Thiet Ke Bo Khoi Dong Mem

B CNG THNG

VIN NGHIN CU IN T, TIN HC, T NG HA &

BO CO KT QU THC HIN TI NCKH&PTCN CP B NM 2010

Tn ti: NGHIN CU THIT K CH TO B KHI NG MM CHO NG C KHNG NG B 3 PHA

C quan ch tr: Ch nhim ti:

VIN NGHIN CU IN T, TIN HC, T NG HA TH.S. MAI VN TU

H NI 2010

B CNG THNG

VIN NGHIN CU IN T, TIN HC, T NG HA &

BO CO KT QU THC HIN TI NCKH&PTCN CP B NM 2010

Tn ti: NGHIN CU THIT K CH TO B KHI NG MM CHO NG C KHNG NG B 3 PHA

C QUAN CH TR VIN TRNG

Nguyn Th Truyn

CH NHIM TI

Mai Vn Tu

Bo co ti Nghin cu, thit k, ch to b khi ng mm ng c khng ng b ba pha

- 1 -

MC LC

DANH MC CC HNH V ................................................................................................. - 2 -

MT S THUT NG NG VIT TT ............................................................................. - 4 -

CHNG I: M U............................................................................................................ - 1 -

1.1 Gii thiu chung. ....................................................................................................... - 1 - 1.2 Tnh hnh nghin cu v ng dng trong v ngoi nc. .......................................... - 1 - 1.3 Mc tiu v ni dung nghin cu ca ti. ............................................................. - 2 -

CHNG II: TNG QUAN V L THUYT. .................................................................... - 4 -

2.1 Cc vn khi s dng ng c khng ng b. ...................................................... - 4 - 2.1.1 Khi ng ng c khng ng b. .................................................................. - 4 - 2.1.2 Mt s phng php khi ng ng c khng ng b ba pha. ..................... - 5 - 2.1.3 Bi ton nng lng. ........................................................................................ - 14 -

2.2 iu p xoay chiu ba pha. ...................................................................................... - 18 - 2.2.1 Mt s mch thng dng. ................................................................................ - 18 - 2.2.2 iu p xoay chiu ba pha mch thun tr ...................................................... - 20 -

CHNG III: THIT K H THNG. ............................................................................... - 24 -

3.1 Chi tit cc tnh nng ............................................................................................... - 24 - 3.2 Thit k phn cng .................................................................................................. - 33 -

3.2.1 S khi ........................................................................................................ - 33 - 3.2.2 Thit k chi tit tng khi ................................................................................ - 36 - 3.2.2.1 Khi ng b theo in p. .............................................................................. - 36 - 3.2.2.2 Khi ng b theo dng in........................................................................... - 38 - 3.2.2.3 Khi Thyristor. ................................................................................................ - 39 - 3.2.2.4 Khi cch li. ..................................................................................................... - 40 - 3.2.2.5 Khi c chc nng bo v. .............................................................................. - 42 - 3.2.2.6 Khi giao tip v khi x l trung tm ............................................................. - 46 -

3.3 Thit k phn mm .................................................................................................. - 49 - 3.3.1 Cc cng c s dng ........................................................................................ - 49 - 3.3.2 C s thit k ................................................................................................... - 49 - 3.3.3 Lu trng thi phn mm. ........................................................................... - 52 -

CHNG IV: TH NGHIM ............................................................................................. - 55 -

5.1 Cc chc nng cn th. ............................................................................................ - 55 - 5.1.1 Mu HS2P-200 ................................................................................................ - 55 - 5.1.2 Mu HS3P-200 ................................................................................................ - 55 -


- 2 -

5.2 Phng php th ...................................................................................................... - 55 - 5.3 Chun b. .................................................................................................................. - 55 - 5.4 Thc hin v kt qu. ............................................................................................... - 56 -

5.4.1 Trong phng th nghim. ................................................................................. - 56 - 5.4.2 Th nghim thc t. ......................................................................................... - 60 -

PH LC .............................................................................................................................. - 70 -

5.1 Cc s u ni ca b khi ng mm ............................................................... - 70 - 5.2 Mt s lu khi vn hnh thit b ........................................................................... - 71 -

5.2.1 B HS2P-200 ................................................................................................... - 71 - 5.2.2 B HS3P-200 ................................................................................................... - 72 -

5.3 Gii thiu v thit b o dng v p hiu dng U/I RMS-HTC .............................. - 73 - 5.4 Tm hiu cc vn lin quan n b khi ng mm trung th. ........................... - 75 -

KT LUN V KIN NGH ............................................................................................... - 77 -

TI LIU THAM KHO. .................................................................................................... - 78 -

DANH MC CC HNH V Hnh 2.1: S khi ng trc tip. ......................................................................................... - 5 - Hnh 2.2: S khi ng i ni sao- tam gic. ..................................................................... - 6 - Hnh 2.3: c tnh dng theo thi gian ca phng php i ni Y/ ..................................... - 8 - Hnh 2.4: S khi ng nh cun khng. ............................................................................. - 8 - Hnh 2.5: S khi ng nh bin p t ngu. ..................................................................... - 10 - Hnh 2.6: M my bng cch mc in tr ph vo roto. ....................................................... - 11 - Hnh 2.7: S mch lc bin i xung p xoay chiu ba pha. ............................................. - 12 - Hnh 2.8: Cc ng c tnh vi cc phng php khi ng khc nhau. ............................ - 13 - Hnh 2.9: Mi quan h hiu sut ng c vi ti lm vic. ..................................................... - 15 - Hnh 2.10: Mi quan h h s cng sut ng c vi ti ........................................................ - 15 - Hnh 2.11: M hnh tiu th nng lng in ca ng c ..................................................... - 16 - Hnh 2.12: c tnh Moment theo trt vi cc ch lm vic. ..................................... - 17 - Hnh 2.13: M hnh tiu th in ca ng c ........................................................................ - 18 - Hnh 2.14: S u sao c trung tnh. .................................................................................. - 19 - Hnh 2.15: S u sao khng trung tnh ............................................................................. - 19 - Hnh 2.16: S u tam gic ................................................................................................ - 20 - Hnh 2.17: Dng pht xung iu khin .................................................................................... - 20 - Hnh 2.18: th in p trn ti khi 030a = ........................................................................ - 21 - Hnh 2.19: th in p trn ti khi 075a = ........................................................................ - 22 - Hnh 2.20: th in p trn ti khi 0120a = ...................................................................... - 22 - Hnh 2.21: c tnh in p hiu dng trn ti theo gc m ................................................ - 23 - Hnh 3.1: Qu trnh tng p trn ti khi khi ng .................................................................. - 24 - Hnh 3.2: Qu trnh gim p trn ti khi dng mm. ............................................................... - 25 -


- 3 -

Hnh 3.3: c tnh p v dng vi chc nng khi ng c kick ........................................... - 26 - Hnh 3.4: c tnh p v dng vi chc nng khi ng c gii hn dng ............................ - 27 - Hnh 3.5: c tnh in p hiu dng trn ti theo thi gian ................................................... - 28 - Hnh 3.6: Bn phm v chc nng ca tng phm ................................................................... - 29 - Hnh 3.7: Cu trc menu. ......................................................................................................... - 30 - Hnh 3.8: Chn ti khi ng. ................................................................................................. - 31 - Hnh 3.10: Ly li tham s mc nh ca h thng. ................................................................ - 33 - Hnh 3.11: S cu trc b iu khin khi ng mm HS2P-200. .................................... - 34 - Hnh 3.12: S cu trc b iu khin khi ng mm HS3P-200. .................................... - 35 - Hnh 3.13: To xung ng b dng IC khuch i thut ton. ................................................ - 37 - Hnh 3.14 : S nguyn l khi ng b dng coupler. ........................................................ - 37 - Hnh 3.15: Gin xung ng b theo in p. ...................................................................... - 38 - Hnh 3.16: S nguyn l khi bo khi ng xong ............................................................. - 38 - Hnh 3.17: Khi cch li. ........................................................................................................... - 41 - Hnh 3.18: Bng la chn R, C bo v van. ............................................................................ - 42 - Hnh 3.19: S nguyn l khi bo mt pha. ........................................................................ - 43 - Hnh 3.20: Gin xung ng b ca ba pha. ........................................................................ - 43 - Hnh 3.21: Bng chn l khi pha. ........................................................................................ - 44 - Hnh 3.22: Bng chn l khi mt pha A ................................................................................... - 44 - Hnh 3.23: Bng chn l khi mt pha B ................................................................................... - 44 - Hnh 3.25: S nguyn l mch bin i dng cch li. ......................................................... - 45 - Hnh 3.26: S chn v nguyn l hot ng ca Thermostats. ........................................... - 46 - Hnh 3.27: S mch nguyn l khi phn hi nhit. ........................................................... - 46 - Hnh 3.28: Khi giao tip. ....................................................................................................... - 47 - Hnh 3.29: S chn vi x l ATMega162. .......................................................................... - 48 - Hnh 3.30: Khi x l trung tm. ............................................................................................. - 49 - Hnh 3.31: Qui lut bin i in p t vo ng c theo thi gian. ..................................... - 50 - Hnh 3.32: Mi quan h gia U v . ...................................................................................... - 51 - Hnh 3.33: Lu trng thi chng trnh ca b HS2P-200 ................................................ - 52 - Hnh 3.34: Lu trng thi chng trnh b HS3P-200 ....................................................... - 53 - Hnh 4.1: S u ni th nghim. ....................................................................................... - 56 - Hnh 4.2: th in p v dng vi b HS2P-200 ................................................................ - 58 - Hnh 4.3: th in p v dng vi b i chng SM44 IP20 ............................................. - 58 - Hnh 4.4: th p v dng vi b HS3P-200. ....................................................................... - 59 - Hnh 4.5: th p v dng vi b i chng XFE132 ca FairFord. ................................... - 60 - Hnh 4.6: ng c 45kW vi ti l qut ht cho trm trn Asphalt ....................................... - 61 - Hnh 4.7: B sn phm ca ti v my o M/I RMS HTC. ............................................. - 62 - Hnh 4.8: My tnh phc v vic lu tr v th ha............................................................ - 63 - Hnh 4.9 : th p v dng khi khi ng dng i ni sao tam gic. ................................. - 64 - Hnh 4.10: th p v dng vi b HS2P-200 ch Standard. .......................................... - 65 - Hnh 4.11 : th p v dng vi b HS2P-200 ch High inertia Fan. ............................. - 66 - Hnh 4.12 : Chc nng khi ng c kick. .............................................................................. - 67 - Hnh 4.13 : in p v dng trn ng c vi b HS3P-200. ................................................. - 68 - Hnh 4.14 : Qu trnh khi ng c kick ca b HS3P-200. ................................................... - 69 - Hnh 5.1: S u ni vi b HS2P-200 .............................................................................. - 70 - Hnh 5.2: S u ni vi b HS3P-200 .............................................................................. - 71 -


- 4 -

Hnh 5.3: Bng cc loi li ca b HS3P-200 ......................................................................... - 73 - Hnh 5.4: S khi thit b U/I RMS-HTC. ......................................................................... - 73 - Hnh 5.5: Giao din ca phn mm trn my tnh. .................................................................. - 74 - Hnh 5.6: Giao din ca phn mm trn my tnh. .................................................................. - 74 - Hnh 5.7: S khi b khi ng trung th. ......................................................................... - 75 - Hnh 5.8 Ghp ni cc Thyristor. ............................................................................................ - 76 -

MT S THUT NG NG VIT TT 1. LCD: Liquid Crystal Display 2. EEPROM: Electrically Erasable Programmable Read-Only Memory 3. ALU: Arithmetic Logic Unit 4. RICS: Reduced Instruction Set Computer. 5. CISC: Complex Instruction Set Computer 6. CPU: Center Processing Unit 7. PWM: Pulse Width Modulation 8. ADC: Analog Digital Converter 9. SPI: Serial Peripheral Interface 10. IIC: Inter Intergrated Circuit 11. D.O.L: Direct on line 12. IM: Inductor motor


- 1 -

CHNG I: M U

Ni dung chnh:

v Gii thiu chung

v Tnh hnh nghin cu v ng dng trong v ngoi nc

v Mc tiu v ni dung nghin cu ca ti

1.1 Gii thiu chung. ng c khng ng b c s dng rng ri trong nn cng nghip quc dn.

u im ni bt ca ng c ny l : Cu trc n gin, lm vic chc chn, tin cy, gi thnh h c bit l n c kh nng dng trc tip li in m khng cn qua cc b bin i. Tuy nhin n c nhc im l khng ch cc qu trnh qu , c bit l khi khi ng cng nh iu khin tc gp nhiu kh khn.

