmchcun dy cng tc t lm vic. S ni dy nh hnh v. Tc ng ca bo v: Khi khi ng hoc ang lm vic, nu v l do no , dng in kch t ng c nh di mccho php,rledng inRTTs mtipimcanlmcngtctKmt inctphnngngcrakhingun cung cp. ivingckchthchclpcn chp hnh cc quy nh:- ng mch kch thch trc khi ng mch phn ng. - Mch iu khin v mch kch t phi c bo v bng mt cu ch chung khi c s c mch kch t, cu ch tc ng c mch kch thch v mch iu khin u mt in, dn n cng tc t lm vic s ngt mch phn ng ra khi ngun in. - Phi c in tr phng in trit tiu sc in ng t cm ca dy qun kch t khi ngt ng c ra khi ngun in. e. Khu lin ng lm chc nng bo v: Trong h thng trang b in t ng ha cc my sn xut thng c nhiu tc ngc lin quan n nhau. S lin kt ca cc hot dng c gi l tc ng lin ng. Khulin ngtronghthngtrangbintng haccmysnxutnhmm bo: - S an ton cho thit b- Trnh t lm vic ca h thng. - Chng ngn mch ngun cung cp trong cc truyn ng o chiu quay. Khulin ngcthlckh hoc inviccs ni ph hp.Tutheoyu cu cng ngh s dng cho hp l. Lin ng phi m bo sao cho k c khi ngi vn hnh thao tc nhm vn khng xy ra s c cho mch. Hnh 1-10: Khu bo v mt t thng ng c mt chiu. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT24V d: Trong truyn ng o chiu quay, nu v l do g c 2 cng tc t T, N u c inthnguncungcpsbngnmch.chnghintngny,ngitasdng lin ng nh sau: - Dngcctip imthngknca cccngtctT,Ncnivo mch cun dy ca nhau m bo nu mt cng tc t no ang lm vic (ang c in), tip im thng kncansm,docngtct kia s khng th c in.Lin ng nh vy c gi l lin dng in. - Dng kt cu c kh nu T ang lm vic, mch t ca N s b kho v ngc li. Lin ng nh vy gi l lin ng c kh. 1.3.3. Tn hiu ha trong h thng truyn ng in Nhm gip nhn vin vn hnh tin vic theo di tnh trng hot ng ca h thng v cccxlngntrongtrng hphthnghotdngkhngbnhthng,ng thi gip cho nhn vin sa cha nhanh chng tm ra khu vc b s c, hn ch thi gian dng my, trong h thng trang b in t ng ho cc my sn xut cn c h thng tn hiu bng nh sng, m thanh ph hp phn nh tnh trng hot ng ca h. Cc dng tn hiu ha thng dng l: * Tn hiu ch s c mt ca ngun cung cp bng nh sng (n hiu) * Tn hiu bo tnh trng lm vic hay ngh ca b phn quan trng * Tn hiu bo chun b v kt thc lm vic ca cc b phn chuyn ng nh cn trc, my nng, bng ti...bng chung, ciHnh 1-11: o chiu quay ng c mt chiu v xoay chiu Hnh 1-12: S dng tip im thng kn thc hin lin ng in (kho cho) Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT25 * Tn hiu d bo, cp bo tnh trng lm vic xu ca h thng bng n bo hoc chung, ci... I-4.MT S S KHNG CH CC NG C THNG DNGI-4-1.Cc s khng ch ng c mt chiu. 1. S khng ch ng c mt chiu cng sut nh lm vic trn tc c bn a. Gii thiu s . - Phn ng ng c - Cc in tr khi ng v hm rf, rh. - in tr iu chnh kch t rkt. -RlednginRIhnchdnginphn ng. Dng in tc ng ca RI nh hn dng khingcangc,dnginnhc chn theo iu kin tng tc ca ng c. - Cc rle khi ng, hm RG, RH. - Rle bo v t thng RTT - Cun kch t ng c CKT - Cc cng tc t lm vic, hm K, H. - Cc nt n iu khin D, M b. Chc nng ca s . -Khingntccbnquaintr ph, khng ch theo tc . - Tng tc trn tc c bn nh gim t thng kch t c khu hn ch dng in phn ng (khu rung) - Hm dng ng c theo phng php hm ng nng, khng ch theo nguyn tc tc . c. Hot ng ca s . Khi ng n tc c bn. ng in vo mch, cun kch t CKT c in ngay, dng in kch t l ln nht, t thng kch t ng c l nh mc, r le RTT tc ng, ng tip im ca n trong mch cng tc t K, cho php khi ng ng c. Hnh 1-14: S nguyn l mch iu khin ng c mt chiu lm vic trn tc c bn Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT26 khi ng dng c, n nt M, cng tc t K c in, ni phn ng ng c vo mch in. - Lc ny, r le RG cha tc ng nn in tr rf c ni vo mch phn ng ng c hnchdnginkhing.RlednginRIngtipimthng mtrong mch kch t. - Khi tc ng c tng, in p t ln RG tng. Khi tc t tr s chnh nh, in p tlnGRbngvitrs htcan,RGtcng ngtip imlm ngnmch in tr ph, ng c tng tc n tc c bn. Tng tc trn tc c bn. - Khi tc ng c t tr s chnh nh, dng in phn ng gim n tr s nh ca RI, tip im RI m, in tr rkt c ni vo mch kch t lm dng kch t gim dn n t thng ng c gim, ng c tng tc. - Do qun tnh in t v qun tnh c hc ca ng c khc nhau nn ti thi im ban u, dng in phn ng tng cng vi s tng ca tc ng c. Nu dng in phn ng t tr s tc ng ca RI, in tr rkt li b ngn mch lm t thng ng c tng. Lc ny ng c vn tip tc tng tc do qun tnh, dng in phn ng gim xung - Khi dng phn ng gim n tr s nh ca RI, in tr rkt li c ni vo mch kch t lm dng phn ng li tng. - Qu trnh c lp i lp li nh vy cho n khi dng in tng nhng khng t tr s tc ng ca RI na, in tr rkt c ni chc chn vo mch kch t, ng c tng tc n tc lm vic ng vi tr s ca rkt trong mch kch t. - Qu trnh ng ct in tr rkt c gi l qu trnh rung. Mc ch ca qu trnh rung nhm hn ch s tng qu mc ca dng phn ng khi tng tc trn tc c bn. Dng ng c. - Khi ng c ang lm vic, tip im thng kn K m, r le hm RH khng c ni vo mch. - dng ng c, n nt dng D, cng tc t K mt in, ct phn ng ng c ra khi mch, tip im thng kn K ng li, ni rle hm RH vo mch phn ng ng c. RHtcng ngtip imca ncp in chocngtct hmH.Htc ng ng tip im ni in tr hm rh vo mch phn ng. ng c hm ng nng. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT27- Qu trnh hm ng nng kt thc khi tc ng c gim lm in p phn ng gim n tr s nh ca RH, tip im RH m, cng tc t H mt in, ct in tr rh ra khi mch phn ng, mch in tr v trng thi ban u. 2. S iu khin ng c mt chiu kch thch hn hp, cng sut trung bnh v nh. a. Gii thiu s . -ngcc2cunkcht.Cun kchtsongsongCKS,cunkcht ni tip CKN. -Ccintrkhingvhmr1, r2, rh. -Ccrlethigian1RTZ,2RTZ khng ch qu trnh khi ng. - Cc r le 1RH, 2RH khng ch qu trnh hm ngc. - Cc r le dng in 1RI, 2RI bo v qu ti v ngn mch cho ng c. -RleinpRAbovkhngv cc tiu. -Cccngtctkhingvhm K1, K2, H - Cc cng tc t lm vic v hm C, 1T, 2T, 1N, 2N, H - B khng ch ch huy KC c 4 tip im v 3 v tr lm vic ca tay gt iu khin. b. Chc nng ca s . -Khingtheochiuthunvchiungcqua2cpintrph,khngchtheo nguyn tc thi gian. - o chiu quay theo trnh t hm ngc khng ch theo nguyn tc tc ri t ng khi ng theo hiu ngc li. - Dng ng c theo phng php hm ngc hoc hm dng t do. c. Hot ng ca s . Khi ng. Hnh 1-15: S nguyn l mch iu khin ng c mt chiu kch t hn hp, cng sut trung bnh v nh. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT28- ng in vo mch. Cun kch t song song CKS c in ngay. -Taygtiukhinbkhngchvtr0,tipimKC0kn,rleinpRAc in. Nu in p RA tc ng, ng tip im t gi v cp ngun cho mch iu khin pha sau. - khi ng ng c theo chiu thun, a tay gt iu khin b khng ch sang phi, cc tip im KC1, KC2 kn. Cc cng tc t C, 1T, 2T c in, ng cc tip im ca chng ni phn ng ng c vo mch, ng c khi ng. - Lc ny theo iu kin chn, r le hm 1RH tc ng, ng tip im cp ngun cho cngtcthmH,Htcngngtipimngnmchintrrh,rlethigian 1RTZ mt in. - Khi c dng in qua cc in tr khi ng, to ra st p lm r le thi gian 2RTZ tc ng, m cc tip im thng kn ca n m bo trnh t khi ng. - Sau thigianchnh nhca1RTZ,tipimthngkn 1RTZngli,cp ngun cho cng tc t K1, K1 tc ng ng tip im ngn mch in tr r1, ng c tip tc khi ng vi in tr cn li. Khi r1 b ngn mch, 2RTZ mt in. -Sauthigianchnhnhca2RTZ,tipimcanng,cpngunchoK2lm ngn mch r2, ng c tng tc n tc lm vic. o chiu quay. - o chiu quay, a tay gt iu khin v v tr i din, khi tay gt qua im 0, tip im KC1, KC2 m, cc cng tc t C, 1T, 2T mt in, ngt mch phn ng ng c. - Khi tay gt v v tr lm vic mi, cc tip im KC1, KC3 kn cp nghun cho C, 1N, 2N ng cc tip im ca chng o chiu dng in phn ng ng c, ng c hm ngc. - in p t ln r le 2RH ~ 0, 2RH khng tc ng,cc cng tc t H, K1, K2 khng c in, c 3 in tr u c ni vo mch phn ng hn ch dng in hm ngc ca ng c. - Khi tc ng c theo chiu c bng 0, in p t ln 2RH t tr s tc ng ca n, 2RH ng tip im cp in cho H, H tc ng ngn mch in tr rh, ng c khi ng theo chiu ngc tng t nh chiu thun. Dng ng c. - Khi cn hm dng nhanh, cho ng c hm ngc, khi kt thc hm ngc, ct ngun hoc a tay gt iu khin v 0. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT29- Trong trng hp khng cn thit cho ng c hm dng t do bng cch a tay gt iu khin v gia hoc ct ngun iu khin.3. Mchiukhinngcmtchiukchthchclpcngsuttrungbnhv ln. a. Gii thiu s . - Phn ng ng c . - Cc in tr khi ng v hm r1,r2, r3, rh. - R leRI bo v qu dng phn ng - R le dng in RT thc hin khu rung. - R le hm RH. -Ccrlethigian1RTZ,2RTZ,3RTZ khng ch qu trnh khi ng. - R le bo v mt t thng kch t RTT. - R leinpRAkimtra iukinkhi ng. -Cccngtctkhing,lmvicv hm. - Cc nt n iu khin M, D, MT, MN. b. Chc nng ca s -Khingntccbntheochiu thunvngcqua3cpintrph, khng ch theo nguyn tc thi gian. -Tngtctrntccbnnhgimt thng kch t. - Dng ng c theo phng php hm ng nng, khng ch theo nguyn tc tc . - Mch khng cho php o chiu quay trc tip ng c. c. Hot ng ca s . Khi ng. - ng in vo mch, r le 1RTZ c in, m tip im thng kn ca n trong mch cc cng tc t khi ng. - Cng tc t KT c in, ng tip im ngn mch in tr iu chnh kch t Rkt, t thng ng c l nh mc. Hnh 1-16: S nguyn l mch iu khin ng c mt chiu kch t c lp, cng sut trung bnh v ln. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT30- n nt M kim tra iu kin khi ng, nu in p , r le RA tc ng, ng tip im RA t gi v cp din cho mch iu khin. - n MT khi ng theo chiu thun. Cng tc t T c in qua tip im thng kn ca r le hm RH, T tc ng ni phn ng ng c vo li vi 3 in tr khi ng trong mch phn ng. - R lethigian 1RTZmt in.Khic dnginchy quacc intrr1,r2,stp trn in tr lm cc r le thi gian 2RTZ, 3RTZ tc ng. Sau thi gian chnh nh ca 1RTZ, tip im thng kn 1RTZ ng, cng tc t K1 c in, ngn mch in tr r1. ng c tng tc vi 2 in tr ph - R le 2RTZmt in,sauthigian chnh nhca 2RTZ,cngtctK2c in ngn mch r2, 3RTZ mt in, n thi im cui loi b in tr r3 ng c tng tc n tc c bn. - Khi in tr r3 b ngn mch, r le dng in RT tc ng, tip im thng m ca n ng li duy tr cp ngun cho cng tc t KT nn Rkt vn b ngn mch. Khi ng c tngtc ntc c bn, dng inphn nggim ntrs nhcarleRT,tip im thng m RT m, cong tc t KT mt in, in tr Rkt c ni vo mch kch t, t thng ng c gim, ng c tng tc n tc s lm vic. Qu trnh tng tc trn tc c bn c th xy ra hin tng rung nh tc ng ca RT v KT. ochiuquay.Munngcquaytheochiungcli,cnphidngngc. Mch khng cho php o chiu quay trc tip. Khi qu trnh hm dng kt thc, n nt MN ng c khi ng theo chiu ngc tng t nh chiu thun. Dng ng c. - n nt dng D, cng tc t T (hoc N) mt in. Phn ng ng c c ct ra khi ngun,tipimthngknT,Nngcpnguntrlicho 1RTZ,chunbcholn khi ng sau. - Do sc in ng ng c ln nn r le hm RH ang tc ng, cng tc t hm H c in, ni intr hm ngnngrhvo mch phn ng. ngcthc hin hm ng nng. Qu trnh hm ng nng kt thc khi in p t ln RH gim n tr s nh ca RH, tip im thng m RH m ra, ct ngun cng tc t hm H, tip im thng kn RH ng li cho php ng c khi ng tr liI-4-2. Cc s khng ch ng c rotor lng sc. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT311. S iu khin ng c khng ng b cng sut nh, dng r le tc hm ngc. a. Gii thiu s : - R le tc RKT c 2 tip im RKT1, RKT2.Rotor ca r le ni ng trc vi rotor ng c. - Cc cng tc t lm vic theo chiu thun v chiu ngc T, N. -RletrunggianRGhmdng ng c. b. Chc nng: -Khingtrctiptheochiuthun v chiu ngc. -o chiu quay trc tip. - Dng: Hm ngc, khng ch theo tc c. Hot ng ca s : Khi ng: Khi khi ng, mch stator ng c c ni trc tip vo li qua cctipimthnghcacccng tc t T hoc N, ng c khi ng trc tip v tng tc n tc lm vic Mch in lm vic cp cho T, N qua tip im thng kn ca RG. Khi ng thun n MT, khi ng ngc n MN. o chiu quay: Nu ng c ang quay thun, n MN, tip im thng kn MN m ct in cun dy cng tc t T, tip im thng kn T ng li cp ngun cho N. N tc ng o pha din p dt vo stator ng c, ng c o chiu quay trc tip. o chiu trc tip nh MN hoc MT. ng c hm ngc ri khi ng theo chiu ngc li. Dng: Tu thuc chiu quay hin ti ca C m RKT1 hoc RKT2 ng. V d: ng c ang quay theo chiu thun, RKT2 ng. n nt dng D,r le trung gian RG c in m tip im thng kn, ct mch in lm vic ca T, N. Hnh 1-17: S iu khin ng c KB cng sut nh, dng r le tc hm ngc Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT32Tip imthng hRG ng,cpinchoNquatip imthng hRGvRKT2. inptvoCo pha, ngc hm ngc.Khitc Cgim ntrs nh ca r le tc , tip im RKT2 m, N mt in lm RG mt in, C c ct ra khi li. 2. S iu khin ng c cng sut nh, tn s o chiu nhanh. a. Gii thiu s Trongcctruynngo chiuquayvitnsln,do cckhcinxoaychiuc thigiantcngringkh lnnntnsngctnh nnngitathngsdng cckhcinmtchiu iukhinngc.Bov qu ti v ngn mch cho ng c bng r le dng in Mch iu khin dng b khng ch ch huy. RA: bo v 0 v cc tiu. Cc cng tc t lm vic v hm C, 1T, 1N, H Phanh hm in t FH phanh trc ng c khi ct ng c ra khi ngun. b. Chc nng ca s : -Khi ng trc tiptheo chiu thun v chiu ngc.-o chiu quay trc tip -Hm dng nh phanh hm in t. c. Hot ng ca s : Khi ng. ng in vo mch ng lc v iu khin, tay gt iu khin BKC v tr 0. Tip im KC0 kn, r le in p RA c in, nu in p RA tc ng, ng tip im t gi v cp ngun cho mch iu khin. R le thi gian RTZ c in. khi ng ng c theo chiu no, a tay gt iu khin ca b khng ch v v tr tng ng. V d, khi ng thun, a tay gt sang phi, cc tip im KC1, KC2 kn, Hnh 1-18: S iu khin ng c KB cng sut nh, tn s ng m Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT33cccngtctC,1Tcin,ningcvoli,cngtctHc in,ngtip im cp ngun cho phanh hm FH, phanh hm tc ng gii phng trc ng c, ng c khi ng trc tip v tng tc n tc lm vic. Khi ngckhi ng, dng inkhi ngca ngcln hn dng intc ng ca cc r le 1RI, 2RI (chnh nh bo v qu ti), cc r le ny tc ng, cc tip im thngkn1RI,2RIm,nhtipimRTZmchmnnmchcpngunchoRA c duy tr. Khiktthckhi ng,cctip imthng kn 1RI, 2RI ngli,tip im RTZ m ra, cc r le dng in 1RI, 2RI thc hin bo v qu dng cho ng c. o chiu. o chiu quay, a tay gt iu khin v v tr i din, khi tay gt qua im 0, cc tip im KC1, KC2 m, cc cng tc t C, 1T mt in, ct ng c ra khi ngun, phanh hm mt in kp cht trc ng c, ng c ngng quay, r le thi gian RTZ c intrlichunbcholnkhingsau.Khitaygtvvtrlmvicmi,cc cng tc t C, 1N c in tr li, ng c khi ng theo chiu ngc. Dng: a tay gt iu khin v 0, cc r le, cng tc t mt in, ct ng c ra khi ngun, phanh hm mt in kp cht trc ng c, ng c ngng quay, mch in tr v trng thi ban u.3. S iu khin ng c 3 cp tc . a. Gii thiu s . ng c c 2 b dy qun. Mt b chuyn i tam gic - sao kp thay i tc khilmvic,tcngbtngngkhichuynil1500/750(v/ph)hoc 3000/1500. Mt b dy qun n thc hin hm ti sinh ng c trc khi dng. Tc ng b thng l 500 vg/ph. Cc thit b in trn s : - Cc r le trung gian 1RG, 2RG iu khin o chiu quay ng c, r le 3RG thc hin chuyn i tam gic / sao kp khi ng c khi ng. - Cc r le thi gian khng ch cc qu trnh khi ng v hm dng ng c. - Cc cng tc t lm vic theo chiu thun v chiu ngc T, N - Cc cng tc t chuyn i tam gic / sao kp K1, K2, K3.- Cng tc t K4 ni b dy qun n vo lm vic. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT34 b.Chc nng ca s . - Khi ng theo chiu thun v chiu ngc i ni tam gic - sao kp, khng ch theo thi gian. -ochiuquaytrctiptheotrnhthmngcritngkhingtheochiu ngc li. - Hm dng ng c qua 2 giai on: Hm ti sinh, chuyn sang hm ng nng kch t c lp, khng ch theo thi gian, c. Hot ng ca s . Khi ng. - ng in vo mch ng lc v iu khin, s dng cc nt n MT hoc MN khi ng theo chiu thun hoc chiu ngc. Gi s khi ng theo chiu thun, n nt MT, r le trung gian 1RG c in, ng cc tip im thng m ca n cp ngun cho cc r le thi gian 1RTZ, 2RTZ v cng tc t T. Do tip im 1RTZ ng chm nn lc u cng tc t 1K c in, b dy qun A/YY c ni vo ngun vi s ni dy hnh tamgic.Sauthigian chnhnhca 1RTZ,rletrunggian 3RGc in,ct ngun Hnh 1-19: S iu khin ng c 3 cp tc Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT35cng tc t K1, cp ngun cho cc cng tc t K2, K3, ng c chuyn sang ni hnh sao kp v tng tc n tc lm vic. o chiu quay. Nu ng c ang quay thun, n nt MN, tip im thng kn ca MN m lm r le 1RG mt in, tip im thng kn ca 1RG ng li, cp in cho 2RG, cng tc t T mt in, cng tc t N c in o pha in p t vo ng c ng c hm ngc ri t ng khi ng theo chiu ngc li theo trnh t i ni tam gic - sao kp nh 1RTZ. Hm dng ng c. nnt dngD,rletrunggian 1RG, 2RG mt in,cctip im thng mca