ĐỒ ÁN ĐIỆN TỬ CÔNG SUẤT_T2TĐH_600A

8/14/2019 N IN T CNG SUT_T2TH_600A

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n in t cng sut :Thit k ngun m mt chiu 8:45 a11/p1111/2/2009

NIN T CNG SUT

tI :Thit k ngun m mt chiu

MCH M BO CC YU CU SAU : Ngun m lm vic theo nguyn tc gi dng inkhng i trong sut qu trnh m. Mch c khu bo vqu p, qu ti v ngn mch.

Phng n lachn

in p voAC 50Hz

in pra(VDC)

Dng ti Imax(A)

3 x380 24 600

Trnh t thit k n:1. Gii thiu chung v chng loi thit b s thit k2. xut cc phng n, phn tch u nhc im ca tng

phng n la chn phng n ph hp.3. Thit k mch lc v mch iu khin.

4. Thuyt minh nguyn l lm vic v s km theo.5. Tnh ton mch lc v mch iu khin.6. Rt ra kt lun sau qu trnh thit k n.

Dng vn Khoa TC06-4073 _ Nhm 13 LpT2 TH K46Email:[email protected]

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`

Li ni u

Ngy nay m kim loi tr thnh mt ngnh k thut pht

trin mnh m hu ht cc nc trn th gii, phc v mtcch c lc cho mi ngnh khoa hc k thut sn xut vi sng con ngi.

Lp m kim loi trn b mt cc chi tit my,dng csinh hot, phng tin sn xut, giao thng vn ti, khai thcm a cht,thng tin lin lc, k thut in t, c khchnh xc, thit b y t, trang tr bao b ..Vy m in l g ?

Mt cch n gin nht c th hiu m in l qu trnhkt ta kim loi ln b mt nn mt lp ph c nhng tnhcht c, l, ho ... p ng c cc yu cu k thut mongmun.

M kim loi khng ch lm mc ch bo v khi b nmn m cn c tc dng trang tr, lm tng v p, sc hpdn cho cc dmh c my mc v trang sc..

Ngy nay khng ring g nc pht trin m ngay trongnc ta k thut m c nhng bc pht trin nhy vt, thomn yu cu k thut trong sn xut cung nh trong kinhdoanh

K thut m i hi phi khng ngng pht trinnghin cu ci tin k thut ,my mc chuyn dng thit bdy chuyn sn xut ng b t ng ho vi tin cycao. iu ny s gip nng cao cht lng m v h gi thnhsn phm, chng nhim mi trng.

c mt lp m tt ngoi nhng yu t khc th ngunin dng m l rt quan trng.

i vi sinh vin t ng ha, mn hc in t cngsut l mt mn rt quan trng. Vi s ging dy nhit tnhca cc thy c trong khoa em tng bc tip cn mn hc. c th lm vng l thuyt p dng vo thc t, hck ny em c cc thy giao cho n mn hc vi ti :Thit k ngunm mt chiu. y l mt ti c quy mv ng dng thc t.


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Vi s c gng ca bn thn cng vi s ch bo ca ccthy c gio trong b mn v c bit l thy V MinhChnh gip em hon thnh n ny.

Do ln u lm n in t cng sut kinh nghimcha c ln em khng trnh khi nhng sai st mong cc thygip . Cui cng em xin chn thnh cm n !

H ni, ngy 12thng 7 nm 2009

Sinhvin

Dng vnKhoa

A. Gii thiu chung v cng ngh m in

ti thit k ngun m mt chiu l mt ti cgi tr thc t ln, bi v trong cng ngh m ngun inmt chiu l mt yu t quan trng.

thy r gi tr ca ti, trc ht ta cn phi nm rmt s khi nim cng nh cc thit b c lin quan n qutrnh m bng in phn.

Ta da vo s in phn nh sau:


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`

S trn l m hnh dng trong phm vi nh nh phngth nghim ng thi cng dng trong qui m sn xut ln.Cc thnh phn c bn ca s in phn :1. Ngun in mt chiu nh : pin, c qui, my pht inmt chiu, b bin i. Ngy nay c dng ph bin nhtl b bin i. B bin i cho qu trnh in phn cin p ra thp : 3V, 6V, 12V, 24V Tu theo yu cu kthut m chn in p ra cho ph hp. Mt b bin i cth ly ra mt s in p cn thit cho mt s qui trnh.2. Ant :l in cc ni v cc dng ca ngun in mtchiu. Trc khi in phn ant cn phi nh sch du m,

lp gAnt dng trong m in c hai loi : ant ha tan v

ant khng ho tan. Ant ho tan c dng tronh cc trng hpm niken, m ng, m km, m thic Trong qu trnh inphn ant tan vo dung dch m theo phn ng in cc :

+

+

=

=

2

2

2

2

CueCu

NieNi

Cc cation kim loi tan vo dung dch in phn v in catt. Phn ng in ha ant l phn ng oxi ha.


Dung dchm

Chi tit

cn m

Ngunin

1 chiuincc

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Ant khng ha tan dng trong trng hp m Crm. Khiin phn b mt

ant khng ho tan cng din ra qu trnh oxi ha ClOHOH ,,2

+=

=

22

2

244

22

OOHeOH

CleCl

Kh thot ra ant trong qu trnh in phn thng chnhl 2O hay 2Cl .3. Catt : l in cc ni vi cc m ca ngun in mtchiu. Trong m in catt l vt m. Trn b mt vt m

lun din ra phn ng kh cc ion kim loi m. V d nh :M niken : =++ NieNi 22

M km =++ ZneZn 22

ng thi vi in kim loi b kh, +OH3 cng b kh giiphng ra kh 2H theo phn ng : OHHeoH 223 22 +=++

Kh 2H thot ra trn b mt ca tt c kh nng thmsu vo mng tinh th kim loi m v cc kim loi nn, lmgim bn c hc ca kim loi (kh 2H khi gp nhit

cao gin n mnh gy ra s rn nt, gin kim loi) .Ngi ta gihin tng ny l hin tng gin kim loi . kim loi m bm cht vo b mt kim lo nn ng

thi cho lp m ng u, bng sng hp dn, trc khi m tacn phi gia cng cho b mt chi tit bng phng, bng vsch cc cht du m mng oxt.

Cat vt m cn phi nhng ngp vo dung dch, thngngp di mt nc 8 15cm v cch y b khong 15cm. Ccch ni phi m bo tip xc tht tt, khng gy ra

hin tng phng in trong cht in phn. Tuyt ikhng chm trc tip gia ant v catt khi ni mchin.4. Dung dich cht in phn : dung dch cht in phndng m thng c hai phn :

_ Thnh phn c bn : gm mui v hp cht cha in cakim loi m v mt s ho cht thit yu khc, nu thiu hacht ny th dung dich khng th dng m c.