Ngy nay cc b iu khin ng c khng ng b c mt rng khp trn th trng trong v ngoi nc. Tuy nhin cu to bn trong cng nh cc qui lut iu khin vn l mt b mt ca cc hng sn xut. V vy ti tp trung nghin cu b khi ng mm vi mong mun c th ch to ra sn phm c th thay th hng nhp ngoi vi gi c r hn.

1.2 Tnh hnh nghin cu v ng dng trong v ngoi nc. Ngoi nc

Do kh nng ng dng ngy cng rng ri ca ng c khng ng b ba pha nn vic ch to ra cc b khi ng mm cho cc ng c ny cng pht trin theo. Hin nay c rt nhiu hng sn xut ch to ra cc b khi ng mm cho ng c khng ng b, ch yu di dng s s dng k thut vi x l. Ty theo cng sut ng c, yu cu v tnh nng cng nh gi c m cc hng a ra cc sn phm vi rt nhiu chng loi khc nhau cho khch hng chn la. C th k tn mt s hng ni ting nh: Fairford, Abb, Siemens, Danfoss

Trong nc

Nc ta ang trong thi k cng nghip ho hin i ho, cc nghnh cng nghip ang c ch trng v pht trin. Trong cc nh my, x nghip vi cc my t ng , dy chuyn sn xut, c cu nng h v vth khng th thiu ng c, c bit l ng c khng ng b. V th nhu cu s dng cc b khi ng mm cho cc ng c ny cng tng theo. Tuy nhin cc b khi ng mm cho cc ng c ny thng l


- 2 -

di dng mch tng t c thit b cng knh, kh nng t ng ha km. Mt s x nghip nhp cc b khi ng mm s ca cc nc khc v nhng vi gi thnh cao.

Cng tc nghin cu: Trong vi nm gn y, cng c mt s nghin cu v vn ny, tuy nhin tt c ch dng li mc l thuyt, mt s bi bo c cp vn ny nhng cng ch mang tnh tho lun v cha c tnh qui m.

1.3 Mc tiu v ni dung nghin cu ca ti. Trong tnh hnh nh vy, ti t ra mc tiu tm hiu v thit k 02 mu khi

ng mm cho ng c khng ng b 3 pha.

Thng s k thut Mu KM n gin (cc tham s t bng nm vn)

Thng s Gi tr

- in vo 3 phase max VAC 230 - Dng ti max AAC 200

- Di iu chnh in p nn, %Un 30-50

- Thi gian Start Sec 1.5-30 - Thi gian Stop Sec 0-30 - Tn sut khi ng vi 500% dng nh mc ln/h 5

Mu KM thng minh (c mn LCD)

- in vo 3 phase max VAC 230

- Dng ti max AAC 200 - Di iu chnh in p nn, %Un 30-50 - Thi gian Start Sec 1.5-30

- Thi gian Stop Sec 0-30

- Tn sut khi ng vi 500% dng nh mc ln/h 5 - Bo v mt pha, qu p, qu dng...

- Gii hn dng in khi ng AAC tng gim c

- Gii hn dng in hot ng AAC iu chnh c

- Tit kim in nng iu chinh in p khi lm vic

Yu cu v tnh nng.

v i vi b n gin (HS2P-200):


- 3 -

C kh nng khi ng mm v dng mm.

Bo li, t ng x l li trong qu trnh hot ng nh: Mt pha, qu dng khi ng, qu nhit, hng Thyristor.

C th chn la chng trnh ng dng cho tng loi ti nh: My bm, qut gi, my nn, my nghin, bng ti

v i vi b thng minh (HS3P-200):

C kh nng khi ng mm v dng mm.

Bo li, t ng x l li trong qu trnh hot ng nh: Mt pha, qu dng khi ng, qu nhit, hng Thyristor.

Giao din ci t n gin vi cc phm bm v mn hnh LCD 16x2 dng gip ngi vn hnh c th d dng ci t cc thay i nh:

o C th khi ng hoc dng nhanh bng cc tham s mc nh. o Thi gian khi ng v dng c th thay i ty theo loi ti. o Di iu chnh in p khi ng hoc dng c th thay i c t

10%-60% in p li a ra in p ph hp vi momen khi ng.

o C ch khi ng kickstart. o C th thay i gii hn dng khi ng . o C th chn la chng trnh ng dng cho tng loi ti nh: My bm,

qut gi, my nn, my nghin, bng ti

o C th chn la ch chy ca ng c sau khi khi ng . Ni dung nghin cu ca ti

t c cc mc tiu trn, ti cn tin hnh cc ni dung sau:

v Kho st mt s b khi ng mm s ca mt s hng, la chn cc phng php thit k cho ph hp.

v Tm hiu cc vn l thuyt khi ng mm.

v Thit k xy dng s nguyn l

v Thit k ch to mch in, lp rp linh kin, hiu chnh phn cng

v Xy dng phn mm nhng cho vi x l.

v Th nghim kt qu trong phng th nghim vi ng c cng sut nh.


- 4 -

CHNG II: TNG QUAN V L THUYT.

Ni dung chnh:

Cc vn khi s dng ng c khng ng b.

o Khi ng ng c khng ng b. o Mt s phng php khi ng ng c khng ng b. o Bi ton nng lng.

iu p xoay chiu ba pha.

2.1 Cc vn khi s dng ng c khng ng b. 2.1.1 Khi ng ng c khng ng b.

Bin i nng lng, t in nng thnh c nng lm quay rotor l c im c bn nht ca hu ht cc loi ng c in. Tuy nhin vic iu khin dng nng lng ny, c bit trong qu trnh khi ng ng c l mt qu trnh phc tp. Cc mch iu khin dng contactor cho php ng hoc ngt trc tip ng c vi ngun cp l phng php n gin nht. Thm ch ngy nay, sau hn 100 nm t khi pht minh ra ng c khng ng b, th h thng iu khin ng c da trn contactor vn cn c s dng rng ri. Tuy nhin, vic iu khin ny gy ra nhiu tc hi khng mong mun. Nh bit, moment khi ng ca ng c t l vi bnh phng dng in:

2

motorM I Dng khi ng li t l vi in p cp cho ng c

2

motorM U Moment khi ng s rt ln nu ng c c ng trc tip vo li in,

gy ra cc tc hi c v c kh ln in nng. - Tc hi v in nng: Gy st p li in. Dng khi ng ln, nu duy tr

trong thi gian di gy nng v hi ng c. - Tc hi v c kh: Moment khi ng ln gy ra hin tng git c kh ->

nhanh d (khp ni...), dn (cu roa, bng ti) lm cc b phn truyn ng nhanh hng, gim tui th ca thit b.

gim thiu nhng tc hi trn th cn phi gim dng khi ng ca ng c. iu l gii v sao vn khi ng ng c khng ng b ni chung v c bit l ng c cng sut ln l vn cn c quan tm nhiu.


- 5 -

2.1.2 Mt s phng php khi ng ng c khng ng b ba pha. Tu theo tnh cht ca ti v tnh hnh ca li in m yu cu v khi ng i

vi ng c in cng khc nhau. Ni chung khi khi ng ng c cn xt n yu cu c bn sau:

Phi c Momen m my ln thch ng vi c tnh c ca ti.

Dng in m my cng nh cng tt.

Phng php m my v thit b cn dng n gin, r tin, chc chn.

Tn hao cng sut qu trnh m my cng thp cng tt.

Di y l mt s phng php c bn khi ng c khng ng b ba pha.

Da trn mi quan h 2

motorM U nn hu ht cc phng php khi ng ng c bng cch gim in p t vo ng c trong qu trnh khi ng qua dng khi ng cng gim.

2.1.2.1 Khi ng trc tip. y l phng php n gin nht khi ng ng c. Nng lng in c

cp trc tip cho ng c thng qua vic ng contactor K.

Hnh 2.1: S khi ng trc tip.


- 6 -

Phng php iu khin ny c u im l n gin, gi thnh thp. Tuy nhin phng php ny gy ra dng khi ng rt ln gy ra cc tc hi khng mong mun nh c cp trong mc 2.1.1. Phng php ny thng ng dng cho nhng ng c cng sut nh( thng khng qu 22kW) hoc ng dng cho nhng ni c cng sut ngun cp ln.

2.1.2.2 i ni sao tam gic. Da trn mi quan h moment t l vi bnh phng in p, nn vic khi ng

ng c thng qua vic gim in p khi ng c ng dng trong thc t. Phng php n gin nht l khi ng ng c bng i ni sao tam gic.

Hnh 2.2: S khi ng i ni sao- tam gic.


- 7 -

Phng php ny thch ng vi nhng ng c khi lm vic bnh thng u tam gic. Bng vic s dng ba contactor v mt relay thi gian, b i ni sao-tam gic s lm thay i s u ni ca ng c. Lc khi ng, K3 ng, K2 ct nn ng c chy ch ti hnh sao(= 58% in p nh mc khi chy ch hnh sao). Khi ng c t khong 80% tc , b i ni s chuyn trng thi lm vic ca ng c t sao sang tam gic nh relay thi gian thng qua vic ng K3 v ct K2.