chngmra,tonbccrle,cngtct1RTZ,2RTZ,1K,2K,3K,3RGumt in, b dy qun A/YY c ct ra khi ngun. Do tip im 2RTZ m chm nn cng tc t T (hoc N) vn c in (do tip im t gi). Cc tip im thng kn 1RG, 2RG ng li cp ngun cho cng tc t K4 v r le thi gian 3RTZ. Do tc quay ca rotor ln hn tc ng b ca t trng quay (do b dy qun n to nn trong my) nn ng c hm ti sinh. Qu trnh hm ti sinh kt thc khi tip im m chm ca 2RTZ m, cc cng tc t T, N, K4, 3RTZ mt in, ng c c ct ra khi li xoay chiu. Cc tip im thng kn T, N ng cp ngun cho cng tc t hm H a dng 1 chiu vo dy qun stator, ng c hm ng nng. Qu trnh hm ng nng kt thc khi tip im thng m m chm ca 3RTZ m ra. Mch in tr v trng thi ban u. I-4-3. S khng ch ng c rotor dy qun dng b khng ch ch huy.1. Gii thiu s . - ng c c bo v qu ti v ngn mch bng cc r le dng in 1RI, 2RI. - Mch rotor c ni i xng vi 4 in tr ph, cc in tr r1, r2, r3 l in tr khi ng, in tr rh l in tr hm. - R le dng in 3RI khng ch qu trnh hm ngc khi ng c o chiu quay v hm dng. - R le in p RA thc hin khu bo v khng v cc tiu, in p ht ca n khng nh hn 95% in p nh mc ca ng c. - R le trung gian RG ng vai tr l r le kha, phi hp vi r le 3RI m bo trnh t lm vic ca s . - Cc cng tc t lm vic theo chiu thun v chiu ngc T, N Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT36- Cc cng tc t khi ng v hm K1, K2, K3, H - Ccr lethigiannisongsongcngcccngtctH,K1,K2 khngch qu trnh khi ng ca ng c. - B khng ch ch huy KC c 7 tip im v 9 v tr lm vic ca tay gt iu khin. 2. Chc nng ca s . - Khi ng thun, ngc qua 3 cp in tr ph, khng ch theo thi gian. -ochiuquaytheotrnhthmngckhngchtheodngdinritngkhi ng theo chiu ngc li - Thay i tc nh thay i tr s in tr ph trong mch rotor. - Hm dng t do hoc hm dng nhanh. 3. Hot ng ca s a. Khi ng. Hnh1-20: S nguyn l mch iu khin ng c rotor dy qun dng b khng ch ch huy. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT37- ng in vo mch iu khin v ng lc, tay gt iu khin b khng ch v tr 0, tip im KC0 kn, r le RA c in. Nu in p , RA tc ng cho php khi ng ng c. - Mun khi dng ng c theo chiu no, a tay gt iu khin v v tr tng ng. V d, khi ng ng c theo chiu thun, a tay gt v v tr s 4 bn phi, cc tip im KC1, KC3, KC4, KC5, KC6 ng.- Dng in khi ng ca ng c nh hn tr s tc ng ca 3RI nn cc cng tc t T, H c in ni ng c vo mch khi ng vi cc in tr khi ng. R le thi giannisongsongvicngtctH(khngvtrns)khngchthigiankhi ng cp 3 in tr ph. Sau thi gin chnh nh ca r le, cng tc t K1 c in ngnmch intrr1. Qutrnhloibcc intrr2, r3tngt nhtrn.Ktthc qu trnh khi ng, ton b cc in tr ph b ni tt, ng c tng tc n tc lm vic. b. o chiu quay. o chiu quay, a tay gt iu khin v v tr s 4 i din (bn tri). Khi tay gt qua im 0, cc tip im ca KC m, cc cng tc t u mt in, ng c c ct ra khi ngun. Khi tay gt v v tr lm vic mi, cc tip im KC2, KC3, KC4, KC5, KC6 kn, cp ngun cho cng tc t N, o pha ddienj p t vo ng c. ng c hm ngc. Do dng in hm ca ng c ln hn dng in tc ng ca r le dng in 3RI, r le tc ng m tip im thng kn ca n, mch cp in cho cc cng tc t H, K1, K2, K3 b ngt, c 4 in tr ph c ni vo mch rotor hn ch dng in hm. Khitc ngctheochiuc~0, dnginrotorgim ntrs nhca 3RI, tip im 3RI ng,cngtc tHc in, ngn mch intr hmtrckhi ng c khi ng theo chiu ngc li. Qu trnh khi ng tng t nh theo chiu thun. c. iu chnh tc . thay i tc lm vic ca ng c, a tay gt iu khin v cc v tr 1,2,3,4 phi hoc tri, tr s in tr ph trong mch rotor thay i dn n thay i tc ng c. V d: tay gt v tr s 3, tip im KC6 m, cng tc t K3 khng th c in, in tr r3 c ni vo mch rotor, ng c lm vic trn ng c tnh bin tr. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT38Tngt,nutaygtvtrs2,cc cngtctK2,K3,khngcin,ng c lm vic vi 2 in tr ph. Khi tay gt v tr s 1, ng c lm vic vi c tnh thp nht, tc ng c l nh nht. d. Dng ng c. -Khicnhmdngnhanh,chongc hmngc,khiktthchmngc,ct ngun hoc a tay gt iu khin v 0. -Trongtrnghpkhngcnthitcho ngc hm dngt do bngcch atay gtiukhinvgiahocctnguniu khin.

n3 r3 r2+r3 r1 + r2 +r3 Hnh 1-21: th c tnh c khi thay i in tr ph trong mch rotor. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT39Chng2:CCHTHNGTRUYNNGTRONGMCHIN IU KHIN CC MY SN XUT2.1. CC PHNG PHP IU CHNH TC CC MY SN XUT.2.1.1. Cc ch tiu iu chnh tc truyn ng in. Qu trnh lm vic ca cc my cng tc ni chung u c yu cu thay i tc p ng i hi ca qu trnh sn xut. Ty thuc tnh cht lm vic ca h truyn ng, c im ca ph ti c hc m phi la chn phng php iu chnh tc ca h khai thc tt nht cc c tnh kinh t - k thut ca phng n truyn ng. nh gi cht lng ca iu chnh tc , ngi ta da vo cc ch tiu c bn sau y: Phmviiuchnhtc.cnhgibngtsgiatclmvicn nh ln nht v tc lm vic n nh b nht ng vi mt dng in ph ti no . Thng thng ngi ta xc nh phm vi iu chnh tc ng vi dng ph ti l nh mc. Phm vi iu chnh tc d c k hiu l D. minmaxee= D trn iu chnh. N ln s sai khc gia 2tc n nh k nhau ca gii iu chnh. nh gi trn iu chnh thng qua h s trn diu chnh: iiee1 +=Theo nh ngha v trn diu chnh ta c iu chnh tc c cp nu 1 v iu chnh v cp nu 1. Sais iu minmaxee= D chnh. Ni ln kh nng duytr tc lmvic thctso vi tc t ca h thng, thng c nh gi theo %. Thng thng ngi ta tnh saisiuchnhngvi tc lmvicn nhln nhtvtc lmvicn nh nh nht ca gii iu chnh. % 100 . %maxmax maxmaxdtt See e = Tn tht nng lng trong iu chnh tc . Ch tiu ny cn c gi l ch tiu kinh t - k thut ca phng n iu chnh. Khi la chn phng n iu chnh cn tnh ton tn tht kinh t do tn tht nng lng trong iu chnh vi ph tn u t ban u IC, MC emax I , Memi n I , Me Hnh 2-1 Phm vi iu chnh tc Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT40caphngn(sosnhchiphvnhnhvikhuhaovnutcaphngn). Phng n c coi l c tnh kinh t k thu tt nht l phng m c chi ph tnh ton nh nht. Hng iu chnh tc . Ch tiu ny ni ln kh nng iu chnh tc ng c theo hng cao hn hay thp hn tc d c bn ca ng c, t d ra phng php iu chnh tc ng c hp l. Ph ti cho php ca ng c trong iu chnh. Ph ti cho php ca ng c ph thuc vo phng php iu chnh tc . S pht nng ca ng c ch yu ph thuc votnhaong,nghalphthucvodnginphti.Trongmitrnghp khng cho php vn hnh ng c vi dng in ph ti ln hn dng in nh mc ca ng c. Nu iu chnh tc vi cng sut l hng s th ph ti cho php ca ng c c nh gi theo cng sut, ngha l [P] s Pm. Nu iu chnh tc vi m men l hng s th ph ti cho php ca ng c c nh gi theo dng in, ngha l [I] s Im Sph hpvictnhti.Chtiu nynilnhctnh iuchnhtc ca ng c phi ph hp vi c tnh c ca my cng tc. V d, vi ng c truyn ngchotruynngchnhcamyctkimloithphilachnphng phpiu chnh tc c P = const, vi ng c truyn ng cho c cu nng h th phi la chn phng n iu chnh vi M = const 2.1.2. Cc phng php iu chnh tc cc my cng tc 1.iu chnh tc bng phng php c kh. Lphng php iuchnhtc trc lm vicca mycng tc bngphng php c kh thun ty. ng c truyn ng c ni vi trc lm vic ca my cng tc thng qua hp truyn ng (hay cn gi l khu truyn lc), trong qu trnh lm vic tc ng c c gi nguyn, cn tc ca trc lm vic c xc nh theo biu thc: iLVee = ; trong i l t s truyn ca hp tc . thay i tc lm vic ta thay i t s truyn i. Cc hp truyn ng thng dng bao gm: Truynng dng bnhrng(hps): 21ZZi = , Z1, Z2lsrngca bnhrng ch ng (ni vi trc ng c in) v bnh rng b ng (ni vi trc lm vic) Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT41 Truyn ng rng xch: Bnh rng ch ng v bnh rng b ng c ni vi nhau bng dy xch (truyn ng c khong cch), t s truyn cng l t s gia s rng ca bnh rng ch ng v s rng ca bnh rng b ng Truyn ng ai. Bnh ai ch ng c ni vi trc ng c, bnh ai b ng cnivitrclmviccamycngtc,ktni2bnhaibngdyai(ai truyn), ma st gia dy ai v bnh ai s truyn lc t ng c sang trc lm vic ca my cng tc. T s truyn ca b truyn ai l t s gia ng knh ca bnh ch ng v bnh b ng Truynngtrcvt-bnhvt,bnhrng-thanhrng.Phngthctruyn ng ny bin chuyn ng quay ca rotor ng c thnh chuyn ng tnh tin ca b phn chuyn ng ca mycng tc. Vi truyn ng trc vt bnh vt, trc vt c ni vi trc ng c in, khi ng c quay, trc vit quay, cn bnh vt ln trn trc vt kotheob phnchuynng dichuyn. Vitruynng bnhrng-thanhrngth ng c quay bnh rng lm thanh rng chuyn ng tnh tin