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TP ON BU CHNH VIN THNG VIT NAMTRNG TRUNG HC BCVT V CNTT MIN NI

........................................

BI GING

NGUN IN THNG TIN(Dng cho h Trung cpTVT)

Bin son:Bi Tun Ngc

THI NGUYN 2010

LI NI U

V N P T

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Ngun in trong vin thng givai tr quan trng i vi shot ng ca ccthit b trong i trm. Vic nghin cu tm hiu v ngun in sgip cho cng tc vnhnh khai thc cng nh khc phc s c em li hiu qu, gp phn m bo s lmvic n nh ca mng li.

p ng c nhu cu thc t sn xut cng nh nhu cu v hc tp ca hcsinh v ging dy ca gio vin trong nh trng, ti bin son cun bi ging

NGUN IN THNG TIN da theo cng chng trnhca: TP ON BUCHNH VIN THNG VIT NAM ban hnh.

y l cun bi gingchuyn v ngun in dng cho cc thit b vin thng, tch

hp c l thuyt v thc hnh. Ni dung gmbn bi:

Bi 1: Tng quan v h thng ngun trong trm vin thng

Bi 2: Ngun in mt chiu

Bi 3: Ngun inxoay chiu

Bi 4: Cc t ngun

Sau mi bi l mt s cu hi, bi tp gip h thng ho kin thc hc.

Hy vng rng, cun sch ny phn no gip cho vic ging dy, hc tp cng nhtham khoc thun li hn.

Mc d su tmv tng hpnhiu ti liu c lin quan trong qu trnh bin

son, song khng trnh khi nhng thiu s. V vymong nhn c nhng kin ng

gp xy dng ca bn b v ng nghip ti liu ny c hon thin hn.Xin chn thnh cm n !

Tc gi bin son

Bi Tun Ngc

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MC LC

Li ni uTrang

Bi 1: TNG QUAN V H THNG CP NGUN CHO TRMVIN THNG 9

1.Yu cu ca h thng cp ngun cho trm vin thng 91.1. tin cy 91.2. n nh 91.3. Hiu sut cao 101.4. Gn nh 102.1. Phng thc cp ngun c in li quc gia 102.2. Phng thc cp ngun khng c in li quc gia 11

Cu hi n tp 13Bi 2: NGUN IN MT CHIU 141. c quy axit 141.1. Khi nim 141.2. Cu to 141.3. Nguyn l lm vic 151.4. Cc i lng c trng ca cquy 161.5. Cc chng ngi ca cquy axit 161.6. Bo dng cquy axit 171.7. u ni cquy 192. Pin mt tri 232.1. Cu to 232.2. Nguyn l hot ng 242.3. S tng ng 252.4. c trng Vn Ampe 252.5. u ni pin mt tri 252.6. Bo dng pin mt tri 283. H thng nn in v chnh lu 283.1. Mch chnh lu na chu k 28

3.2. Mch chnh lu c chu k 303.3. Mch chnh lu cu 32

3.4. Mch chnh lu bi p 343.5. Mch chnh lu ba pha 36Cu hi n tp 42Bi 3: NGUN IN XOAY CHIU 431. ng c t trong 431.1. Vai tr 431.2. Cc tham s 43

1.3. Cc h thng chnh 441.4. Nguyn tc hot ng 54

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1.5. Nhn bit cc h thng ca ng c t trong 571.6. Bo dng ng c t trong 612. My pht in ng b ba pha 642.1. Khi nim 642.2. Cu to 64

2.3. Nguyn l hot ng 652.4. Bo dng my pht in ng b ba pha 662.5. Vn hnh t my n pht in 67Cu hi n tp 70Bi 4: CC T NGUN 711. S khi ca h thng cp ngun 711.1. S khi 711.2. Nguyn l lm vic 731.3. Cc thnh phn thit b ch yu 742. Mt s thit b cp ngun s dng trong trm vin thng 812.1. T ngun Lorain 300 812.2. T ngun VPRS 400 843. Vn hnh t ngun 864. Bo dng t ngun 87

4.1. Bo dng thng xuyn 87

4.2. Bo dng nh k 87

Cu hi n tp 88Ti liu tham kho 89

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Bi 1:TNG QUAN V H THNG CP NGUNCHO TRM VIN THNG

Mc tiu ca bi:

Hc xong bi ny hc sinh s c kh nng trnh by ng cc yu cu i vi hthng cp ngun cho trm vin thng, cc phng thc cp ngun cho trm vin thng.