Khi ti l hnh sao th in p t ln ti l:

* 3dY FU U=

V dng in qua ti:

Y FI I=

Khi u tam gic:

LU UD =

3 FI ID =

Nh vy:

3YII D=

3dYU UD=

Do momen t l vi bnh phng in p nn:

3MTT

YMM =

Nhn xt: Dng khi ng gim 3 , momen khi ng gim 3 ln so vi khi ng trc tip. Mc d phng php ny c ci tin hn so vi vic khi ng trc tip, tuy nhin n vn khng gii quyt trit nhc im ca vic khi ng trc tip. Mt khc khi chuyn t sao sang tam gic s tn ti thi im ng c khng c kt ni vi ngun cp, nhng dng in qua rotor vn tn ti gy ra t trng ct cc cun dy stator. Theo nguyn l cm ng in t, s c in p trn cun dy stator m tn s ph thuc vo tc quay ca rotor. Nu lc qun tnh ca ti nh nh ti bm hoc lc masat ln s lm gim ng k tc ca ng c trong thi gian khng kt ni ny. Khi ng c c kt ni li vi ngun cp ch ti tam gic, s c lch pha ln ngun cp vi dng qua rotor l nguyn nhn khin dng qua ng c tng vt.


- 8 -

Hnh 2.3: c tnh dng theo thi gian ca phng php i ni Y/

Tuy ch tn ti trong thi gian ngn nhng hin tng trn vn gy ra nhng h hng nht nh.

2.1.2.3 Dng cun khng khi ng.

Hnh 2.4: S khi ng nh cun khng.

Mt mt khong thi gian di ngi ta mi nhn ra c nhng nhc im ca phng php khi ng i ni sao tam gic nh cp. Sau ngi ta mi pht minh ra phng php iu khin m hn l dng cun khng khi ng.


- 9 -

Khi khi ng, K2 ct. Lc ny, trong mch in stato c t ni tip mt cun khng. Sau mt thi gian, ta hon tt vic khi ng bng cch ng K2 th in khng trn s b ngt khi mch. C th iu chnh tr s in khng c c dng in m my cn thit. Cng c th mc thm nhiu cun khng qu trnh khi ng m hn. Do c st p trn in khng nn in p t vo ng c UDC s gim i v nh hn in p li UL.

Gi s:

( 1)LDC CKCK

UU KK

= >

KCK h s st p.

Gi dng in m my v mmen m my trc tip l IMTT v MMTT. Sau khi thm in khng vo, dng in m my cn li IMCK:

*DC L MTT

MCKDC CK DC CK

U U IIZ K Z K

= = =

V mmen m my t l vi bnh phng ca in p nn Mmen khi ng khi c in khng s l :

2CK

MTTMCK

MMK

=

Dng khi ng gim i KCK ln, momen khi ng gim 2CKK ln so vi phng

php khi ng trc tip.

2.1.2.4 Dng my bin p t ngu. Trong hnh 2.5, T l bin p t ngu c cao p ni vi li in, h p ni vi

ng c. Khi khi ng ta ng D3 v m D2. Sau khi khi ng ng c xong ta ct my bin p ra bng cch ng D2 v m D3.

Vi my bin p ta c:

1

2BA

U kU

=


- 10 -

Hnh 2.5: S khi ng nh bin p t ngu.

Mt khc da vo s ta thy:

1 2 1 2; ; ;L DC L DCU U U U I I I I= = = =

Nn ta c:

LDC

BA

UUk

=

*DC L L

DCDC BA DC BA

U U IIZ k Z k

= = =

2MTT

MBABA

MMk

=

Dng khi ng gim i kBA ln, momen khi ng gim 2BAk ln so vi khi

ng trc tip.

2.1.2.5 Mc in tr ph vo roto.


- 11 -

Hnh 2.6: M my bng cch mc in tr ph vo roto.

Phng php ny ch dng cho ng c dy qun v c im ca ng c ny l c th thm in tr vo cun dy roto. Khi in tr roto thay i th M=f(s) cng thay i. iu chnh in tr mch roto thch hp ta s c c trng thi m my l tng.

Khi c in tr ph Rf th:

' ' 2 ' 21 2 1 2( ) ( )

MRf

f

UIR R R X X

=+ + + +

(1-7)

2 '2

' ' 2 ' 21 1 2 1 2

3* * *( )

2 ( ) ( )f

MRf

f

p U R RM

f R R R X Xp

+=

+ + + + (1-8)

Nh vy khi c in tr ph th ImRf gim v MmRf s ln.

Sau khi my quay gi mt momen in t nht nh trong qu trnh m my th ta cn ct dn in tr ph. Khi ct dn cc in tr ph s lm thay i tc ng c. Sau khi ct ht cc in tr ph th tc ng c t n im lm vic sau 3 cp in tr khi ng.


- 12 -

Nh vy ng c khng ng b 3 pha dy qun c th t c tc m my cao, dng khi ng nh nn c ng dng nhng ni c yu cu m my kh khn, yu cu m my cao. Tuy nhin nhc im ca ng c dy qun l gi thnh cao, cu to phc to, kh bo qun

2.1.2.6 Dng thyristor.

IM

L3L2L1

Hnh 2.7: S mch lc bin i xung p xoay chiu ba pha.

Ngun in qua b bin i c a n cp cho ng c. B bin i gm su Thyristor mc song song ngc. Nh b bin i ny ta h thp c in p trc khi a n khi ng ng c sau tng dn in p n gi tr nh mc ca ng c (v th ngi ta gi l b bin i xung p xoay chiu). Dng in t l vi in p nn khi gim in p cp cho ng c th dng in khi ng cng gim theo.

C th so snh c tnh khi ng bng Thyristor vi cc phng php khi ng khc thng qua cc c tnh khi ng:


- 13 -

Hnh 2.8: Cc ng c tnh vi cc phng php khi ng khc nhau.


- 14 -

Phng php khi ng dng Thyristor khc phc c nhc im ca cc phng php khc. Khng nhng gim c dng khi khi ng, thm vo qu trnh khi ng m, khng pht sinh tia la in, c th khi ng c cng sut t nh n ln, linh hot trong iu khin, vn hnh n gin, an ton, tin cy cao. Mt khc mt s loi ti yu cu phi dng mm ng c, tc l gim dn dng ct vo ng c nh thang my, my bm... Nu dng cc phng php truyn thng th kh c th tch hp chc nng ny vo trong khi vic iu khin in p ra ca Thyristor kh linh hot nn hon ton c th gii quyt c yu cu ny.

T cc nhn xt trn ta thy khi ng bng Thyristor l u vit nht. Mt trong nhng khu quan trng trong vic thit k b b khi ng theo phng php ny l thit k mch iu khin b bin i. Vi nm v trc ngi ta vn dng mch iu khin bng in t tng t. Mch ny tuy c nhiu u im nhng c nhng nhc im l cng knh, kh ci tin, kh t ng ha, su van c iu khin bi su knh ring bit nn khi mt knh no hng th ton b mch cng hng nn gy ra vn v tin cy.

Trong vi nm li y, cng ngh s v cng ngh bn dn pht trin mnh. c bit l s ra i ca cc dng vi x l vi tc tnh ton rt nhanh cho php thc hin c nhiu cng vic trn mt chip duy nht nn cc b iu khin s cng ra i. Mch iu khin s khc phc c cc nhc im ca mch tng t nh n gin, gn nh, c bit l kh nng t ng ha cao, vi nhiu tnh nng iu khin, bo v phong ph cho cc di h th, trung th v cao th (ti hng chc KV) v vi gi thnh rt hp l.

2.1.3 Bi ton nng lng. 2.1.3.1 Gii thiu chung.

Phn ln cc ng c s dng trong cng nghip l nhng ng c khng ng b ba pha lm vic vi tc khng i. Chng tiu th phn ln cng sut in trong x nghip. V vy vn tit kim nng lng khi s dng nhng ng c ny tr ln quan trng.

Cng mt ng c nhng ty theo ti m hiu sut ng c cng khc nhau. Khi lm vic y ti hoc gn y ti th hiu sut ng c ba pha tng i cao t 85% - 95%. Tuy nhin hiu sut ng c gim mnh khi ti nh hn 50% (non ti). C th thy


- 15 -

r vn ny thng qua ng c tnh th hin mi quan h gia hiu sut ng c vi ti lm vic theo hnh 2.9.

Hnh 2.9: Mi quan h hiu sut ng c vi ti lm vic.

Trong thc t c t ng c lm vic y ti hoc phi lm vic vi ti bin thin. Vi nhng ng c lm vic ch non ti ny lun tn ti lng d dng t ha, gy tn hao cng sut v suy gim h s cng sut.

Hnh 2.10: Mi quan h h s cng sut ng c vi ti

d hnh dung ta xt mt ng c khng ng b ba pha 20kW lm vic vi 20% ti. Khi cng sut thc t u ra s l:

20 * 20% 4kW kW=


- 16 -

Theo ng c tnh hiu sut theo ti, hiu sut ca ng c khi lm vic 20% ti khong 54%. Khi cng sut cn cp cho ng c s l:

4 / 54% 7.4kW kW Nh vy c 4kW cng sut u ra, ng c cn ly 7.4kW li. C n

46% nng lng t ngun cp l v ngha. Cc thnh phn ny b suy hao v cc nguyn nhn nh pht nhit cun dy, do dng t ha, do masat

Hnh 2.11: M hnh tiu th nng lng in ca ng c

2.1.3.2 Nguyn tc tit kim in nng. Khi t mt in p vo dy qun stator th trong dy qun stator c dng in I1.

Dng in ny bao gm hai thnh phn l dng t ha I0 v dng qua rotor I2 to ra sc t ng lm quay rotor:

1 0 2I I I= + Khi ng c lm vic ch non ti, moment ti gim, dng qua rotor gim. Nu in p t ln stator khng i th dng qua stator hay nng lng cung cp cng khng i. Do khi dng qua rotor gim th ton b lng gim t rotor s bin thnh tn hao do dng t ha theo phng trnh trn. Chnh iu ny l nguyn nhn dn n hiu sut ng c b gim. gim thiu tn tht khi dng I2 suy gim, r rng t phng trnh trn ta c th gim I1 mt cch tng ng. Mt khc khi I1 li t l vi in


- 17 -

p t vo stator nn tng hiu sut ng c ta c th thay i in p t vo ng c ty theo ti lm vic ca ng c.

C th hnh dung nguyn l ca phng php ny thng qua ng c tnh th hin trn hnh 2.12.

s

moment

100%

80%

A

A B

Moment khi in p nh mc

Moment khi gim in p

Moment y ti khi in p nh mc

Moment khi non ti

snh mcsng b

Hnh 2.12: c tnh Moment theo trt vi cc ch lm vic.

Gi s khi ng c lm vic ch y ti v vi tc nh mc th im lm vic ca ng c l im A. Nu vn gi nguyn in p t vo ng c trong khi ti lm vic ca ng c gim tc ng c tng, im lm vic s chuyn sang im B c moment ca ng c gim. Mt khc moment t l vi bnh phng in p nn khi gim p th moment gim theo. Gim p n mt gi tr thch hp th im lm vic ca ng c s chuyn sang im A c tc bng vi tc ca ng c khi y ti. Gim p t vo ng c ng ngha vi vic cng sut cp cho ng c gim v theo


- 18 -

dng t ha gim, hiu sut ca ng c tng trong khi tc ng c c gi khng i. Vic gim p c thc hin sao cho dng t ha gim xung gi tr nh khi ng c chy ch khng ti.

Nh vy vic tit kim in nng thc cht l vic tng hiu sut ng c hay chnh l ci thin h s cng sut ca ng c khi ng c chy non ti. C th thy ch li ca vic lm ny thng qua hnh 2.13.