ko theo b phn chuyn ng ca my cng tc di chuyn. ng c truyn ngthng dng l ng c khng ng b rtor lng sc. u, nhc im : Kt cu mch in n gin, s dng loi ng c c kt cu chc chn, r tin. Mmen qun tnh ca h truyn ng ln do c nhiu khu chuyn ng. Hp truyn ng c kch thc ln, khi lm vic gy ting n, hiu sut truyn ng thp do ma st kh ln. Kch thc chung ca c my ln. iu chnh tc theo phng php c kh thng dng trong cc my cng tc c phm vi iu chnh khng ln, yu cu diu chnh khng cao, iu chnh c cp 2. iu chnh tc bng phng php in thun tu:iuchnhtctheo phngphpinthuntylsdngccphngphp iniuchnhtcngctruynng.Tythucvoloingcccc phng php iu chnh ph hp. Trc ng c in c ni trc tip n trc lm vic ca my cng tc. u nhc im : Ktcuckhca myngin, gn nh, qun tnh nh,kchthc ca my nhTrng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT42 Cht lng iu chnh tt, iu chnh su, s cp tc , phm vi iu chnh ln, c kh nng iu chnh tc v cp. D t ng ho ton b qu trnh sn xut Hiu sut qu trnh iu chnh ni chung ln do khng c khu truyn lc trung gian Kt cu mch in ng lc v iu khin phc tp, Gi thnh ca h thng nhn chung kh cao3. iu chnh tc in c kt hp: Thc t, ngi ta thng kt hp c phng php in c kh iu chnh tc ca my cng tc. Trc ng c v trc lm vic ca my cng tc c ni qua khu truyn lc c vi cp tc . Vic iu chnh tc c tin hnh c iu chnh tc ng c in v thay i t s truyn ca hp tc . Phng n ny cho php vn hnh my linh hot, kt cu ca c phn c v in u khng qu phc tp. Hu ht cc my cng tc u thc hin iu chnh theo phng n in c kt hp. Phm vi iu chnh tc ca my s bng tch s ca phm vi iu chnh tc theo 2 phng n. 2.2 H THNG MY PHT NG C MT CHIU 2-2-1. H thng F- n gin 1. Khi nim chung: Trongcctruynngsdngngcmtchiulunphicmtbngun mt chiu cungcpchocc mch inca ngcv ngc khngthlyin trc tip t li in xoay chiu. Bngunmtchiucgilbbiniinxoaychiu-mtchiu.Tu thuc vo cc thit b s dng to ra ngun in mt chiu m c cc loi b bin i nh b bin i my in, b bin i in t, b bin i bn dn... B binimyinlb bin isdngmyphtin mt chiucungcp cho mch phn ng ca ng c mt chiu ko my sn xut. My pht in mt chiu li do mt ng c xoay chiu 3 pha ko. Nh c h thng ny m dng in xoay chiu nhn trc tip t li bin thnh dng in mt chiu cp cho ng c in bin thnh c nng ko my sn xut. Tu thuc vo yu cu v cng sut ca truyn ng m ngi ta s dng cc b bin i my in khc nhau. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT43 Sau y ta s xt mt vi h thng truyn ng dng b bin i my in .2 . H thng my pht - ng c n gin S nguyn l ca h thng my pht- ng c n gin nh hnh v 2 - 2.

Hnh 2-2: S nguyn l h thng my pht ng c n gin Cc phn t ca s bao gm: ng c xoay chiu KB ( h thng cng sut ln s dng ng c ng b) ko cc my pht mt chiu K, F quay vi tc khng i. MyphtkchthchK cungcpkchthchchongc mt chiu v my phy F My pht F cung cp cho mch phn ng ca ng c ko my sn xut ng c mt chiu ko my sn xut. Cc cun kch thch ca cc my in mt chiu CKK, CKF, CK Nguyn l lm vic ca h thng:ng c xoay chiu AK ko cc my pht K, F quay vi tc khng i. My pht K l my pht t kch pht ra in p cung cp kch thch cho my pht F v ng c . Khi c kch thch, my pht F pht ra in p cung cp cho ng c . ng c quay ko theo my cng tc quay. Trong qu trnh lm vic t thng ng c c gi nguyn. iuchnh tc ngc, tin hnhthayikchthch my pht nh bintr ni trong mch kch t my pht, dn n sc in ng my pht thay i lm in p mch phn ng ng c thay i lm thay i tc ng c. o chiu quay ng c ta o chiu dng kch t my pht nh cu dao o chiu CD. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT44 Phng trnh c tnh ca h thng: (2-1)

T phng trnh 2-1 ta c nhn xt: -c tnh c mm hn c tnh t nhin do c st tc gy ra bi in tr cun dy phn ng my pht. -Phngtrnh2-1chothytcngcphthucvtthngkchthch my pht, ngha l ch r c nguyn l iu chnh tc ca h. -Khi phtithayilmtc ngcthayi,khckhnng phc hi tc n nh c. l do, khi ph ti thayi ng vi kch thch my pht khng i nhng in p phn ng b thay i nn tc ng c khng cn t l bc nht vi dng ph ti. Trong thc t, ngi ta khng dng h thng F - n gin. n nh tc ng ckhilmvic, ngitaavo hthng ccphn hi,khi hthng trthnh h kn.2.2.2. H thng my pht ng c vi cc phn hi1. H thng F- vi phn hi dng dng inphn ng Trong qu trnh lm vic khi c s bin ng ca ph ti lm tc ca ng c cng thay i theo. iu khng p ng c yu cu n nh tc ca h. a phn hi dng dng in vo, tc ca h thng c duy tr khng i. S nguyn l ca h thng F - vi phn hi dng dng in phn ng nh hnh v 2-3. d duF uD F F Fd duF uD FKr r I KKr r I Eu+ u=u + =.) ( . ..) ( ee Hnh 2-3: H thng F - vi phn hi dng dng in phn ng v thi c tnh ca h khi khu phn hi tc ng Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT45Thay v s dng my pht kch thch K, ngi ta a vo h thng my in khuych i t trng ngang. l my in mt chiu c bit c 2 cp chi than, trong c mt cp ngang trc c ni ngn mch. Nh vy dng in chy trong dy qun ngang trc kh ln to ra t trng ca my ln nn h s khuch i ca my rt ln. Trn my c nhiu cun kch thch, trong c mt cun ch o c cung cp t ngun mt chiu c lp c th thay i c tr s. Cc cun cn li c ni vi cc khu phn hi. T trng do cc cun phn hi cng chiu hoc ngc chiu vi t trng chnh l do tnh cht ca phn hi. Trn hnh 2-2, myinkhuch iMKc2cunkcht.Cun ch oW1 c cung cp t ngun in p mt chiu c lp. Dng in chy trong cun W1 to ra sc t ng ch o F1. Cun phn hi dng dng in W2, ngun cung cp cho W2 l st p trn in tr Rs. St p ny ph thuc vo dng in trong mch phn ng ng c. Dng in chy trong cun W2 to ra sc t ng ch o F2 cng chiu F1. Phng trnh cn bng sc t ng myin khuch i: F = F1 + F2(2-2) iu chnh tc ng c, ta thay i sc t ng ch o kch thch cho my khuych i F1 nh bin tr R n i trong mch kch t ca my khuch i Qu trnh n nh tc c minh ho trn th: Gi s ng c ang lm vic vi tc n nh ng vi kch thch ch o F1 , khi c bin ng ph ti, lm tc ng c thay i. V d, dng ph ti tng n tr s I1, tc ng c gim, im lm vicmica hl imB.Tuynhin do dngphn ngtng nnsct ngF2tng dn n sc t ng tng ca my khuych i tng, kch thch ca my pht tng lm in p pht ra ca my tng, ng c tng tc n im lm vic mi- im A trn c tnh. Khi dng phn ng gim, l lun tng t, im lm vic mi ca h l A. Kt qu l khi ph ti thay i nhng tc ng c vn duy tr khng i v bng tc t ng vi sc t ng ch o. Trong qu trnh khi ng, do c tc ng phn hi, xy ra cng bc khi ng ca h thng. Do dng khi ng ln nn sc t ng kch thch ca my khuych i ln dn n in p my pht tng nhanh lm tng gia tc khi ng ca ng c. iu ny c th gy ra va p, nh hng n ng c v cc chi tit c kh lin quan. hn ch gia tc khi ng, ngi ta a vo h thm khu phn hi kt hp, l phn hi m in p phn ng ng c.Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT46Thct, ngitakhngdng ring phn hi dng dngtrong hthng truyn ng do nhc im nu m cn c nhc im na l dng phn hi dng lm xu c tnh qu ca h nh lm tng lng qu iu chnh, tng s ln dao ng ca h v ko di thi gian qu trnh qu ca h. 2. H thng F- vi phn hi m p - dng dng kt hp Phn hi m in p phn ng ly trn in tr Ra. Dng in chy qua cun W3 to ra sc t ng F3 ngc chiu F1. Phng trnh cn bng sc t ng ca my in khuych ai: 3 2 1F F F F + =(2-3) Khiakhuphnhipkthp,qutrnhnnhtcdinranhanhhn, ng thi khc phc c hin tng cng bc khi ng. C th iu chnh c gia tc khi ng thng qua kt hp iu chnh cc h s phn hi. Vic s dng khu phn hi m p dng dng kt hp cho php ci thin iu kin khi ng ca h thng, ng thi gim thi gian n nh tc khi c bin ng phtidoc2khuphnhingthitcng.ccthitbsdngthucloin gin, r tin d lp t v sa cha. Hnh 2-4: H thng F - vi phn hi m p - dng dng kt hp Tuy nhin do s dng cc in tr ni trong mch phn ng ng c nn gy tn thtnnglngchohthngvctnhccahmm.Nhngnhcimcbn nht ca phn hi ny l phm vi iu chnh tc hp do ng c khng th lm vic vng tc thp. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT47Phn hi m p dng dng kt hp thng c dng trong cc h truyn ng cngsuttrungbnhvnh,phmviiuchnhtchp,yucuchtlngdiu chnh khng cao. Phn hi ny chyu dng trong cc h truyn ng Khuch i t ng c mt chiu vi cng sut n vi kW. 3. H thng F- vi phn hi m tc khc phc nhc im ca khu phn hi m p dng dng kt hp, ngi ta s dng phn hi m tc phn ng ng c vi s nguyn l ca h thng nh hnh 2 5.