2.Yu cu ca h thng cp ngun cho trm vin thng

H thng cung cp in cho thit b vin thng c v tr quan trng nht v c thc xem nh l tri tim ca thit b.

Trong nhng nm gn y, lnh vc vin thng pht trin nhanh chng, ng dngnhiu cng ngh tin tin, hu ht cc thit b vin thng, mng li vin thng u lcc thit bcng ngh cao. Do yu cu i vi h thng cung cp ngun li cng phic quan tm hn, v hot ng ca h thng ngun khng m bo c th s lm cho

thng tin b dn on, in p ra ca ngun khng n nh hoc qu ln s lm gim chtlng thng tin v thm ch gy hng cc thit b.

V vy, h thng cung cp in vin thng v c bn phi m bo tin cy, nnh, hiu sut cao, ngoi ra phi m bo tnh gn nh.

1.1. tin cy

m bo thng tin thng sut, ngoi vic nng cao tin cy ca thit b vinthng, cn cn phi nng cao tnh lin tc ca h thng ngun. Thng thng, h thngngun phi cung cp in cho nhiu thit b, v vy khi h thng ngun gp s c s nh

hng rt ln n tnh lin tc ca thng tin.Cc quc gia c ngnh vin thng pht trin u coi tin cy trong cung cp in

l yu cu quan trng i vi h thng ngun. Nhng nm gn y, do k thut vi in tv k thut my tnh c ng dng nhiu trong thit b vin thng, khi ngun b ginon, cth lm mt thng tin. ng thi, do dung lng thit b vin thng ang tngrt nhanh, khi ngun b gin on s gy nh hng rt ln. V d: Mt trm in thoic dung lng khong hai n ba vn thu bao tr ln, khi ngun b mt s gy tn thtkinh t to ln v nh hng nghim trng n an ninh quc gia.

m bo tin cy cao cn phi cung cp in theo phng php kt hp,nhng thit b vin thng do ngun xoay chiu cung cp in u phi s dng ngunxoay chiu lin tc. Trong h thng cung cp in mt chiu, cn s dng phng thccung cp in mc song song b chnh lu v c quy. Ngoi ra, cn cn phi nng cao tin cy ca cc b ngun. Cc b chnh lu tin tin hin nay u mc song song nhiu

b chnh lu nu c b chnh luno gp s c s khng nh hng n vic cung cpin. Hin nay, thi gian khng xy ra s c bnh qun ca cc b ngun tin tin l haimi nm.

1.2. n nh

Cc thit b vin thng u yu cu in p n nh, khng c vt qu phm vibin ng cho php. in p ngun qu cao s gy tn hi cho cc linh kin in t trongthit b vin thng. Ngc li, nu in p ngun qu thp, thit b vin thng s khng

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10

=

TBK

=

BA

TBCM1

2

AC1BBD1

DC

AQ

BBD2

AC2TBVT

TBP

ng vng AC

Hnh 1.1: S h thng cp ngun c in li

F

th hot ng bnh thng. Ngoi ra, nhiu trong in p ngun mt chiu cng phi nhhn gi tr cho php, nu khng s nh hng nghim trng n cht lng thng tin.

Khi ngun in cung cp cho thit b vin thng c s t bin ca in p s gynh hng ln n thit b vin thng, v vy cc thit b vin thng ni chung u phido ngun n p cung cp.

1.3. Hiu sut caoCng vi vic tng dung lng ca thit b vin thng, ti ca h thng ngun cng

khng ngng tng ln. tit kim in nng, cn phi nng cao hiu sut ca ngun.