_ Thnh phn th hai : bao gm cc cht ph gia

+ Cht lm bng lp m


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+Cht m gi cho pH ca dung dch n nh+Cht gim sc cng ni ti m bo lp m khng

bong nt

+Cht san bng m bo cho lp m ng u hn+Cht lm tng dn in cho lp m ng uhn

+ Cht chng th ng ha ant nhm n nh mMt s c im dung dch m :

_ Dung dch m cn phi c n in cao. nin ca dung dch khng nhng ch gim c tnthtin trong qu trnh m m cn lm cho lp m ngu hn._ Mi dung dch cho lp m c cht lng trong mt khong pH

nht nh. V d m Niken pH=4,5 n 5,5. M km trongdung dch amniclorua pH= 4,5 n 5,5. M km trong dungdch axt pH= 3,5 n 4,0_ Mi dung dch cho lp m c cht lng cao trong mt khong

nhit nht nh. VD m Niken khong nhit lC.7055 , m vng C.7060 . Nhn chung, khi in phn

nhit dung dch khng vt qua nhit si ca dungdch.

_ Mi dung dch c mt khoang mt dng catt thch hp._ Dung dch cha mui phc ca kim loi thng cho lp m ccht lng tt hn lp m t chnh kim loi thu c t nuin. VD lp m thu c t dung dch 24)(CNZnhoc 23)(CNZn tt hn lp m thu c t dung dch mui

4CuSO .5. B in phn : lm t vt liu cch in, bn ha hc,bn nhit. Thnh v mt trong ca b thng c lt bngcht do c bn ha hc, bn nhit. Lp cht do lt phikn tuyt i, nc khng thm qua c. Mt ngoi snnhiu lp chng g. B m thng c dng hnh ch nht,iu ny gip cho lp m c phn b u hn b c hnhdng khc. C nhiu b m nh b m tnh, thng m quay,

Trn dy l ton b s tng qut ca qu trnh mbng in phn.

Trong cng ngh m cn c mt s yu cu v gia cngb mt trc khi m.Yu cu b mt trc khi m :


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- Trc khi m vt cn m c tin hnh gia cng c kh c b mt bng phng, ng thi ty xa cc lop g,nh bng b mt theo yu cu s dng.

- Ty sch du m cc hp cht ha hc khc c th ctrn b mt vt m.Tm li trc lc chi tit vo b in phn, b mt cn

phi tht bng phng, sc nt bng tuyt i sch du m,cc mng oxit c th c. Trong iu kin nh vy lp m thuc mi c bng tt, khng sc, khng sn si, bng uton lp m ng nht nh .

Phng php gia cng b mt kim loi trc khi m :- Phng php gia cng c kh bao gm : mi th, mi

tinh, nh bng quay bng hay sc bng trong thng quay.- Phng php gia cng ha hc hay in ha hcbao

gm : ty du m, ty g, ty li lm bng b mt, ra sch.S la chn phng php gia cng cho hiu qa tt nht li

c gi thnh r, i hi ngi k thut vin phi c hiu bity v nht l phi c kinh nghim sn xut. Bt kthiu st no d nh hoc nh gi khng ng cng vicchun b b mt u dn n gim st cht lng v hnhthc lp m. Cht lng lp m ph thuc mt cch c bn vophng php c la chn, k thut v iu kin tin hnhchun b b mt lp m. Khng bao gi chng ta coi nhvic chun b b mt vt m.

B. phn tch v La chn phng nI. Phn tch cc phng n

Nhim v t ra i vi n l thit k ngun m mtchiu c in p thp v dng rt ln. Ngun m lm victheo nguyn tc gi dng in m trong qu trnh np.Mch c khu bo v chng chm in cc.

Trong cng ngh m in th ngun in l mt yu tht sc quan trng, n quyt nh nhiu n cht lng lpm thu c. Ngun in mt chiu c th l c quy, mypht in mt chiu, b bin i Chng ta phn tchtng loi ngun quyt nh la chn phng n no :1. c quy : Tong cng ngh m in c quy ch c sdng trong phng th nghim hay sn xut quy m nh. Dohn ch v lng in tch ln c quy ch dng m cc chi


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tit nh, cn vi cc chi tit ln th khng dng c quy c.c bit khi dng in m i hi ln th c quy khng thp ng c. V vy m trong cng ngh m ngi ta t s

dng c quy lm ngun m.2. My pht in mt chiu : Trong cng ngh m dng mypht in mt chiu khc phc c cc nhc im ca cquy. My pht in mt chiu trong thc t c th c sdng rng ri trong quy m sn xut ln. Nhng gi thnh ut cho my pht in mt chiu ln, c cu iu khin hotng kh phc tp .My pht in mt chiu vi nhiu nhcim : c gp mau hng; thit b cng knh; lm vic cting n ln. My pht in mt chiu cn thng xuyn botr sa cha. Chnh v cc l do trn ln trong cng nghipngi ta khng dng my pht in mt chiu.3. b bin i :

Hin nay trong cng nghip th dng in xoaychiu c s dng rng ri. Cng ngh ch to cc thit bbn dn ngy cng hon thin, cc thit b hot ng vi tin cy cao. c bit cng ngh sn xut Thyristor t -

c nhiu thnh tu. Chnh v vy cc b bin i dngin xoay chiu thnh dng mt chiu ngy cng c sdng nhiu trong cc nghnh cng nghip. Ngy nay trongcng ngh m in th b bin i c dng rng ri nht.Cc b bin i dng trong qu trnh in phn c th chora cc in p nh : 3V, 6V, 12V, 24V, 30V, 50v. Tu theo yucu k thut m chn in th cho ph hp.B bin i vicc u im : thit b gn nh; tc ng nhanh; d t ngha; d iu khin v n nh dng. Chi ph u t cho bbin i cng r, hiu qu lm vic cao v n nh. So vidng ngun m l c quy hoc my pht in mt chiu thb bin i p ng c hn c v mt kinh t cng nhcc tiu chun k thut. Vy quyt nh phng n l dng bbin i.

Vi mch chnh lu c rt nhiu : chnh lu mt pha, chnhlu ba pha, chnh lu khng iu khin, chnh lu c iukhin Trong yu cu ca n l thit k ngun

m in p thp v dng kh ln. Trc ht ta xt trng hpchnh lu c iu khin, sau ta c th xt trng hpchnh lu it khng iu khin vi gc iu khin 0= .


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Cc phng n kh thi :

+ Chnh lu tia ba pha

+ Chnh lu cu ba pha i xng+Chnh lu cu ba pha khng i xng+ chnh lu su pha c cun khng cn

bng

Phng n 1: Chnh lu tia ba phaS nguyn l

T1

T2B

T3C

L R

A

Chnh lu tia ba pha c cu to t mt bin p ba pha vi thcp u sao c trung tnh, ba van bn ni cng cc tnh ni vi ti , ba u cn li ca van bn dn ni ti cc pha bin

p .Ti ni gia u ni chung ca van bn dn vi utrung tnh.

Khi bin p c ba pha u sao (Y) trn mi pha A, B, Cni mt van ba catod u chung cho in p dng ca ti,cn chung tnh bin p s l in p m. Ba pha in p A,B, C dch pha nhau mt gc l 120o theo cc ng congin p pha, c in p ca mt pha dng hn in p cahai pha kia trong khong thi gian 1/3 chu k (120o). T


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thy rng, ti mi thi im ch c in p ca mt pha d-ng hn hai pha kia.

Nguyn tc iu khin cc tit y l: khi anod catit no dng hn tit mi c kch m. Thi imin p ca hai pha giao nhau c coi l gc thng t nhin(nh vy trong chnh lu ba pha, gc m nh nht = 0o sdch pha so vi in p pha mt gc l 30o).