Phnhicthchinquamyphttc.Myphttclmyinmtchiukch thch bng nam chm vnh cu. in p pht ra ca FT t l bc nht vi tc ca ng c. Rotor ca FT c ni ng trc vi rotor ng c. Ph ti ca my pht tc l cun kch thch W4 ca my in khuch i. Dng din chy trong W4 to ra sc t dng F4 ngc chiu F1 Phng trnh cn bng sc t ng: 4 1F F F = (2-4) Qu trnh n nh tc c gii thch nh phng trnh cn bng sc t ng v th c tnh c ca h. Phnhim tc van nhctcca htruynngvat ng iu chnh gia tc ca h khi khi ng. C th tin hnh iu chnh vng tc rt thp do m rng c phm vi iu chnh. Cht lng iu chnh cng nh n nh tc rt tt. Phn hi ny c s dng rt rng ri.4. H thng F- vi phn hi c ngt: Hnh 2-5: H thng F - vi phn hi m tc Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT48a. Phn hi m dng c ngt Khi thc hin cc phn hi trong h, tc ng c c duy tr khng i theo tc tchotrc.Khixyra quti, ngccth bchy.Vicsdngccthit b bo v c th gy phc tp cho qu trnh vn hnh v nh hng n nng sut my, c bit l cc trng hp c qu ti tm thi. Do ngi ta a vo h thng khu phn hi m dng c ngt nh hnh 2-6.

Phn hibaogmmtkhu phn himdngin phnngvmtkhusosnh nh hnh 2-5. Van bn dn D c t vo mt in p l hiu ca in p phn hi v in p so snh. Khi dng in phn ng cha vt khi tr s cho php, van D khng dn dng, s.t.F5 = 0. Khi dng in vt qu tr s chnh nh, van D m, F5 = 0 lm gim s.t. ca MK, dn n kch thch my pht gim, ng c gim tc , ng c tnh dc n n = 0. Tr s dng in ti khu ngt bt u tc ng c gi l dng in ngt. c tnh c ca h thng c dng nh hnh v 2 5. b. Phn hi m p c ngt. Khi ch s dng phn hi m in p n nh tc ng c lm gim tn tht trong qu trnh iu chnh tc , tuy nhin, trong qu trnh khi ng, phn hi s lm chm giatcca h.Khu ngt nhmkhng cho phn hi thamgiavo qutrnhkhi ng ca h. Khi qu trnh khi ng kt thc, phn hi c a vo n nh tc ng c. thc hin ngt, ngi ta cng dng khu so snh nh hnh 2-6. Khi khi ng, in p phn ng nh nn in p phn hi nh hn in p so snh do van D kho, Hnh2-6:HthngF- viphnhimdngc ngt v c tnh c ca h. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT49phn hi khng tham gia. Kt thc khi ng, in p t ln van D dng, vanm qua cun W6 c dng in v to ra s.t.F6ngc chiu F1 n nh tc ng c. 2.2.4. H thng my in khuych i - ng c mt chiu nhng hthngtruynngcngsutkhngln,ngitasdngtrctipcc my in khuych i cung cp cho mch phn ng ng c. Trong h cng dng cc phn hi nh i vi h F - . Nh vy lm gim c thit b ca h, gim cng sut t v lm vic tin cy hn. S nguynlca hthngtrnhnh2-7.Ccphnhithngdngcphn tch tng t nh cc trng hp nu. Hthngtruynngmyinkhuchingcmtchiuthngdng trongcctruynngcngsut n 10kW nhtruynng quaychititccmymi trn, truyn ng bn cc my mi phng, my doa .. Hnh2-7:HthngF- vi phn hi m p c ngt Hnh 2-8: H thng MK - Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT502.2.5.nh gi h thng truyn ng dng BB my din Trong mch lc ca h thng khng c phn t phi tuyn nn h thng c nhng c tnh ng rt tt, rt linh hot khi chuyn i cc ch lm vic. Khi phi hp c iu chnh tc 2 vng: iu chnh kch thch my pht v iu chnh kch thch ng c, o chiu quay bng o chiu quay bng cch o chiu kch thch my pht. ng c s c cc ch lm vic nh sau:-Hm ng nng khi kch thch my pht bng khng-Hm ti sinh khi gim tc hoc khi o chiu dng kch t-Hm ngc cui giai onhm ti sinh khi o chiu hoc khi lm vic n nh vi ti c tnh th nng (khi h ti trng) Nh vy h thng F- c c tnh in y c 4 gc phn t ca mt phng to . u imnibtcahthnglkhnngqutiln,schuynitrngthi lm vic rt linh hot, cc phn t trong h thng l tuyn tnhnn qu trnh qu ca hthngrttt,ckh nnggichoctnhccngcaovkhng i trongsut gii iu chnh. NhcimcbncahthngF-lsdngnhiumyinquaydo chim din tch khng gian ln, gy ting n ln trong qu trnh lm vic. My pht in mt chiu c t d ln nn iu chnh tc vng tc thp v rt thp rt kh khn. H thng F- rt thch hp vi cc truyn ng c phm vi iu chnh tc ln, phtibinngtrongphmvirng,qutrnhquchimphnlnthigianlm vic ca h thng (thng xuyn khi ng, hm, o chiu...) 2.3. H TRUYN NG CHNH LU BN DN C IU KHIN NG C MT CHIU.2.3.1 S khi ca h truyn ng.BB: S dng cc van bn dn c iu khin (thyristor) c ni theo cc s khc nhau (ty thuc cng sut ca truyn ng). Ph ti ca BB l mch phn ng ca ng c in mt chiu.S dng cc phn hi tc v dng in n nh tc v bo v qu dng cho CTrng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT51Mch K c nhim v to ra cc xung iu khin thay i gc m ca cc van ca BB nhm thay i in p u ra ca BB Nguyn l lm vic c bn: tinpxoaychiunhnt li vo BB v mch K MchKccckhucnthit storaccxunginpcthngs ph hp vi s ni ca BB v cng sut ca van. Ccxungnyscan cc iukhin ca van kch m van lmuracaBBcinp tln phn ng ng c lm ng c quay Tythucthiimaxung m n cc iu khin ca van m in puracaBBthayi,dnn thay i tc ng c Khirotorngcquay,myphttcFTphtrainpavomchiu khin, in p phn hi ny s phi hp vi in p ch o ca mch iu khin lm n nh tc lm vic ca ng c Khu phn hi m dng c ngt phn nh thng s v dng in phn ng ca ng c. Khi dng in phn ng nh hn gi tr chnh nh ca n (dng in ngt) khu ny khng tham gia vo hot ng ca mch Khi I > Ing khu phn hi s tc ng lm thay i gc m ca van lm gim in p u ra ca BB lm tc ng c gim, dng in phn ng c duy tr trong gii hn cho php, bo v qu dng cho ng c. 2.3.2. c tnh c ca h truyn ng Khi cc van ca BB dn dng, dng in chnh lu chnh l dng phn ng. Do ph ti ca chnh lu c tnh R-L-E nn khi U~ < E, Id = 0, khi U~ > E phng trnh c tnh c xy dng t phng trnh cn bng in p ca mch. IKX RKUK dou+u=oecos. XK c trng cho st p do chuyn mch gia cc van BB FX C FT -|I-n Hnh 2-9: S khi ca h truyn ng chnh lu bn dn c iu khin ng c mt chiu (H T ) Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT52 2.3.3. Cc s ni dy ca b chnh lu c iu khin Trong cc b chnh lu bn dn c iu khin cc van chnh lu c dng l thyristor. Thyristor c ch to vidnginnhmcnhngtrmampe,inp nh mc n hng nghn vn. Cc b chnh lu c ni vi 2 loi s c bn l s tia v s cu.1. S ni dy hnh tia:S nguyn l ca mch chnh lu hnh tia 3 pha, katot ni chung nh hnh 2 12. Cng c th thc hin kiu s anot ni chung. Mi pha ca bin p ngun c ni vi 1 van chnh lu. c im ca s ni dy hnh tia:-Svanchnhlubngsphacanguncung cp -Ccvancmtincccngtnnichung, incccnlinivingunxoaychiu.Nuin ccnichunglkatt,tacskattchung,nu in cc ni chung l ant, ta c s ni ant chung. -Hthng inp ngunxoaychiu m phaphi c im trung tnh. trung tnh ngun l in cc cn li ca in p chnh lu.2. S hnh cu:nhnghtruynngyucucaovchtlnginpchnhlu, ngita thng s dng s ni dy hnh cu. Vi truyn ng cng sut nh, s dng s cu 1 pha, cn cc truyn ng cng sut ln (trn 10kW) ngi ta s dng s cu 3 pha. S nguyn l mch chnh lu cu 3 pha nh hnh 2- 13. c im ca s chnh lu cu:-S van chnh lu bng 2 ln s pha ca in p ngun cung cp. Hnh 2-11. c tnh c h truyn ng T - Hnh 2-12: S nguyn l h thng CL - hnh tia 3 pha katot ni chung Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT53-Cc van c ni thnh tng nhm. Nhm van c kattnichung(ccvan1,3,5)tothnhccdng ca inp ngun.Nhmvancant nichung( 2, 4, 6) to thnh cc m ca in p chnh lu-Miphacainpngunnivi2van,1 nhm ant chung, 1 nhm katt chung. 2.3.4.Nguyn l lm vic ca h truyn ng T - 1. S tia:Xt s tia 3 phakatt ni chung mt Thyristor m cn c 2 iu kin-in p Ant - Katt phi dng ( UA > 0) -Ctnhiuiukhintvoincciu khin v Katt ca vanT s ni dy ca s ta thy: Do katot cc van ni chung nn c chung in th, v vy ch van no c th anot dng nht mi c th m.Do c imva nu mtrongstia3phaccvanch mtrong mtgiisn nht nh. V d: pha A, trong khong et = 0 t uA > 0Tuy nhincc khong et = 0 t/6 uC > uA v et = 5t/6 t ub > uA