Bin php tit kim ch yu l s dng b ngun c hiu sut cao, trc y, ccthit b vin thng thng s dng b chnh iu khin pha c hiu sut tng i thp(

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=

TBK

=

DC1

BBD1

DC2

AQ

BBD2

AC2TBVT

TBP

ng vng AC

PMT

=

AC1

AC3

TBXLCS

i t chn

FG

FBBD3

Hnh 1.2: S h thng cp ngun khng c in li

BA: my bin p

F: t my pht in

AQ: t c quy

TBCM: thit b chuyn mch

TBK: thit b iu khinBB1: b bin i in p xoay chiu/mt chiu

BB2: b bin i in p mt chiu / xoay chiu

TBVT: thit b vin thng

TBP: thit b ph

H thng ny c nhn nng lng in t hai ngun. Ngun cung cp chnh lngun in li, ngun d phng l t my pht in v t c quy. s dng kt hphai ngun cung cp ny, ngi ta dng thit b chuyn mch (c th iu khin bng tay

hoc t ng). Khi chuyn mch v tr 1, h thng nhn nng lng t in li cungcp. Trong qu trnh vn hnh, nu v mt l do no in li gp s c ngng cungcp in th chuyn mch s chuyn sang v tr 2, lc ny my pht s tip tc cp nguncho h thng.

Trong qu trnh h thng s dng mt trong hai ngun cung cp ni trn th c quyc np m. Khi c hai ngun ny ng thi ngng cung cp th c quy s cung cpin cho h thng.

2.4. Phng thc cp ngun khng c in li quc giai vi cc trm vin thng t nhng ni khng c ng dy in li i qua

nh: rng, ni, hi o, ... thng t chc h thng cp ngun nh sau:

F: t my pht in

FG: my pht in sc giPMT: pin mt tri

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AQ: t c quy

TBK: thit b iu khin

TBXLCS: thit b x l cng sut

BB1, BB3: b bin i in p xoay chiu/mt chiu

BB2: b bin i in p mt chiu/xoay chiuTBVT: thit b vin thng

TBP: thit b ph

H thng ny s dng my pht in bng sc gi,pin mt tri, c quy v t mypht in. Mc ch ca h thng ny l li dng cc u im ca tng ngun ring rnhm em li hiu qu kinh t cao v li dng trit iu kin a l ti ni t trm, bxung v h tr cho nhau (Hnh 1.2).

- Pin mttri gm cc modul u ni tip v song song t cng sut yu cu v

phi hp vi cc ngun nng lng khc trong h thng. Khi c nng, pin mt tri bom vic cung cp nng lng, nu d tha nng lng s np cho c quy.

- My pht in bng scgi khng trc tip cp ngun cho thit b trong trm mch lm nhim v np in cho c quy.

- T my pht in s cung cp cho trm vin thng v np cho c quy khi ccngun ni trn ngng cung cp.

S hot ng ca h thng nh sau:

Bnh thng, pin mt tri v my pht in bng sc gi cng vi c quy phi hpcp ngun cho trm cn t my pht in lm nhim v d phng. Do cng sut ca pinmt tri v my pht in bng sc gi c cng sut nh v n nh khng cao nn

phi thng qua thitb x l cng sut trc khi cp cho h thng, nng lng d sc np cho c quy. Trong thi gian nng lng nng, gi khng cung cp th c quys cp ngun, nu tnh trng ny ko di, c quy phng ti mc ti thiu cho php th tmy pht in s pht in cp ngun cho h thng, ng thi np in cho c quy.

Trn y l hai phng thc cp ngun t hp hin nay ang v s c dng phbin. Tuy nhin, tu tnh hnh c th ca tng khu vc t trm vin thng m ngi tac th kt hp sao chova m bo yu cu k thut, va m bo tnh kinh t.

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CU HI N TP

1. H thng cp ngun cho trm vin thng cn phi c yu cu c bn nh th no?Ti sao?

2. Trnh by phng thc cp ngun c in li?

3. Trnh by phng thc cp ngunkhng c in li?

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Bi 2: NGUN IN MT CHIU

Mc tiu ca bi:

Hc xong bi ny, hc sinh s c kh nng:

- Trnh by ng cu to v nguyn l hot ng ca cquy axit, pin mt tri, cc hthng chnh lu.

- Bo dng v u ni c t cquy.

- Bo dng, u ni pin mt tri.

1. c quy axit

1.1. Khi nim

c quy c kh nng 2 chiu (bin in nng thnh ha nng ri bin ha nng thnhin nng) v c th thc hin nhiu chu k bin i nh vy gi l chu k np in,

phng in ca c quy nn s dng c lu di.

