i hc s phm k thut Hng Yn

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LI NI UNgy nay vi s pht trin nhanh chng ca k thut bn dn cng sut ln, cc thit b bin i in nng dng cc linh kin bn dn cng sut c s dng nhiu trong cng nghip v i sng nhm p ng cc nhu cu ngy cng cao ca x hi. Trong thc t s dng in nng ta cn thay i tn s ca ngun cung cp, cc b bin tn c s dng rng ri trong truyn ng in, trong cc thit b t nng bng cm ng, trong thit b chiu sng... B nghch lu l b bin tn gin tip bin i mt chiu thnh xoay chiu c ng dng rt ln trong thc t nh trong cc h truyn ng my bay, tu thu, xe la... Trong thi gian hc tp v nghin cu, c hc tp v nghin cu mn in t cng sut v ng dng ca n trong cc lnh vc ca h thng sn xut hin i. V vy c th nm vng phn l thuyt v p dng kin thc vo trong thc t, chng em c nhn n mn hc vi ti: Thit k va ch to mch nghch lu mt pha. Vi ti c giao, chng em vn dng kin thc ca mnh tm hiu v nghin cu l thuyt, c bit chng em tm hiu su vo tnh ton thit k phc v cho vic hon thin sn phm. Di s hng dn ch bo nhit tnh ca thy Quang Huy cng vi s c gng n lc ca cc thnh vin trong nhm chng em hon thnh xong n ca mnh. Tuy nhin do thi gian v kin thc cn hn ch nn khng trnh khi thiu st khi thc hin n ny. V vy chng em rt mong s nhn c nhiu kin nh gi, gp ca thy c gio, cng bn b ti c hon thin hn.

Chng em xin chn thnh cm n!

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i hc s phm k thut Hng Yn

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NHN XET CUA GIAO VIN ......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... ..........................................................................................................................................

Hng Yn, thng 1 nm 2010. Giao vin hng dn Quang Huy

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i hc s phm k thut Hng YnMC LC A.LI M U NHN XT CA GIO VIN HNG DN. PHN I : YU CU V MC TIU CA TI. 1.1. 1.2. 1.3. 1.4. Phn tch yu cu ca ti. Mc tiu ca ti. Cc phng n thc hin. ngha ca ti.

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PHN II : C S L THUYT. 1. Gii thiu v cc van bn dn cng sut. 1.1. it cng sut. 1.2. Tiristor cng sut. 1.3. Tric. 1.4. Transistor cng sut. 1.4.1. Transistor lng cc ( BJT ). 1.4.2. Transistor MOS cng sut ( MOSFET ). 2. Gii thiu tng quan v nghch lu v mt s mch ng dng 2.1 Gii thiu tng quan v nghch lu 2.2Mt s mch ng dng 3. My bin p v c quy. 3.1. My bin p. 3.2. c quy.

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i hc s phm k thut Hng YnPHN II : TNH TON V THIT K SN PHM. 41. Tnh ton my bin p 4.2. MOSFET cng sut K956 4.3. Thit k mch iu khin 4.4.Mch cch ly 4.5. Nguyn l hot ng ton h thng v s Board PHN III : NG DNG CA SN PHM B. KT LUN

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i hc s phm k thut Hng Yn

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TN TAI

Thit k va ch tao mach nghich lu mt pha

* S liu cho trc - Cac giao trinh va tai liu chuyn mn - Cac trang thit bi o, kim tra tai xng thc tp, thi nghim.

1.1 Phn tch yu cu ca ti. Vi yu cu ca ti khi chng ta phi i thit k mt b nghch lu cho ra in p xoay chiu l 220V t ngun c quy 12V, tn s trong mch o c l 50Hz, cng sut ra ca b nghch lu l 300W. Mch ly ngun c quy 12V cp trc tip cho mch v cho bin p. Bin p y s dng nh mt b kch nhm kch ngun p ln gi tr cao hn nhiu ln so vi gi tr p ban u. Chnh v mch c kh nng bin i ngun mt chiu thnh ngun xoay chiu nn mch c tnh thit thc rt ln trong thc t. Mch l mch cng sut v vy linh kin c s dng phn ln l linh kin cng sut. Mch s dng cc van bn dn cng sut nh Transistor, MOSFET, IGBTTrong qu trnh chy mch th xung to ra l xung vung v c khuych i ln bng cc van bn dn l Transistor, IGBT

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i hc s phm k thut Hng Yn1.2 Mc tiu ca ti.

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Nm c mt cch tng quan v cc phn t bn dn cng sut. Nghin cu v cc mch nghch lu, hiu c nguyn l lm vic ca mch nghch lu, cc phng php bin i t la chn mt phng n ti u nht c p dng trn n ca mnh v ngoi thc tin. C kh nng tnh ton, thit k v ch to mch nghch lu in p mt pha vi cng sut cho trc.

1.3 ngha ca ti. gip sinh vin c th c th cng c kin thc, tng hp v nng cao kin thc chuyn nghnh cng nh kin thc ngoi thc t. ti cn thit k ch to thit b, m hnh cc sinh vin trong trng c bit l sinh vin khoa in in t tham kho, hc hi to tin ngun ti liu cho cc hc sinh, sinh vin kho sau c thm ngun ti liu nghin cu v hc tp. Nhng kt qu thu c sau khi hon thnh ti ny trc tin l s gip chng em c th hiu su hn v cc b nghch lu, cc phng php bin i in p. T s tch lu c kin thc cho cc nm hc sau v ra ngoi thc t.