Hnh 2.13: M hnh tiu th in ca ng c

Vn dng ng c 20kW nh ni trong mc 2.1.3.1, cng sut trn trc ng c l 4kW, thay v cp cng sut u vo l 7.4kW, bng vic gim p u vo ng c sao cho dng t ha gim xung bng vi dng t ha ca ng c khi chy khng ti. Lc cng sut cn cp cho ng c s l 5.6kW v hiu sut ng c 71%, nng lng in tit kim c mi gi l 7.4 - 5.6 = 1.8kW.

2.2 iu p xoay chiu ba pha. 2.2.1 Mt s mch thng dng.

S u sao c trung tnh


- 19 -

Hnh 2.14: S u sao c trung tnh.

S u sao khng trung tnh

Hnh 2.15: S u sao khng trung tnh

S u tam gic


- 20 -

L3L2L1

Z1

Z2

Z3

Hnh 2.16: S u tam gic

2.2.2 iu p xoay chiu ba pha mch thun tr

Gi l gc m ca Thyristor tnh t thi im in p trn Thyristor i qua im khng. Vic pht xung iu khin cho cc Thyristor c th m t theo hnh 2.17.

Hnh 2.17: Dng pht xung iu khin

Khi mch hot ng, cc van s c pht xung m cch nhau u n 600 m bo trong mt chu k li in( 3600) qu trnh s lp li. Th t m ca cc van


- 21 -

ph thuc vo th t pha ca in p ng b. Lc ti mi thi im s c ba kh nng xy ra:

Mi pha c mt van dn, tng ng ti c mc y ba pha vo li do in p pha trn ti bng in p ngun.

C hai van dn hai pha. Nh vy c mt pha ti b ngt v hai pha ti cn li chia nhau in p dy no c ni vo ngun.

Khng c van no dn tng ng l ti b ngt khi ngun.

n gin ta xt trng hp xung p xoay chiu ba pha ti thun tr. Cc giai on lm vic ca cc van bn dn c th phn thnh nh sau:

Khong dn ca van ng vi 00 60a :

Trong phm vi ny c giai on ba van cng dn, c giai on hai van cng dn ni tip nhau.

Hnh 2.18: th in p trn ti khi 030a =

Cng thc tnh ton:

1 5 3 3 3( 3 sin 2 os2 )2 2 4 4

mHD

UU cp a a ap

= - + +

Khong dn ca van ng vi 060 90a< :

Trong phm vi ny lun ch c hai van cng dn


- 22 -


in p hiu dng trn ti:

3 3 3( sin 2 os2 )4 3 4 4HD m

U U cp a ap

= + +

Khong dn ca van ng vi 0 090 150a< :

Trong phm vi ny c giai on hai van cng dn, c giai on khng van no dn.


in p hiu dng trn ti:


- 23 -

1 5 3 3 3( 3 sin 2 os2 )2 2 4 4

mHD

UU cp a a ap

= - + +

T cc cng thc trn bng cch dng phn mm Matlab ta xy dng c ng c tnh in p hiu dng trn ti theo gc m nh hnh 2.21.

0 0.5 1 1.5 2 2.5 30

0.2

0.4

0.6

0.8

1

1.2

1.4

Hnh 2.21: c tnh in p hiu dng trn ti theo gc m

i vi ng c, do c thnh phn L trong ti nn cc qu trnh ng m ca van phc tp hn. Cc trng thi trn ngoi ph thuc vo gc m cn ph thuc vo

gc ca ti. y arctan LR

wj = .Tuy nhin vn c ba vng lm vic c bn nh

sau:

a. 00 a j< , ti nhn y in p ngun.

b. ghj a a< , trong mt chu k s xen k cc giai on hai van hoc ba

van dn. Trong gha xc nh bi:

3tan2 1arctan ( )23gh

ep

ja j-

= - +

c. 0150gha a< < , vng ch c giai on hai van hoc khng van no dn.


- 24 -

CHNG III: THIT K H THNG.

Ni dung chnh:

Chi tit cc tnh nng

Thit k phn cng

Thit k phn mm

3.1 Chi tit cc tnh nng v Chc nng khi ng mm

ng nh tn gi, khi ng mm l tnh nng u tin v quan trng nht ca mt b khi ng mm. Thc cht ca khi ng mm l tng dn in p t vo ng c t gi tr ban u n gi tr nh mc.

Hnh 3.1: Qu trnh tng p trn ti khi khi ng


- 25 -

Thi gian khi ng cng nh in p ban u khi ng ph thuc vo loi ti chn hoc cng c th thay i.

Gi tr mc nh: Ustart = 20%, time start = 5s.

Di thay i: Ustart = 10%-60%, time start = 1-255s.

v Chc nng dng mm

Mt s loi ti c qun tnh ln, vic ct trc tip ngun cp khi ng c gy ra cc tc hi v c kh nh cc loi ti bm, bng ti tnh nng dng mm hn ch vn trn.

Stop time time

Uload

Umax

UStop

Hnh 3.2: Qu trnh gim p trn ti khi dng mm.

Cng nh khi ng mm, in p ban u v thi gian dng mm ca ng c cng ph thuc vo loi ti chn hoc cng c th thay i.

Gi tr mc nh: Ustop = 10%, time stop = 10s

Di thay i: Ustop = 10%-60%, time stop = 0-255s

v Khi ng kick

i vi cc loi ti c qun tnh ln hoc ti c tnh bm vi mi trng lm vic nh cc bng ti i hi moment khi ng ban u ln. Nu moment khi ng nh khng thng c moment kha lm ng c khng quay c dn n dng khi ng s tng vt. Chc nng khi ng c kick gii quyt vn trn. Ban u in


- 26 -

p t ln ng c ln nhm m bo moment khi ng ln. in p ny c duy tr trong mt khong thi gian sau s c gim xung gi tr in p khi ng v bt u qu trnh khi ng mm.

Irate

Ikick

Kick time

Ukick

Soft StarterD.O.L

Iload

time

time

Uload

Umax

UStart

Start Time

Hnh 3.3: c tnh p v dng vi chc nng khi ng c kick

Gi tr mc nh: Trng thi mc nh: Tt.

Ukick = 75%, time kick = 25 chu k li in.

Di thay i: Ukick = 60%-90%, time kick = 10- 40 chu k li in.


- 27 -

v Chc nng gii hn dng khi khi ng

Mt qu trnh khi ng trong mt thi gian di vi dng khi ng ln s dn n vn pht nhit nh hng n ng c. Chc nng gii hn dng khi ng nhm trnh tc hi ny. Nu chc nng ny c cho php th khi pht hin dng khi ng t ti gi tr dng gii hn, b khi ng mm s pht xung iu khin cc Thyristor sao cho in p trn ti c gi gi tr tng ng vi dng gii hn . Ht thi gian duy tr dng gii hn, qu trnh khi ng mm li c tip tc t gi tr in p tng ng vi dng gii hn.

Hnh 3.4: c tnh p v dng vi chc nng khi ng c gii hn dng


- 28 -

Vic chn dng gii hn cng nh thi gian duy tr dng gii hn phi do ngi s dng ci t.

v Chc nng tit kim in nng(Optimise).

Sau khi khi ng xong, nu c cho php th chc nng Optimise s c bt u sau khong thi gian tr Dwell. C th m t ton b qu trnh lm vic ca mt b khi ng mm thng qua ng c tnh theo hnh 3.5:

Hnh 3.5: c tnh in p hiu dng trn ti theo thi gian

v Cc chc nng bo v

Pht hin v t ng x l li vi cc trng hp nh mt pha, qu dng khi khi ng, qu nhit, hng Thyristor

v Giao tip bn phm, LCD

o Bn phm Bn phm c s dng trong giao tip vi ngi dng bao gm nm phm

vi cc chc nng khc nhau:


- 29 -

Enter

#

Startstop

Tr v mc menu trchoc hy b mt thay i

Cho php tng mt lp la chnhoc tng mt gi tr

Cho php gim mt lp la chnhoc gim mt gi tr

Chuyn n mc menu mihoc lu mt thay i

Bt u khi ng mmhoc bt u dng mm

Hnh 3.6: Bn phm v chc nng ca tng phm

o Cu trc menu


- 30 -

Hnh 3.7: Cu trc menu.


- 31 -

S dng menu:

Application Menu:

Menu ny cha danh sch cc ti ng dng phc v cho vic ci t cc tham s ca h thng. Chng hn chn Crusher lm ti khi ng th qu trnh chn c th c miu t nh sau:

Hnh 3.8: Chn ti khi ng.

Advanced Menu:

Menu Advanced vn gi cc tham s la chn trc , ch ci t thm cc tnh nng b sung. Cc la chn trong menu ny bao gm:

- Current: L mt menu con ca menu Advanced. Menu ny cha cc tham s ci t:

Rate Current: Ci t gi tr dng nh mc.

Current Limit: Ci t gii hn dng khi ng.

Current Limit Timeout: Thi gian cho php duy tr dng gii hn.

- Kick Start?: Bt hoc tt chc nng khi ng c kick. - Kick Pedestal: Ci t mc in p cho vic kick. C gi tr mc nh l

75%.

- Kick Time: Ci t thi gian cho vic kick tnh theo n v chu k li in. Gi tr mc nh l 25 chu k li in.


- 32 -

- Dwell Time: Ci t thi gian delay sau khi khi ng xong v trc khi chuyn sang ch Optimise.

Basic Menu

o Start Pedestal: Cho php thay i in p khi ng. o Start Time: Cho php thay i thi gian khi ng. o Stop Pedestal: Cho php thay i in p dng. o Stop Time: Cho php thay i thi gian dng. o Protection: Cho php truy nhp ti menu con Protection. Menu ny c

chc nng chn ch chy ca ng c sau qu trnh khi ng.

Full: Cho php chy full p khng bypass sau khi khi ng xong. Trong ch ny Thyristor c m hon ton.

Optimise: Cho php chy optimising sau khi khi ng xong. Ch ny c chn l mc nh.

Bypass: Cho php chy bypass sau khi khi ng xong.

ApplicationAdvanced

Start and ready1:

enter Full

enter

#

enter

#

Start PedestalStart Time

BasicMonitoring

ProtectionStart Pedestal

enter

#

FullOptimise

Hnh 3.9: Chn ch chy ca ng c sau khi khi ng

Monitoring Menu:

C chc nng hin th mt s thng s lm vic ca b iu khin cng nh ng c:

o Current: Hin th dng qua ng c. o Power: Hin th cng sut ng c


- 33 -

o Temperature: Nhit b tn nhit. o Voltage Supply: in p lm vic.

Parameter Menu

Ly li cc tham s mc nh ca h thng.

Hnh 3.10: Ly li tham s mc nh ca h thng. About: Mang thng tin v phin bn phn mm.

3.2 Thit k phn cng 3.2.1 S khi

thc hin c cc tnh nng nh ni th mt b khi ng mm bao gm cc khi sau:

v i vi b n gin hai pha (HS2P-200):


- 34 -

Hnh 3.11: S cu trc b iu khin khi ng mm HS2P-200.