Lc u, c quy c u vo ngun in mt chiu bin i in nng thnhha nng (qu trnh tch in), sau c quy tr thnh ngun in c kh nng cung cpin nng cho ti (qu trnh phng in).

c quy l ngun in ha hc c tnh cht thun nghch, va l ngun in (khiphng in) va l thit b dng in (khi np in).

1.2. Cu to

V c bn c quy gm: v, bn cc v dung dch in phn (Hnh 2.1).- V c quy lm nhim v cha cc cc bn,

dung dch in phn, cc tm cch v li bo v. Vc quy thng lm bng nha cng polivinin hay

polietylen. V thng c dng hnh hp ch nhthoc hnh vung v c chia lm nhiu ngn tytheo yu cu mc in p s dng, thng l 3 ngnhoc 6 ngn, di y ngn c cc g nh cctm cc ng thi to nn cc rnh cha cc bt

ch t bn cc ri xung trong qu trnh lm victrnh gy ngn mch cc bn cc. Pha trn cc ngnc np y, mi np c l rt dung dch v c ntxoy.

- Bn cc: bn cc ca c quy axit l nhng tmkhung xng ch hnh mt li, l hp kim ch 94% v antimon 6% tng cngca khung mt li. Khung xng ch lm bn cc dng dy hn khung xng ch lm

bn cc m. Bn cc dng c bao ph bt xit ch PbO2(c mu nu) cn bn ccm c bao ph bt ch Pb (c mu xm).

tng dung lng c quy, ngi ta dng nhiu bn cc cng loi u chung thnhmt nhm to thnh nhm bn cc dng v nhm bn cc m, mi nhm ny u ara mt cc chung v c nh du cc (+) v cc (-) ca c quy. Cc bn cc c ci

Hnh 2.1: Cu to c quy Axit

V

Bn c cDung dchin phn

ddH2SO 4

Cc -(Pb)

Cc +(PbO)

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xen k nhau, gia chng c tm cch in xp v tt c c t chc chn trong v ccha dung dch in phn.

- Dung dch in phn c nhim v cng vi cc bn cc to nn cc phn ng hahc thc hin chuyn ha nng lng t in nng thnh ha nng (khi c quy npin) v t ha nng thnh in nng (khi c quy phng in). Dung dch in phn l

axit sulfuaric H2SO4pha vi nc ct c t trng 1,18g/cm3

n 1,26g/cm3

.1.3. Nguyn l lm vic

- Qu trnh phng in:

Khi ni 2 cc ca c quy np no vi ph ti th cquy s cho dng in qua ph ti gi l c quy phng in(Hnh 2.2). mch ngoi, dng in s i t cc dngqua ti sang cc m cn trong dung dch, SO4

-- trong dungdch s dch chuyn v pha cc m tc dng vi Pb tothnh PbSO4 gii phng ra in t, cn H

+ trong dung

dch s dch chuyn v pha cc dngtc dng vi PbO2nhn thm in t to thnh PbSO4.

Ta c phng trnh phn ng ha hc nh sau:

+ cc m:

Pb + SO4-- PbSO4 + 2e

+ cc dng:

PbO2 + 2H+ + H2SO4+ 2e PbSO4 + 2H2O

+ Phn ng ha hc ca qu trnh phng in din ra nh sau:Pb+ 2H2SO4 + PbO2 PbSO4 + 2H2O + PbSO4

(-) (dung dch) (+) (-) (dung dch) (+)

T phng trnh, ta thy khi phng in c 2 cc dng v m u chuyn hothnh ch sulfat PbSO4cn dung dch chuyn ho dn thnh nc. iu ny s lm chosc in ng ca c quy b gim dn.

- Qu trnh np in:

Khi c quy ht in, phc hi sc in ng v

dung lng ca c quy th phi np in cho c quy bngcch ni cc cc ca c quy vi cc cc cng tn cangun in mt chiu (Hnh 2.3).

Khi s xut hin dng in np (in) i t cc (+)my np n cc (+) c quy v cc (-) ca c quy n cc(-) my np. Lc ny ion dng H+i theo chiu dng inv cc (-) ca c quy, cn ion SO4

-- i ngc chiu dng vcc (+) c quy.