Ti mi thi im no ch c mt tit dn, nh vydng in ti lin tc, mi tiristor dn trong 1/3 chu k (-ng cong I1, I1 , I3 trn hnh) cn nu in p ti gin onth thi gian dn ca cc tiristor nh hn. Tuy nhin, trong chai trng hp dng in trung bnh ca cc tit u bng(1/3)Id. Trong khong thi gian tiristor dn, dng in catiristor bng dng in ti, trong khong tiristor kho dngin tiristor bng 0. in p ca tiristor phi chu bngindy gia pha c tiristor kho vi pha c tiristor ang dn. Vd trong khong t2 : t3 tiristor T1 kho cn T2 dn do tiristor T1 phi chu mt in p y UAB, n khong t3 : t4cc tiristor T1, T2 kho, cn T3 dn lc ny T1 chu in pdy UAC.

Khi ti thun tr dng in v in p ti lin tc haygin on ph thuc gc m ca cc tiristor. Nu gc m

Tiristor nh hn 30o, cc ng cong Ud, Id lin tc hnh1.8b, khi gc m ln hn > 30o in p v dng in tigin on (ng cong Ud, Id )

Khi ti in cm (nht l in cm ln) dng in, inp ti l cc ng cong lin tc, nh nng lng d tr trongcun dy ln duy tr dng in khi in p idu, nh ng cong nt m (tng t nh vy l ng congUd ) Trn hnh m t mt v d so snh cc ng cong inp ti khi gc m =60o ti thun tr hnh v ti in cmhnh

Tr s in p trung bnh ca ti s c tnh nu inp ti lin tc, khi in p ti gin on (in hnh khi tithun tr v gc m ln) in p ti c tnh:


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1 sin( )33

dod

UU

= +

Trong : Udo = 1,17.U2f - in p chnh lu tia ba phakhi van l itU2f - in p pha th cp bin p

Nhn xt : Chnh lu tia ba pha c cht lng in mt chiu

tt , vic iu khin cc van bn dn trong trng hp nycng tng i n gin. Dng in mi cun dy th cpl dng mt chiu, do bin p ba pha tr m t thng lithp bin p l t thng xoay chiu khng i xng lm cho

cng sut bin p phi ln . Nu y bin p c ch tot ba bin p mt pha th cng sut cc bin p cn ln hnnhiu. Khi ch to bin p ng lc, cc cun dy th cpphi c u sao (Y), c dy trung tnh phi ln hn dypha v dy trung tnh chu dng in ti.

Phng n 2 : Chnh lu cu ba pha khng i xngS nguyn l :

T1

T2

T3

LR

D1

D2

D3

Loi chnh ny c cu to t mt nhm (NA hoc NK) c

iu khin v mt nhm khng iu khin . Trn hnh mt gin in p chnh lu Uf, sng in p ti Ud, khongdn cc van bn dn T1, T2, T3, D1, D2, D3. Cc Tiristor c dn


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A B C


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t thi im c xung m cho n khi m Tiristor ca pha ktip.

V d T1 dn t t1 (thi im pht xung m T1) ti t3

(thi im pht xung m T2). Trong trng hp in p tiging on Tiristor c dn t thi im c xung mch nkhi in p dy i du. Cc it t ng dn khi in pt ln chng thun chiu. V d D1 phn cc thun trongkhong t4 t6 v n s m cho dng in chy t pha B vpha A trong khong t4 t5 v t pha C v pha A trong khongt5 t6.

Chnh lu cu ba pha iu khin khng i xng cdng in v in p ti lin tc khi gc m cc tiristor nhhn 60o, khi gc m tng ln v thnh phn in cm ca tinh, dong in v in p s gin on.

Theo dng sng in p ti, tr s in p trung bnhttrn ti bng 0 khi gc m t ti 180o. Ngi ta c th coiin p trung bnh trn ti l kt qu ca tng hai in pchnh lu tia ba pha.

max max

3 3 3(1 cos ) (1 cos )

2 2tb f day

U U U

= + = +

iu khin cc tiristor trong chnh lu cu ba phaiu khin khng i xng d dng hn, nhng cc iuho bc cao ca ti v ca ngun ln hn.

Khc vi chnh lu cu ba pha iu khin i xng, trongs ny vic iu khin cc van bn dn c thc hinn gin hn. Ta c th coi mch iu khin ca b chnhlu ny nh iu khin mt chnh lu tia ba pha.u im :

Chnh lu ba pha khng i xng d i khin , ngin kinh t.Cht lng in p , dng in tt.

Dng sng c bn


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`

Phng n 3: Chnh lu cu ba pha i xngS nguyn l:

T1

T5

T3

LR

T2

T4

T6

S cu ba pha i xng gm 6 thyristor, chia lm hainhm :

- nhm catt chung T1, T3, T5- nhm ant chung T2, T4, T6


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0

Ud

t

BA C


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in p cc pha : sin2 2UUa =

)3

2sin(2 2

= UUb

)3

4sin(2 2

= UUc

a. Hot ng ca s :

Gi thit T5, T6 ang cho dng chy qua bGcF VVVV == ,

+ Khi +

==6

2 cho xung iu khin m T1. Thyristor

ny m v 0>aU . S m ca T1 lm cho T5 b kho li mtcch t nhin v ca UU > . Lc ny T6 v T1 cho dng i qua.

in p ra trn ti :baabd UUUU

==

+ Khi +

==6

32 cho xung iu khin m T2. Thyristor

ny mv T6 dn dng, n t bU ln catt T2 m cb UU > .S m ca T2 lm cho T6 kho li mt cch t nhin v cb UU >.

Cc xung iu khin lch nhau3

c ln lt a n

cc cc iu khin ca cc thyrist theo th t 1, 2, 3,4, 5, 6,1,..Trong mi nhm, khi 1 thyristor m th n s kho ngay

thyritor trc n, nh trong bng sau :

Thi im M Kho 1 = /6 +

2 = 3 /6 +

3 = 5 /6 +

4 = 7 /6 +

5 = 9 /6 +

6 = 11 /6

+

T1T2T3T4T5

T6

T5T6T1

T2T3

T4


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Dng sng c bn

ng bao pha trn biu din in th im Fng bao pha di biu din in th im G

in p trn mch ti : GFd UUU = l khong cchthng ng gia hai ng bao

cos63

.sin22

6 26

5

6

2

=

= +

+

UdUUd

Gi tr in p ngc ln nht trn mi van :22max 45,26 UUUng ==

Dng in trung bnh chy qua van 3d

T II ==

b.u nhc im ca s :+ u im :

- s xung p chnh lu trong 1 chu k ln, v vy p mch ca in p chnh lu thp, cht lng in pcao.

- khng lm lch pha li in.+ Nhc im


15

du

di

dI

0

0


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- s dung s van ln, gi thnh thit b cao- s ny ch dung cho ti cng sut ln, dng

nh v in p chnh lu i hi bng phng.

Do dng ti dng trong m in c ti s ln, nn khng pdng c phng php ny, v cc van khng chu c dngti ln.

Phng n 3 : Chnh lu 6 pha c cun khng cn bng

a. S nguyn l

L

T5 T4 T3 T2 T1

R

T6

P Q

S chnh lu 6 pha c cun khng cn bng, c biudin nh trn s , bao gm my bin p ng lc, c cun

khng cn bng cbC , 6 thyristor chia lm hai nhm T1,T3,T5v T2,T4,T6 .