- 35 -

v i vi b thng minh (HS3P-200):

ThyristorModule

L1 L2 L3

T1 T2 T3

ng b theo in p

Cch liKhuch i

xung

AVR

ngun nui

3x380V~/50Hz

t tham

s, hin th

thng bo

Nhn tn hiu ng b, kim tra mt

pha, hng Thyristor

Nhn tn hiu bo v qu

nhit, qu dng

To lut pht xung iu khin

LCD

LED

Bn phm

Phn hi dng

Phn hi nhit

220V~/50Hz

IM

ng b theo dng in

A B C

W U V

Hnh 3.12: S cu trc b iu khin khi ng mm HS3P-200.


- 36 -

v Chc nng ca tng khi

- Khi ng b: Cha thng tin v pha ca in p li t ln Thyristor.

- Khi iu khin: Vi iu khin s thc hin cc chc nng sau:

Nhn cc tham s nhp vo t bn phm, lu cc tham s ny vo EEPROM.

Hin th cc thng bo ln LCD. Nhn tn hiu ng b t khu ng b, tnh ton v a ra tn hiu

iu khin Thyristor.

X l cc s c xy ra bt ng. - Khi cch li v khuch i xung: Cch li gia mch cng sut v mch

iu khin, ng thi to ra cc tn hiu iu khin c bin , cng sut v rng m Thyristor.

- Khi giao tip: Nhn cc thng s ngi dng ci t, hin th cc thng bo ln LCD v n LED.

- Cc khi c chc nng bo v: Thng tin v in p, dng u ra, nhit hot ng ca Thyristor t l c s x l cc s c.

3.2.2 Thit k chi tit tng khi 3.2.2.1 Khi ng b theo in p. v Nhim v v yu cu thit k

Khu ng b l mt trong nhng khu quan trng quyt nh n tnh chnh xc thi im kch m Thyristor. N c chc nng to ra cc xung vung tn s 50Hz lch pha nhau 1200, ng pha vi in p pha ca li. V vy khi thit k khu ny phi m bo cc yu cu sau:

- Tn hiu sau khu ng b phi mang thng tin v pha ca in p li tc l to in p dng xung vung c pha ng pha vi in p li.

- Phi cch li in p li vi mch iu khin.

v La chn linh kin

thc hin c cc yu cu trn ta c th dng IC khuch i thut ton trong mch to xung ng b theo s mch trong hnh 3.13.


- 37 -

T1

Trans

31

84

2 1

U1ALM393D

1KR1

1KR2 1K

R3

100pF

C?Cap D?

Diode

dong bo

Hnh 3.13: To xung ng b dng IC khuch i thut ton.

in p sau my bin p h p s c a vo chn khng o ca IC so snh. in p ny s c so snh vi in p mc khng u vo o. Ta c:

- Khi 3 0U < : u ra ng b s mc cao.

- Khi 3 0U > : u ra ng b s mc thp.

Nh vy in p thu c sau IC comparator s c dng xung vung cng pha vi in p li. Mch ny c u im l thi gian p ng xung u ra so tn hiu u vo nhanh nhng c nhc im l cng knh do mi pha phi mc thm mt my bin p h p. Ngoi phng php dng IC khuch i thut ton, ngy nay ngi ta ch to ra cc optocoupler c th to c xung ng b vi kch thc gn hn nhiu. Mt trong nhng tiu ch chn la loi coupler ny chnh l thi gian p ng ca tn hiu ra so vi tn hiu vo v h s chuyn i dng. Mt s loi optocoupler c th k n bao gm: 1N168, 1N169, 4N35 Ring 1N169 c h s chuyn i dng rt cao, nh nht l 400% vi thi gian p ng sn xung ch 1us.

NC4

3

2

NC1

5

6

7

8

6N139

IC13

L1

180K

R59

C24

102

100R34

120kR33

21kR31

D14

1kR32

102C18

D24

0.1UC29

+5

+5

DB1

TT

Hnh 3.14 : S nguyn l khi ng b dng coupler.


- 38 -

Cc u vo khi ng b chnh l in p pha ca cc pha vi t l t chung ca c ba pha(u TT). Cc t C29.. c tc dng lc cc sng hi bc cao, cc diode D24... chng in p ngc t ln n LED ca optocoupler. u ra bao gm ba xung ng b DB1, DB2, DB3 s c a vo ba chn ca vi x l c th m t bng s :

Hnh 3.15: Gin xung ng b theo in p.

3.2.2.2 Khi ng b theo dng in. v Nhim v v yu cu thit k

Nu nh ng b theo in p cho bit thi im i qua im khng ca in p t trn cc Thyristor th ng b theo dng in cho bit thi gian dn hay khng dn dng ca cc Thyristor.

v Thit k mch nguyn l

NC4

3

2

NC1

5

6

7

8

6N139

IC10

2

D20-D23

T1

L1 51kR56

102C7

100R29

120kR28

21kR26

D13

1kR27

102C17

+5

+5

ALARM_1

Hnh 3.16: S nguyn l khi bo khi ng xong


- 39 -

Nguyn l hot ng:

Bnh thng khi Thyristor cha m, s c s chnh lch in p gia hai u T1 v L1 lm Led ca Coupler pht quang v u ra Alarm_1 s mc thp. Khi Thyristor bt u dn, trong thi gian dn ny, in p trn hai u T1 v L1 l bng nhau do u ra Alarm_1 s mc cao. Nh vy thng qua trng thi ca chn Alarm_1 m ta bit c trng thi dn dng ca cp Thyristor tng ng.

3.2.2.3 Khi Thyristor. Cc Thyristor c nhim v thay i in p cp cho ng c. Vic la chn Thyristor thng qua cc thng s m ti ng k. y ta c Ud = 380V, Ie = 200A, t ta tnh c cc yu cu c bn i vi vic chn van nh sau:

in p ngc ln nht t ln van:

. ax 6 * 6 *220 538,89ng mU U V= = =

in p ca Thyristor cn chn phi m bo sao cho lun ln hn gi tr Ung.max. Tuy nhin cng phi m bo mt d tr nht nh v in p, ngha l phi chn t nht bng 1,2 n 1,5 ln gi tr bin ln nht ca in p ngc Ung.max. V th in p chn Thyristor l:

. ax1,5* 1,5*538,89 808.34Th ng mU U V= = =

Dng in qua van: Ta c Ie(motor) = 200A. Nu ti mc hnh sao th dng qua van:

( ) ( ) 200e van e motorI I A= = Nu ti mc tam gic:

( )( )

200 1183 3

e motore van

I AI A= =

m bo d tr dng in th dng qua van cn chn l:

( ) ( )1,3* 1,3*200 260e van e motorI I A= = = Vi cc s liu trn m bo an ton cho van ta chn van SKKT273/16E ca

hng SEMIKRON vi cc thng s nh sau: in p ngc ln nht: Ung.max = 1600V. Dng in trung bnh qua van: Itb = 273A. in p iu khin: Udk=2V.


- 40 -

Dng iu khin: Idk=150mA. dU/dt = 500V/us. Di nhit lm vic: -400C n 1300C.

3.2.2.4 Khi cch li. v Nhim v v yu cu thit k:

Khi cch li chnh l cc b to xung iu khin c nhim v sau:

To ra cc xung c bin , cng sut v rng ln m Thyrisor.

Cch li gia mch cng sut v mch iu khin.

Ngoi ra cn c mch tr gip van c tc dng bo v Thyristor.

v La chn linh kin

i vi yu cu to ra cc xung c cng sut kch m Thyristor hay ni cch khc l khuch i xung do mt khi to xung quyt nh. Cc b to xung thng c cc dng sau:

B to xung n: c nhim v to ra cc xung n c di n nh.

B to xung c di ty v c trn vi mt xung c tn s cao to thnh xung chm.

B to xung c di xung khc nhau ty theo ch v s .

Trong cc b to xung trn th b to xung n l n gin nht, tin cy cao v thng c dng vi mch n gin. Vi hai b to xung sau cho php s dng to ra xung c di ty tuy nhin li lin quan n gi thnh v tn hao cng sut trn cc iu khin.

Ngoi chc nng khuch i xung nh ni, khi cch li cn c nhim v cch li gia mch ng lc v mch iu khin. thc hin vic ny ta c th dng bin p xung hoc cch li quang.


- 41 -

3, 4

T2

3, 4

T1

L1T1

VDR4

D41

D40

IC20

MOC3083

IC21

MOC3083

100mHL4

0.1uC32

100

R65

39

R68

100R51 1

2

6

4

1

2

6

4

3, 4

T2

3, 4

T1

L2T2

VDR3

D39

D38

IC15

MOC3083

IC16

MOC3083

100mHL3

0.1uC30

100

R61

39

R62

100R39 1

2

6

4

1

2

6

4

3, 4

T2

3, 4

T1L3

T3VDR2

D37

D36

IC11

MOC3083

IC12

MOC3083

100mHL2

0.1uC28

100

R57

39

R58

100R30 1

2

6

4

1

2

6

4

IN11

IN22IN33

IN44

IN55

IN66

IN77

OUT1 16

OUT3 14

OUT4 13

OUT5 12

OUT6 11

OUT7 10

OUT2 15

COM 9GND8

IC7

ULN2003A

12V

K2Relay-SPST

K1

Relay-SPST

10uC37

+5

+5

+5

+5

DK3

DK2

DK1

RELAY1

RELAY2

Hnh 3.17: Khi cch li.


Qua cc phn tch trn ta c thy c th thc hin ng thi nhim v khuch i v cch li bng optotriac theo s nguyn l nh sau:

IC ULN2003 c tc dng khuch i dng iu khin. Optotriac c tc dng cch li gia mch cng sut v mch iu khin. Bnh thng, u ra iu khin mc cao nn n LED ca opto tt. Khi c tn hiu iu khin, u ra iu khin mc thp, LED ca opto sng s kch m triac. n gin ta xt pha A. Khi triac c m, ty


- 42 -

theo trng thi u vo Line 1 m hay dng m dng s qua mt trong hai diode D5 hoc D7. Dng ny c a qua in tr R17 v cun cm L1 hn ch dng u vo cc iu khin. Khi Thyristor m, dng in c ni ngn mch qua Thyristor. Cc gi tr ca R17 v L1 c chn sao cho dng vo cc iu khin c cng sut m Thyristor v cng ko qu ln gy tn hao cng sut trn cc iu khin. Ngoi ra mch RL ni tip cn c tc dng gim bin thin dng in vo cc iu khin v to ra thi gian duy tr dng in vo cc iu khin( rng xung iu khin). Vi cng sut Thyristor chn, thng ngi ta chn 100 ; 100R L mH= W = .

Mch RC mc song song vi van c tc dng bo v van, gim tn tht do qu trnh ng ct trn v gim xung p trn van. T C c chn sao cho dao ng k sinh do qu trnh chuyn mch gy ra l tt dn. R c chn sao cho khi kha dng c th chuyn sang mch tr gip m in p trn van khng vt qu in p qui nh. Cng c th chn cc gi t R v C theo bng tra ca nh sn xut:

Hnh 3.18: Bng la chn R, C bo v van.