+ Ti cc dng, SO4-- s oxy ha PbSO4 theo phn

ng:PbSO4 + 2H2O + SO4-- PbO2 + 2H2SO4 + 2e

ip

-+

H2SO4

Hnh 2.2: c quy phng in

in +

+ -

-

Hnh 2.3: c quy np in

=

H2SO4

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+ Ti cc m, ion dng H+ tc dng vi PbSO4theo phn ng:

2H+ + PbSO4 + 2e H2 SO4 + Pb

+ Phn ng ha hc ca qu trnh np in din ra nh sau:

PbSO4 + 2H2O + PbSO4 PbO2 + 2H2SO4 + Pb

(+) (dung dch) (-) (+) (dung dch) (-)T phng trnh trn ta thy rng:

Trc khi np in c hai cc u l ch sunfat (PbSO4), khi np in th cc dngtr thnh ch ixit (PbO2), cc m tr thnh ch nguyn cht (Pb) nng dung dchtng v trong c quy hnh thnh sc in ng. Cui qu trnh np, sc in ng ca cquy c th ln n 2,6V n 2,7V, ng thi c bt kh thot ra (hin tng c quy si)lc ny ta cn kt thc qu trnh np, nu tip tc np th dng in ch c tc dng phntch nc thnh H2 v O2bay hi, hao tn nng lng v gim tui th c quy.

1.4. Cc i lng c trng ca cquy

1.4.1. Dung lng

Dung lng ca bnh c quy (Q) thng c tnh bng ampe gi (AH). AH l tchs gia dng in phng vi thi gian phng in. Dung lng ny thay i tu theonhiu iu kin nh dng in phng, nhit cht in phn, t trng ca dung dch, vin th cui cng sau khi phng.

1.4.2. Sc in ng

Sc in ng ca ngun inmt chiu l in p o c gic 2 u cc ca cquy khi h mch. n v ca sc in ng l Vol.

V d: Ta c b ngun u ghp 4 bnh c quy loi 12V, m ta o c in p gia2 u cc ca b ngun l 48 Vol th sc in ng ca b ngun l E=48Vol.

1.4.3. Dng phng nh mc

Dng phng nh mc l dng in phng ca c quy qua ti c gi tr bng mtphn mi dung lng ca c quy.

Ipm =1Q

10

1.4.4. Cng sut

L i lng c xc nh bng tch ca sc in ng ca c quy vi dng inqua .

P= EI

Trong : P l cng sut ca c quy

E l sc in ng ca c quy

I l dng mt chiu chy qua c quy

1.5. Cc chng ngi ca cquy axit

- c quy axit thng c khi lng nng do cc bn cc c lm bng ch. Ngoira, nu c quy phng ti di mc in p cui qu su hoc khng s dng trong mt

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+ Khi u hn hp th phi m bo cc nhnh c cng dung lng,cng in p

+ Khng c thng xuyn np in qu mc cho c quy v dung dch si btnhiu s lm ri rng cht hu hiu, lm gim dung lng v tui th ca c quy.

1.6.2. Np in

Qu trnh np in cho c quy c nh hng rt nhiu n tui th ca c quy. Tytheo mc ch yu cu m ngi ta chia ra lm nhiu ch np in khc nhau.

* Np in ln u:

Ch tin hnh i vi c quy axit vi mc ch phn cc cho c quy v np dunglng u tin cho c quy, tui th v cht lng ca c quy ph thuc rt nhiu vo chtlng np ln u, qu trnh np ln u c thc hin nh sau:

- c quy mi mua v cn bc b tm bng dnh bo v, sau dng phu thy tinhv ca nhc in dch vo c quy, in dch phi m bo t trng trong khong 1,20n 1,25 g/cm3ty theo loi c quy c nh hay di ng. Mc in dch phi cao hn cc

tm ccbn l 1,5 n 2 cm. Sau yn tnh trong khong 3 n 4 gi cht indch ngm su vo trong cc cc bn, lc ny t trng in dch c th gim xung, lhin tng bnh thng khng cn iu chnh. Sau , ta thc hin np in nh sau:

- Bc 1: u c quy vi my np chc chn, ng cc tnh ri cp ngun ph hpcho my np.

- Bc 2: iu chnh dng in np theo ch dn ca nh ch to hoc c th iuchnh bng 7% dung lng nh mc ca c quy (In = 7%Q).

