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8/7/2019 baocao_nghich luu

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n in t cng sut GVHD: NGUYN TUN ANH

PHN 1 : M U.

in t cng sut l cng ngh bin i in nng t dng ny sang dng

khc trong cc phn t bn dn cng sut ng vai tr trung tm. B bin i

in t cng sut cn c gi l b bin i tnh (static converter) phn bit

vi cc my in truyn thng (electric machine) bin i in da trn nguyn

tc bin i in t trng. in t cng sut c ng dng rng ri trong hu

ht cc ngnh cng nghip hin i. C th k n cc ngnh k thut m trong

c nhng ng dng tiu biu ca cc b bin i bn dn cng sut nh

truyn ng in, giao thng ng st, nu luyn thp, gia nhit cm ng, in

phn nhm t qung m, cc qu trnh in phn trong cng nghip ha cht,

trong rt nhiu cc thit b cng nghip v dn dng khc nhau...Trong nhng

nm gn y cng ngh ch to cc phn t bn dn cng sut c nhng tin

b vt bc v ngy cng tr nn hon thin dn n vic ch to cc b bin

di ngy cng nh gn, nhiu tnh nng v s dng ngy cng d dng hn.

Mt trong nhng mch ng dng rt ph bin hin nay trong lnh vc in

t cng sut l mch nghch lu. Hy vng nhng phn m chng em vit

di y phn no gip cc bn hnh dung v hiu r thm v ng dng rtthng dng ca mch nghch lu. Do kin thc tm hiu v hc c cn hn

ch nn khng th trnh khi nhng thiu st . Chng em mong c s gp

t cc bn v thy c. Chng em xin chn thnh cm n thy gio:NGUYN

TUN ANH v bn b gp gip trong qu trnh hon thnh n ny !

ti : Mch nghch lu
http://vi.wikipedia.org/wiki/Truy%E1%BB%81n_%C4%91%E1%BB%99ng_%C4%91i%E1%BB%87nhttp://vi.wikipedia.org/wiki/Truy%E1%BB%81n_%C4%91%E1%BB%99ng_%C4%91i%E1%BB%87n


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PHN 2: GII THIU CC LINH KIN V NHIM V

CA N TRONG MCH

1/ it zener.

Cu to : Diode Zener c cu to tng t Diode, Diode Zener c ng

dng trong ch phn cc ngc, khi phn cc thun Diode zener nh diode

thng nhng khi phn cc ngc Diode zener s gim mt mc in p c

nh bng gi tr ghi trn diode.

Hnh 1.hnh dng th t,k hiu v c tuyn ca diode zener

Nguyn tc hot ng:

Diode Zener, cn gi l "it nh thng" hay "it n p": l loi it c ch

to ti u hot ng tt trong min nh thng. Khi s dng it ny mc

ngc chiu li, nu in p ti mch ln hn in p nh mc ca it th it

s cho dng in i qua

Khi c phn cc thun diode Zener hot ng ging diode bnh thng Khi

c phn cc nghch, lc u ch c dng in tht nh qua diode. Nhng nu

in p nghch tng n mt gi tr thch ng: Vngc = Vz (Vz : in p Zener)th dng qua diode tng mnh, nhng hiu in th gia hai u diode hu nh

ti : Mch nghch lu


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Hnh 4. hnh dng thc t CD4047

y l ic gm 14 chn ng gi dng dip 100T. in p hot ng

trong khong t 3 n 15 V. Chng ta cn quan tm ti chc nng

ca cc chn sau:

Chn 1 u vo t C

Chn 2 u vo in tr R

Chn 3 u vo R-C to dao ng vi tn s nh sn

Chn 10 u ra xung vung bn chu k dng

Chn 11 u ra xung vung bn chu k m

Chn 7 cp ngun m

Chn 14 cp ngun dng

S khi bn trong IC:

ti : Mch nghch lu


6/14


Hot ng ca IC nh sau:

- Hot ng ca chn astable c php khi t u vo chn 5 mc cao

hoc mc thp ca chn 4 hoc ca 2 chn.

