Bài tập lớn tổng hợp hệ thống điện cơ FUll

5/28/2018 Bi t p ln tng hp h thng i n c FUll

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O N

BI TP LNMN HC:

TNG HP HTHNG IN C

GGiioovviinnhhnnggddnn:: NNgguuyynnnnggKKhhaanngg

SSiinnhhvviinntthhcchhiinn ::

NNgguuyynnTTrruunnggTToonn

LLpp::HHTTHH22KK55

H ni - 8/2013

I HC CNG NGHIP H NI

O N


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Bi tp ln: Tng hp hthng in c

2 GVHD: Nguyn ng Khang

Mc Lc

Li ni u.............................................................................................................................................. 5

CHNG I: TNG QUAN VHTRUYN NG IN T-....................................................... 6

1.1.Gii thiu Tiristor......................................................................................................................... 6

1.2 Gii thiu ng c mt chiu........................................................................................................ 7

1.3 Htruyn ng chnh lu ng c mt chiu.......................................................................... 12

CHNG II: XY DNG S CU TRC CA H................................................................ 15

2.1 Xy dng cu trc ca hthng:................................................................................................ 15

2.2. Xc nh cc tham sca s cu trc htruyn ng.......................................................... 16

CHNG III: XY DNG CU TRC V THAM SBIU CHNH DNG THEO TIUCHUN MODUL TI U.................................................................................................................. 17

3.1. Tng hp biu chnh............................................................................................................. 17

3.2. Tnh ton thng sbiu chnh............................................................................................... 19

CHNG IV: XC NH CU TRC V THAM SBIU CHNH TC THEO TIUCHUN MODUL TI U I XNG............................................................................................. 21

4.1. Tng hp biu chnh............................................................................................................. 21

4.2. Tnh ton thng sbiu chnh............................................................................................... 23

CHNG V: KHO ST C TNH NG HC CA H.......................................................... 25

5.1. M phng trn Matlab Simulink................................................................................................ 25

CHNG VI: XY DNG S NGUYN L V TNH CHN THIT B........................... 32

6.1. S nguyn l......................................................................................................................... 32

6.2. Tnh chn mch ng lc.......................................................................................................... 32

6.2.1. S mch ng lc h chnh lu cu ba pha thyristor................................................... 32

6.2.2. Cc thng s ca ng c................................................................................................... 33

6.2.3. Tnh chn thyristor.............................................................................................................. 34

6.2.4. Tnh ton my bin p chnh lu......................................................................................... 35

6.3. Mch iu khin ........................................................................................................................ 42

6.3.1. S nguyn l .................................................................................................................. 42

6.3.2. Nguyn tc iu khin......................................................................................................... 42

6.3. Cc khu c bn ca mch iu khin:...................................................................................... 45

6.3.1. Khu ng pha :.................................................................................................................. 45

6.3.2. Khu so snh :.................................................................................................................... 47

6.3.3. Khu khch i.................................................................................................................... 49

6.3.4.Khu to xung chm :......................................................................................................... 51

6.4. S mch iu khin v nguyn l hot ng........................................................................ 53


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6.5 Tng quan vTCA 785............................................................................................................... 55

6.5.1 Gii thiu............................................................................................................................. 55

6.5.2 S vi mch TCA 785....................................................................................................... 55

6.5.3.M t chc nng................................................................................................................. 57

6.6. Tnh ngun nui ....................................................................................................................... 61

6.7. Tnh ton my bin p ngun nui v ng pha........................................................................ 63

6.8. Tnh chn it cho bchnh lu ngun nui............................................................................. 63

6.9. Tnh chn cc thit bbo vmch ng lc ............................................................................ 64

6.9.1. S mch ng lc c cc thit b bo v........................................................................ 64

6.9.2. Bo v qu nhit cho cc van bn dn................................................................................ 65

6.9.3. Bo v qu dng cho van................................................................................................... 66

6.9.4. Bo v qu in p cho van............................................................................................... 67

6.10 Thit kcun khng lc............................................................................................................ 697. Mch o lng cm bin............................................................................................................... 73

8. Kt Lun........................................................................................................................................ 74

9. Ti Liu tham kho....................................................................................................................... 75


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ti

Cho hiu chnh tng T mt chiu c khi nh hnh v:

Bchnh lu dng chnh lu cu 3 pha i xng. Hskhuch i bchnh lu

Kcl =m+2 ( vi m l sthtnhm).Tvo+ Tk= 0,0015s

ng c 1 chiu kch tc lp c thng s: Pm=2*m (kw) vi m

sthtnhm; Um= 400V; m= 0,9;

nm=955v/pht ; T=0.07 s; Tc=0,22 s

Ti=0,003 s; T=0,05 s Ki=0,04 ; K= 0,01.

1. Tng quan vhT T-2. Xy dng s cu trc ca h.3. Xc nh cu trc v tham sbiu chnh dng theo tiu chun modul

ti u.4. Xc nh cu trc v tham sbiu chnh tc theo tiu chun

modul i xng.4. Kho st t tnh ng hc ca hbng phn mm simulink v rt ra kt

lun.

5. Xy dng s nguyn l h( bao gm s nguyn l y cmch

iu khin dng TCA785, mch lc, mch o lng cm bin). Tnh chn cc

thit blinh kin.


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Li ni u

Trong cng cuc i mi cng nghip ho hi i ho t c hin nay , vnp dng khoa hokthut vo cc quy trnh sn sut l v cp bch hng

u . Cng vi spht ca mt shh h in t, cng nghthng tin , nghnhkthut iu khin v t ho pht ti vc bc .Tng ho cc quy trnhsn sut a c phbin , c ththay sc lao co i , em li sut cao cht lng sn phm tt .

Hin nay , cc hthng dy chuyn tng trong cc nh my , x nghipc sdng rt rng ri , v hh c tin cy cao . V quan trng trong ccdy chuyn sn sut l iu khi iu chnh tc c hay o chiu quay c cao st ,Vi htruy in.

c ta hin nay mt smt chi c ng dng nhiu trong cc yu cuiu chnh cao , cng vi spht trin khng ngng ca kthut in tv kthutvi in t. Htruy ng mt chi iu chh ng thi in p phn cv tth tthnh gii php tt cho cc hthng c yu cu cht lng caody chuyn nhp ngoi , vi mt sl do khch quan cho nn mt sthit bkhi cv scphi nh chy ia c ngoi . Vvic thay thv iu khint bc hi nhp cng vi spht trin chung ca khoa hc kthut .

Trong qu trnh nghin cu khng thtrnh khi thiu st knh mong qu thyc chbo em c hiu thm , c kin thc nht h phc vcho chuyn

nghnh ca mnh sau ny .Em xin chn thnh cm st th ip ca thy Nguyn ang Khang

v cc thy c t ho hng dn , gip , to iu kin thun li cho emho thh ti ny .

Em xin chn thnh cm !

H ni, y th m 2013.

Sinh vin thc hin

Nguyn Trung TonV Trung Dng


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CNG I: TNG QUN V TRUYN NG N T-

1.1.Gii thiu TiristorTiristor l phn t bn dn cu to t bn lp bn dn p-n-p-n, to ra 3 lp

tip gip p-n J1 ,J2 ,J3. Tiristo c 3 cc anot A, catot K, cc iu khin G nhhnh di

Hnh 1.1 Cu to v k hiu ca Tiristor.

Nguyn l lm vicca Tiristor:Tiristor ch cho php dng chy qua mt chiu, t anot n catot v cn

tr dng chy theo chiu ngc li. Tiristor dn dng ngoi iu kin phi cin p UAK> 0 cn phi thm mt s iu kin khc na. Do tiristor ccoi l phn tbn dn c iu khin phn bit vi mt s phn t bn dnkhc khng iu khin nh iot.

M Tiristor:Khi c phn cc thun, UAK>0, tiristor c th m bng hai cch:

- Th nht, c th tng in p anot catot cho n khi t gi tr in pthun ln nht. Khi in tr tng ng trong mch anot catot s gimt ngt v dng qua tiristor hon ton do mch ngoi xc nh. Phng php

ny khng p dng ngoi thc t do nguyn nhn m khng mong mun vkhng phi lc no cng tng c in p n gi tr Uth,max. V li s xy ratrng hp tiristor s t m di tc dng ca cc xung p ti mt thi imngu nhin khng xc nh c.

- Th hai, phngphp c p dng trong thc t , l a mt xung dngin c gi tr nht nh vo gia cc iu khin v catot. Xung dng in iukhin s chuyn trng thi ca tiristor t tr khng cao sang tr khng thp mc in p anot catot nh. Khi nu dng qua anotcatot ln hn gi trnht nh, gi l dng duy tr (Idt) th tiristor s tip tc trong trng thi m

dn dng m khng cn n s tn ti ca xung iu khin na. iu ny nghal c th iu khin cc tiristor bng cc xung dng c rng xung nht nh,do cng sut ca mch iu khin c th l rt nh, so vi cng sut camch lc m tiristor l mt phn t ng ct v khng ch dng in.

Kha Ti ri stor:Mt khi Tiristor m th s hin din ca tn hiu iu khin Igkhng

cn l cn thit na. kha Tiristor c 2 cch:- Gim dng in lm vic I xung di gi tr dng in duy tr IH.

- t mt in p ngc ln Tiristor (bin php thng dng)Khi t in p ngc ln Tiristor UAK< 0, hai mt ghp J1v J3b phncc ngc, J2by gi c phn cc thun. Nhng in t, trc thi im o


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cc tnh UAK, ang c mt ti P1,N1, P2by gi o chiu hnh trnh, to nndng in ngc chy t katt v ant, v cc m ca ngun in p ngoi.

Lc u ca qu trnh, t t0n t1, dng in ngc kh ln, sau J1riJ3tr nn cch in. Cn li mt t in t b gi li gia hai mt ghp J1v J3,hin tng khuch tn s lm chng t dn i cho n ht v J2khi phc li

tnh cht ca mt ghp iu khin.Trong cc s chnh lu trn, gi tr in p trung bnh mt chiu ra tiph thuc vo gc iu khin m ca Tiristor:

Ud= Ud0.cos Do , khi thay i gc iu khin th ta s thay i c gi tr in

p trung bnh ra ti. Nu tng gi tr gc iu khin th in p trung bnh sgim, ngc li, gim th in p trung bnh s tng. Gi tr ln nht ca inp trung bnh ra ti l Ud0, ng vi gc =0.