Thi gian np phi ko di khong 16 n 18 gi lin tc. Trong qu trnh np, nuthy dung dch b cn th b sung nc ct, nu nhit dung dch tng ti 40 0C th ta c

th gim dng np i mt na, ng thi lm mt cho c quy cho ti khi no nhit dung dch gim xung, ta li tng dng in np ln.

* Np in thng (np nh k):

Np in thng phc hi dung lng cho c quy, thng c p dng trongmt s trng hp nh: c quy sau khi phng ht dung lng quy nh (thng l75% dung lng nh mc), c quy phng khng lin tc khong mt tun, hoc c quykhng s dng trong vng mt thng. Khi , quy trnh np thc hin nh sau:

- Bc 1: Kim tra v iu chnh mc dung dch in phn, nu cn b sung thphi dng nc ct.

- Bc 2: u c quy vi my np chc chn, ng cc tnh ri cp ngun ph hpcho my np.

- Bc 3: iu chnh dng in np theo ch dn ca nh ch to hoc c th iuchnh bng 10% dung lng nh mc ca c quy (In = 10%Q). Qu trnh ny cng phithc hin lin tc.

Khi no thy dung dch in phn trong cc ngn si u th c khong 20 n 30pht th tin hnh o kim tra t trng ca dung dch v in p ca c quy mt ln. Nuqua 2 n 3 ln o m thy t trng ca dung dch in phn n nh, in p trn mi

ngn t 2,6V n 2,7V th chng t c quy no v dng qu trnh np.*Np qu mc:

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y l hnh thc ko di thi gian np, trong qu trnh np khng c dng npqu ln, in p khng c qu cao. Hnh thc ny thng c p dng trong mt strng hp sau: c quy phng di mc in p cui, c quy phng ht dung lngv c thi gian qu lu cha np li, c quy thng xuyn phng vi dng ln qumc.

Quy trnh ny c chia thnh hai giai on v c hai cch thc hin.- Cch 1:

+ Giai on u: Thc hin nh ch np in thng.

+ Giai on sau: Khi kt thc np thng, vn tip tc np cho c quy nhng lcny phi gim dng np i mt na v duy tr trong khong 2 n 4 gi.

- Cch 2:

+ Giai on u: Np in nh ch np thng.

+ Giai on sau: Khi kt thc np thng th dng np 1 gi, sau li np 1 gi

vi dng np In =Q/10 cho n khi dung dch si u li dng np 1 gi. Sau li tiptc np nh trn, c tip tc nh th 3 n 4 ln cho n lc h c np l dung dch lisi th c. Kim tra t trng dung dch, in p v mc mc dch li ln na trc khingng np ri sau tho c quy ra.

1.7. u ni cquy

thc hin ni dung ny, cn chun b cc thit b, vt t sau:

c quy Axit loi 12V/135Ah 8 bnh

ng h vn nng 2 ci

Km vn nng v c l 10/12 2 b

Dy u ni 2x4 5m

Gi lau 3 ci

to ra b ngun c in p v dung lng (dng in phng) theo yu cu cnphi u ni cc bnh c quy vi nhau. C ba phng php u ni: ni tip, song songv hn hp. Vic u ni c tin hnh theo cc bc sau:

- Bc 1: Chun b

T yu cu thc t v thng s ca bnh c quy, a ra c phng php u niv tnh slng bnh c quy cn s dng.

Chun b s lng c quy cn u ni, cu ni, dy u ngun, ng h vol kmt chiu DC, c l v km vn nng.

- Bc 2: Thc hin u ni

u ni tip:

Mc ch to ra b ngun c in p ln hn in p trn cc c quy thnh phn.

Phng php thc hin:+ Xp t c quy ln gi theo mc chu ni.

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+ Dng cu ni cc (-) ca c quy ny vi cc (+) ca c quy kia hoc ngc li.C nh vy n c quy cui cng, hai cc cn li trn c quy u tin v c quy cuicng l hai cc ca b ngun (Hnh 2.4).

iu kin u ni tip l cc c quy phi cng dung lng: Q1 = Q2 = Q3 = ... = Qn

Cng thc tnh ton khi ni tip:

in p tng ca b ngun: U = U1 + U2 + U3 + ... + Un =n

ii=1

U = nUi

Dung lng ca b ngun: Q = Q1 = Q2 = Q3 = ... = Qn = Qi

Dng in phng nh mc ca b ngun: Ip= Q/10

Ni tr trong ca b ngun: R0 = r01 + r02 + r03 + r0n=n

0ii=1

r

Trong : n l s bnh c quy mc ni tip.

u song song:Mc ch to nn b ngun c dung lng phng ln hn c quy thnh phn.