1.4 Ni dung cn hon thnh: - Lp k hoach thc hin. - Gii thiu mt s ng dng v c im ca mch nghch lu mt pha. - Phn tch nguyn l lm vic v cc thng s trong mch nghch lu mt v ba pha.

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- Thit k, ch to mch nghch lu mt pha m bo yu cu: + in p u vo mt chiu U = 12V ly t c quy. + in p u ra dng cho cc thit b in xoay chiu U = 220V f = 50HZ , P = 300VA. + Th nghim, kim tra sn phm, sn phm phi m bo yu cu k thut, m thut. Quyn thuyt minh.v cc bn v Ao, Folie m t y ni dung ca ti. -

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i hc s phm k thut Hng YnPHN I :C S L THUYT

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I. Gii thiu v cc van bn dn cng sut. Cc phn t bn dn cng sut u c nhng c tnh c bn chung, l : Cc van bn dn ch lm vic trong ch kho, khi m cho dng chy qua th c in tr tng ng rt nh, khi kho khng cho dng chy qua th c in tr tng ng rt ln. Cc van bn dn ch dn dng theo mt chiu khi phn t c t di in p phn cc ngc, dng qua phn t ch c gi tr rt nh, c mA, gi l dng r.

1.1. it cng sut. it do hai lp vt liu bn dn P N ghp li thnh. in tch mt ghp c khi t ti hng chc cm2, vi mt dng in 10A/mm.

Anot p J n KatotUng.max I r

i

0 Uo

u

H

nh 1 : Cu to v ng c tnh V A ca it

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i hc s phm k thut Hng Yn1.2. Tiristor : ( SCR ).

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Tirirtor l mt thit b gm bn lp bn dn P 1,N1,P2,N2 to thnh, tirirtor phi c cp mt xung dng th n mi hot ng. Do SCR thit k phi c 3 chn : chn Anot, Katot v chn iu khin G.G K N2 P2 N P1 1 J3 J2 J1 A

a : Cu to ca tiristorK A GK A G

G

K

BT... A

b : K hiu v hnh dng thci IV Ung.max I r 0 Uv.th Uth.max u IG2 > IG1 > IGO IG = 0

c : c tnh V A ca tiristorHnh

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i hc s phm k thut Hng Yn1.3. Tric.

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Tric l thit b bn bn ba cc, bn lp c ng c tnh volt ampe i xng, nhn gc m cho c hai chiu. Thc cht Tric c ch to ging nh 2 SCR ghp song song vi nhau, dng dn dng AC c hai chiu khi cc G c kch xung dng hoc p m.

A1

A2

A1

A2 G

G

Hnh 3 : K hiu ca tric

1.4. Transistor cng sut. 1.4.1. Transistor lng cc ( BJT ). Transistor lng cc l thit b gm ba lp bn dn NPN hoc PNP, c dng ng ct dng in mt chiu c cng tng i ln. H s khuych i dng, k hiu l = 10 100. in p Vbe 1V; ( 1 1,5 ) V. Vcc =

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i hc s phm k thut Hng YnC C Ic N B P N E Vbe Ie E B Ib V ce

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a : Cu trc k hiu ca Transistor cng sut NPNIc Ib2 Ib1 Ib = 0 0 V Ib2 > Ib1

b : c tnh vn ampe ca Transistor cng sut NPN Hnh 4 : Cu to v c tnh V A ca Transistor cng sut NPN Cng sut tn tht trong Tr khi lm vic vi ti xc nh nh hn nhiu ln so vi cng sut tn tht khi transistor chuyn trng thi. Tch cng sut chuyn trng thi pc vi thi gian chuyn trng thi tc l nng lng tn tht trong qu trnh chuyn trng thi. Nng lng tn tht t l thun vi tn s hot ng ca transistor, khi nhit bn trong Tr khng c vt qu 200oC.

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gim nh nng lng tn tht do Tr chuyn trng thi gy nn ngi ta dng cc mch tr gip. Vic s dng cc mch tr gip c xem l bt buc khi Tr lm vic cc iu kin sau : f > 5 kHz hoc VC 60V, IC > 5A.

1.4.2. Transistor MOS cng sut ( MOSFET ). Transistor MOS c ba cc : D - cc mng ( drain ) : cc in tch a s t thanh bn dn chy ra mng. S - cc ngun ( source ) : cc in tch a s t cc ngun chy vo thanh bn dn. G - cc cng ( gate ) : cc iu khin. Tng ng v thut ng gia Transistor MOS v Transistor lng cc. Transistor MOS D S G VDD : ngun in mng. VGG : ngun in cng. ID : dng in mng. Transistor lng cc Colect C Emit E Baz B VCC VBB IC

2. Tng quan v nghch lu v mt s mch ng dng . 2.1.Tng quan v nghch lu 3 2

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Trong cng ngh, ta thng gp vn bin i in p mt chiu thnh in xoay chiu v ngc li bng cc thit b nn in. Cc thit b c gi l nghch lu. Khi nim: Nghch lu l qu trnh bin i nng lng mt chiu thnh nng lng xoay chiu. Phn loi: Cc s nghch lu c chia lm hai loi. - S nghch lu lm vic ch ph thuc vo li xoay chiu. - S nghch lu lm vic ch c lp (vi cc ngun c lp nh c quy, my pht mt chiu ....) Nghch lu ph thuc c s nguyn l ging nh chnh lu c iu khin. Mch nghch lu ph thuc l mch chnh lu trong c ngun mt chiu c i du so vi chnh lu v gc m ca cc tiristo tho mn iu kin ( /2 <