Dng in trung bnh qua ti:

d

d

Z

UI vi 22 RXZ Ld

Trng hp trong mch ti c thm sut in ng phn khng:

d

d

Z

EUI

1.2 Gii thiu ng c mt chiuTrong nn sn xut hin i, ng c mt chiu vn c coi l mt loi

my quan trng mc d ngy nay c rt nhiu loi my mc hin i s dng

ngun in xoay chiu thng dng.Do ng c in mt chiu c nhiu u im nh kh nng iu chnhtc rt tt, kh nng m my ln v c bit l kh nng qu ti. Chnh vvy m ng c mt chiu c dng nhiu trong cc nghnh cng nghip cyu cu cao v iu chnh tc nh cn thp, hm m, giao thng vn ti,ccnghnh cng nghip hay i hi dng ngun in mt chiu...

Bn cnh , ng c in mt chiu cng c nhng nhc im nhtnh ca n nh so vi my in xoay chiu th gi thnh t hn ch to v boqun c gp in phc tp hn (d pht sinh tia la in)... nhng do nhng uim ni tri ca n nn ng c in mt chiu vn c mt tm quan trngnht nh trong sn sut.1.2.1 Cu to ca ng c in mt chiung c in mt chiu c th phn thnh hai phn chnh: phn tnh v phnng.1.2.1.1. Phn tnh

y l ng yn ca my, bao gm cc b phn chnh sau:+ Cc t chnh: l b phn sinh ra t trng gm c li st cc t v dy

qun kch t lng ngoi li st cc t. Li st cc t lm bng nhng l thp kthut in hay thp cacbon dy 0,5 n 1mm p li v tn cht. Trong ng cin nh c th dng thp khi. Cc t c gn cht vo v my nh cc

bulng. Dy qun kch t c qun bng dy ng bc cch in v mi cundy u c bc cch in k thnh mt khi tm sn cch in trc khi t


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trn cc cc t. Cccun dy kch t c t trn cc cc t ny c ni tipvi nhau.

+ Cc t ph: Cc t ph c t trn cc cc t chnh v dng cithin i chiu. Li thp ca cc t ph thng lm bng thp khi v trn thncc t ph c t dy qun m cu ro ging nh dy qun cc t chnh. Cc t

ph c gn vo v my nh nhng bulng.+ Gng t: Gng t dng lm mch t ni lin cc cc t, ng thi lmv my. Trong ng c in nh v va thng dng thp dy un v hn li.Trong my in ln thng dng thp c. C khi trong ng c in nh dnggang lm v my.

+ Cc b phn khc:-Np my: bo v my khi nhng vt ngoi ri vo lm h hng dy

qun v an ton cho ngi khi chm vo in. Trong my in nh v va npmy cn c tc dng lm gi bi. Trong trng hp ny np my thnglm bng gang.

- C cu chi than: a dng in t phn quay ra ngoi. C cu chithan bao gm c chi than t trong hp chi than nh mt l xo t chy ln cgp. Hp chi than c c nh trn gi chi than v cch in vi gi. Gichi than c th quay c iu chnh v tr chi than cho ng ch. Sau khiiu chnh xong th dng vt c nh li.1.2.1.2. Phn quay

Bao gm nhng b phn chnh sau :+ Li st: L phn ng dng dn t. Thng dng nhng tm thp k

thut in dy 0,5mm ph cch in mng hai mt ri p cht li gim tnhao do dng in xoy gy nn. Trn l thp c dp hnh dng rnh sau khip li th dt dy qun vo.

Trong nhng ng c trung bnh tr ln ngi ta cn dp nhng l thnggi khi p l thnh li st c th to c nhng l thng gi dc trc.Trong nhng ng c in ln hn th li st thng chia thnh nhng onnh, gia nhng on y c mt khe h gi l khe h thng gi. Khi mylm vic gi thi qua cc khe h lm ngui dy qun v li st.Trong ng c in mt chiu nh, li st phn ng c p trc tip vo trc.Trong ng c in ln, gia trc v li st c t gi rto. Dng gi rto c th

tit kim thp k thut in v gimnh trng lng rto.+ Dy qun phn ng: Dy qun phn ng l phn pht sinh ra sut in

ng v c dng in chy qua. Dy qun phn ng thng lm bng dy ngc bc cch in. Trong my in nh c cng sut di vi kw thng dngdy c tit din trn. Trong my in va v ln thng dng dy tit din chnht. Dy qun c cch in cn thn vi rnh ca li thp. trnh khi quay b vng ra do lc li tm, ming rnh c dng nm cht hoc ai cht dy qun. Nm c lm bng tre, ghay bakelit.

+ C gp: dng i chiu dng in xoay chiu thnh mt chiu. C

gp gm nhiu phin ng c c m cch in vi nhau bng lp mica dy t0,4 n 1,2mm v hp thnh mt hnh trc trn. Hai u trc trn dng hai hnhp hnh ch V p cht li. Gia vnh p v tr trn cng cch in bng mica.


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ui vnh gp c cao ln mt t hn cc u dy ca cc phn t dy qunv cc phin gp c d dng.

+ Cc b phn khc:- Cnh qut: dng qut gi lm ngui my. My in mt chiu

thng ch to theo kiu bo v. hai u np my c l thng gi.

Cnh qut lp trn trc my , khi ng c quay cnh qut ht gi t ngoivo ng c. Gi i qua vnh gp, cc t li st v dy qun ri qua qutgi ra ngoi lm ngui my.

- Trc my: trn t li st phn ng, c gp, cnh qut v bi.Trc my thng lm bng thp cacbon tt.

1.2.2 ng c mt chiu kch t c lp1.2.2.1 S nguyn l:

Hnh 1.2: S nguyn l ng c mt chiu kch t c lp

Ta c phng trnh c tnh c: 2

K

RR

K

U fuu

T phng trnh c tnh c ta thy C ba thng s nh hng n ctnh c l:

- T thng ng c ().- in p phn ng (U).- in tr phn ng.Sau y ta s ln lt i xt nhng nh hng ca tng tham s :

1.2.2.2 nh hng ca in tr phn ng:Gi thit : U=Um=const

= m=constKhi ta i in tr mch phn ng ta c tc khng ti l tng:

0 = ConstK

U

dm

dm

cng c tnh c:

= VarRRKM

fu

2)(

Rf

Uu

C

CKTD

+_

_+

RKT

UKT

I

IKT


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Khi Rf cng ln, cng nh ngha l c tnh c cng dc. ng vi Rf =0

Ta c c tnh c t nhin:

tn= -uR

K 2)(

tnc gi tr ln nht nn c tnh c t nhin c cng hn tt c ccng c tnh c in tr ph. Nh vy khi thay i in tr ph Rf ta cmt h c tnh bin tr c dng nh hnh 1.4. ng vi mt ph ti M cno ,nu Rfcng ln th tc ng c cng gim, ng thi dng in ngn mchv mmen ngn mch cng gim. Cho nn ngi ta thng s dng phng

php ny hn ch dng in v iu chnh tc ng c pha di tc cbn.

Hnh 1.3: Cc c tnh ca ng c mt chiu kch t c lp

khi thay i in tr ph mch phn ng1.2.2.3 nh hng ca in p phn ng:Gi thit : = dm= const

R= constKhi thay i in p phn ng : U


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Hnh 1.4: Cc c tnh ca ng c mt chiu kch t c lp

khi gim p t vo phn ng ng c

1.2.2.4nh hng ca t thng:

Gi thit : U= Um= constR = const

Khi ta thay i t thng tc l ta thay i dng kch t (Ikt) ng c.

Tc khng ti l tng: var0

x

dmx

K

U

cng c tnh c: var)( 2

u

x

R

K

Do cu to ca ng c in, thc t thng iu chnh gim t thng. Nnkhi t thng gim th x

0

tng, cn s gim. Ta c mt h c tnh c vi

x0 tng dn v cng ca c tnh gim dn khi gim t thng.

Hnh1.5:c tnh c in (a)v c tnh c (b)khi thay i t thng

Ta nhn thy rng khi thay i t thng:

Dng in ngn mch: ConstR

UI

U

dmnm

M men ngn mch: Mnm= KxInm= varCc c tnh c in v c tnh c ca ng c khi gim t thng c biudin trn hnh 1.6.

Vi dng mmen ph ti Mcthch hp vi ch lm vic ca ng cth khi gim t thng tc ng c tng ln (Hnh 1.5b)


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1.3 H truyn ng chnh lu ng c mt chiu

1.3.1 Khi nim chung v h truyn ng chnh lu ng c mt chiuL b chnh lu lin h ngun xoay chiu vi ti mt chiu, ngha l i

in p xoay chiu ca ngun thnh in p mt chiu trn ph ti.in p mt chiu trn ti khng c l tng nh in p ca c quy

m c cha cc thnh phn xoay chiu cng vi mt chiu.u ra ca cc s chnh lu c coi l mt chiu nhng thc s lin p p mch. Tr s in p mt chiu, hiu p sut nh hng ca chngdo ngun xoay chiu rt khc nhau.

B bin i Thyristor vi chuyn mch t nhin c in p (dng in) ral 1 chiu l cc thit b bin ngun in xoay chiu 3 pha thnh in p 1 chiuiu khin ngc.

Hot ng ca mch do ngun in xoay chiu quyt nh v nh mc th thc hin c cc chuyn mch dng in gia cc phn t lc.

Vic phn loi chnh lu ph thuc nhiu yu t:- Theo s pha c: Chnh lu 1 pha, chnh lu 3 pha...- Theo s ni c: Chnh lu na chu k, chnh lu 2 na chu k, chnh

lu hnh cu, chnh lu hnh tia...- Theo s iu khin c: Chnh lu khng iu khin, chnh lu c iu

khin, chnh lu bn iu khin.