Phng php thc hin:

+ Xp t c quy ln gi theo mc chu ni.

+ Dng cu ni: Ni chung cc m (-) ca tt c c quy vi vi nhau, cc dng(+) ca cc c quy vi nhau (Hnh 2.6). Cc m chung v dng chung chnh l hai ccca b ngun.

iu kin u song l cc c quy phi c cng in p v cng dung lng:

U1 = U2 = U3 = ... = Um

+

Hnh 2.4: u ni tip c quy

+ + + ---- -+

U1 U2 U3 Un

U= Ui

Hnh 2.5: S nguyn l u ni tip

Hnh 2.6: u song song c quy

-

+ + + ---

+

+ -

UmU3U2U1 U =Ui

Hnh 2.7: S nguyn l u song song

+

-

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U

Hnh 2.9: S nguyn l u hn hp

U1 U2 U3 Un1

2

3

m

Q1 = Q2 = Q3 = ... = Qm

Cng thc tnh ton:

in p b ngun: U = U1 = U2 = U3 = ... = Um = Uj

Dung lng ca b ngun: Q = Q1 + Q2 + Q3 + ... + Qm =n

j

j=1

U = mQj

Dng in phng ca b ngun: Ip= Q/10

Ni tr trong ca b ngun: R0 = r01/m = r02/m = r03/m = ... = r0n/m = r0j/m

Trong m s nhnh song song ca b ngun.

u hn hp:

Mc ch l to ra b ngun c in p v dung lng ln hn in p v dunglng ca c quy thnh phn.

Phng php thc hin:- u ni tip c quy thnh tng nhnh c in p theo yu cu.

- u song song cc nhnh li thnh c dung lng theo yu cu (Hnh2.8).

S c quy mc ni tip trn mt nhnh l n v s nhnh u song song l m.

iu kin l cc c quy phi c cng in p v cng dung lng:

U1 = U2 = U3 = ... = Un

Q1 = Q2 = Q3 = ... = Qn

Cng thc tnh ton:in p b ngun:

U= Un1 = Un2 = Un3 = ... = Unm = U1 + U2+ U3 + ... + Un =n

ii=1

U = nUi = Uni

Dung lng ca b ngun:

Q = Qn1 + Qn2 + Qn3 + ... + Qnm = Q1 + Q2 + Q3 + ... + Qm =n

j

j=1

Q = mQj = mQnj

Dng in phng nh mc ca b ngun:I= Q/10

Ni tr ca b ngun: 00

nrR

m

Trong :

Unil in p trn nhnh th i.

Qnjl dung lng trn nhnh th j.

r0l in tr trong ca c quy.

- Bc 3: Ni tiu ni cc cc ca c quy vi cc cc

cng tn ca ti ph hp. m bo tip xc ti

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cc v tr u ni phi chc chn.

-Bc 4: Nhn xt

Sau mi phng php u ni, tin hnh kim tra:

+ o in p ca tng c quy.

+ o in p ca tng nhnh.

+ o in p ca b ngun.

+ o dng phng ca tng nhnh.

+ o dng phng ca b ngun.+ Kt lun.

Hnh 2.8: u hn hp c quy

+ - + - + - +-

+ - + - + - +-

+ - + - + - +-

+ - + - + - +-+

-

U

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Bn dn n

Bn dn p

in cc mt trn

in cc mt di

Lp tip gip

Hnh 2.10: Cu to pin mt tri

2. Pin mt tri

2.1. Cu to

V c bn, c th ni pin mt tri c cu to bi 3 thnh phn sau (Hnh 2.10):mt ghp bn dn p-n, in cc v lp chng phn x.

- Mt ghp bn dn p-n: S dng tinh th Silic (Si), y l thnh phn chnh ca pin,thng c din tch b mt rng v c lp n cc mng nh sng c th chuyn qua ti mt tip gip.