My bin p c hai h thng th cp a,b,c v a,b,c. Cccun dy trn mi pha a v a; bv b;c v c c s vng nhnhau nhng c cc tnh ngc nhau. H thng dy cun thcp my bin p c im trung tnh ring bit P v Q. P, Qc ni vi nhau qua cun khng cn bng.


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A B C


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_ u im :+ Dng in p ra c bng phng cao, c p

mch ln

+ Dng trung bnh qua van nh bng 1/6 dng quati._ Nhc im :

+ S van s dng ln gi thnh cao+ My bin p phc tp c s cun th cp nhiu.

* Dng in m kh ln, cn c vo u nhc im ca phngn ny, ta thy dng qua van nh trung bnh bng 1/6 dngqua ti. V vy ta chn b bin i dng lm ngun m lchnh lu 6 pha, c cun khng cn bng.

II.Chn phng n thit kChnh lu tia ba pha thng c la chn, khi cng sut

ti khng qu ln so vi bin p nguncp ( trnh gy mti xng cho ngun li), v khi ti c yu cu khng qu caov cht lng in p mt chiu. i vi cc loi ti c in pmt chiu nh mc l 220V, s tia ba pha c u imhn tt c. Bi v theo s ny, khi chnh lu trc tip t

li c in p mt chiu l220V. 1,17 = 257,4V. c in p 220V khng nht thit

phi ch to bin p, m ch cn ch to ba cun khng antca van l .

Chnh lu cu ba pha nn chn, khi cn cht lng inp mt chiu tt, v y l s c cht lng in p ratt nht, trong cc s chnh lu thng gp. S chnhlu cu ba pha iu khin khng i xng c mch iukhin n gin hn, nn trong a s cc trng hp ngi ta

thng chn phng n cu ba pha iu khin khng ixng. V d lm ngun cho my hn mt chiu, iu khinkch t my pht xoay chiu cng sut nh, cc b ngun chocc thit b in ho nh m ien, in phn...

S chnh lu cu ba pha iu khin i xng cdng nhiu trong cc trng hp ti c yu cu v vic hontr nng lng v li, v d nh iu khin ng c inmt chiu.


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gim nh hng ca hi bc ba ln li, i vi ti c cngsut ln s cp bin p thng ni tam gic . gim tit dindy qun th cp , cc bin p c th u tam gic.

S tia su pha ,vic ch to bin p phc tp v philm thm cun khng cn bng , nn thng c la chn khidng ti c dng in qu ln m theo s cu ba phakhng la chn c van theo dng in.

Cng tr s in p v dng ti nh nhau, s dng s cng nhiu pha dng in ca van bn dn cng nh. Ccs cu bao gi cng c in p lm vic ca van nhhn vi s tia cng loi.

Sau khi phn tch v nh gi v chnh lu, t cc unhc im ca cc s chnh lu trn th phng n:chnh lu cu ba pha iu khin khng ixng l hp lhn c . Bi l cng sut va, khng qu ln th s nyn gin v kinh t m cht lng in p tt m bo xy dng ngun m.Nn s la chn thit k l :

S chnh lu cu ba pha iu khinkx

C. trnh t Thit k chnh lu cu 3 pha kx

S mch lc:


19

A B C


20/55


T1

LR

D1

T2

T3

D2

D3

1. Tnh chn Tiristor.Tnh chn da vo cc yu t c bn ca dng ti,

iu kin to nhit, in p lm vic, cc thng s c bnca van c tnh nh sau:

- in p ngc ln nht m Tiristor m Tiristor:

Unmax = Knv.U2 = . .24 25,1( )3d

nv

u

UK VK

= =

Trong : Knv =3. 6

6nv uK K

= =

- in p ngc ca Tiristor cn chn:Unv = KdtU.Unmax = 1,8.25,1 = 45,18

Trong : KdtU l h s d tr in p, chn KdtU = 1,8- Dng lm vic ca van tnh theo dng hiu dng:

Ilv = Ihd = Khd.Id =

600346,5( )

3 3

dI

A= =

Chn iu kin lm vic ca van l c cnh to nhit , y din tch to nhit v c qut i lu khng kh.Vi iu kin dng nh mc ca van cn chn :

. 2,5.346,5 886,25( )dm i lv

I K I A= = =

Trong :Ki l h s d tr dng in, chn Ki = 2,5T cc thng s : Unv, Idmv ta chn 3 Tiristor loi C435A doNht sn xut


20


21/55


C cc thng s sau:in p ngc cc i ca van: Un = 100VDng in nh mc ca van : Idm = 900 A

nh xung dng in: Ipik = 800ADng in ca xung iu khin: Idk = 0,2Ain p ca xung iu khin: Udk = 3,0VDng in r: Ir = 45mASt p ln nht ca Tiristor trng thi dn l: U = 2,5V

Tc bin thin in p : 200dU

dt= V/ s

Tc bin thin dng in :dI

dt= 180A/ s

Thi gian chuyn mch : tcm= 20 sNhit lm vic cc i cho php : Tmax = 125oC

2. Tnh ton my bin pChn my bin p 3 pha 3 tr s u dy/Y lm mt

bng khng kh t nhin.Tnh cc thng s c bn:

- Tnh cng sut biu kin ca my bin p:S = Ks. P = 1,05.24.600 = 15120 (VA)- in p s cp my bin p

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

Phng trnh cn bng in p khi c ti:Udo . cos min = Ud + 2. Uv + Udn + Uba

Trong :min = 10o l gc d tr khi c s suy gim in li

Uv = 2,5 V l s st p trn Tiristor

Udn

0 l s st p trn dy ni Uba = Ur + Ux l s st p trn in tr vin khng my bin p .

Chn s b: Uba = 6%.Ud = 6%.400 = 1,4V

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

Udo =min

2. 24 2.2,5 0 1,430,5

cos cos10

+ + + + + += =d v dn ba

o

U U UV

in p pha th cp my bin p:


21


22/55


U2f =30,5

13( )2,34

= =d

u

UV

k

- Dng in hiu dng th cp ca my bin p:I2 =

2 2. .600 489,8

3 3= =dI A

- Dng in hiu dng s cp my bin p

I1 = Kba.I2 =2

2

1

13. .489,8 16,7

380= =

UI A

U

- Xc nh kch thc mch tTit din tr:

215120

. 6. 60, 2

. 3.50

= = =ba Fe QS

Q k cm

m f

Trong : Qk - h s lm mt, ly 6Qk =

m- s tr ca my bin pf- tn s xoay chiu, f = 50

Chn kch thc tr theo t la/b = 1,25Q = a.bh = 3.a

Suy ra: a = 7,2 cm ; b = 9cmh = 21,6 cm

- Tnh ton dy qun+ S vng dy mi pha s cp my bin p

+ 11 4380

262( )4,44. . . 4,44.50.64,8.10 .1

= = = Fe T

UW vng

f Q B

+ S vng dy mi pha th cp my bin p2

2 11

13. .262 9( )

380= = =

UW W vng

U

- Tnh tit din dy dn my bin p : chn J1 = J2 = 2,75A/mm2

+ Mt dng s cp:

2111

16,76

2,75= = =

IS mm

J

Chn dy dn tit din hnh ch nht, cch in bc sithu tinh


22


23/55


Kch thc dy k c cch inS1c = a1.b1 = 1,5 . 4,5 mm2

+ Mt dng th cp:

22

2

2

489,8178

2,75= = =

IS mm

J

Chn dy dn tit din hnh ch nht, cch in bc sithu tinhKch thc dy qun k c cch in

S2c = a2.b2 = 5 . 20 mm2

* Kt cu dy qun s cp- Thc hin dy qun kiu ng tm b tr theo chiu dctrc- S vng trn mt lp ca cun s cp

11

1

2 21,6 2.1.5. .0,95 39,2( )

0,45

= = =g c

h hW k vng

b

Chn W11= 39 vngTrong :

kc = 0,95 h s p chth - chiu cao trhg khong cch t gng n cun dy

- S lp dy cun s cp11

11

2626,7

39W

nW

= = = lp

Chn s lp l n1= 7 lp

* Kt cu cun th cp- Chiu cao cun th cp h2 = h1 = 21,6- S vng trn mt lp

222

2

18,6. .0,95 17,6( )

1,0

c

hW k vng

b

= = =

Chn W22 = 18 vng- S lp dy qun th cp

22

22

90,48

18,6W

nW

= = = lp

Chn 3 lp tr chia lm 4 lp kiu qun (9 0 9). 2 ccu ra c ghp li thnh 1 cun cng cc tnh 2 u cc.* Tnh ton kch thc mch t :

Dng thp 300x36 dy 0,35 mm ct theo hnh ch I v

xp nh hnh v


23


24/55


36 mm

300 mm

Kch thc li thp : chiu rng a = 7,2 cmb dy b = 9 cm

chiu cao h = 21,6 cm


Cundy

Mch t tthp

H

L

24


25/55


3. bo v mch ng lcKhi van bn dn lm vic, c dng in chy qua

van, trn van c st p U, do c tn hao cng sut .

Tn hao ny sinh nhit, t nng van bn dn, nhit cavan tng ln do cng sut tn hao trn van gy ra. Khi nhit ca van cao hn nhit mi trng xung quanh nhit l-

ng c truyn vo mi trng. Nu nhit ca van vt qugii hn cho php s ph hy van, v vy lm mt cho van lmt vn rt quan trng. van bn dn lm vic c anton , khng b chc thng v nhit, phi chn v thit kh thng to nhit hp l.

C cc bin php lm mt thng c s dng :+ Lm mt bng cch gn cc l tn nhit vo van,hiu sut lm vic t c 40%.

+ Lm mt t nhin : ch da vo s i lu khng khxung quanh van, hiu sut lm vic ca van thp chkhong 25%

+ Lm mt bng qut gi cng bc c gn cnh tn nhitto lung khng kh vi tc ln qua van y nhanhqa trnh truyn nhit ca van vo khng kh, hiu sutlm vic ca van l 70%.

+ Lm mt bng nc : van c gn thm tm ng rngcho nc chy qua. y l bin php lm mt rt hiu quhiu sut lm vic ca van t n 90%, nhng h thnglm mt phc tp ch ph hp vi yu cu cng sut ln v cngun nc ti v tr lp t thit b.

Qua phn tch trn ta chn bin php lm mt bngthng gi c qut cng bc thi qua cnh tn nhit ynhanh qu trnh truyn vo khng kh t hiu sut lmvic ca van l 70%.

- Dng trung bnh qua van l :600

200( )3 3

dv

II A= = =

* Cc bin php bo v van:Thyristor lm vic vi in p qu cao dng qu ln so

vi nh mc s b ph hngNguyn nhn gy ra c chia lm hai loi :

Nguyn nhn ni ti :- Do lm vic qu dng , qu p nh mc


25


26/55


- Kho thyristor bng in p ngc cc in tch ingc hnh trnh to ra dng in ngc trong khong thi gianrt ngn.

- S bin thin nhanh chng ca dng in gy ramt sut in ng cm ng trong cc in cmlun lun c ca ng dy ngun dn n ccthyristor. V vy gia ant v katt xut hin quin p.

- Xung in p do ct t ngt bin p non ti.Nguyn nhn bn ngoi : Nhng nguyn nhn ny th-

ng xy ra ngu nhin nh khi c st nh, khi ng ct mybin p ngun. Ct my bin p ngun tc l ct dng in

t ha my bin p, by gi ng lng t trng tch lu trongli st t chuyn thnh nng lng in cha trong cc t ksinh, rt nh gi cc dy cun s cp v th cp my binp. in p ny c th ln gp 5 ln in p lm vic.

S bo v mch lc:


26


27/55


LR

D1

T2

T3

D2

D3

R1

T1

C

P Q

Bo v qu nhit cho cc van bn dnChn phng php lm mt van bng qut thng gi cng

bc y lung khng kh qua khe cnh tn nhit gim nhanhnhit ca van ra mi trng xung quanh.Cc thng s cn c:

p tn hao cng sut chnh nhit so vi mi trng

Nhit lm vic cho php ca Tiristor Tcp =1250CNhit trn cnh tn nhit Tlv = 800C

= Tlv- Tmt = 400CKm H s to nhit, Km = 8 w/m2 0C

Tn tht cng sut trn 1 Tiristor p = U.Ilv = 2,5.346,5 =886,25 (kw)


27

A B C


28/55


Din tch b mt to nhit: STN = p/Km. = 866,25/ 8.40 =2,7m2

Kch thc mi cnh Stn = (25cmx25cm)x2 mt =

3,1m2

Bo v qu dng in cho vanBo v ngn mch v qu ti v dng in : dng cuch ,automat, rle dng in nhit hoc bo v bngrle in t.

Chn 1 automat c dng15120

22,97( )3.380 3.380

balv

SI A= = =

Dng in automat cn chn

1,1. 1,1.22,97 25,2( )380( )dm lv

dm

I I AU V

= = =

=

Dng ngn mch2,5. 2,5.22,97 57,4( )nm lv I I A= = =

Dng qu ti1,5. 1,5.22,97 34,5( )qt lv I I A= = =

T thng s trn chn automat Fuji do Nht sn xut30( )

400( )

dm

dm

I A

U V

=

=

Bo v qu in p cho van- Mc ni tip vanDa vo cc thng s lm vic ca van, trng hp khng chnc van c in p cao phi tin hnh mc ni tip ccvan .Khi mc ni tip cc van, cn chn cc van c c tnhging nhau nhm m bo s phn b in p nh nhau trncc van. Do c tnh ca van khng hon toan ging nhau

cn phn b li in p.- Cc bc tnh ton :

+ Xc inh h s qa in p theo cng thc

im

pim

Ub

Uk

.

.=

+ Xc nh cc thng s trung gian :)(),(),( *min

*

max

*

min kRkRkC

+ Tnhdt

dimax khi chuyn mch


28


29/55


+ Xc nh lng tch t Q=f(di/dt), s dng cc ngcong trong s tay tra cu

+ Tnh cc thng s trung gian

imUQ

CC2

.*

min=

Q

LURR

Q

LUR imim

22

*

max

*

min

Trong L l in cm ca mch RLCCui cng ta chn

=

=

80

25,0

R

FC

Cc bin php c s dng

T1

T2

R1

R2

T1

T2

C1

C2

T1

T2

R1

R2

C1

R3

C2

R4

- Bo v xung in p khi chuyn mch van bn dn:Bo v xung in p do qu trnh ng ct cc van cdng mcch R- C mc // vi cc van bn dn. Khi c s chuynmach , do s phng in t van ra ngoi to nn xung inp trn b mt tip gip P- N. Mch R- C mc // vi van bn


29


30/55


dn to nn mch vng phng intch qu trong qutrnh chuyn mch van.