1.3.2 Gii thiu s


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Hnh 1.6: S h thng chnh lu ng c mt chiu

Trong :+ : ng c mt chiu kch t c lp, thc hin chc nng bin nng

lng in mt chiu thnh c nng truyn ng cho c cu sn xut+ BB: l b bin i van c iu khin, thc hin chc nng bin nng

lng in xoay chiu thnh nng lng in mt chiu cung cp cho ng c+ Utn hiu in p t+ FT my pht tc thc hin chc nng khu phn hi m tc+TH & K l khi tng hp v khuych i tn hiu+ FX l mch pht xung

1.3.2.1 Hot ng ca h thngGi s ban u h thng c ng vo li vi in p thch hp, lc

ny ng c vn cha lm vic. Khi ta t vo h thng mt in p t Ung

vi mt tc no ca ng c. Thng qua khu TH & KH v mch FX ssut hin cc xung a ti cc chn iu khin ca cc van ca b bin i, nulc ny nhm van no ang c t in p thun, van s m vi gc m .u ra ca BB c in p Udt nn phn ng ng cng c quay vitc ng vi Uban u.

Trong qu trnh lm vic, nu v mt nguyn nhn no lm cho tc ng c gim th qua biu thc : UK= U- n.khi n gim UKtng gim Udtng n tng v im lm vic yu cu.Khi n tng qu mc cho php th qu trnh din ra ngc li. y l nguyn l

n nh tc .* c tnh c ca h thng truyn ng:

Ch dng in lin tc:Dng in chnh lu Idchnh l dng phn ng.Da vo s thay th (hnh 2.2) vit c s c tnh.

c tnh c c cng

Xk: c trng cho st p do chuyn mch gia cc van.Thay i gc iu khin:

+ Khi s chnh lu bin thin t Edon - Edov ta cmt h c tnh song song nhau nm na bn phi mt phng to docc van khng cho dng in phn ng i chiu.

Cc c tnh c ca h T - mm hn cc c tnh c ca h F - bi

thnh phnst p do hin tng chuyn mch gia cc van bn dn gynn.

IK

XR

K

En

dm

K

dm

do

..

cos.

MK

XR

K

En

dm

K

dm

do

2).(.

cos.

K

dm

XR

K

2)(

0 M,

kU


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Hnh 1.7: H c tnh c ca h

+ Khi : B bin i lm vic ch chnh lu, ng c c

th lm vic ch ng c nu s E > 0 v ch hm ngc nu s Ei chiu.

+ Khi : B bin i lm vic ch nghch lu ph thuc,

bin c nng ca ti thnh in nng xoay chiu cng tn s li v tr v liin. ng c lm vic ch hm ti sinh khi ti c tnh th nng.

Dng in trung bnh ca mch phn ng:

Phng trnh c tnh:

- Ch dng in gin on:Trong thc t tnh ton h T - ch cn xc nh bin gii vng dng

in gin on, l ng phn cch gia vng dng in lin tc v dng ingin on. Trng thi bin lin tc l trng thi m gc dn = /p v gcchuyn mch .

ng bin lin tc gn l ng elip. gim ln ca trc nh elip, tng s pha ca chnh lu. Tuy

nhin khi tng s pha chnh lu s s phc tp.1.3.2.2 nh gi cht lng ca h thng

- u im:+ Tc nhanh, khng gy ting n v d t ng ho do cc van bn

dn c h s khuch i cng sut cao.+ Cng sut tn ho nh, kch thc v trng lng nh+ Gi thnh r, d bo dng sa cha.

-Nhc im:+ Mch iu khin phc tp, in p chnh lu c biu p mch

cao, gy n tn tht ph ng k trong ng c v h thng.

20

ma x2

K

d

XR

EEI

IK

XR

K

E

dm

K

dm

do .cos.

2

0


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+ Chuyn mch lm vic kh khn do ng c tnh nm trong mtphng to .

+ Trong thnh phn ca h bin i c MBA nn h s cos thp.+ Do vai tr ch dn dng mt chiu nn vic chuyn i ch lm

vic kh khn vi cc h thng o chiu.

+ Do c vng lm vic gin on ca c tnh nn khng ph hptruyn ng c ti nh.

CNG : XY DNG S CU TRC C

2.1Xy dng cu trc ca h thng:

T s nguyn l ca h truyn ng T- ta c s cu trc trng thi nnh:

BB

-

-

-E


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- Trong :- R:Biu chnh tc quay.

- Ri: B iu chnh dng in.- U: in p ch o.

- U: in p phn hi tc - Ui: in p phn hi m dng in.- Ki: H s phn hi m dng in.- K: H s phn hi m tc .

2.2. Xc nh cc tham s ca s cu trc h truyn ng.

P =14Kw U=400Vn = 0.9 nm= 955(vng/pht)

+ Im =

=

= 38.88(A)

+R=0,5(1-n).

=0,5(1-0,9).

= 0,514()

+m= =

= 100(Rad/s)

+Km = =

= 3.8

+J=

=0.4 kg.m2

Kcl = 9, Ki = 0.04, K= 0.01Tvo + Tk= 0.0015sT = 0.07s, Ti = 0.003sT= 0.05s


17/75



CNG : XY DNG CU TRCV TM S BU CN DNG TEO TU CUN MODULT U

3.1. Tng hp b iu chnhTrong cc h truyn ng t ng cng nh cc h chp hnh th mch vng

iu chnh dng in l mch vng c bn. Chc nng c bn ca mch vng

dng in l trc tip hoc gin tip xc nh m men ko ca ng c, ngoi ra

n cn c chc nng bo v, iu chnh gia tc...

Do qun tnh c hc ln hn rt nhiu so vi qun tn in t (Tc >> T)

cho nn bin i tc chm hn bin i tc dng in.

Trong mch vng dng in c th coi 0E .Lc ny mch vng dng inc dng:

Hnh 3-1. S khi mch vng dng in

Trong :

- hm truyn ca b iu chnh dng in (cn tm)B(p) - hm truyn ca b bin i, c dng nh sau:

Vi: - h s chnh lu

- hng s chuyn mch chnh lu- hng s thi gian mch iu khin chnh lu

A(p) - hm truyn ca ng c khng tnh n sut in ng phnng

Vi: - hng s thi gian phn ng.


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- hm truyn ca khu phn hi dng in, c dng nh sau:

Vi: - hng s thi gian ca sensor dng in

=0.04- h s phn hi mch vng dng inTa chuyn i mch phn hi dng in v mch phn hi n v, ta c

s tng ng nh sau:

Hnh 3-2 : S tng ng .

- Ta c hm truyn h kn ca s khi cha chuyn i:

- Ta c hm truyn h kn ca s khi chuyn i:

Mt khc: - Vy p dng tiu chun ti u mun cho hm truyn s

chuyn i:

- Thay cc hm truyn tng ng vo vi:

B(p) A(p) U I

-


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Mt khc, cc hng s thi gian rt nh so vi hng sthi gian in t . t th c th vit li dng gn ng nh sau:

Trong , ta chn thay vo ta c:

Vy hm truyn ca mch vng kn s l:

3.2. Tnh ton thng s b iu chnh- H s bin i dng in:

Hnh 3-3 S my bin dng.- Ta s dng mch bin dng, o dng trc tip t ngun 3 pha a

qua b chnh lu it c lc ly phn hi dng in v cho ng

c. - H s chnh lu

- in p iu khin a vo mch chnh lu (chn ) =0,0015+0,003=0.0045 (s)

- Hm truyn


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- Thit k mch iu chnh dng in

Vy mch iu chnh dng ca ta s b iu chnh PI

Hnh 3-4. S b iu chnh PI

Mt khc:

Ri(p) =+

Suy ra:= 11.11 v R1C2= 0.0063

Chn R1= 5K , R2 = 55.55K

C2= 12.610-6F.


21/75



CNG V: XC N CU TRCV TM S B UCN TC TEO TU CUN MODUL T U

XNG

4.1. Tng hp b iu chnhV ng c cn b nh hng bi yu t thay i ca ti trng nntrong trng hp ny chng ta s tng hp mch vng iu chnh tc theo tiu chun ti u i xng c th t c yu cu v sai cpcao

S khi ca mch vng iu chnh tc :

Hnh 4-1 : S khi mch vng iu chnh tc .

Trong :

- Hm truyn b iu chnh tc - Hm truyn h kn ca vng iu chnh dng in

- Hm truyn khu phn hi tc

Vi: - H s phn hi ca my pht tc

- Hng s thi gian ca my pht tc

C(p) - Hm truyn c hc ca ng c khi b qua ma st trntrc ng c

C(p)


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Vi: J - Mmen quan tnh ca ng c

- p dng hm chun ti u i xng (v tnh n nn tng hptheo tiu chun ti u i xng sai s ca h thng c gimthiu):

- Hm truyn h kn ca s trn

- p dng hm chun ti u i xng (s dng cch bin i s

ging nh phn thit k mch vng dng in) ta c:

- Thay cc hm truyn tng ng vo

Vy:

Mt khc, ta c th b qua thnh phn v l v cng bv cc hng s thi gian v rt nh nn t

, ta c hm truyn gn ng nh sau:

V l tng cc hng s thi gian v cng nh nn ta chn , ta c:

( )

Vy hm truyn ca mch vng kn s l


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4.2. Tnh ton thng s b iu chnh- H s phn hi ca my pht tc:

Ta c s ca my pht tc nh sau:

Hnh 4-2 : S my pht tc .

Ta c: K=0.01

Mt khc ,Ts=0,059 (s)- Hm truyn

( )

Thit k mch iu chnhtc

y ta s dng mch iu chnh vi khu PI

trnh qu trnh qu ca c to ra bi khu iu chnhtc ca h thng, ta s s dng mt khu hn ch c th lm bo hain p qu gip dng in phn ng s khng cn b qu iu chnhln na

S nh sau:


24/75



Hnh 4-3 : S mch iu chnh tc vi khu PI.

Mt khc:Ri(p) =

+

Suy ra:= 3,565 v R1C2= 0.0662

Chn R1= 1K , R2 = 3,565K

C2= 66,2x103uF.

Hm truyn ca cc khu tm c nh sau:

(Wb)


25/75



CNG V: O ST C TN NG C C

5.1. M phng trn Matlab Simulink

A.Lc khng ti .(cha hiu chnh bPID).Dng in lc khng ti .