NhvyvanT1nivophaAchcthm trong khong et = t/6 5t/6. Trong khong ny nu tn hiu n cc iu khin ca T1 th T1 m. Tng t vi T2 v T3.Thi im m ca T2 chm hn thi im m T1 mt gc 1200, cn T3 m chm hn T2 cng 1200 Thi im t ng vi gc o0 = et = t/6 c gi l thi im m t nhin ca s chnh lu 3 pha. Nu truyn tn hiu m van chm hn thi im m t nhin mt gc in th khong dn dng cu van s thay i (nh hn 2t/3) dn n tr s trung bnh ca in p chnh lu s gim i. Khi gc m o cng ln th Ud cng nh. Ngha l thay uAuB uC t/6 5t/6 T1 mT2 mT3 m u ett 2t Hnh2-14:Ginthi gianmcaccvantrong stia3phakatotni chung Hnh 2-13: S nguyn l h thng CL hnh cu 3 phaTrng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT54i thi im truyn tn hiu m van s lm thay i gc m ca van dn n thay i in p chnh lu.2. S cu: T kt cu ca s chnh lu cu ta c nhn xt: - c dng qua ph ti th trong s phi c t nht 2 van cng thng, mt nhm ant chung, mt nhm katt chung. -Vigithitlslmvicchdnglin tc v b qua qu trnh chuyn mch th khi b chnh lu cu m pha lm vic, mt thi im bt k trong s lunc 2vancthdndngkhicxungiukhin: Vannhmkattchungniviphacinpdng nhtvvannhmantchungniviphacinp m nht. - Thi im m t nhin ca s cu cng c xc nh nh i vi s tia c s pha tng ng. Ngha l:-Trong mt chu k ngun xoay chiu mi van dn dng ti a trong mt khong thi gian bng 1/m chu k-S chuyn mch dng t van ny sang van khc ch din ra vi cc van trong cng nhm v c lp vi nhm kia-Trong mt chu k ca ngun xoay chiu, in p chnh lu lp li 2m ln ging nhau (khi m l ) hoc m ln (khi m chn). -iukhininpchnhlutrnphtimtchiutathayithiima xung iu khin n cc cc iu khin ca cc van, lm thay i khong dn dng ca van lm in p trung bnh ca chnh lu thay i. 2.3.5. Dng in chnh lu trn ph ti mt chiu: Doinpchnhlulpilpli2m(hocm)lntrongmtchukcainp ngun nn ch xc lp th dng qua ti cng lp i lp li nh vy (tu thuc s chnhlul tiahaycu,s phachn hayl).Nhvychcnbit dngvptrnti trong khong thi gian l 1 / m chu k hay l tng ng gc in2t / q ( q=2mhocq=m).xcnhdngvptrntitadavosthaythcachnhlu trong mt khong thi gian lm vic ca mt van.T1 mT3 mT5 m ett 2t uAuB uC u T6 m T2 mT4 m Hnh2-15:Ginthi gianmcaccvantrong s cu 3 phaHnh2-12:Sthaythcachnh lu trong khong thi gian lm vic ca van Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT55-u: tng is inp ngunxoaychiutc ngtrong mchvng niviccvan ang dn dng trong s thi gian ang xt. -Nu l s tia th ch c 1 van m, u = uf. -Nu l s cu th c 2 van 2 pha khc nhau cng lm vic, u = ud.-Nu chn mc thi gian xt t = 0 l thi im bt u m mt van trong s th u = Um.sin(et + )+ Um - Bin in p ngun (pha hoc dy) + - gc pha u, c xc nh: = t / 2 - t / q + o -T c trng cho van ang dn dng, s tia l 1 van, s cu l 2 van ni tip nhau, b qua st p trn van-Ed, Rd, Ld l cc phn t ca ph ti-Ud, Id - dng v p trn ti. Phng trnh cn bng in p t s thay th:(2-5) Gii phng trnh ny ta nhn c biu thc ca dng in chnh lu:

]) ( 1) sin(1 [ ]) ( 1) sin(1 [2/20etet =et et t+ + + + =arctg tI earctgI i imtm d(2-6) Tu thuc c tnh ph ti, dng s ,gi tr gc iu khin m c th c cc ch lm vic khc nhau: -Nu trong ton b thi gian lm vic id >0 ta c ch dng ti lin tc-Nutrongmtchuklmvicmdngticqkhongbngkhngvqkhong khc khng ( q = m nu l s tia, q = 2m nu l s cu ) ta c ch dng ti gin on. -Ch gii hn gia 2 ch nu trn c gi l ch dng bin lin tc. 2.3.6. o chiu trong h thng T - Trong nhiutrnghpcn phithayi cchiu dng in qua ph tica b chnh lu. Do tnh dn dng mt chiu ca cc van nn phi o chiu bng cng tc t hoc s dng cc s c bit gm 2 b chnh lu, mi b dn dng theo mt chiu. o chiu dng s r le, cng tc t c cc nhc im nh tui th thp, tn s o chiu nh. Vi truyn ng cng sut ln (dng in ln) h quang s nhanh chng lm chy hng tip im ca cng tc t.... d mdd d dE t UdtdiL i R + = + ) . sin( . . . eTrng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT56 o chiu dng 2 b bin i: C 2 b chnh lu iu khin l s u cho v s song song ngc. V mt nguyn l th s u cho hoc s song song ngc hot ng tng t nh nhau. Khi BB ny lm vic th BB kia ngh, khi i ch ca BB th dng in qua ti c i chiu. Thc t ngi ta hay s dng s u song song ngc vi cc phng php iu khin khc nhau. iu khin 2 BB song song ngc c th s dng: -iu khin ring r (iu khin c lp): L s dng 2 b pht xung c lp nhau. Khi b pht xung ny lm vic (pht xung m cho BB) th b kia ngh, do cc van trongBBcnlikhng th m c.Khicn ochiuthcho bnyngh,sau cho b th 2 pht xung m cc van ca BB th 2. Phng php iu khin ny c nhc im l tn s o chiu khng cao v cc van Thyristor cn c thi gian khi phc c tnh kho ca n. -iukhinphthuc:Sdngmtbphtxungngthiaxungncc BB, trong mt b lm vic ch chnh lu, b cn li lm vic ch nghch luch. im cbitca hthng iukhin nylphi m bosaochotnggc iu khin ca 2 s chnh lu lun lun bng 1800 . Khi s dng phng php ny, s cdnginkhngcnbngchytrongccBB.hnchdngnyngitas dng cc cun khng cn bng.

2-4: H TRUYN NG BIN TN NG C XOAY CHIU 3 PHA.2.4.1. Nhng vn chung v b bin i mt chiu - xoay chiu Trong lnhvcbin i nnglng nhiutrnghp phithc hinqutrnhbin i mt ngun in mt chiu thnh dng in hoc in p xoay chiu c th iu chnh cgitrvtnscadng,p ura.Thchinqutrnhbin itrnlccb Hnh2-16:Sni songsongngccah thngCL-co chiuquay,iukhin chung. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT57bin i mtchiu -xoaychius dngcc van bn dnc iukhin. BB nycn c gi l b nghch lu. C nhiu kiu s nghch lu khc nhau. Da vo c tnh ngun cung cp, c tnh ti th cc BB mt chiu - xoay chiu c chia thnh:-B nghch lu p: Ngun cung cp l ngun p, ph ti khng c tnh cht dao ng cng hngp, hoc nucththtnscng hng nh hn rt nhiutnsca in p xoay chiu u ra ca BNL. to ra ngun p cp cho BNL p trong thc t ngi ta mc song song vi 2 cc u ra ca ca BCL mt t in c in dung ln sao cho n c th duy tr in p trn 2 cc ca BCL khng thay i-Bnghchludng:Nguncungcplngundng,phtikhngctnhcng hng dng inhoc tn s cng hng nh hn nhiu tn s dng in u ra ca BNL. Ngun cung cp cho BNL dng l cc b chnh lu, trn u ra ca n c mc nitipvicuncmLctrsln,cuncmctcdngduytrdngin ngun khng i khi BNL lm vic. 2.4.2. ng dng ca BB mt chiu - xoay chiu: CcBBmtchiu-xoaychiucngdngnhiuthitbinkhcnhau trong cng nghip v i sng hng ngy. Trong lnh vc truyn ng in th BB mt chiu-xoaychiucdngiuchnhtcngcxoaychiutheophng php thay i tn s. y l cng dng quan trng nht ca BB ny. Ngoi ra BB ny cn dng lm b ngun cung cp cho cc l tn s.Thit b bin tn c chia thnh 2 loi:-B bin tn trc tip: L thit b bin tn trc tip t ngun in p xoay chiu (thng t li in tn s cng nghip) thnh in p xoay chiu khc c tn s thay i c. Nhc im ca thit b bin tn trc tip l phm vi thay i tn s hp, cht lng in p xu, nh hng n in p ngun -Bbintngintip:Lthitbbintnthngquamtskhutrunggian, trongBBmtchiu-xoaychiulmtkhutrongbbintngintip. Thitbbintnloinykhcphc cccnhcimvanucabintn trc tip, tuy nhin c kch thc cng knh hn v hiu sut thp hn. Thc t th b bin tn gin tip c s dng rng ri hn nhiu.2.4.3. H truyn ng BBT - ng c xoay chi 3 pha. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT58 ngcxoaychiu3 phacktcugnnh,chcchn,lmvictincy.Nhc imcbncangc xoaychiul iu chnh tc khkhn.Ccphng php iu chnh c bn thng ch thc hin c gii tc di tc c bn v thng lm gim m men ng c, ngha l lm gim kh nng ti ca ng c. Tuy nhin nu c th to ra c b ngun xoay chiu c in p u ra thay i c tn s th vic iu chnh tc ng c s thun li hn rte nhiu. Cc b bin i tn s dng thit b bn dn ngy cng ng vai tr quan trng trong iu khin t ng hin i. iu chnh tc ng c khng ng b bng thay i tn s ngun cung cp c nhiu u im c bit l n c th to ra h c tnh tng t c tnh iu chnh ca ng c mt chiu khi thay i tc 2 vng: vng di tc c bn iu chnh vi m men l hng s, vng trn tc c bn iu chnh vi cng sut l hng s. Vn t ra l phi iu chnh th no m bo kh nng ti ca ng c v khi iu chnh tn s s ko theo mt lot gii php k thut phi thc hin p ng c yu cu iu chnh . Ta xt mt s vn sau. 1. Nguyn l iu chnh in p - tn s khi iu chnh tc ng c xoay chiu theo phng php tn s Khi iu chnh tn s phi bo m cho cc c tnh iu chnh c cng cao trong sut di iu chnhv ng c phi c kh nng qu ti tt. Ta xt cc iu kin cn thit khi iu chnh t c cc yu cu trnKhi iu chnh f < f1m: vng iu chnh ny s lm tng dng t ho do tng tr t ho gim. iu dn n mch t b bo ho, lm tng tn tht t ho. loi b tc hi ny cn tm quy lut iu chnh sao cho dng t ho ng c khng thay i nhm m bo kh nng ti ca ng c. T biu thc S.. dy qun MXC v b qua tng tr mch stator:U1 ~ E1 = 4,44.kdq1.w1.f.| 1 1 11. . . 44 , 4 f W kUdq= u Nu gi U1 = const, gim tn s f dn n| tng, dng t ho trong ng c rt ln, mch t ng c c th b bo ho, tn tht st ln ng c b pht nng qu mc c th chy ng c. Mt khc, t biu thc ca m men in t ca ng c: Mt = Pc / e Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT59 Trong : Pc =(1-s).Pt = (1-s).m2.E2.I2.cos2 (2-8) ;e= (1-s).e1 ;e1 = 2t.f1/p;f1 = pn1/60 Thay biu thc ca s.. rotor khi rotor dng yn: u = . . . . . 22 2 1 dqk w f E t(2-9) Ta c:2 2 2 2cos . . . . .21 u =dqk W p m MKhi ng c lm vic tc thp, c th gim t thng m men khng i, ngha l gi cho t thng khng i. Khi ta c quy lut iu chnh khi gim tn s l: U1/ f =constCh :Khi iu chnh tn s rt nh (tc rt thp) in khng dy qun stator v rotor kh nh lm m men ti hn ca ng c b suy gim mnh, m men ng c t l nghch vi in p cng gim nh. duy tr kh nng ti ca ng c ngi ta tin hnh gim in p chm hn.Khi iu chnh f > fm: Do khng th tng in p ng c trn in p nh mc nn khi tng tn s trn tn s nh mc phi duy tr in p t vo stator bng in p nh mc.Khi tthngngc gim dnnmmen ngccngsuy gim.Hc tnh iu chnh nh bit. 2.S nguyn l h truyn ngBBT - C XC 3 pha: Gii thiu s :