C th chn R = 5 30 ; C = 0,5 - 4F

T

R

C

R C

R C R C

- Bo v van bn dn khi b nh thng do xung in t li. bo v xung t li in cn mc // vi ti u vo

mt mach R C, nhm lc xung. Nh c mch ny m xungnh gn nh nm lai hon ton trn ng dy.

Tr s R, C ph thuc vo ti c th chn R = 20 , C = 4F

C1R1 C2R2

R3 C3

- Bo v van khi b nh thng do ct bin p non ti


30

R

R


31/55


bo v van do ct in t ngt bin p non ti,trong b ngun mc thm mch R C u chnh lu cu bapha ph bng cc it cng sut b .

Tr s t C:2

2

2

30. .1TU

I IC

K U=

Trong K- Dng in t ho bin p %I2, U2 Dng in , in p th cpKTU Kh nng tng in pcho php ca van, KTU=

1,25Tr s thng c chn khong

C = 10F ; R1 = 470 ; R2 = 1,4 K

R1

D2 D1

D4

D6

D3

D5

C

R2

4. Thit k cun khng lcS p mch ca din p chnh lu lm cho dng in

ti cng p mch theo , lm xu i cht lng dng mtchiu ca ti. Do lm xu i cht lng m.

Thit k cun khng lc lm tng cht lng in p v sgin on ca dng in

- Xc nh gc m ca vanchn gc m cc tiu ca van l van l 100

Gc m ln nht0min

24cos cos 40,2

2,34.30,5max do

Uar ar

U = = =


31


32/55


- Xc nh cun khng lcXc nh tr s in cm ca cun khng lc

4

*

1

.100 30,5.1003,9.10

2. . . . .% 2.6.314.4,89.600dnmax

L

ddm

UL F

K m I I= = =

5. Thit k mch iu khin

Xy dng mch iu khin m bo cho mch lc

hot ng tt trong mi trng hp.Cc yu cu c bn i vi h thng iu khin :

- m bo pht xung vi y cc yu cu m van :+ rng tx+ bin Ux+ Sn xung ngn sts 15,0 =

- m bo tnh i xng ca cc knh- m bo cch ly gia mch lc v mch iu khin, V d

i vi MBAX thng c s dng nh mt khu truyn xungcui cng tng khuych i xung.

- m bo ng quy lut v pha iu khin. y l yucu v m bo phm vi iu chnh gc .

- C th hn ch phm vi gc iu khin khng s thayi ca in p li.

- Khng gy nhiu i vi cc h thng iu khin int khc xung quanh.

- C kh nng bo v qu p, qu dng v bo hiu khi cs c.

S cu trc ca h thng iu khin .


32


33/55


Udk

Khu ng pha c nhim v to ra in p ta ngb vi in p li. Ngha l cho php xc nh gi tr banu ca goc iu khin .

Khu so snh c nhim v so snh gia in p ta vin p iu khin. Ti thi im hai in p ny bngnhau th pht xung gi sang tn khuych i.Khu khuych i : to ra xung v khuych i xung to raxung c rng cn thit v ur cng sut a niu khin thyistor trong mch lc.

Trong thc t ngi ta thng dng hai nguyn tc iu khin :thng ng tyun tnh v thng ng arccos thchin iu chnh v tr xung trong na chu k dng cain p t trn thyristor.

* Gii thiu cc phn t c bn c dng trong mch iukhin :- Khuych i thut ton :

KTT l phn t c bn c s dng rnh rI trong cc

mch in t vi chc nng x l cc tn hiu tngt .Khuych i thut ton c k hiu nh sau :


33

K.ng pha K. So snh K.To xung


34/55


-

+ +

A

Mt s ng dng ca khuych i thut ton :Mch khuych i o : s nh sau

-

+

A2

R2

R1

R3Uo

Ui

Ta c :io UR

R

U .1

2

=

- Khu so snh+ Mch so snh mt cng :

R4

-

+

A3R5

UdkUra

du vo khuych i thut ton tng tr Ri rt ln nndng I vo KTT l khng ng k, nn

( ) 5 41 24 5 4 5

( ) ( )iR R

U U UR R R R

= ++ +

Nu 0)( >iU th U3 s bo ho UnNu 0)(


35/55


+ Mch so snh hai cng :

R4

-

+

A3R5

UdkUra

Nu : U1>U2 th U3 = -UnNu : U1


36/55


S mch iu khin mt knh ca chnh lu cu 3 phakx

Nguyn l hot ng ca s iu khin :- Khu ng pha v to xung rng ca

-

+

A1

D1

T1

R1

C1

N1 N2

TR1

-

+

A2

VR3

R2

Uac

Udf

Tn hiu in p xoay chiu c dng hnh sin, trngpha vi in p ca Tiristor t cun th cp ca bin p TR1qua in tr R1 c a vo ca o ca khuch i thut

ton A1.Khi tn hiu in p a vo ca m ca khu so snh

A1 ln hn in p trn ca dng ca A1 th ti ca ra ca A1l mt in p dng. Cn khi in p trn ca m ca A1nh hn in p trrn ca dng th in p ra ca A1 s lmt in p m. Nh vy A1 c nhim v so snh in pna hnh sin ca TR1 a vo to ra chui xung lin tiphnh ch nht,

Tn hiu in p xung dng ch nht qua iod D1 tiA2 phn tch thnh in p ta rng ca Urc, rng xungph thuc vo t C1. Phn m ca in xung lm m

transitor T1 lm ngn mch A2 do Urc = 0 trong vng m.Khi u ra ca A2 c chui in p rng ca Urc b ginon.- Khu so snh

R4-

+

A3R5

UdkUra


36


37/55


in p ta rng ca Urc c so snh vi tn hiu in piu khin Uk ti u vo ca A3, tng i s Urc + Ukquyt nh du in p u ra ca khuch i thut tonA .Nu Ur D1 qua A1 v mngun .

Do s ng m ca Dd lm trn t C1 phng np to ratrn R4 mt in p hnh rng ca . dc ca rng ca c th

thay i qua trit p VR3. in p rng ca c a vo cao ca A3 v so snh vi in p iu khin. in p iu

khin ny c ly t in p phn hi a vo so snh viin p t qua b cng o du. Trong mch vng phnhi c mch vng phn hi dng in . Dng in qua sun

thay i th in p phn hi qua sun thay i. Tn hiuiu khin a vo ca cng ca khu so snh . Nu U rc

>Uk thu ra ca A3 l xung m. Nu Urc < Uk th u ra ca A3l xung dng.- Khu pht xung chm

Mch a hi to xung chm A4 to ra chui xung tn scao , tn s xung ph thuc vo in p v tr s phng npca t , tr .Do b pht xung chm di s phng np ca tC2 to ra chui xung hnh ch nht.- Khu khuch i

T2

AND

C3

D2

T3

D3

N1 N2

TR2

R10

R9


37


38/55


39/55


+ rng xung iu khin: tx= 2.tm = 160 ( s ) tng -ng khong 3o in

+ Tn s xung iu khin: fx = 3 kHz

+ mt i xng cho php:

= 4o

+ in p ngun nui mch iu khin: U = 12V+ Mc st bin xung: sx = 0,15

- Tnh bin p xung:+ Chn vt liu lm li l st Ferit HM. Li c dng hnh

xuyn, lm vic trn mt phn ca c tnh t ho c: B= 0,3 T, H = 30 A/m , khng c khe h khng kh.+ T s bin p xung: thng m = 2 3, chn m = 3+ in p cun th cp my bin p xung: U2 = Uk = 3,0 V

+ in p t ln cun my bin p xung: U1 = m. U2 =3.3 = 9 V+ Dng in th cp my bin p xung: I2 = Ik = 0,2 A+ Dng in s cp bin p xung: I1 = I2/m = 0,2/3

= 0,066A+ t thm trung bnh tng i ca li st : tb = B/ o

. H = 8.103

Trong : o = 1,25 . 10-6 (H/m) l t thm cakhng kh.