26/75



Tc lc khng ti :

1.Mch vng iu chnh dng in.+Mc=Mt=0

+thi gian t ti trng thi n nh:1,6s

+sai lch tnh:0%

Nhn xt:

Hthng t trng thi n nh kh nhah.

2.Mch vng tc .

+Mc=Mt=0

+qu iu chnh 53%

+thi gian t ti trng thi n nh:2,85 s

+thi gian t ti tn hiu t:0.15s

+sai lch tnh:0%

B.Lc c ti(cha hiu chnh b PID).Dng in khi c Mc = Mdm


27/75



1.Mch vng iu chnh dng in.

+Mc=Mt=147.4

+I=38.8A

+thi gian t ti trng thi n nh:1,7s

+sai lch tnh:1%

Nhn xt:dng in tng ln ti gi trnh mc

2.Mch vng tc .

+Mc=Mt=147.4

+qu iu chnh rt ln

+thi gian t ti trng thi n nh: ln

+thi gian t ti tn hiu t:ln

+tc vn t trng thi n nh khi c ti tuy nhin thi gian t n nh lu.


28/75



Hiu chnh li b PID.TngI ca bRln 10 vgim P ca bRxung 3,4.

A.Khng ti

Dng khng ti .

Tc Khng ti :


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* Nhn xt:

1.Mch vng dng in.

+I=0;

+Thi gian tn hiu t trng thi n nh:1 s

+Imm < 2Idm.

Nhn xt:thi gian t ti trng thi n nh kh nhanh

2.Mch vng tc .

+Mc=Mt=0

+qu iu chnh 38,5 %

+thi gian t ti trng thi n nh:1 s

+thi gian t ti tn hiu t:0.156s

+sai lch tnh:0%


30/75



B. Trng hp c ti

Dng in

1.Mch vng dng in.

+I=38.8A;

Nhn xt:

+ dng in tng ln gi trnh mc+ thi gian t n nh: 0,9 s.

+ thi gian t gi trnh mc v n nh tng i nhanh.


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Tc :

2.Mch vng tc .

+Mc=Mt=147.4

+khi c ti tc gim nhng nhanh chng n nh lai tc nh mc

+sai lch tnh:0,5%

+thi gian t n nh: 0,9s.

+ thi gian n nh ca hthng nhanh, sai lch rt b.


32/75



CNG V: XY DNG S NGUYN L VTN CN TT B

6.1. S nguyn l

Hnh 6-1 S nguyn l

6.2. Tnh chn mch ng lc.

6.2.1. S mch ng lc h chnh lu cu ba pha thyristor.Trong phn ny ta chn b truyn ng T-


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Hnh 6-2 : S mch ng lc ca bchnh lu cu ba pha thyristor hT-.

6.2.2. Cc thng s ca ng c.- ng c mt chiu kch t c lp c cc thng s sau:

Pdm= 14 Kw Udm= 400 V

Idm= 40 A ndm= 955 vng/pht


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6.2.3. Tnh chn thyristor.

Tnh chn thyristor da vo cc yu t c bn nh : dng in ti , s

chnh lu , iu kin tn nhit , in p lm vic .

- in p ngc ln nht m thyristor phi chu :

Unmax= Knv.U2= Knv.u

d

K

U=

6.3.6 dU

=3

.400 = 418.89 V ;

Trong : Knv= 6 ; Ku=

63;

- in p ngc ca van cn chn :

Unv= Kdtu.Unmax = 1,8 .418,89 = 754 V ;Trong : Kdtu: H s d tr in p , thng chn Kdtu= 1,8 ;

- Dng in lm vic ca van c tnh theo dng hiu dng :

Ilv= Ihd= khd.Id =3

dmI =3

40= 23,09 A ;

( do trong s cu ba pha , h s dng in hiu dng : khd=3

1) .

- Chn thyristor lm vic vi iu kin c cnh tn nhit v din tch

tn nhit , khng c qut i lu khng kh , vi iu kin c dng in nh

mc ca van cn chn :

Idm= ki.Ilv= 3,2 . 23,09 = 73,9 A ;

ki: H s d tr dng in , chn ki= 3,2 .

chn thyristor lm vic vi cc tham s nh mc c bn trn , ta tra

bng thng s van , chn cc van c thng s in p ngc , dng in nh

mc ln hn gn nht vi thng s tnh . Vy ta chn thyristor cho mch

ng lc loi

TF440-06X c cc thng s sau :

- Dng in nh mc ca van: Idm= 400 (A) ;

- in p ngc cc i ca van: UnT= 600 (V) ;

- nh xung dng in : Ipk= 4000 (A) ;

- st p trn thyrisor : UT= 2,0 (V) ;


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- Dng in ca xung iu khin : Ig= 200 (mA) ;

- in p ca xung iu khin : Ug = 3,0 (V) ;

- Dng in r : Ir= 25 (mA) ;

- Nhit lm vic cc i : Tmax= 1250C ;

- Dng in duy tr : Ih = 70 mA ;

- Tc bin thin in p :dt

du = 200 (V/s) ;

- Thi gian chuyn mch : tcm= 15 (s) ;

6.2.4. Tnh ton my bin p chnh lu.

chn cc thit b trong mch ng lc cng nh mch bo v , trcht cn xc nh in p ra ca b bin i Thysitor .

Chn my bin p ba pha ba tr c s ni dy /Y , lm mt t nhin

bng khng kh .

My bin p l mt b phn quan trng ca h thng in , thc hin cc

chc nng sau .

- Bin i in p ngun cho ph hp vi yu cu s ph ti .

- Bo m s cch ly gia ph ti vi li in vn hnh an ton v

thun tin

- Bin i s pha cho ph hp vi s pha ca s ph ti .

- To im trung tnh cho s hnh tia .

- Hn ch dng in ngn mch trong chnh lu v hn ch mc tng dng

Ant bo v van .

- Ci thin hnh dng sng in li lm cho n bin dng so vi hnh

sin , do nng cao cht lng in p li .

* Tnh cc thng s c bn :

- Tnh cng sut biu kin ca my bin p :

SBA= Ks.Pdm= 1,05.14000 = 14700 (VA) ;

- in p pha s cp my bin p :

U1 = 380 V ;- in p pha th cp my bin p :


36/75



Phng trnh cn bng in p khi c ti :

Ud0.cosmin = Ud+ 2UV+ 2Udm+ UBA

Trong :

min= 00l gc d tr khi c suy gim in p li ;

UV= 21 V l st p trn thyristor ;

Udm 0 l st p trn dy ni :

UBA= Ur+ Ux l st p trn in tr v in khng trn my

bin p;

Chn s b :

UBA= 6%.Ud = 0,06. 400 = 24 V ;

T phng trnh cn bng in p khi c ti ta c :

Ud0=mincos

22

BAVd UUU =00

24.221.2400

Cos

= 490 V ;

in p pha th cp mybin p :

U2=u

d

k

U=

63

490= 209 V ;

- Dng in hiu dng th cp my bin p :

I2=3

2.Id=

3

2.40 = 32,6 A ;

- Dng in hiu dng s cp my bin p :

I1= kBA.I2=1

2

U

U.I2 =

380

209 .32,6 = 17,93 A ;

* Xc nh kch thc ca mch t .- Tit in s b tr .

QFe = kQ.fm

SBA.

;

Trong : kQ: H s ph thuc phng thc lm mt , ly kQ= 6 .

m : S tr ca my bin p , m = 3 .f : Tn s ca ngun xoay chiu , f = 50 Hz .


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Thay vo ta c : QFe = 6 .50.3

14700 = 59,4 cm2.

- ng knh tr :

d = FeQ.4

= 4,59.4

= 8,7 cm .

Chun ha ng knh tr theo tiu chun : d = 11 cm .

- Chn loi thp k thut in , cc l thp c dy 0,5 mm .

Chn s b mt t cm trong tr BT= 1 T .

- Chn t s m =d

h = 2,3 . Suy ra h = 2,3d = 2,3 . 11 = 25,3 cm .

( Thng thng m = 2 2,5 ) .

Chn chiu cao tr h = 25 cm .

* Tnh ton dy qun .

- S vng dy mi pha s cp my bin p :

W1=0,1.10.4,59.50.44,4

380

...44,4 41

TFe BQf

U = 288 vng .

Ly W1= 290 vng .

- S vng dy mi pha th cp my bin p :

W2=1

2

U

U.W1 =

380

209 .290 = 159,5 vng .

Ly W2= 160 vng .

- Chn s b mt dng in trong my bin p :

Vi dy dn bng ng , my bin p kh , chn J1 = J2 = 2,75 A/mm2.

- Tit din dy dn s cp my bin p :

S1 =1

1

J

I =

75,2

15,29 = 10,6mm2.

Chn dy dn thit din hnh ch nht , cch in cp B .

Chun ho tit din theo tiu chun : S1 = 14,2 mm2.

Kch thc ca dy c k n cch in l : S1cd = a1 b1 = 1,68 8,6

mm .


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- Tnh li mt dng in trong cun s cp :

J1 =1

1

S

I=

2,14

93,17 = 1,26 A/mm2.

- Thit din dy dn th cp my bin p :

S2 =2

2

J

I =

75,2

6,32 = 11,85 mm2.

Chn dy dn c tit din ch nht , c cch in cp B .

Chun ho tit din theo chun : S2 = 50,1 mm2

Kch thc ca dy c k n cch in l : S2cd = a2 b2 = 5,1 10 mm

.

- Tnh lai mt dng in trong cun th cp :

J2 =2

2

S

I =

1,50

6,32 = 0,65 A/mm2.

* Kt cu dy qun s cp .

Thc hin dy qun kiu ng tm b tr theo chiu dc trc .

- Tnh s b s vng dy trn mt lp ca cun s cp :

W11 = 95,0.86,05,1.225.2

1

cg k

bhh = 24 vng .

Trong : kc: L h s p cht , ly kc= 0,95 .

h : Chiu cao tr h = 25 cm .

hg: Khong cch t gng cun dy s cp .

Chn s b khong cch cch in gng hg= 1,5 cm .

- Tnh s b s lp dy cun s cp :

n11=24

290

11

1 W

W = 12,08 lp .