- in cc: dn in ra ph ti th trn mi mt ghp p -n phi c cc in cc.Vt liu lm in cc phi va c dn in tt, va c bm dnh tt vo cht bndn, bi th, in cc thng c ch to gm ba lp: Titan (Ti), Paladi (Pe) v bc

(Ag).+ Lp Titan: L lp trong cng, tip xc trc tip vi cht bn dn v Titan bm

dnh rt tt vi Si.

+ Lp bc: L lp v tr ngoi cng c tnh dn in tt v d hn ni.

+ Lp Paladi: L lp gia ca in cc c tc dng ngn cch gia lp Titan vbc, v nu hai lp ny tip xc trc tip th chng s phn ng ho hc vi nhau gyhng in cc.

to s lin kt tt gia cc lp ca in cc th sau khi ch to, ngi ta phi

trong nhit t 5000

C n 6000

C. Ngoi ra, i vi in cc mt trn ca pin cn phim bo hi ho gia vn che sng v in tr ca in cc. Thng thng in cc c to di dng mt li c che khng qu 10% din tch mt pin.

- Lp chng phn x: Trong qu trnh lm vic, nu s phn x nh sng cng nhius lm cho hiu sut ca pin cng gim. V vy, chng phn x cho pin th phi phmt hoc hai lp SiO2 hay TiO2 ngoi pin.

Do sc in ng ca pin mt tri nh (khong 0,5V) nn khi ch to phi u ninhiu pin vi nhau thnh dng tm (cn gi l modul pin mt tri). V pin phi lm vicngoi tri nn bo v v tng tui th ca pin th mt trn ca cc tm pin phi c

ph mt lp cht do trong sut, thng l: Polyvinyl butirat (PVB) hoc Etylen Vinylaxetat (EVA) v trn cng l tm thu tinh.

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2.2. Nguyn l hot ng

phn tch nguyn l lm vic ca pin mt tri, phi xt trn s nguyn l(Hnh 2.11). Nh bit, khi cho hai cht bn dn p v n tip xc vi nhau th in t t

bn dn n s khuch tn sang bn dn p, cn l trng ca bn dn p s khuch tn mtcch tng i sang bn dn n. Kt qu l min tip gip ca bn dn n tch in dng

cn min tip gip ca bn dn p tch in m. Trong min tip gip hnh thnh mt intrng (gi l in trng tip xc - Etx) v do c mt in p tip gip (cn gi lin p tip xc - Utx). Lc u, in trng tip gip tng nhanh, nhng khi ln sngn cn s khuch tn ca cc in t v l trng qua min tip gip (trng thi cn

bng ng).

Do cc ht dn khuch tn sang cc pha i din nn min tip gip, nng ccht dn l rt nh hay c th ni in tr ca min tip gip iu kin bnh thng l rtln. in trng Etx v in p Utx ch tn ti trong min tip gip, v th trong iu kin

bnh thng, nu ni cc u bn dn n v p vi nhau bng mt dy dn th trong dy vnkhng c dng in chy qua.

By gi, nu chiu nh sng vo b mt lp tip gip th cc in t v l trngquang s nhn c nng lng v tr thnh cc ht dn t do. Cc ht dn ny c E txgia tc v cc pha i din (l trng v pha bn dn p cn in t v pha bn dn n).Kt qu l to ra mt sc in ng gi l sc in ng quang in. Nu ni cc u bn

dn n v p vi mt ph ti th s c dng in chy qua. Sc in ng ny ph thucvo bn cht cc cht bn dn, vo nhit min tip gip, vo bc sng v cng nh sng. Hin tng xut hin sc in ng quang in khi chiu nh sng vo tipgip p-n c gi l hiu ng ni quang in.

Nh vy, mt tip gip p-n khi c chiu nh sng c th tr thnh mt ngunin cho ra mt cng sut hu ch. Hiu ng ni quang in trn cc tip gip p-n chuyn ho quang nng thnh in nng c gi l pin quang in. Nu s dng pinquang in chuyn ho bc x mt tri thnh in nng th pin c gil pin mttri.

Etx

n p

++

+++++

--

-----

n p

+++

++++

---

----

nh sng

A

V

- +

R

a)

b)Hnh 2.11: S nguyn l pin mt tri

a) Khi cha c nh sng chiub) Khi c nh sng chiu

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