Hnh 2- 17: S nguyn l ca h thng truyn ng BBT - CXC3pha.T7T9T11 T10T8 T12 L0 C0 D7D9D11 D10D8D12 L T1T3T5 T4T6T2 D1D3D5 D4D6D2 C1 C3 C5 C4C6 C2 C 3 pha Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT60S gm cc khu chc nng sau: -Khu chnh lu: chnh lu in p xoay chiu thnh in p mt chiu c th thay i c tr s nh thay i gc m ca cc Tiristor phi hp iu chnh tn s - in p vng tc thp. -Khu trung gian mt chiu gm cc cun cm L0 v t in C0 to nghch l ngun dng hoc nghch lu ngun p. Nu truyn ng cng sut nh s s dng ngun p, cn vi truyn ng cng sut ln s dng nghch lu ngun dng. -Khu nghch lu ph thuc gm cc Tiristor T1 - T6 c ni theo cc nhm ant chung v katt chung, cc it D1 - D12, cc t in C1 - C6 lm nhim v bin in p mt chiu thnh in p xoay chiu tn s thay i cung cp cho ng c . Cc i tvt intrns dng lm mchphng inchos...tcm cadyqunngckhicyngcrakhili,giminpngctlncc Tiristor v to iu kin kho, m dt khot cc Tiristor. Nguyn l iu chnh tn s: to ra in p xoay chiu 3 pha c tn s thay i ln lt cho cc Tiristor m theo mt quy lut nh sau: Mi Thyristor m trong mt khong thi gian ti a ng vi mt na chu k, cc Thyristormlchnhaumtkhongl1/6chuk.Nhvyctrong1/6chukc3 Thyristor cng m. Cng c th iu khin m mi van 1/3 chu k. Khi ti mi thi im ch c 2 van cng m, mt van thuc nhm a nt chung v mt van thuc nhm ka tt chung. Khi thay i thi gian m ca cc Thyristor, s thay i thi gian chu k ca in p xoay chiu to ra, ngha l thay i c tn s ca in p xoay chiu . Cc TiristorT1,T4 mtothnhdngphaA,T3, T6mthnhdng phaBv T5, T2 m thnh dng pha C. Sau y ta xt lut iu khin m cc van vi thi gian m l 1/2 chu k. Trong 1/6 chu k u tin T1, T6, T5 cng m, dng in mt chiu chy t cc dng ca in p chnh lu qua T1, T5v khpmch qua dy qun pha A, pha C, tr vccminpchnhluquaphaB.phnsuchuktiptheoT1,T2,T6m, dng in t cc dng ca ngun 1 chiu qua pha A, khp mch v cc m qua pha B v pha C. Suy lun tng t cho cc phn su chu tip trong mt chu k. th in p cc pha: Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT61 in p ging trn dy qun cc pha c xc nh nh sau: Gi thit dy qun ng c ni sao v tng tr dy qun cc pha nh nhau, ta c s thay th ca ng c phn su chu k u tin nh hnh v: T s thay th ta tnh c: ,32.dbUZ I u = =(2-11)

Suyluntngtchocckhong1/6chuktiptheotaxydngcth in p cc pha nh hnh v 2-12. Hnh 2- 18: Gin iu khin m van v th in p pha ca BBT khi iu khin m van mt na chu k.in p dy trn dy qun ng c: Uab = ua - ub, Ubc = ub - uc, Uca = uc - uac v bng cch tr th cc in p pha trn.Tr hiu dng in p cc pha c tnh: 3 2.22.d dc aU ZZZU ZI u u =+= = = Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT62

dd d dfU dUdUdUU .32. )3( . )32( . )3( 2 .213232322 2302=(((

} }+ +}=tttttu u ut (2-12) 2-5: IU KHIN THIT B BIN I2.5.1. Yu cu v chc nng ca mch pht xung iu khin: cc b chnh lu bn dn c iu khin c th lm vic c cn c mt h thng to ra cc dng xung a n cc iu khin ca van. H thng c gi l h thng phtxungiukhinmvan.Mimtvanbndncncmtknhphtxung.Cc knh pht xung phi lm vic ng b vi quy lut m cc van trong s mch lc.1. Yu cu: ccvanBBmtithiimmongmuncnphicmchinphtracc xungiukhinaticcTiristor.Xungiukhinphipngcccyucu nh:bin,tns,cngsut,rngcaxung(thigiantnticaxung)m chc chn cc van.2. Chc nng: iu kin m Thiristor: UA > 0 v c xung m. Sau khi Ti m th xung iu khin khng c tc dng na, dng in qua Ti do thng s ca mch ng lc quyt nh. Mch iu khin c cc chc nng sau:-iu chnh c v tr xung iu khin trong phm vi na chu k dng ca in p ant-To ra cc xung iu kin m c Ti, xung iu khin thng c bin t 2 10 V, rng xung tX = 20 -100s. 2.5.2. Cc phng php pht xung iu khin: 1. Pht xung iu khin theo nguyn tc pha ng: H thng ny to ra cc xung iu khin nh vic so snh gia in p ta hnh rng ca thay i theo chu k in p li v c thi im xut hin ph hp vi gc pha ca li vi in p iu khin mt chiu thay i c. H thng ny c u im ni bt nh:- rng xung m bo yu cu lm vic-Tng hp tn hiu d dngTrng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT63- dc sn trc ca xung m bo h s khuych i ph hp, lm vic tin cy, chnh xc cao vi nhy theo yu cu. -C th iu khin c h thng c cng sut ln. Khong iu chnh gc m o c th thay i c trong phm vi rng v t ph thuc vo s thay ica in p ngun. -Dtng ho, michuk cainpantcaTiristorchc mt xung c a n m nn gim tn tht trong mch iu khin. 2.Pht xung iu khin dng it 2 cc gc UJT: Phng php ny cng to ra cc xung nh vic so snh gia in p rng ca xut hin theo chu k ngun xoay chiu vi in p m ca UJT. Phng php ny n gin nhng phm vi iu chnh gc m o hp v ngng m ca UJT ph thuc vo in p ngunnui.Mtkhctrongmtchukinpli,mchthngaranhiuxung iu khingy nn tn tht ph trong mch iu khin.3. Pht xung iu khin theo pha ngang: Phngphpnycuimlmchphtxungnginnhngcmtsnhc imphmvi iuchnhgcmhp,nhycm visthayica inp ngunv kh tng hp tn hiu iu khin. 2.5.3. Mch iu khin theo pha ng: Hnh 2- 19: S khi khu pht xung theo nguyn tc pha ng Khi 1: Khi ng b ho v pht sng rng ca c nhim v ly tn hiu ng b ho v pht ra sng in p hnh rng ca a vo khi so snh. Khi 2:Khisosnhc nhimvsosnhgiatnhiu inpta hnhrngcavi in p iu khin pht ra xung in p a ti mch t xung. Khi3:Khito xungc nhimvtora ccxung iukhin aticc iukhin ca Tiristor. U1:in p li xoay chiu cung cp cho b chnh lu. urc: in p ta hnh rng ca ly t u ra cakhi BH - FXRCuk: in p iu khin mt chiudng iu khin gi tr gc m o Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT64 Nguyn l lm vic c bn ca mch pht xung theo nguyn tc pha ng: in p cp cho mch ng lc ca BB c a n mch ng b ho ca khi 1. Trn u ra ca mch ng b ho c in phnh sin cng tn s vi in p ngun cung cp v c gi l in p ng b.in p ng b c a vo mch pht xung rng ca to ra in p rng ca cng tn s vi in p cung cp. in p rng ca v in p iu khin (thay i c tr s) a vo mach so snh sao cho cc tnh ca chng ngc nhau. Ti thi im tr s ca 2 in p ny bng nhau th u ra ca mch so snh thay i trng thi xut hin xung in p. Nh vy xung in p c tn s xut hin bng vi tn s xung rng ca bng vi tn s ngun cung cp.Thay itrsngun iukhinslm thayithi im xut hinxungraca mch so snh. Xung ny c th a n cc iu khin ca Thyristor m van. Thc t th xung u ra ca mch so snh thng khng rng v bin m van, do ngi ta s dng mch khuych i v truyn xung. Nh m cc xung ra ca mch ny iu kin m chc chn cc Thyristor. Mi Thyristor cn c mt mch pht xung, do trong s c bao nhiu van cn c by nhiu mch pht xung. Vn l phi phi hp s lm vic ca cc mch pht xung ny ph hp vi quy lut m cc van mch ng lc.2.5.4.Cckhucbncamtmchphtxungiukhintheonguyntcpha ng: 1. Mch ng b ho v pht xung rng ca: toramththngccxungxuthinlpilplivichukbngchuk ngun xoay chiu cung cp cho s chnh lu v iu khin c thi im xut hin xungtrong michuk,taphis dngcc mch phtxung phtraccxung ng b vi in p xoay chiu ca mch chnh lu. Do nguyn tc lm vic ca mch pht xung iu khin pha ng l so snh in p iu khin vi in p ta hnh rng ca nn cn phi to ra in p dng rng ca c tn s bng vi tn s in p xoay chiu. to ra in p rng ca c yu cu nh trn cn c mch ng b ho v pht xung rng ca. Mch ng b ho: to ra in p ng b theo yu cu t ra, thng s dng 2 kiu mch n gin l mch phn p v mch dng bin p ng b. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT65 Mch phn p dng in tr hoc kt hp in tr, in dung, in cm nhm to ra inpxoaychiu hnh sincngtns,trnghoclch phavi inpcungcpcho mch chnh lu. Mch dng bin p ng b l mch dng mt bin p cng sut nh to ra in p ngb.Thcpcabinpcthcmt hocnhiucunthcp,mtpha,3pha hoc 6 pha... tu thuc vo s ca chnh lu..y l loi mch ng b thng c dng nhiu nht. Mch pht sng rng ca: C th dng cc loi mch pht sng rng ca nh sau -Mch dng it - in tr - t in (D-R-C) -Mch dng D-R-C v TransistorSau y ta xt mt vi s BH - FXRC n gin. S dng it v t in: na chu k dng ca in p ngun ung, cc it D1, D2 b kho. T in C c np nh ngun mt chiu u qua in tr R1. D D n ng g i i n n n n p p c c x x c c n nh h t th he eo o c c n ng g t th h c c: :C R eRUitC. ; .11= =tt t l hng s thi gian ca mch np. inprngcatngtrngtuyntnh cn tho mn iu kin: t >> T = 1 / f. Trong f l tn s ca in p ngun ung thi imu1urc = ung, t C bt u phng in theo mch vng C - W2 -R2 - D2 - C. Thi gian phng in ca t C ph thuc vo R2 v t C. n thi im u2, t C phng in ht. Khi ny in p ngun chuyn sang na chu k m, t C li b np in theo chiu ngc. loi b iu ny, cn la chn cc in tr R1, R2 theo iu kin:1 25RURUng>(2-14) th in p trn cho thy phm vi iu chnh b gii hn bi gc u1 < 1800 . iu ny hn ch gc iu khin ca van. Mt khc mch trn khng th to ra s tng trng tuyn tnh ca in p rng ca do dng np ca t khc hng s. Trong thc t mch to Hnh 2-20: Mch to xung rng ca dngD- R -C Hnh 2- 21: Gin in p khu to xung rng ca Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT66xung nh trn t dng hoc ch dng nhng mch n gin, pham vi iu chnh in p khng nhiu. S dng Transistor v t in:Trng hp cc b bin i i hi phm viiuchnhtcn1800in,ngita thng dng s nh hnh 2-19. S nyc u im va n gin,va tincy.na chukdngcainpung,Tr b kho do van D m.t C c np cc tnh nh hnh v. Na chu k tip theo, D kho Tr m, t C phng in qua Tr, thi gian phng ph thuc v in tr R3. 2.Mch so snh: Vic so snh in p rng ca v in p iu khin c th thc hin bng Transistor hoc vi mch in t. Vic ghp ni tn hiu c th ni tip hoc song song min l m bo tn hiu rng ca v tn hiu iu khin c tc dng ngc chiu nhau. Phng php so snh ni tip c u im l chnh xc cao nhng khi tn hiu rng ca c dng xoay chiu th vic so snh gp nhiu kh khn Vic so snh bng Transistor n gin nhng khng chnh xc v Transistor khng m khi: ,URC - Uk , s 0. Dng vi mch cho php xc nh gc o chnh xchn do cc vi mch ch s khuych irt ln vbo ho rt nhanh. S so snh dng Tr, cc ngun iu khin v rng ca mc ni tip trn mch B - E ca Tr. u ra l st p trn trn tip gip C - E ca Tr. Khi in p B - E dng, Tr m in p ra bng khng. Ch khi Tr kho u ra c in p. Hnh 2 -22: S nguyn l v th in p khu tao xung dng Transistor Hnh 2-23: S nguyn l khu so snh dng Transistor2t Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT67 3. Khu to xung: m bo ccyu cu v chnh xc ca thi im xut hin xung, s i xng ca cc xung cc knh khc nhau, ngi ta thng thit k cc khu so snh lm vic vi cng sut nh, do xung ra cha cc thng s yu cu ca in cc iu khin . c xung c cc thng s yu cu cn thit ta phi thc hin vic khuych i xung, thay i li di xung, trong mt s trng hp phi phn chia li xung v cui cng l truynxungturacamch phtxungncciukhincathyristor.Vvyta phi s dng mt s mch in thc hin cc cng vic nu. Cc mch in ny l: Mchsa xung, mchkhuychixung, mch phnchiaxung, mchtruynxungn thyristor. Ton b cc mch ny hp thnh mch to xung. Tu tng trng hp c th m c th c tt c cc mch nu hoc ch c mt hoc mt s mch no . Mch sa xung:Xutphttnguynlhotngca khu so snh ta thy: Khi thay i tr s in p iu khin Uk thay igc iu khinoth di ca cc xung ra ca khu so snh thay i. Nh vy s xut hin tnh trng mt s trng hp di xung qu ngn khng m cc Tiristor hoc di xung qu ln, gy tntht ln trong mch pht xung. Hnh 2-25 S nguyn l mch sa xung Hnh 2-24: Gin in p u ra ca khu so snh dng transistor.t 2t Uk URC Ura o Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT68 Mchsa xung nhm khc phc cc vn nu trn. Mch lm victheo nguyn tc khi c xung vo vi di khc nhau nhng mch vn cho xung ra c di bng nhau theo yu cu v gi nguyn thi im xut hin ca mi xung. S nguyn l ca mt mch sa xung nh hnh v. Trongs:Uvlinpvocamch,chnhlinpracakhusosnh (im E) c mc bo ho dng v m. Cc phn t R11 v C2 s quyt nh di ca xung ra. Nguyn l lm vic ca mch sa xung nh sau: -Khi in p vo Uv mc bo ho dng cngvi in tr nh thin R12, Tr6 m bo ho, t C2 c np vi cc tnh nh pha trn (qua C2 R11-Tr6). Tr6 m bo ho lm im F c mc lgc 0. Mc lgc ny tn ti trong sut qu trnh Uv bo ho dng.-KhiinpUvmcbohom,tC2phngin(quaD1...)tthmln mch pht gc ca Tr6 lm Tr6 kho dn n im F c mc lgc 1, ngha l u ra nhn c xung ra. Do in tr ngc ca Tr6 rt ln nn Ura ~ Ucc. Khi C2 phng ht in tch, n s c np theo chiu ngc li. Nh c R12 m th (+) li t ln mch pht gcca Tr6 lm u ra li c mc lgc 0. Mcd cn xung m u vo nhng nh c R12 mTr6 m bo ho. Thi gian tn ti xung c xc nh theo biu thc:(2-15) dicaxungchphthucvogatrcaR11 v C2 do cc xung ra lun c gi tr khng i. Thit b u ra(Mch truyn xung): Thng thng c 2 cch truyn xung t u ra h thng iu khin mchG- Kca Tiristorl truynxungtrctipvtruynxung qua my bin p xung. Truyn xung trc tip l bin php truyn xung n gin nht, dng dy dn inni t u ra ca mch pht xung n cc in cc iu khin v katt ca van. Bin php ny t c s dng v c mt s nhc im sau: tx = R11.C1.l n2 Hnh 2-22: Gin in p khu sa xung. Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT69-C s lin h trc tip v in gia mch ng lc v mch iu khin ca b chnh lu. -Khthchintruynxungngthinmtsthyristormcnitiphocsong song. -Khphihpttgiangunmtchiucungcpchomchkhuychixungvi bin xung cn thit trn thyristor. Truyn xung qua BAX c u im l:-m bo s cch ly tt v in gia mch ng lc v mch iu khin b chnh lu. -D dng thc hin vic truynng thi cc xung n cc Tiristor mc ni tip nhau hoc song song bng cch dng BAX nhiu cun th cp. -D dng phi hp gia in p ngun cung cp cho tng khuych i cng sut xung v bin xung cn thit trn cc iu khin ca Ti nh vic chn t s BAX hp l. -BAX v c bn kt cu ging nh bin p bnh thng cng sut nh. Hot ng ca BAX tng tbin p thng vi dng in khng sin hoc c th xc nh nh l phituynvsbngkhngkhimchtboho.BAXcoamchtrtchngbo ho, n ch hot ng trong thi gian ngn.Mchkhuychixung:khuychi cngsutcaxungiukhin,hinnayph bin nht l cc s khuych i bng Ti v Tr.Hnh 2-23 l s mch khuch i xungdng Transistor kh ph bin hin nay. TnhiuuvoUvcamchkhuych i xung s dng 2 Tr ghp ni tip (cn gi l ghp kiu Darlinhtn). Tr7 v Tr8mc ni tiptngngmtTransistochs khuychi dng in: | = |1.|2.(2-16) Chc nng ca cc phn t trong s : D2 l itc tc dng gimdngin qua cun dy s cp ca BAX khi cc Tran kho,ng thi hn ch qu in p trn Tr. D3bovcundythcpcaBAXnhiviD2camchscp.D4 ngn xung m c th ti cc iu khin ca Tiristor nh cc Transistor khc. Hnh 2-26: S nguyn l mch khuych i v truyn xung Trng H SPKT VinhKhoa in cng bi ging Trang b in 1 i hc CNKT70 Cc in tr hn ch xung p u vo v dng in cc gp ca Transistor. Nguyn l lm vic ca s : Tn hiu vo ca mch l l tn hiu ra ca mch gi xung l tn hiu lgc. Gi txv l thi gian tn ti ca mt xung in p votbh l thi gian tnh t lc c dng in mt chiu qua cun dy s cp ca BAX (khi Tr7 v Tr8 m bo ho) n lc li thp bo ho t. txr l thi gian tn ti ca xung ra. -Xt trng hp tbh > txv:Trongkhong thigiant= 0 t1, cha c xung vo,khngcdngquaBAXnnthcpcamy khng c tn hiu. Khit=t1,xuthinxungvo,Tr7,Tr8mbo honncunW1cdnginchyqua,lmcm ngsangphathcpxunginp,todngin qua D4 n mch G-K ca Thyristor. -Xt trng hp tbh > txv:-Trong khong thi giant= 0 t1, cha c xung vo,khng c dng qua BAX nn th cp ca my khng c tn hiu. -Khit = t1, xut hin xung vo, Tr7,Tr8 m bo ho nn cun W1 c dng in chy qua,lm cm ng sang pha th cp xung in p, to dng in qua D4 n mch G-K ca Ti. -Khi t = t2 ( lc ny mch t cha bo ho) mt xung vo. Tr7,8 ng dng in s cp gimvkhng quaD2.Bnthcpc s.. cmng(ngcchiuviban u dot cm)nhngnhD4 mxungmkhngtruyntiTi.Xung dngmkhp mchqua R17 v D3 thiu tn trn