Chn s lp n11 = 12 lp .

Nh vy c 290 vng chia thnh 12lp , vy 11 lp u c 24 vng v lp

th 12 c 26 vng

- Chiu cao thc t ca cun s cp :


39/75



h1 =95.0

86,0.24. 111 ck

bW = 21,726 cm .

- Chn ng qun dy lm bng vt liu cch in c b dy :

S01= 0,1 cm .

- Khong cch t tr ti cun s cp :

a01= 1 cm .

- ng knh trong ca ng cch in :

Dt= dFe+ 2a012S01 = 11 + 2 . 12 . 0,1 = 12,8 cm .

- ng knh trong ca ca cun s cp :

Dt1= Dt + 2S01 = 12,8 + 2 . 0,1 = 13 cm .

- Chn b dy cch in gia cc lp cun s cp :

cd11= 0,1 mm .

- B dy cun s cp :

Bd1= ( a1+ cd11 ).n11= ( 1,68 + 0,1 ).8 = 14,24 mm = 1,424 cm

.

- ng knh ngoi ca cun s cp :Dn1 = Dt1+ 2Bc1= 13 + 2 . 1,424 = 15,848 cm .

- ng knh trung bnh ca cun s cp :

Dtb1 =2

848,1513

211

nt DD = 14,424 cm.

- Chiu di dy qun s cp :

l1 = W1..Dtb = . 290 . 14,424 = 13141,156 cm = 131,41 m .

- Chn b dy cch in gia hai cun s cp v th cp :

cd0= 1 cm .

* Kt cu dy qun th cp .

- Chn s b cun chii cao cun th cp :

h2 = h1 = 21,726 (cm) .

- Tnh s b s vng dy trn mt lp :


40/75



W12 = ckb

h.

2

2 = 95,0.1

726,21 = 20 vng .

- Tnh s b s lp dy qun th cp:

nl2 =20

160

2

2 lW

W = 8 lp .

chn n12 = 8 lp .

- Chiu cao thc t ca cun th nht :

h2=95,0

1.2022 c

l

k

bW = 21,05 cm .

- ng knh trong ca cun th cp :

Dt2 = Dn1+ 2a12 = 15,848 + 2 . 1 = 17,848 cm .- Chn b dy cch in gia cc lp dy cun th cp :

cd22 = 0,1 mm .

- B dy cun th cp :

Bd2 = ( b2 + cd22 ). nl2= ( 1 + 0,01 ) . 3 = 3,03 cm .

- ng knh ngoi ca cun th cp :

Dn2

= Dt2

+ 2.Bd2

= 17,848 + 2 . 3,03 = 23,908 cm .

- ng knh trung bnh ca cun th cp :

Dtb2 =2

908,23848,17

222

nt DD = 20,878 cm .

- Chiu di dy qun th cp:

l2 = .W2.Dtb2 = . 160 . 20,878 = 10494 cm = 104,94 m .

- ng knh trung bnh ca cc cun dy :

D =2

908,2313

2

21

nt DD = 18,454 cm .

Suy ra : r =2

454.18

2

D = 9,227 cm .

* Cc thng s ca my bin p :

- in tr trong ca cun s cp my bin p 75oC :

R1 = .1

1

s

l = 0,02133.

14

41,131 = 0,2 .

Trong : = 0,02133 .mm2/m.


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- in tr trong ca cun th cp my bin p 75oC :

R2 = .2

2

s

l = 0,02133.

1,50

94,104 = 0,045 .

- in tr my bin p quy i v th cp :

RBA = R2+ R1.(1

2

W

W)2= 0,045 + 0,2.(

290

160 )2 = 0,06 .

- St p trn in tr my bin p :

ur = RBA.Id = 0,06 . 40 = 2,4 V .

- in khng my bin p quy i v th cp :

XBA= 8.2.(W2)

2.(qh

r)(a12+

3

21 dd BB )..10-7.

XBA= 8 . 3,142 . 1602. (

726,21

227,9) . (0,01 + 210.

3

03,3424,1 ) . 314 . 10-7

XBA= 0,67 .

- in cm my bin p quy i v th cp :

LBA =

BAX =

314

67,0 = 2,13.10-3H = 2,13 mH.

- St p trn in khng my bin p :

ux =

3 .XBA.Id =

3 .0,67.40 = 25,6 V .

- in p ngn mch tc dng :

Unr = 100.209

6,32.06,0100

2

2 U

IRBA = 0,93 % .

- in p ngn mch phn khng:

Unx = 100.209

6,32.67,0100

2

2 U

IXBA = 10,5 % .

- in p ngn mch phn trm :

Un = 2222 5,1093,0 nxnr UU = 10,54 % .


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Bng thng cc thng s ca my bin p ng lc .

6.3. Mch iu khin .

6.3.1. S nguyn l .

Hnh 6-3 : S khi iu khin thyristor.

6.3.2. Nguyn tc iu khin.Trong thc t ngi ta thng dng hai nguyn tc iu khin sau :

Thng ng tuyn tnh v thng ng arccos , thc hin v tr xung trong

na chu k dng ca in p t trn thyristor .

Cng sut my bin p biukin

SBA = 14,7 kVA

in p pha s cp U1 = 380 V

in p pha th cp U2 = 209 V

Dng in hiu dng s cp I1 = 17,93 A

Dng in hiu dng th cp I2 = 32,6 A

S vng dy mi pha s cp W1 = 290 vng

S vng dy mi pha th cp W2 = 160 vng

in tr quy i v th cp RBA = 0,06

in khng quy i v th cp XBA = 0,67

in cm quy i v th cp LBA = 2,13 mH

in p ngn mch phn trm Un = 10,54 %

IN P TA

K XUNG

P

SSUc

T


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6.3.2.1. Nguyn tc iu khin thng ng tuyn tnh:

Theo nguyn tc ny ngi ta thng dng hai in p :

- in p ng b ( Us) , ng b vi in p t trn ant catt ca

thyristor , thng t vo u o ca khu so snh .

- in p iu khin ( Ucm ) , l in p mt chiu , c th iu chnh c

bin . Thng t vo u khng o ca khu so snh .

Hnh 6-4 : Nguyn tc iu khin thng ng tuyn tnh.

Do vy hiu in th u vo ca khu so snh l :

Ud= UcmUs ;

Khi Us= Ucmth khu so snh lt trng thi , ta nhn c sng xung

ca in p u ra ca khu so snh . Sn xung ny thng qua a hi mt

trng thi bn n nh to ra xung iu khin .

Nh vy bng cch lm bin i Ucm, ta c th iu chnh c thi im

xut hin xung ra , tc l iu chnh gc .

Gia v Ucmc quan h sau :

=max

.s

cm

U

U ; Ngi ta ly Ucmmax= Usmax ;

Us

-Usm

Ucm

t

Ucm

2

Us


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6.3.2.2. Nguyn tc iu khin thng ng arccos:

Theo nguyn tc ny ngi ta dng hai in p :

- in p ng b Us, vt trc UAK= UmSint ca thyristor mt gc

2

Us= UmCost .

- in p iu khin Ucml in p mt chiu , c th iu chnh c

bin theo hai chiu dng v m .

Hnh 6-5 : Nguyn tc iu khin thng ng arcoss

Nu t Usvo cng o v Ucmvo cng khng o ca khu so snh th

:

Khi Us= Ucm, ta s nhn c mt xung rt mnh u ra ca khu so

snh khi khu ny lt trng thi .

UmCos = Ucm; (3-

1)

Do = arcos(m

cm

U

U) ; (3-

2)

Khi Ucm= Um th = 0 ;

Khi Ucm= 0 th =2

;

Ucmt

UAK

0

Us

UAK

Us

2

Um

-Um


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Khi Ucm= - Um th = ;

Nh vy , khi iu chnh Ucmt tr Ucm= +Um, n tr Ucm= -Um ta c th

iu chnh c gc t 0 n .

Nguyn tc iu khin thng ng arcos c s dng trong cc thit b chnh

lu i hi cht lng cao .

6.3. Cc khu c bn ca mch iu khin:

6.3.1. Khu ng pha :S hnh 35a l s n gin , d thc hin vi s linh kin t nhng

cht lng in p ta khng tt . di ca phn bin thin tuyn tnh ca

in p ta khng ph ht 1800. Do , gc m van ln nht b gii hn . Hay

ni cch khc , nu theo s ny in p ti khng iu khin c t 0 ti

cc i m t mt tr s khc n tr s cc i .

khc phc nhc im trn v di iu chnh ca s hnh 35a

ngi ta s dng s to in p ta bng s trn hnh 3-5b . Theo s

ny , in p ta c phn bin thin tuyn tnh ph ht na chu k in p . Do

vy khi cn iu khin in p t khng ti cc i l hon ton c th p ng

c .

Vi s ra i cacc linh kin ghp quang , ta c th s dng s to

in p ta bng b ghp quang nh hnh 3-5c . Nguyn l v cht lng ca

hai s trn hnh 3-5b v 3-5c tng i ging nhau . u im ca s trn

hnh 3-5c ch khng cn bin p ng pha , do c th n gin hn trong

vic ch to v lp t .

Cc s trn u c chung nhc im l vic m , kho cc tranzitor

trong vng in p ln cn 0 l thiu chnh xc , lm cho vic np , x t trong

vng in p li gn 0 khng c nh mun .

Ngy nay cc vi mch c ch to ngy cng nhiu , cht lng ngy

cng cao , kch thc ngy cng gn , ng dng cc vi mch vo thit k mch

ng pha c th cho ta cht lng in p ta tt . Trn s 3-5d m t vic

ta in p ta dng khch i thut ton .


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Di y ta gi thiu mt s khu ng pha c bn

Hnh 6-6 Mt s khu ng pha in hnh.

u1 u1ura

u2D1

D2R1

R2

C

-E

A B C

Hnh-a

R2

R1

D1

A

C ura

Tr

Hnh-b

+E

Ghp quang

uv

R1

D

R2

uraC

-E

Ura

u1D1

A2

R1AB

R2Tr

C

C

Hnh-d

A1

-12

+12+12

-12_

++

_


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Hnh 6-7 : Gin ca khu ng pha

6.3.2. Khu so snh :

xc nh c thi im cn m thyristor , cn so snh hai tn hiu Udk

v Urc, vic so snh hai tn hiu c th c thc hin bng tranzitor (Tr) nh

trn

hnh 3-6a . Ti thi im Udk= Urcu vo Tr lt trng thi kho sang m (

hay ngc li t m sang kho ) , lm cho in p ra cng b lt trng thi , ti

ta nh du c thi im cn m thyristor .