Th tch ca li thp cn c : V = Q.L = ( tb . o.tx.sx.U1.I1)/ B2

Thay s V = 0,834.10-6 m3 = 0,834 cm3

Chn mch t OA 20/25 6,5 c th tch V = Q.1 =0,162.7,1 = 1,15 cm3.

Vi th tch ta c kch thc mch t nh sau:

A = 2,5 mm ; b = 6,5mm; Q = 0,162 cm2 = 16,2 mm2;Qcs = 3,14cm2


39

D

b

a


40/55


D = 20mm; D = 25 mm . Chiu di trung bnh mcht: l = 7,1 cm

+ S vng qun dy s cp bin p xung:

Theo nh lut cm ng in t:U1 = w1 . Q. dB/dt = w1 . Q . B/txW1 = U1.tx / B. Q = 227 vng;

+ S vng dy th cp: W2 = w1/m = 227/3 = 75 (vng)+ Tit din dy cun th cp: S1 = I1/J1 = 33,3 .1-3/6 =

0,0056 mm2

Chn mt dng in j1 = 6 (A/mm2)

+ ng knh dy cun s cp: 114

0,084S

d

= = cm

Chn d1 = 0,1 mm; S1 = 0,00785 mm2

+ Tit din dy qun th cp: S2 = I2/J2 = 0,1/4 = 0,025mm2

Chn mt dng in J2 = 4 A/mm2

+ ng knh dy qun th cp : 224

0,178S

d

= = mm

Chn dy c ng knh d2 = 0,18 mm, S2 =0,02545 mm2

+ Kim tra h s lp y:

1 1. 0,00785.227 0.02545.75 0,0117314ld csS wKQ

+= = =

Nh vy , cu s din tch cn thit.- Tnh tng khuych i cui cng:Chn Tranzit cng sut loi 2SC9111 lm vic ch xung c cc thng s:

Tranzitor loi npn, vt liu bn dn l Si.in p gia Colecto v baz khi h mch Emito: UCBO = 40 Vin p gia Emito v Baz khi h mch Colecto: UEBO = 4V

Dng in ln nht Colecto c th chu ng: Icmax=500mACng sut tiu tn Colecto : Pc = 1,7WNhit ln nht mt tip gip: T1 =175oCH s khuych i : = 50Dng lm vic ca Colecto : Ic3 = I1 =33,3 nADng lm vic ca Baz : IB3 = Ic3/ =

33,3/50 = 0,66 mA


40


41/55


42/55


9 33

126

2.10b

UR k

I = = ; chn R9 = 6,8k

Trong : U = 12V ; Ic3 = IAND = 2mA < 3cI

= 10mA

Chn C3. R9 = tx = 167 s . Suy ra 3 = tx / R9C = 167/6,8.103 = 0,024 F . Chn C3 = 0,022 F.

- Tnh chn b to xung chm:Mi knh iu khin phi dng 4 khuch i thut

ton , do ta chn 3 IC loi TL084 do hng texasInstrumentsch to, mi IC ny c 4 khuch i thut tons chn :

-

+

-

+

-

+

-

+

\

Vcc 14 13 11 10 9 8

1 2 3 4 5 6 7

12

Thng s ca TL084:in p ngun nui : Vcc= 18V chn Vcc = 12VHiu in th gia hai u vo : 30VNhit lm vic : T = -25 85oCCng sut tiu th : P = 680 mW = 0,68 WTng tr u vo : Rin = 106 MDng in u ra : Ira = 30 pA.Tc bin thin in p cho php : du/dt = 13V/ s

Mch to chm xung c tn s fx = 1/2tx = 3 kHz hay chu kca xung chmT = 1/f = 334 ( s ) ; ta c: T = 2.R8 .C2 . ln(1+2.R8/R7)

Chn R6 = R7 = 33(k ) th T = 2,2R8.C2 = 334 ( s )Vy: R8.C2 = 151,8 ( s )Chn t C2 = 0,1 s c in p U = 16V ; R8 = 1,518 . thun tin cho vic iu chnh khi lp mch th ta chnR8 l bin tr 2K

- Tnh chn tng so snh:


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in tr R2 hn ch dng in i vo baz tranzito Tr1 =c chn nh sau: Chn R2 tho mn iu kin : R2 UNmax/IB12/0,4.103 = 30 K

in tr R2 = 30 in p xoay chiu ng pha: UA = 9 Vin tr R1 hn ch dng in i vo khuch i thutton A1, thng chn R1 sao cho dng vo khuch i thutton Iv< 1mA.Do : R1>UA/IV = 9/1.10-3 = 9 K . Chn R1 = 10 K

6. To ngun nuiThit k my bin p dng cho c vic to in p ng pha

v to nhun nui, chn my bin p kiu ba pha ba tr, trnmi tr c 5 cun dy, mt cun s cp v bn cunth cp.

c3

a4

b3

b4

c4

a3

a1

b1

c1

a2

b2

c2

D3

D1

D6

D2

D4

C1

C2

C3

C4

C5

D5

D4

D2

D5

D1

D3

D6

1

2

3

7812

7812

- Cun th cp th nhtCn to ra ngun in p 12V c n p cp ngun

nui IC. Ngun ny c cp bi ba cun dy th cp a1, b1, c-1. Hai chnh lu tia ba pha to in p ngun nui ixng. in p u ra ca n p 12V. in p vo ca IC np 20V . in p th cp cc cun dy a1, b1, c1 l:

2

2014

2

U V= =


44

380VAC


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Chn U21 = 14V n nh in p ra ca ngun nui ta dng 2 vi

mch n p 7812 v 7912, cc thng s chung ca vi mchny:in p u vo: Uv = 735 Vin p u ra: IC 7812 c Ura = 12V

IC 7912 c Ura = -12VDng in u ra: Ira = 0 1 A

T in C1, C2 dng lc thnh phn sng di bc cao.Chn C1 = C2= C3 = C4 = 470 ( F ) ; U = 35v

- Cun th cp th hai:a2, b2, c2 to ngun nui cho bin p xung, cp xung iu

khin cho cc tiristor (+12V). Do mc st xung cho phptng i ln nn ngun ny khng cn n p. Mi khi phtxung iu khin cng sut xung ng k, nn cn ch tocun dy ny ring r vi cun y cp ngun IC, trnggy st p ngun nui IC.Cun th cp th 3,4:(a3, b3,c3, a4, b4, c4) l cc cun dy ng pha.Cc cun dy

ny cn ly trung thc in p hnh sin ca li, tt nht nncun bin p ring.Tuy nhin theo kinh nghim c th qunchung vi bin p ngun nui cng c th c.