3.2.2.5 Khi c chc nng bo v. Khi bo v chng khi mt pha

v Nhim v v yu cu thit k

Khi ng c ang chy m nu mt mt pha no th dng in trong mch ca hai pha cn li s tng ln t ngt dn n hu qu l ng c b nng qu mc v c th b hng. V vy cn c bin php pht hin s c ny v c phng n x l kp thi.



- 43 -

Thng qua cc tn hiu ng b, trng thi cc pha c th bit c nh mt IC gii m vo 3 ra 8 l IC 74HC138 v mt mch so snh theo s nguyn l:

A1

B2

C3

OE2A4

OE2B5

OE16

Y7 7GND8Y6 9Y5 10Y4 11Y3 12Y2 13Y1 14Y0 15

VCC 16IC9

74HC138N

8

7

4

6

5IC4ALM358AM

9.1kR13

9.1kR14

9.1k

R4

DK_MATPHA

+5

+5

+5

+12

MATPHA

10k

R9

27k

R3

D4DB1DB2DB3

Hnh 3.19: S nguyn l khi bo mt pha.

Ba xung ng b ca ba pha c a vo ba chn u vo ca IC74138. Ty theo trng thi ca cc chn vo m chn u ra MAT_PHA c cc trng thi tng ng. u ra ny tip tc c a qua mt mch so snh vi sai trc khi c a vo chn ngt ngoi ca Vi x l. Nguyn l hot ng ca mch c trnh by c th nh sau:

Xut pht t gin xung ng b khi c ba pha:

U

time

time

time

time

DB1

DB2

DB3

Hnh 3.20: Gin xung ng b ca ba pha.

Ta c bng chn l ca 74HC138 khi ba pha: DONG_BO_A DONG_BO_B DONG_BO_C MAT_PHA


- 44 -

0 1 0 Y2 0 1 1 Y3 0 0 1 Y1 1 0 1 Y5 1 0 0 Y4 1 1 0 Y6

Hnh 3.21: Bng chn l khi pha. Khi c mt pha mt, gi s pha A ta c xung ng b pha A lc no cng tch cc

mc cao: Ta c bng chn l khi mt pha A:

DONG_BO_A DONG_BO_B DONG_BO_C MAT_PHA 1 1 0 Y6 1 1 1 Y7 1 0 1 Y5 1 0 0 Y4

Hnh 3.22: Bng chn l khi mt pha A Tng t khi mt pha B:


Hnh 3.23: Bng chn l khi mt pha B Khi mt pha C


Hnh 3.24: Bng chn l khi mt pha C

C th nhn thy khi mt pha u ra Y7 s tch cc. Thng qua trng thi chn Y7 c th bit c u vo pha hay mt pha.


- 45 -

Khi bo v qu dng

v Nhim v v yu cu thit k

Khi khi ng ng c dng khi ng c th tng ln gp nhiu ln so vi dng nh mc, hoc trong qu trnh hot ng, ng c b qu ti cng lm cho dng tng ln nhiu ln. Thng thng mi ng c c gii hn chu dng l khc nhau v khong thi gian chu qu dng cng khc nhau. Mch phn hi dng v c chc nng o cng dng lm vic ca ng c l c s cho cc cnh bo v x l khi c s c.


BR2

104

C5VDR

10R1

10

R2104

C4

9.1kR5

9.1kR6

84

12

3IC6BLM358AM D2

1kR10

D3R11

13k

18kR7

1uF

C6

CURRENT

VDC

Hnh 3.25: S nguyn l mch bin i dng cch li.

Dng in c a qua bin dng h thp dng in xung ng thi cch li gia mch iu khin vi li in. Dng sau khi c h thp s qua mt cu chnh lu v c bin i thnh p thng qua cc in tr R1 v R2. in p ny tip tc a qua mt mch khuch i o v detector nh trc khi a vo chn ADC.

Khi bo v qu nhit

v Nhim v v yu cu thit k: Vi mi loi Thyristor khc nhau th c mt gii hn nhit lm vic l khc

nhau. Nu nhit ln hn nhit cho php ca Thyristor c th s gy ra cc hin tng khng mong mun nh t dn hoc c th lm hng van. i vi loi Thyristor chn c gii hn nhit lm vic l 1250C nn cn c khi cnh bo cho vi x l bit khi nhit lm vic ca Thyristor vt qua ngng trn.

v La chn linh kin

Hin nay trn th trng ngi ta ch to ra cc loi sensor nhit lm vic vi mt ngng nhit nht nh. Nguyn tc lm vic ca cc sensor ny ta nh mt cng tc ng m theo nhit ( Thermostats). Bnh thng nu nhit thp hn ngng


- 46 -

bo v th hai chn u ra sensor s cch li vi nhau. Khi nhit vt ngng qui nh th hai u ra sensor s ni vi nhau:

Hnh 3.26: S chn v nguyn l hot ng ca Thermostats.

Cc sensor loi ny c u im ln l tch hp cao, mch gn nh nhng y l cc thit b t v him th trng Vit Nam. Hn na kh nng o c v cnh bo sm nhit khng tch hp c vi cc sensor ny.

Cc sensor nhit khc c th k n nh: LM35, LM335.... trong ng l LM35 c u ra in p tuyn tnh vi nhit C u vo. V y l mt sensor nhit kh ph bin v d mua.


i vi Thyristor chn, di nhit lm vic ti a cho php l -40 n 1300C. Tuy nhin khng th o c trc tip nhit ca Thyristor m ch c th o thng qua b mt b tn nhit t tnh ton ngc li nhit ca Thyristor.

8

3

2

4

1A (COMP)

A LM358N

1kR16

1kR15 5.6kR3

LM35THERMAL

Hnh 3.27: S mch nguyn l khi phn hi nhit.

Gi tr in p u ra LM35 s c a qua mch khuch i trc khi a vo chn ADC.

3.2.2.6 Khi giao tip v khi x l trung tm Khi giao tip

v Nhim v v yu cu thit k:


- 47 -

i vi mt b khi ng mm s, tn dng kh nng giao tip ca vi x l vi cc thit b ngoi vi ta c th dng cc cc phm bm la chn chc nng v mn hnh LCD, n LED lm giao tip gia ngi vi h thng nh: Nhp cc tham s h thng, hin th v thng bo cc li. Cc chc nng ca khi ny c trnh by c th trong phn chi tit cc tnh nng.

S nguyn l khi giao din:

LCD_E PXXPXXLCD_RW PXXPXXLCD_RS PXXPXXLCD_DB[7..0]

PXX,PXX,PXX,PXX,PXX,PXX,PXX,PXXPXX,PXX,PXX,PXX,PXX,PXX,PXX,PXX

LCD_LIGHT PXXPXX

2 x 16 Liquid Crystal Display

S1

S2

S3

S4

S5

MOVE

BACK

ENTER

START

STOP

ERWRSD4D5D6D7

Hnh 3.28: Khi giao tip.

Khi iu khin MCU

v Nhim v v yu cu thit k:

Nh ni trn, khi iu khin c cc chc nng c bn nh:

- Nhn cc tham s nhp vo t bn phm, lu cc tham s ny vo EEPROM.

- Hin th cc thng bo ln LCD. - Nhn tn hiu ng b t khi ng b, tnh ton gc m v a ra tn

hiu iu khin Thyristor. - X l cc s c v bo v.

v La chn linh kin

Tiu ch la chn: Phi p ng c cc yu cu thit k t ra. C cc cng c h tr pht trin. Thng dng, gi c phi chng.


- 48 -

Hin nay trn th trng c rt nhiu loi vi x l nh cc h 8031, 8051, ARM, AVR, PIC Vi cc yu cu v tnh nng cng nh v cc I/O vo ra c cp trong cc phn trn, ti chn vi iu khin ATMega162 ca Atmel lm khi x l trung tm. L sn phm ca Atmel nn c h tr Tool lp trnh v debug rt mnh v hon ton min ph l AVRStudio c th vit bng ngn ng Asembly hoc l C vi th vin lp trnh s. S chn vi x l ATMega162:

Hnh 3.29: S chn vi x l ATMega162.



- 49 -

PB0 (OC0/T0)1

PB1 (OC2/T1)2

PB2 (RXD1/AIN0)3

PB3 (TXD1/AIN1)4

PB4 (SS/OC3B)5

PB5 (MOSI)6

PB6 (MISO)7

PB7 (SCK)8

RESET9

PD0 (RXD0)10

PD1 (TXD0)11

PD2 (INT0/XCK1)12

PD3 (INT1/ICP3)13

PD4 (TOSC1/XCK0/OC3A)14

PD5 (OC1A/TOSC2)15

PD6 (WR)16

PD7 (RD)17

XTAL218

XTAL119

GND20

PC0 (A8/PCINT8) 21

PC1 (A9/PCINT9) 22

PC2 (A10/PCINT10) 23

PC3 (A11/PCINT11) 24

PC4 (A12/TCK/PCINT12) 25

PC5 (A13/TMS/PCINT13) 26

PC6 (A14/TDO/PCINT14) 27

PC7 (A15/TDI/PCINT15) 28

PE2 (OC1B) 29

PE1 (ALE) 30

PE0 (ICP1/INT2) 31

PA7 (AD7/PCINT7) 32PA6 (AD6/PCINT6) 33PA5 (AD5/PCINT5) 34PA4 (AD4/PCINT4) 35PA3 (AD3/PCINT3) 36PA2 (AD2/PCINT2) 37PA1 (AD1/PCINT1) 38PA0 (AD0/PCINT0) 39

VCC 40

IC0

ATmega162-16PC

LCD_RSLCD_RWLCD_E

LCD_D4LCD_D5LCD_D6LCD_D7

UPBACK

DOWNENTER

SS

VDC

+5

0.33u

C?

12

8MHzXTAL

22p

C?

22p

C?

1K

R?Res2

0.33u

C?

+5

FB1

DB3SW_T

DB1DB2DB4

FB2

MATPHADK1DK2DK3

DK_SS

RELAY1RELAY2

DK_MATPHAFB3

RST

RST

12345

678910

I3

+5

+5

10uH

L1

100n

C13

CS1

CH02

CH13

Vss4

VDD/VREF 8

CLK 7

DOUT 6

DIN 5

IC8

MCP3202

Hnh 3.30: Khi x l trung tm.

Vi cc nhim v ca khi x l nh ni trn th gn nh ta phi tn dng gn ht cc ti nguyn ca Vi x l. Vi 4 cng tng ng vi 32 chn cng vo ra a mc ch c th lp trnh c, cc chn cng c dng theo s trn hnh 3.30

3.3 Thit k phn mm 3.3.1 Cc cng c s dng

Tool lp trnh v debug: AVRStudio 4.2

Phn mm np cho vi iu khin: AVRISP-U

Phn mm m phng: Proteus 7.6 SP0

Phn mm thit k giao din: Visual Basic 6

Phn mm thit k lu : Visio Microsoft Office 2003

3.3.2 C s thit k Nh cp trong chng l thuyt,phng n khi ng ng c c chn l

dng mch bin i xung p. V bn cht y l phng php h in p t vo ng c. i vi khi ng mm, in p c tng dn mt cch tuyn tnh t gi tr t Ukd n gi tr in p lm vic ca ng c trong mt khong thi gian tkd. Ty theo loi ti m gi tr ca Ukd v tkd l khc nhau. Trong qu trnh dng mm th nguyn l hon


- 50 -

ton ngc li. in p t gi tr lm vic ca ng c c gim tuyn tnh trong mt khong thi gian tkd n gi tr Ustop. Cc gi tr ny c tra theo bng 3.6. Ta c qui lut bin i U theo t nh sau:

Hnh 3.31: Qui lut bin i in p t vo ng c theo thi gian.