Vi mc m bo ho ca Tr ph thuc vo hiu Udk Urc= Ub, hiu

ny c mt vng in p nh hng vi mV , lm cho Tr khng lm vic ch

ng ct nh mong mun , do nhiu khi lm thi im m thyristor b

lch kh xa so vi im cn m ti Udk= Urc.

Khch i thut tonc h s khch i v cng ln , ch cn mt tn hiurt nh (c V) u vo , u ra c in p ngun nui , nn vic ng dng

UA

t

t

UC1

2 3 4

UA

UB

Uk1

Urc

1

t

UC2Uk2

Urc2 2

1

t

32


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khch i thuc ton lm khu so snh l hp l . Cc s so snh dng khch

i thut ton nh hnh 3-6b, c rt thnggp trong cc s hin nay . u

im hn hn ca cc s ny l c th pht xung iu khin chnh xc ti Udk

= Urc

Mt s s khu so snh thng gp nh sau.

Hnh 6-8 : Cc khu so snh thng gp.

a ) Bng tranzitor ; b ) Bng mt cng o ca khch i thut ton

c ) Hai cng khch i thut ton ;

.

Hnh 6-9 : S so snh hai tn hiu khc du.

R1

R2

urc

udkUra

A3

Hnh - b

+

_

-12

+12

Hnh - a

-E

R3

R1

R2

urc

udkUra

R1

R2

urc

udk

Hnh - c

Ura

A3

U

-Vsat

+Vsat

0

Udk

Urc


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6.3.3. Khu khch i.

Vi nhin v to xung ph hp m thyristor tng khch i cui cng

thng c thit k bng tranzitor cng sut , nh hnh 3-8a . c xung dng

kim gi ti thyristor ta dng bin p xung , c khch i cng sut ta dng Tr

, iot D bo v Tr v cun dy s cp bin p xung khi Tr kho t ngt . Mt

d vi u im n gin , nhng s ny khng c dng rng ri , bi l h

s khch ica Tranzitor loai ny nhiu khi khng ln , khch i c

tn hiu t khuso snh a sang.

Tng khchi cui cng bng s Darlington nh hnh 3-8b , Thng hay

c dng trong thc t . S ny hon ton c th p ng c yu cu vkhch i cng sut , khi h s khch i c nhn ln theo thng s ca cc

Tranzitor .

Trong thc t xung iu khin ch cn c rng b ( c khong 10 n

200 s ), m thi gian m thng cc Tranzitor cng sut di ti a mt na chu

k c 0,01s , lm cho cng sut to nhit d ca Tr qu ln v kch thc dy

qun s cp bin p d ln . gim nh cng sut to nhit Tr v kch thcdy qun s cp my bin p xung , ta c th thm t ni tng nh hnh 8-3c .

Theo s ny , Tr ch m cho dng in chy qua trong khong thi gian np

t , nn dng in hiu dng ca chng b hn nhiu ln .


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+E

uv

R

D

Tr

BAX

a)

+E

uv

R

D

Tr

BAX

b)

Tr1

+E

uv

R

D

Tr

BAX

Tr1

D

C

c)

H

nh

6-10 S cc khu khch i v phn phi xung.

a)Bng tranzitor cng sut , b) Bng s Darlington , c) S c t ni

tng ;


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6.3.4. Khu to xung chm :

i vi s mt mch , gim dng cng sut cho tng khch i v

tng s lng cho xung kch m , nhm m bo cho thyristor m mt cch

chc chn , ngi ta hay pht xung chm cho cc thyristor . Nguyn tc pht

xung chm l trc khi vo tng khch i , ta a chn thm mt cng AND (

& ) vi tn hiu vo nhn t tng so snh v t b pht xung chm nh hnh 3-

10 .

Hnh 6-11: S phi hp to xung chm

Vi mch 555 to xung ng h ( hnh 3-11a ) cho ta cht lng xung kh

tt v s cng n gin . S ny thng hay gp trong cc mch to xung.

Trong thit k mch iu khin , thng hays dng khch i thut ton.

Do ng dng v linh kin , khu to xung chm cng c th s

dng khch i thut ton nh cc s trn hnh 3-11b,c . Tuy nhin y s

dao ng a hi (hnh 3-11b) c u im hn v mc n gin do

c s dng kh rng ri trong cc mch to xung ch nht

Hnh 6-12 : th dng sng ca khu to xung chm .

AND

Tso snh

Tchm xung

Ti khch i

t

Ura

0

kVsat

-kVsat

Vsat

-Vsat

uc

T1 T2

0


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Hnh 6-13 : a ) S to xung chm dng vi mch 555 .

b ) S to xung chm a hi bng khch i thut ton .

c ) S to xung chm to bng mch khch i thut ton

.

Uc

R2

R1

_

+

+12

-12

A

R2

R3

R1

R3

A1 A2

R4

C

a )

a )

b ) c )

C

+U

+Urc

C2C1

R2

R1

555

7

2 1

3

8 4


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6.4. S mch iu khin v nguyn l hot ng.

T cc khu gi thiu trn ta chn c s iu khin mt knh

nh hnh 3-13 .

Hot ng ca mch iu khin hnh 3-13 c gii thch nh sau :

in p vo ti im A (UA) c dng hnh sin , trng pha vi ant ca

thyristor , qua khch i thut ton A1cho ta chui xung ch nht i xng UB.

Phn in p dng ca in p ch nht UBqua it D1ti A2tch phn thnh

in p ta Urc. Phn p m ca in p UBlm m thng Tranzitor Tr1, kt

qu l A2b ngn mch

( Vi Urc= 0 ) trong vng UBm . Trn u ra ca A2ta c chui in p rng

ca Urcgin on .

in p Urcc so snh vi in p iukhin Udkti u vo ca A3.

Tng i s Urc+ Udkquyt nh du in p u ra ca khch i thut ton A3

. Trong khong thi gian t 0 t1vi Udk> Urc, in p UD m . Trong khong

t1 t2, in p Udkv Urci ngc li , lm cho UDlt ln dng . Cc

khong thi gian tip theo gii thch in p UDtng t .Mch a hi to xung chm A4cho ta chui xung tn s cao , vi in p

UEtrn hnh 3-13 . Dao ng a hi c tn s hng chc kHz , y ch m t

nh tnh .

Hai tn hiu UDv UEcng c a ti khu AND hai cng vo . Khi

ng thi c c hai tn hiu dng UD , UE ( Trong cc khong t1 t2, t4 t5

) ta s c xung UFlm m thng cc Tranzitor, kt qu l ta nhn c chuixung nhn Xdktrn bin p xung , a ti m thyristor T .

in p Uds sut hin trn ti t thi im c xung iu khin u tin ,

tai cc thi im t2 , t4trong chui xung iu khin , ca mi chu k in p

ngun cp , cho ti cui bn k in p dng ant .

Sau y l s iukhin chnh lu cu 3 pha s dng cc khu trn:


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Hnh 6-14 s iu khin chnh lu cu 3 pha


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Hnh 6-15 :TCA 785

Hnh 6-16 Vi mch TCA785

Hin nay c nhiu hng ch to cc vi x l chuyn dng iu khin

cc thyristor rt tin li . Sau y xin gii thiu v IC TCA 785 do Simens ch

to c chc nng iu khin m cc van Thyristor, Triac.... Trong n ny em

s dng TCA 785 iu khin m van thyristor.

6.5 Tng quan v TCA 785.

6.5.1 Gii thiu.

6.5.2 S vi mch TC 785

Bng ch thch:

PinChn SymbolK hiu Function (Chc nng)

1 GND Ground Ni t


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Vi mch TCA 785 cn c gi l cng tc ngng.

-c bn rng ri trn th trng, vi mch ny do hng Siemens ch to, c

s dng iu khin cc thit b chnh lu, thit b iu chnh dng in xoay

chiu.

-TCA 785 l vi mch phc hp thc hin 4 chc nng ca mt mch iukhin:

+T uin p ng b.

+To in p rng ca ng b.

+So snh.

+To xung ra.

2

3

4

2Q

Q U

1Q

Output 2 inverted u ra s 2 o

Output U u ra U

Output 1 inverted u ra s 1 o

5 VSYNC Synchronous voltage in p ng b

6

7

I

Q Z

Inhibit Chn kho

Output Z u ra Z

8 VREF Stabilized voltage in p chun

9

10

R9

C10

Ramp resistance in tr tuyn

tnh

Ramp capacitance T tuyn tnh

11 V11 Control voltage in p iu

khin

12 C12 Pulse extension M rng xung

13 L Long pulse Xung di

14

15

Q 1

Q 2

Output 1 u ra s 1

Output 2 u ra s 2

16 Vs Supply voltage in p ngun

nui


57/75



6.5.3.M t chc nng.Tn hiu ng b c c qua tr khng cao t in p dy(V5).B pht

hin in p khng s xc nh cc in p khng v chuyn chng n thanh

ghi ng b.

Thanh ghi ng b ny iu khin b to dc(lm dc xung tn hiukhin),t C10 trong b to dc c np vi dng c nh (xc nh bi

R9).Nu in p dc (in p rng ca,tam gic) V10 vt qu in p iu khin

V11(gc m ) th tn hiuin chuyn thnh dng Logic ph thuc vo ln

ca in p iu khin V11m gc m c th c dch chuyn trong khong

(00 1800)

Vi mi 1/2 phn sng mt xung dng c 30 s li xut hin ti cc u ra

Q1,Q2 Gi s tn ti xung c th t ti 1800

qua t C12.Nu chn 12 ni masscc xung trong khong gc ( 1800) s xut hin .

Cc u ra 1, 2 cung cp tn hiu ngc vi Q1,Q2 .Tn hiu ti +1800c

th c dng iu khin mt b Lgic ngoi c ti chn 3.