- Tnh ton my bin p ngun nui v ng pha:+ in p ly ra th cp cun dy ngun nui IC: U21 =

14V+ Cng sut tieu th 3 IC TL 4081 s dng lm khuch

thut ton ta chn 1 IC TL 084 to 6 knh iu khin vhai cng AND.

PIC = 4. PIC = 4. 0,68 = 2,72 W+ Cng sut BAX cp cho cc iu khin Tiristor.

Px = 3. UNX. Ik = 3.3.0,2 = 1,8W+ in p pha th cp cun dy ngun nui bin p

xung: a2, b2, c2

U2 =12

2. 3= 4,91 V; chn 5V

+ in p ly ra th cp cun dy ng pha (a3, b3 ,c3,a4, b4, c4) U3,4 =5V

+ Dng in chy qua cun dy ng pha chn 10 mA


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+ Cng sut cc cun dy ng pha

Pdf = 3. Udf.Idf = 3.5.0,01 = 0,15 W

+ Cng sut s dng cho vic to ngun nui.

PN = Pf + PIC+ Px = 0,15 + 2,72 + 1,8 = 4,67

+ Cng sut ca my bin p c k n 5% tn thttrong my:

S = 1,05. PN = 1,05. 4,67 = 4,9 VA

+ Dng in s cp my bin p:

I1 = S/3 .U1 = 0,00742 A

+ Tit din tr ca my bin p c tnh theo cng thc:

Q1 = kQ . 24,9

6. 1,08. 3.50S

mmf

= =

Trong : kQ = 6- h s ph thuc phng thc lmmt

M = 3- s tr ca bin p

F = 50- tn s in li p

V kch thc ny qu nh nn ta chn chun ho tit dintr theo bng.

Qt = 1,63cm2.

Kch thc mch t l thp dy =0,5 mm

S lng l thp: 68 l

a = 12mm

b = 16mm

c = 30mm

h s p cht kc = 0,85.

+ Chn mt t cm B = 1T trong tr ta c s vngdy s cp:

11

60804,44. . . T

Uw vng

f B Q= =

+ Chn mt dng in J1 = J2 = 2.,75 A/mm2


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Tit din day qun s cp:

2110,0114

0,00412,75

IS mm

J= = =

ng knh dy qun s cp:

114.

0,072S

d

= = mm

Chn d1 = 0,1 mm m bo bn c. ng knh ck cch in:

D1cd = 0,12 mm

+ S vng dy qun th cp W21 :

W21 = W1.2

1

146080. 369220

UU

= = vng

+ S vng dy qun th cp W22:

W22 =22

1

1

8,51. 6080. 235

220U

WU

= = vng

+ S vng dy qun th cp W23:

W23 =

231

1

5. 6080. 138

220

UW

U= =

vng+ ng knh dy qun cc cun th cp v kch thc nh

khng ng k chn 0,26 mm

Cc thng s cn li ca bin p ngun nui c tng nh gii thiu trn.

+ Tnh chn it cho b chnh lu ngun nui:

+ Dng in hiu dung qua it:

IH = 1 5,12. 0,1232,123 3

ICI A =

+ in p ngc ln nht m it phi chu:

UNmax = 6 .U21 = 2,45 . 14 = 34,3 V

+ Chn it c dng nh mc:

Im Ki . IDHD = 10.0,123 = 1,23 A

+ Chn it c in p ngc ln nht:


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Un = ku . UNmax = 2.34,3 = 68,6 V

Chn it loi KII208A c cc thng s:

+ Dng in nh mc: Im = 1,5A

+ in p ngc cc i ca it: UN = 100 V- Khu phn hi:

-

+

IOP9

R11

R12R14

-

+

IOP10 -

+

IOP11

R18

R20

R19

R15

R16 R17

R13

C4

Rs

S khu phn hi

Nguyn tc hot ng ca khu phn hi:Ly in p phn hi ca ngun m thng qua in tr

Sun ,v in p ny nh nn ta cho qua mt b khuych i c in p c ln thch hp trc khi cho vo khuPI.Trong phn trc ta chn loi Sun 1000A-20mV, dng m cangun ln nht l 600A nn in p trn Sun vo khong 10-12mV.Ta chn in p phn hi(u ra ca khu khuychi trn) vo khong vi von th h s khuych i ca OPvo khong 300 ln tu theo gi tr ca in p t.Sau in p phn hi c a qua khu PI loi b ccsng nhiu c tn s cao lm cho mch tng tnh n

nh.in p ra khi khi PI ta gi l in p phn hiUph.Tip theo in p phn hi c a vo b cng (o)vi in p m ta t cho ngun m lm vic ,in p nyta gi l in p t U.Tn hiu ra ca khu cng nychnh l tn hiu iu khin c a vo so snh vi tnhiu ng pha pht ra xung iu khin m cc van,tagi l in p iu khin .Nh c khu phn hi m gicho dng in m c n nh.Tht vy:


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Gi s v mt l do no m dng in ca ngun m bgim,khi in p trn in tr Sun cng gim theo tcUph gim

m Uk = U - Uph nn Uk tng lm gc m

gim--> in p trn ngun m tng nn khin cho dng in lic tng ln.Ngc li ,khi dng in m tng th in tr trn Sun tngkhin cho Uph tng,dn n Uk gim lm tng gc m ,khin cho in p ca ngun m gim xung,dng in lic gim i.Nh vy dng in lun c gi mc nnh.

- Khu bo v

-

+

IOP12R23

T4

T5

R24

Light

R22R21

S khu bo v ngn mch

Nguyn tc hot ng ca khu bo v ngn mch :

u khng o ca khuych i thut ton c ni vi ura ca khuych i phn hi. u vo o ta t mt inp chun gn bng in p khi c ngn mch xy ra ti ura ca

khuych i phn hi. Khi mch lc lm vic bnh thng(khng c ngn mch xy ra) th V+ < V- nn u ra cakhuych i thut ton m, v vy T4 kho dn n T5


49

RL

Vcccc


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cng kho cun ht RL khng c in nn tip im RLtrong mch lc ng, mch lc hot ng bnh thng. Khi cngn mch xy ra V+ > V- nn u ra ca khuych i

thut ton dng, v vy T4,T5 m lm cho cun ht c in,ng tip im RL khu bo v ngn mch li lm chon led sng bo hiu xy ra ngn mch, ng thi ngttip im RL mch lc ra ct ngun in m.

Kt lun

Sau mt qu trnh hc tp v nghin cu, cng vi s hngdn tn tnh ca thy gio v s gip ca cc bn cngnhm, em hon thnh cc nhim v c giao ca bn n : Thit k ngun m mt chiu.

Trong qu trnh thc hin, chc chn bn thn emkhng th trnh khi nhng thiu st, em rt mong nhn -

c nhng kin ng gp ca cc thy v cc bn bn n ny hon thin hn.

Chng em xin chn thnh cm n!

H Ni , ngy 12 thng 7 nm 2009Sinh vin

Dng vn Khoa


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