Mt khc in p cp cho ng c li ph thuc vo gc iu khin . i vi b iu p xoay chiu ba pha, mi quan h gia in p u ra v gc m kh phc tp, ty vo tng khong gi tr ca . i vi ng c c cos=0.85 tc 032 j ta c cc

giai on ca gc nh sau:

v 032a < : in p u ra trn ti chnh bng in p ngun.

v 0 032 150a : s c nhng giai on hai van ca hai pha dn hoc ba van ca ba van dn.

v 0150a > : khng c van no dn.

Mt cch gn ng ta c s mi quan h gia U v nh cp chng l thuyt nh sau:


- 51 -

0 0.5 1 1.5 2 2.5 30

0.2

0.4

0.6

0.8

1

1.2

1.4

Hnh 3.32: Mi quan h gia U v .

Vi ngun in 50Hz, thi gian ca mt chu k li in l 1 2050

T ms= = .

Tng ng vi gc m l t 00 360 . Dng Timer c tn s 125KHz m tng ng 10ms l 1800 tng ng l 1250 ln m==> 10 cn m 1250/180 ln. Bng cch lp bng tra 100 gi tr ca Uload t 0100% ta c c gc m tng ng nm trong khong 0x45 n 0x49C( 10 and 150)

Nh vy vi mi loi ti nht nh ta c c in p v thi gian khi ng tng ng. T ta c c ng c tnh ca U theo t. Ti mi thi im ca t( tng ng l chu k li) ta tnh ra c U t tra bng ra gi tr ca .

Trong mi chu k li, cc van m ln lt cch nhau mt gc 600 tng ng cch nhau s ln m ca Timer 1 l:

125060* 417180

=

Thi im pht xung iu khin cho mi van( tng ng chnh l gc m ) c thc hin ch cn nh n Timer 1 vi chc nng Input Capture v Compare. Mi khi c tn hiu ng b( c sn xung xut hin trn chn ICP ca vi x l), gi tr thanh ghi ICR1A s c lu vo bin synch_time. Thi im m cho cc van c tnh nh sau:


- 52 -

_Txt synch time alpha shift= + +

Trong : - Alpha gc m c tra theo bng ni trn. - Shift l thi gian cn dch i c c gc m ca van k tip

trong cng mt chu k li in c tnh theo cng thc: *417shift n= trong n=16 l th t van theo s .

Gi tr tTx ny s c update cho thanh ghi OCR1A sau mi ln c mt van no m.

3.3.3 Lu trng thi phn mm. 3.3.3.1 Lu trng thi phn mm b HS2P-200

i vi b HS2P-200, chng trnh phn mm c chia thnh cc module c th hin trong hnh 3.33:

Hnh 3.33: Lu trng thi chng trnh ca b HS2P-200


- 53 -

Qu trnh khi ng mm c thc hin thng qua vic ngn mch S0-S1 v vic dng mm c thc hin thng qua h mch S0-S1.

Cc phc v ngt ch c cho php trong qu trnh khi ng mm, qu trnh ch dng mm v qu trnh dng mm. Cc phc v ngt bao gm:

- Ngt chuyn i ADC phc v vic o dng qua ng c. - Ngt bo qu nhit. - Cc ngt cp nht thi gian ng b phc v pht xung iu khin cc van

bn dn.

3.3.3.2 Lu trng thi phn mm b HS3P-200 Cc module phn mm c th hin trong hnh 3.34

Hnh 3.34: Lu trng thi chng trnh b HS3P-200


- 54 -

Qu trnh khi ng mm c thc hin thng qua phm bm START hoc thng qua vic ngn mch S0-S1. Qu trnh dng mm c thc hin thng qua phm bm STOP hoc h mch S0-S1. Trong cc trng thi ca chng trnh th vic giao tip vi bn phm v LCD vn c thc hin ci t cc thng s hoc phc v cho vic hin th. Cc ngt c cho php trong cc trng thi khi ng mm, ch dng mm v trng thi dng mm. Cc ngt ny bao gm:

- Ngt giao tip ISP vi b chuyn i ADC. - Cc ngt phc v vic cp nht thi gian ng b v pht xung iu khin cc

van bn dn.


- 55 -

CHNG IV: TH NGHIM

5.1 Cc chc nng cn th. 5.1.1 Mu HS2P-200

- Kim tra in p cng nh thi gian khi ng v dng. - Kim tra s thay i ca cc thng s U(t) v I(t). - Kim tra cc chc nng cnh bo.

5.1.2 Mu HS3P-200 - Chc nng thit lp cc tham s. - Kim tra in p cng nh thi gian khi ng v dng. - Kim tra s thay i ca cc thng s U(t) v I(t). - Kim tra cc chc nng cnh bo. - Kim tra chc nng tit kim in nng.

5.2 Phng php th - Th ti phng th nghim: S dng ng c ba pha cng sut nh. So snh

sn phm ca ti vi sn phm tng ng ca mt hng nc ngoi.

- Th ti hin trng: S dng ng c ba pha cng sut 30-40kW. - To cc tnh hung tht kim tra cc tnh nng cnh bo ca sn phm.

5.3 Chun b. - Thit b th: Chun b hai mu sn phm ca ti l mu HS2P-200 v

HS3P-200.

- Thit b th i chng: Vi mu n gin l Start Master SM44 IP20 v mu thng minh XFE132 ca FairFord.

- Cc ti liu hng dn s dng ca cc sn phm trn. - Thit b phc v th:

Hai my o Fluke 187 loi Real RMS: mt my o dng hiu dng, mt my o in p hiu dng.

Mt my o U/I RMS-HTC do trung tm cng ngh cao thit k v ch to (xem phn ph CHNG 5.3).

- Mt my tnh v phn mm kt ni vi b U/I RMS-HTC.


- 56 -

- Cc thit b trn c u ni theo s :

Hnh 4.1: S u ni th nghim.

5.4 Thc hin v kt qu. 5.4.1 Trong phng th nghim.

Cng mt s u ni, trn cng mt loi ti v cng mt b tham s nh nhau thc hin trn mu th v mu i chng kt qu nh sau:

5.4.1.1 Mu n gin HS2P-200: v Th chc nng cnh bo li:

Lu khi th vi chc nng ny: Sau mi ln th, cn phi ngt b HS2P-200 ra khi ngun cp ba pha trc khi u ni v th chc nng mi.

Mt pha pha ngun cp:

- Thc hin: Ngt mt pha bt k kt ni t b HS2P-200 vi pha ngun cp. Ngn mch S0-S1(thng qua cng tc Start-Stop) khi ng ng c.

- Kt qu: ng c khng c khi ng, n bo li sng. Mt pha pha ng c:


- 57 -

- Thc hin: Ngt mt pha bt k kt ni t b HS2P-200 vi ng c. Ngn mch S0-S1 khi ng ng c.

- Kt qu: ng c khng c khi ng, n bo li sng. Qu dng khi khi ng:

- Thc hin: Nh c cp trong mc Bo v qu dng mc 3.2.2.5 ca chng

3 v cc chc nng bo v. Cc in tr R1, R2 c chc nng to ra in p sau bin dng. Bng cch thay i gi tr ca R1 v R2 m ngng bo v qu dng cng thay i. i vi b HS2P-200, ng c th nghim c cng sut l 1.1kW, dng lm vic khong 1.7A, dng bin dng c t l

2000/1 nn u ra bin dng l 1.7 0.852000

mA . c th o v cnh bo

qu dng gp 2 ln dng nh mc (= 2*0.85 = 1.7mA) th in tr cn

chn l 5 3001.7

VmA

W . Chn R1 = R2 = 150 lp vo mch.

Kt ni li b HS2P-200 vi li ba pha, chn ti khi ng l Standard. Ngn mch S0-S1 khi ng ng c

- Kt qu: ng c ang khi ng th t ng chuyn sang dng mm v n bo li sng.

Qu nhit.

- Thc hin: Tho sensor tn nhit ra khi b tn nhit. Chun b mt thit b pht nhit (n si t chng hn). Cp in li ba pha cho b HS2P-200. Chn loi ti khi ng l Standard. Ngn mch S0-S1 khi ng ng c. Sau khi ng c khi ng xong, a u sensor nhit li gn bng n.

- Kt qu: ng c s t ng dng mm, n bo li sng. Chc nng khi ng v dng mm:

- Thc hin: Chc nng ny c thc hin trn c hai b l b HS2P-200 v b th mu SM44 IP20 vi vic chn cng mt loi ti khi ng l Standard c thi gian khi ng l 5s v thi gian dng l 10s, in p khi ng l 30%, in p dng l 10%.

- Kt qu:


- 58 -

Hnh 4.2: th in p v dng vi b HS2P-200

Hnh 4.3: th in p v dng vi b i chng SM44 IP20


- 59 -

5.4.1.2 Mu thng minh HS3P-200 v Chc nng thit lp cc tham s h thng.

o Thc hin: Vic la chn loi ti khi ng hoc vic thay i thi gian cng nh in p khi ng v dng c thc hin thng qua cc phm bm v c quan st trn LCD.

o Kt qu: t yu cu. v Chc nng cnh bo v x l li.

Cc chc nng ny c thc hin ging nh th nghim vi b HS2P-200. Kt qu ngoi vic th hin ging nh b HS2P-200 cn th hin thng bo trn mn hnh LCD vi cc m li c cp trong mc 5.2 ca chng 6.

v Chc nng khi ng v dng mm.

- Thc hin: Chc nng ny c thc hin trn c hai b l HS3P-200 vi b tng ng XFE 132 ca FairFord vi vic cng chn mt ch khi ng l Default vi cc tham s: thi gian khi ng l 10s, thi gian dng l 10s, in p khi ng l 10%, in p dng l 10%.

- Kt qu:

Hnh 4.4: th p v dng vi b HS3P-200.


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Hnh 4.5: th p v dng vi b i chng XFE132 ca FairFord.

5.4.2 Th nghim thc t. v a im th nghim: Nh my c kh cng trnh 199 Minh Khai Hai B

Trng H ni.

v Thit b cn th nghim: Hai b sn phm ca ti bao gm b n gin HS2P-200 v b thng minh HS3P-200.

v Thit b phc v th nghim:

o ng c khng ng b ba pha 45kW chy vi ti l qut ht cho trm trn Asphalt.

o Mt my o in p v dng hiu dng U/I RMS HTC do trung tm cng ngh cao ch to.

o Mt my tnh dng kt ni vi b U/I RMS HTC phc v vic gim st v lu tr.

v Tnh nng cn th:


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Cc tnh nng cnh bo c th nghim ti phng th nghim nn vic th nghim thc t l khng thc s cn thit. V vy ti tp trung ch yu vo vic th nghim tnh nng khi ng v dng mm.

v Mt s hnh nh th nghim:

Hnh 4.6: ng c 45kW vi ti l qut ht cho trm trn Asphalt .