Mt tn hiu tng ng vi lin kt NOR ca Q1,Q2 c sn ti ca ra QZ

(chn 7)

Cng vo hn ch c th c dng loi tr hot ng ca cc cng ra Q1,Q2

1, 2.

Chn 13 c th dng mrng cc u ra 1, 2 nhm lp y rng xung

(1800- )

Q

Q

Q

Q

Q

Q


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10

10

V

V

11V10

V

V0

2.15QV

1.14QV

2.15QV

1.14QV

2.2QV

1.4QV

QUV .3

QZV .7

5V in p ng b

in p nh dc

in p dc

in p iu khin in p dc min

Chn 12 t i t

Chn 12 t i t

Chn 13 t i t

Chn 13 t i t

Hnh 6-17 Gin in p

C th iu chnh gc m t 00n 1800in.

-Thng s ch yu ca TCA 785:

in p nui: Vs= - 0.5- 18V

Dng in tiu th: IS= 10 mA

Dng in ra: I = 50 mA

in p rng ca: Vr max

= (VS2) V

in tr trong mch to in p rng ca: R9= 20 k - 500k

in p iu khin: V11= -0,5(Us2) V

T in: C10= 0,5 F

Tn s xung ra:f= 10500 Hz

Dng in u ra ti chn 14 15 : IQ = - 10 -400 mA


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in p cm : V6 = - 0.5 VS

Dng in ra ng b : Isync= - 200 + 200 A

Dng in ra ti chn 2,3,4,7 : IQ = 10 mA

in p ra ti chn 2,3,4,7 : VQ = VS (V)

Nhit tip gip : TJ = 1500C

Nhit lm vic : TSTG = - 550C n 1250C

Nhit xung quanh : TA = - 25oC n 850oC


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Hnh 6-18Mch iu khin chnh lu cu 3 pha dng TCA 785


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Tnh chn thng s mch:

Thng tin t nh sn xut cung cp ta c:

Vi R9bng khong 200K. Ta chn R9= 220K.

Vi C10= 22nF.

Khi t = t0, U10= Ucm= U11Ngi ta nhn c xung ra chn 15 nu V(t) > 0

hoc mt xung ra chn 14 nu V(t) < 0.

t0= C10.

gc

TC12khuch i rng xung ra. C thchn C12= 0 n 330pF rng

xung t30 . Ta chn C12=330pF.

6.6. Tnh ngun nui .

Ta cn to ra ngun in p U 12 V cp cho my bin p xung, nui

IC........

Ta chn mch chnh lu cu ba pha khng iu khin dng 12 con it

to ra in p 12 V , v + 12 V nh hnh 3-17 .

in p th cp my bin p ngun nui l :

U2 =34,2

12= 5,1 V , ta chn U2= 9 V ;

Vicxy dng ngun n p mt chiu bng thyristor c nhc im l

chn v tnh ton phc tp i hi phi c k thut chuyn mn cao . S ra i

ca cc vi mch n p h 7812 v 7912 cho php n gin ho qu trnh ny , v

vy n c s dng rng ri trongthc t .

Vi mch IC 7812 thng c ba chn , chn u vo , chn u ra v chn


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ni t. Do c nhiu hng sn xut ra loi IC ny do hnh dng bn ngoi v

th t ca cc chn c khc nhau .

Hnh 6-19 : S nguyn l to ngun nui 12 V .

V vy n nh in p ra ca ngun nui , ta dng hai vi mch n p l7812 v 7912 , cc thng s chung ca vi mch ny nh sau :

in p u vo : UV= 7 35 V ;

in p ra : Vi IC 7812 th Ura= + 12 V ;

Vi IC 7912 th Ura= - 12 V ;

Dng in u ra : Ira = 0 1 A ;

T in C4 , C5, C6, C7dng lc thnh phn sng hi bc cao .Chn C4= C5= C6= C7= 470 F ; U = 35 V .

470F

A B C

220

V

a b c*a *b *c

** *

C5 C4

470F

C7

470F

C6

470F

7812

7912

0 +12 V-12 V


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6.7. Tnh ton my bin p ngun nui v ng pha.

- Ta thit k my bin p dng cho c vic to in p ng pha v to

ngun nui . Chn kiu my bin p ba pha ba tr , trn mi tr c ba cun dy

, mt cun s cp v hai cun th cp .

- in p ly ra th cp my bin p lm in p ng pha , v lm in

p ca ngun nui .

U2 = U2ph = UN = 9 V ;

- Dng in th cp my bin p ng pha .

I2ph = 1 mA ;

- Cng sut ngun nui cp cho my bin p xung .

Pph = 6.U2ph.I2ph = 6.9.1.10-3 = 0,054 W ;

- Cng sut my bin p xung cp cho cc iu khin thyristor .

Px= 6.Udk.Idk = 6.3.0,2 = 3.6 W ;

- Cng sut s dng cho vic to ngun nui .

PN= Pph+ P8IC+ Px

PN= 0,054 + 5,12 + 3,6 = 8,774 W ;- Cng sut ca my bin p c k n 5% tn tht trong my .

S = 1,05(Pph+ PN) = 1,05(0,054 + 8,774) = 9,269 VA ;

- Dng in th cp my bin p .

I2 =9.6

269,9

.6 2

U

S= 0,172 A ;

- Dng in s cp my bin p .I1 =

220.3

269,9

.3 1

U

S = 0,014 A ;

6.8. Tnh chn it cho b chnh lu ngun nui.

- Dng in hiu dng qua it .

IDhd = 2172,0

22I = 0,122 A ;

- in p ngc ln nht m it phi chu .


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UNmax = 9.6.6 2 U = 22 V ;

- Chn it c dng nh mc .

Idm KI.IDdm = 10.0,1 = 1 A ;

- Chn it c in p ngc ln nht .Un = Ku.UNmax = 2.22 = 44 V ;

Vy chn it loi KIT 208A c cc thng s sau :

+ Dng in nh mc : Idm= 1,5 A ;

+ in p ngc cc i ca it : UN = 100 V ;

6.9. Tnh chn cc thit b bo v mch ng lc .

6.9.1. S mch ng lc c cc thit b bo v.

S mch ng lcc thit b bo v xem hnh 6-20 .


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Hnh 6-20Mch ng lc c thit b bo v .

6.9.2. Bo v qu nhit cho cc van bn dn.

Khi lm vic vi dng in chy qua , trn van c s st p , do c tn

hao cng sut P , tn hao ny sinh ra nhit t nng van bn dn . Mt khc


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van bn dn ch c php lm vic di nhit cho php TCPno , nu

qu nhit cho php th cc van bn dn s b ph hng . van bn dn lm

vic an ton , khng b chc thng v nhit , ta phi chn v thit k h thng

tn nhit hp l .

Tnh ton cnh tn nhit:

- Tn tht cng sut trn mt thyristor .

P = U.Ilv = 2.23,09 = 46,18 W ;

- Din tch b mt to nhit .

Sm =.mK

P ;

Trong :

P : Tn hao cng sut ( W ) ;

: chnh lch nhit so vi mi trng .

Km: H s to nhit bng i lu v bc x . Chn Km= 8 W/m2.0C .

Tlv,Tmt: Nhit lm vic v nhit ca mi trng (0C) .

Chn nhit mi trng Tmt= 400C . Nhit lm vic cho php ca

thyristor Tcp = 1250C . Chn nhit trn cnh tn nhit Tlv = 800C . = Tlv - Tmt= 80 - 40 = 40

0C ;

Vy : Sm =40.8

18,46 = 0,144 m2 ;

Chn loi cnh tn nhit c 12 cnh , kch thc mi cnh l

a b = 16 16 (cm cm ) .

Tng din tch ca cnh tn nhit .

S = 12 . 2 . 16 . 16 = 0,6144 m2 ;

6.9.3. Bo v qu dng cho van.Aptomat dng ng ct mch ng lc , t ng bo v khi qu ti

v ngn mch thyistor , ngn mch u ra b bin i , ngn mch th cp

my bin p , ngn mch ch nghch lu .

- Chn aptomat c :

Idm= k.I = 1,1. 3 .I1 = 1,1 . 3 . 17,93 = 34,16 A ;


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Vi I1: l dng in s cp my bin p .

k : H s an ton .

Udm = 400 V ;

Aptomat c ba tip im chnh , c th ng ct bng tay hoc bng nam

chm in .

Chnh nh dng ngn mch .

Inm= 2,5.I = 2,5. 3 .17,93 = 77,64 A ;

Dng qu ti .

Iqt = 1,5 .I = 1,5 . 3 . 17,93 = 46,58 A ;

- Chn cu dao c dng nh mc .ICD = IdmAP = 34,16 A ;

Cu dao dng to khong cch an ton khi sa cha h truyn

ng .

- Dng dy chy tc ng nhanh bo v ngn mch cc thyristor ,

ngn mch u ra ca b chnh lu .:

Nhm 1CC :

Dng in nh mc dychy nhm 1CC l :

I1CC = 1,1.I2 = 1,1 . 32,6 = 35,86 A ;

Nhm 2CC :

Dng in nh mc dy chy nhm 2CC l :

I2CC = 1,1.IhdV= 1,1 . 23,09 = 25,399 A ;

Nhm 3CC :

Dng in nh mc dy chy nhm 3CC l :

I3CC = 1,1.Idm= 1,1 . 40 = 44 A ;

Vy chn cu chy nhm :

1CC loi 100 A ; 2CC loi 100 A ; 3CC loi 100 A ;

6.9.4. Bo v qu in p cho van.

Linh kin bn dn ni chung v linh kin bn dn cng sut ni ring


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, rt nhy cm vi s thay i ca in p . Nhng yu t nh hng ln

nht ti van bn dn m ta cn c phng thc bo v l :

- in p t vo van ln qu thng s ca van .

- Xung in p do chuyn mch van .

- Xung in p t pha li in xoay chiu , nguyn nhn thng

gp l do ct ti c in cm ln trn ng dy .

- Xung in p do ct t ngt my bin p non ti .

- bo v cho van lm vic di hn khng b qu in p , th ta

phi chn ng cc van bn dn theo in p ngc .

- bo v qu in p ca xung in p do qu trnh ng ct cc van

thyristor c thc hin bng cch mc R C song song vi thyristor . Khi c

s c chuyn mch , cc in tch tch t trong cc lp bn dn phng ra ngoi

to ra dng in ngc trong khong thi gian ngn . S bin thin nhanh

chng ca dng in ngc gy ra sc in ng cm ng rt ln trong cc in

cm , lm cho qu in p gia ant v catt ca thyristor . Khi c mch R C

mc song song vi thyristor , to ra mch vng phng in tch trong qu trnh

chuyn mch nn thyristor khng b qu in p .

Theo kinh nghim R1= ( 5 30 ) ; C1= ( 0,25 4 ) F ;

Ta chn : R1= 5,1 ; C1= 0,25 F ;

Hnh 6-20 : Mch R C bo v qu in p khi van chuyn mch .

- bo v cho xung in p li t in p li , ta mc song song vi ti

u vo mt mch R C nhm lc xung . Khi xut hin xung in p trn

R1 C1


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ng dy , nh c mch lc ny m nh xung gn nh nm li hon tan trn

in tr ng dy .

Tr s R, C ph thuc nhiu vo ti .

Theo kinh nghim R2= ( 5 30 ) ; C2= 4 F ;Ta chn : R1= 12,5 ; C1= 4 F ;

Hnh 6-21 : Mch R C bo v xung in p t li.

6.10 Thit k cun khng lc.

6.10.1Xc nh gc m cc tiu v cc i in p iu khin cc tiu, cc

i

Khi gc m nh nht = min th in p trn ti ln nht :

Ud max = Ud0.Cosmin = Ud.dmv lc ny tng ng vi tc ng c

s ln nht nmax= ndm.

min= arccos( ) = = arc = 35o

in p iu khin tng ng gc m 350

= 1,95V (Urcmax= Us2V = 12- 2 = 10V)

R2 R2C2 C2

C2R2


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Ta c:

D =m in

m ax

n

n=

,,

,,

.

.

.m in.

..

udmud

udmudmd

RIU

RIU

Ud.min= dmudmud

RIDUD ..

m in. ,, ..11

Ud.min = dtBAudmu RRRIDUD ,, ..1cos..34,2

1.m in2

Ud.min =

BABAudmu XRRIU

3..120cos..34,2

20

1,, .min2

Thay svo ta c :

Ud.min =

67,0.

306,001,0.40.120cos.209.34,2

20

1min

Vy : Ud.min= 53,25 V .

Thay Ud.minvo cng thc ( 3-3 ) ta c :

max = arcos(0

m in.

d

d

U

U) = arcos(

209.34,2

25,53) = 780 .

= 4,33V (Urcmax= Us2V = 12- 2 = 10V)

6.10.2. Xc nh cc thnh phn sng hi.

thun tin cho vic khai trin chui Fourier , ta chuyn gc to sang

1, khi in p tc thi trn ti khi thyristor T1v T4dn :

Ud= Uab= 6 .U2cos( -6

+ ) ; Vi = .t ;

in p tc thi trn ti Udkhng sin v tun hon vi chu k :

=36

22

p;

Trong p = 6 l s xung p mch trong mt chu k in p li .

Khi khai trin chui Fourier ca in p Ud:

Ud= ).2

sin.2

cos.(2 1

0

kbka

an

K

n

;

Hay :


71/75



Ud= ).6sin..6cos.(2 1

0 kbkaa

n

K

n

=

=

1

.

0 )6sin(2 K

mn kkUa

Trong :

*an=

0 0

2 .6cos)6

cos(66

.6cos2

dkUdkUd ;

an =

cos

1)6(

)2(63cos

6sin2.

1)6(

)2(.

632222

kU

kU ;

*bn=

0 0

2 .6sin)6

cos(66

.6cos2

dkUdkUd ;

bn =

sin

1)6(

)2(.

63sin

6sin2.

1)6(

)2(632222

kU

kU ;

Ta c :

cos63

2 2

0 Ua ;

Vy ta c bin ca in p :Uk.n = 22 nn ba ;

Uk,n =

222

22 sin)6(cos

1)6(

163k

kU

;

Uk.n = 2 22

2

0 )6(11)6(

tgkk

Ud

;

Ud n

nkU )6sin(cos63 1.

;

6.10.3.Xc nh in cm cun khnglc :

T phn tch trn ta thy rng , khi gc m cng tng th bin thnhphn sng hi bt cao cng ln , c ngha p mch ca in p , dng in tngln .S p mch ny lm xu ch chuyn mch ca vnh gp , ng thigy ra tn hao ph di dng nhit trong ng c . hn ch s p mch ny, ta phi mc ni tip vi ng c mt cun khng lc ln Im 0,1.Idm .

Ngoi tc dng hn ch thnh phn sng hi bt cao , cun khng lccn c tc dng hn ch vng dng in gin on .

in khng lc cn c tnh khi gc m = max.Ta c :

Ud+ u~= E + R.Id+ R.I~+ Ldt

di

Cn bng hai v :

u~ = R.i~ + Ldt

di v R.i~


72/75



Trong cc thnh phn xoay chiu bt cao , thnh phn sng bt k = 1 cmc ln nht , gn ng ta c :

u~ = U1msin ( 6 + 1)Nn :

i = 11 6cos.

..2.

1

Lf

Udtu

L

m = Im.cos ( 6 + 1)

Vy :

Im =Lf

U m..2.6

1

0,1.Idm

Suy ra : L dmu

m

If

U

,.1,0..2.6

1

Trong : = 6 l s xung p mch trong mt chu k in p .

U1m = 2.

max22

2

max0 6116

cos.

tg

Ud

U1m = 2.

0222

78.61.16

78cos.209.34.2tg

o

= 166,55 .

Thay s trn ta tnh L :

L =dmu

m

If

U

,.1,0..2.6

1

=

40.1,0.50..2.6

55,166

= 0,02H .

in cm mch phn ng c :Lc = L+ 2LBA

Trong :

Ll in cm mch phn ng ca ng c v c tnh theo cng thcUmanxkiLindvil :

L = .dmdm

dm

Inp

U

...2

60.

Trong = 0,25 l h s ly cho ng c c cun b .

L= dmdm

dm

Inp

U

...2

60.

= 0,25.

40.955.4.2

60.400

= 6,25.10-3H = 6,25 mH .

Ta c in cm phn ng c :Lc= L+ 2LBA= 6,25 + 2 . 2,13 = 10,51 mH .

in cm cun khng lc :Lk = LLc = 0,02.10

310,51 = 9,49 mH .6.11. Thit k kt cu cun khng lc .

Cc thng s ban u :in cm yu cu ca cun khng lc : Lk= 9,49 mH .Dng in nh mc chy qua cun khng lc : Im= 40 A .Bin dng in xoay chiu bt 1 : I1m= 10%.Idm= 4 A .- Do in cm cun khng ln v in tr rt b , ta c th coi tng tr

cun khng xp x bng in khng ca cun khng .

Zt = Xk = 2.f.Lk = 2.50.9,49.10-3

= 2,98 .- in p xoay chiu ri trn cun khng lc .


73/75



U = Zk.2

1mI = 2,23.2

4= 6,307 V .

- Cng sut ca cun khng lc .

S = U.2

1mI = 10,249.2

4= 28,42 VA .

7. Mch o lng cm bin.

7.1. Thit b o lng7.1.1 o dng in, in p 1 chiu c cch ly

- Yu cu: m bo chnh xc, m bo cch ly gia mch lc

v mch iu khin.S mch cch ly o i lng 1 chiu:

7.1.2 o dng xoay chiu.- o dng xoay chiu 3 pha n gin nht dng bin dng, sau

a qua chnh lu c dng 1 chiuS nguyn l:

+-

+-

+

-

+-

+-

Rs U=

A

B

C

C

+

+

-

+


74/75



8. Kt Lun.

Sau mt thi gian hc tp v nghin cu v thc hin ti vi schbotn tnh ca cc thy c gio trong bmn tng ho v c bit l thyNguyn ng hangcng vi snlc ca bn thn n ychng em hon thnh y cc cng vic m ti tt nghip yu cu.

Trong qu trnh lm ti em tch luc mt skin thc c thnng cao cho trnh ca mnh mt cch chc chn hn, Kt quthu c:

- Hiu r hn vHtruyn ng in T-.

- Cc nguyn tc iu chnh tng truyn ng in.

- Cch xy dng cc biu chnh dng in, tc .

-Xy dng c mch iu khin cho htruyn ng in T-

- Hiu r hn vphn mm Matlab, m phng c c tnh n nh ca h.

- Tm hiu c chc nng ca IC TCA785 v mt slinh kin khc.

- .

Tuy nhin vi thi gian c hn nn ti nghin cu c nhiu chcn hn chnht nh .

Trong thi gian ny , mc d cgng nlc ht mnh song khng trnhkhi nhng thiu st . Em rt mong nhn c sgp xy dng ca cc thyc ti ca em c hon thin hn . Mt ln na em xin chn thnh cm

R0R0

R0

IaIb Ic

I2

R1

0

U2I

U2I0

R

C


75/75



n thy gio hng dn v cc thy c gio gip em hon thnh tt tiny .

9. Ti Liu tham kho.

Trong qu trnh lm ti chng em c s dng mt s ti liu thamkho sau:

Ti liu tham kho:

[1] Bi Quc Khnh- Nguyn Vn Lin, iu chnh tng truyn ng in.

[2] Nguyn Trng Thun (2004) , iu khin Logic & ng dng,NXB KHKT,H

Ni.

[3] Nguyn Phng Quang (2004), Matlab&Simulink dnh cho ks iu khin

tng,NXB

KHKT,H Ni.

[4] Nguyn Phng Quang (1996), iu khin tng truyn ng in xoay

chiu ba pha,NXB Gio dc.

*5+ Sch in tcng sut

[6] Sch truyn ng in

[7] Vi mch TCA 785 ca Simens

Ting Anh

[8] Antoni Arias Pujol, Improvements in direct torque control of induction

motors

(Unpublished work style). Unpublished

[9] Cc ngun ti iu khc trn Internet.

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