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Hnh 4.7: B sn phm ca ti v my o M/I RMS HTC.


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Hnh 4.8: My tnh phc v vic lu tr v th ha.

v Kt qu th nghim:

Vic th nghim c thc hin trn c hai b sn phm ca ti vi vic chn cc loi ti khi ng khc nhau thng qua nm vn(vi b HS2P-200) hoc thng qua giao din phm bm v mn hnh LCD(vi b HS3P-200). So vi phng php khi ng i ni sao tam gic(c thit k sn cho ng c ny), r rng phng php khi ng mm dng Thyristor u vit hn hn.


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o Phng php i ni sao tam gic: Vi rle thi gian c t ngng 10s, ton b in p v dng khi ng c th hin trn hnh 4.9. Phng php ny khng c chc nng dng mm.

Hnh 4.9 : th p v dng khi khi ng dng i ni sao tam gic.


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o Khi ng mm vi b HS2P-200: Chn ti khi ng l Standard:

- Thi gian khi ng: 5s. - Thi gian dng: 10s. - in p khi ng: 30%. - in p dng: 10%.

Hnh 4.10: th p v dng vi b HS2P-200 ch Standard.


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Ti khi ng l High inertia Fan:

- Thi gian khi ng: 15s. - Thi gian dng: 0s. - in p khi ng: 30%. - in p dng: 0%.

Hnh 4.11 : th p v dng vi b HS2P-200 ch High inertia Fan.


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Chc nng khi ng c kick:

- Ukick = 75%. - Thi gian kick: 25 chu k li in (= 0.5s). - Thi gian khi ng: 5s. - Thi gian dng: 15s. - in p khi ng: 530%. - in p dng: 10%.

Hnh 4.12 : Chc nng khi ng c kick.


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o Khi ng mm vi b HS3P-200: Chn loi ti khi ng l Default vi thi gian khi ng l 10s, thi gian dng l 10s, in p khi ng l 10%, in p dng l 10%. Vic khi ng l c kick. in p v dng c th hin trn hnh 4.13. v hnh 4.14 bn phng to qu trnh khi ng ca b ba pha.

Hnh 4.13 : in p v dng trn ng c vi b HS3P-200.


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Hnh 4.14 : Qu trnh khi ng c kick ca b HS3P-200.


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PH LC

5.1 Cc s u ni ca b khi ng mm

Hnh 5.1: S u ni vi b HS2P-200


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Hnh 5.2: S u ni vi b HS3P-200

5.2 Mt s lu khi vn hnh thit b

5.2.1 B HS2P-200

Trong qu trnh vn hnh, mt s li c th xy ra trong qu trnh khi ng v vn hnh ng c v cc phng n x l:

a. Khng khi ng c.


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C th nguyn nhn l do mt pha h thng. Cn kim tra kt ni t b HS2P-200 ti ngun cung cp v ti ng c. Cng cn kim tra kt ni gia 2 chn S0 v S1. Lu l cn reset li ton b h thng khi mi th kim tra xong. b. Khi ng nhng sau li dng.

C th qu dng khi ng. C th gii quyt bng cch chn mt ti c thi gian khi ng di hn. Nu vn xy ra vn ny th di lm vic ca dng qua Thyristor nh hn ca ng c. Cn chn b HS2P-200 c di lm vic ca dng ln hn. c. Khi ng v chy mt thi gian sau li dng. C th hu ht cc nguyn nhn l do mt pha hoc ng c qu ti ng c khi chy ch normal.

5.2.2 B HS3P-200

Nh cp trong mc chi tit cc tnh nng, b HS3P-200 c kh nng pht hin, t x l v thng bo li thng qua mn hnh LCD. Mi khi c li xy ra, ngi vn hnh cn xem loi li v khc phc li. Di y l bng cc loi li:

M li Ch thch

1 Phase los Mt pha bn u vo khi bt u khi ng, trong qu trnh khi ng, khi chy normal.

2 Too hot Nhit cao hn mc cho php 3 SCR firing Hng Thyristor khi chy normal. 4 SCR signal Hng Thyristor hoc mt pha bn ng c trong qu trnh khi

ng hoc khi chy normal. 5 SCR signal Mt pha bn u vo khi chy normal hoc mt pha bn ng

c trong qu trnh khi ng hoc khi chy normal. 6 Sensing signal Hng Thyristor, nhiu ngoi hoc mt pha bn ng c trong

qu trnh khi ng hoc khi chy normal. 7 Motor, SCR los Hng Thyristor hoc mt pha bn ng c khi bt u khi

ng. 8 Sensing signal Hng Thyristor trong qu trnh khi ng hoc khi chy

normal.


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9 SCR shorted Hng Thyristor hoc mt pha bn motor trong qu trnh khi ng.

10 Low current Dng di mc cho php ch trong ch normal. 11 C/L time out Dng trong qu trnh khi ng ln hn dng cho php vt

qu thi gian cho php. Ex: 3.5 FLC c php duy tr trong 5s. 12 Overload Qu ti trong tt c cc trng thi hot ng. 13 Thermistor Hng sensor nhit 14 Bypass fault Contactor bypass khng ng

Hnh 5.3: Bng cc loi li ca b HS3P-200

5.3 Gii thiu v thit b o dng v p hiu dng U/I RMS-HTC v S khi v nguyn l lm vic:

Hnh 5.4: S khi thit b U/I RMS-HTC.

Mch bin i in p cch li: in p c ly nguyn dng vi in p u vo nhng c gi tr nh hn thng qua mt IC chuyn dng trc khi a vo chn ADC ca vi x l.

Mch bin i dng cch li: Dng c ly nguyn dng vi dng u vo thng qua bin dng sau c chun ha trc khi a vo chn ADC ca vi x l.


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Vi x l: c cc kt qu chuyn i ADC v, tnh ton v gi kt qu in p, dng hiu dng v trung bnh ln my tnh qua cng RS-232.

v Giao din ca phn mm kt ni vi my tnh:

Dng mt my tnh vi phn mm kt ni vi thit b U/I RMS-HTC. My tnh lin tc c v gi tr t vi x l gi ln phc v vic th ha v lu tr.

Hnh 5.5: Giao din ca phn mm trn my tnh.

Hnh 5.6: Giao din ca phn mm trn my tnh.


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5.4 Tm hiu cc vn lin quan n b khi ng mm trung th. B khi ng mm trung th c s khi nh hnh 5.7. vi nguyn l lm vic khng c g khc nhiu so vi b KM h th nhng do in p ngun cp ca b khi ng mm trung th t 2,3kV n trn 10kV nn c mt s cc vn k thut c th cn c gii quyt, bao gm cc vn sau

Hnh 5.7: S khi b khi ng trung th.

- V mt cu trc cn tch bit gia phn h th vi trung th nn b KM trung th chia lm 2 bung ring bit vi in p cch ly ln:

Bung h th: Bao gm board mch chnh CPU, cc module giao tip v truyn thng

Bung trung th: Bao gm cc module to xung kch m Thyristor, mch lc u ni Thyristor (Gate Drive), mch o nhit /dng in (TM/TC), cc my bin p cch ly


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- Chng nhiu: B khi ng trung th phi lm vic trong mi trng c in p cao nn nhiu in trng rt ln. Do giao tip gia bung h th v bung trung th bao gm ton b cc tn hiu i t board mch chnh n cc module iu khin (xung iu khin kch m Thyristor, xung iu khin Relay ) hoc cc tn hiu phn hi v board mch chnh (Nhit Thyristor, nhit ng c, dng qua ng c) bt buc phi qua cp quang chng nhiu v cch ly in p. Cc mch to xung kch m cc Thyristor v cc mch o nhit /dng in cng phi tnh ton n vn nhiu ny.

- Ngun nui cho cc mch trong bung h th cng nh cc bo mch trong bung trung th u c cp t ngun in trung th thng qua cc bin p cch ly in p cao hng chc kV

- Mch lc Thyristor: Hin nay c th dng mi pha mt cp Thyristor cho in p ln c 2.3kV. i vi in p cao hn th phi tng tng ng s cp Thyristor u ni tip vi nhau. Khi phi c bin php ph hp phn p mt cch ng u trn cc Thyristor trong c qu trnh lm vic. Nu phn p khng u s dn ti vic in p tp trung qu cao vo mt Thyristor no dn ti qu p v lm hng Thyristor

Hnh 5.8 Ghp ni cc Thyristor.

- Cc ng c trung th c cng sut ti hng MW nn cn phi gim st nhit ti nhiu im o. Khi CPU cn phi c thit k p ng c yu cu ny.


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KT LUN V KIN NGH

Trn c s nhng ni dung v kt qu c th m ti thc hin, cn c vo cc ni dung ng k c th nh gi v ti nh sau:

ti thc hin y cc ni dung ng k. Cc sn phm y v s

lng v tnh nng, u c th nghim v sn sng trin khai ng dng . ti lm ch cc vn k thut kh phc tp lin quan ti vic iu p i

vi ng c khng ng b ba pha trong cc qu trnh khi ng mm, chy tit kim nng lng v dng mm

Thit b o p/dng hiu dng do ti thit k ch to phc v o lng v

nh gi th nghim cng l mt sng to ca ti, phc v rt hiu qu cho ti trong c qu trnh pht trin sn phm v th nghim, v c th s dng cho nhiu ng dng khc cn gim st U/I hiu dng.

Kin ngh cc vn cn nghin cu tip:

ti cn u t nghin cu bc tip theo l hon thin cc sn phm c to ra sn phm thng mi, ng thi phi tip tc nghin cu to ra b khi ng mm cho ng c trung th v y chnh l dng sn phm c kh nng cnh tranh cao so vi cc sn phm nhp ngoi.


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TI LIU THAM KHO.

1. My in 1&2 V Gia Hanh ch bin Nh xut bn khoa hc v k thut. 2003.

2. in t cng sut V Minh Chnh ch bin Nh xut bn khoa hc v k thut. 2004.

3. Phn tch v gii mch cng sut - Phm Quc Hi Nh xut bn khoa hc v k thut. 1997.

4. Truyn ng in Bi Quc Khnh Nh xut bn khoa hc v k thut. 5. Power electronics and AC drivers - B.K.Bose. Prentice-Hall - New Jersey, USA,

1986.

6. Power Engineering Using Thyristor Mullard 1970. 7. Cc bi bo v khi ng mm:

Nghin cu h thng khi ng mm dng vi x l PSOC ca Phm Quc Hi, V Minh Hi. i hc Bch Khoa H Ni.

Khi ng mm, bin tn v vn tit kim nng lng ca TS. Nguyn Hng.

8. XFE manual FairFord. 9. MATLAB. Users Guide. 10. Mt s wedsite: http://www.dientuvietnam.net, http://www.fairford.co.uk/,

http://www.amazon.com/, http://winavr.scienceprog.com/ ,

Bia_BCTK DTCB KDMbao cao de tai final

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