- rng ca xung vung ca Q v Q l hm ca u vo ph thuc vo

RC

Chn 5 astable cho php mch lm b to dao ng a hi qua cng 5. rng

xung chn 13 bng 1/2 u ra Q trong ch astable. Tuy nhin iu ny ch

ng 50%

Trong ch n nh n khi c sn dng u vo +trigger(8) khi chn

trigger(6) mc thp cc xung u vo c th thuc bt k thi im no tng

ng vi xung u ra

Chn 12 cho php kch m tr li khi n l xung dng

c im ca vi mch nh sau:

- Cng sut tiu th thp

- Hot ng trng thi n l ch khng n nh

ti : Mch nghch lu


7/14


- Cc u ra n nh mc cc th b b xung ch yu cu mt tn hiu duy

nht ngoi R hoc C cc u vo c im kim tra tnh in p 20Vc

chun ho c tnh , c tnh u ra chun v i xng.

4. IRF Z44

IRF Z44 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.

Hnh 8.hnh dng v k hiu IRF Z44

Tng ng v thut ng gia Transistor MOS v Transistor lng cc.

Transistor MOS Transistor lng cc

D Colect C

S Emit E

G Baz BVDD : ngun in mng. VCC

VGG : ngun in cng. VBB

ID : dng in mng. IC

ti : Mch nghch lu


8/14


Hnh 9.thng s c bn ca IRF Z44

IRF Z44 c th cho dng Id = 49A i qua vi sin p 55V,khi tr khng ca

kha in t ny ch khong 0,024.

PHN 3: C S L THUYT V S KHI.

1/ C s l thuyt .

Nh chng ta bit hin nay th dng in xoay chiu khng th thiu

c trong cuc sng , cng nghip, dch v C nhiu cch to ra dng

in xoay chiu . Trong cng nghip nng s dng dng in xoay chiu vi

in p ln , cng sut ln th ngi ta c th dng thy in , nhit in, sc

gi , nng lng nguyn t Nhng trong s dng vi cc ngi tiu dng

hng ngy th khng cn thit phi u t vi sc ngi , sc ca ln nh vy

m c th s dng phng php kh n gin l dng cc linh kin in t

gim gi thnh vi ngi tiu dng . l mch in nghch lu to ra dng

xoay chiu t dng in mt chiu.

2/S khi.

ti : Mch nghch lu


9/14


A. Khi ngun DC :

y l phn cung cp cho khi cng sut in p . Ngun ny l ngun mt

chiu c ly t acquy 12v- 100Ah. Cng sut pht l 1200W. N c th cp

ngun cho n 20W sng lin tc trong vng 60 gi.

B/ Khi cng sut :

Khi c nhim v nhn tn hiu dng sng t khi pht v khuyech i a

n khi bin p to ra in p xoay chiu. Ngi ta s dng cc linh kin

chu dng ln trong khi ny nh thyristor , transistor Do cng sut khi ny

ti : Mch nghch lu

KHI NGUN DC

KHI CNG SUT

BIN P

KHI TOXUNG(F=50HZ)


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ln nn cc linh kin thng b nng nn ta thng gn km tn nhit trn linh

kin lm mt.

C/ Khi to xung ( f=50hz).

Nhim v ca khi l to ra tn hiu xung n nh a vo khi cng sut

vi tn s 50hz . L do chn tn s ny l do yu cu u ra ca mch l dng

in xoay chiu c f=50hz . Khi ny c nhim v kh quan trng nn trn thc

t ngi ta s dng thm khi m n nh tn hiu xung , gim tr khng

u vo cho khi cng sut.

D/ Khi bin p .

y l loi bin p nghch lu. N quyt nh n cng sut pht ca mch.

Thng th ta dung loi bin p nghch lu 12V-220V / 40A. t c cc tr

s th tnh ton kch thc bin p , t s vng dy gia cun s cp so vi

cun th cp.

PHN 4: S NGUYN L , MCH IN V PHNTCH MCH IN.

Do ti ch yu l i su vo mch nguyn l v phn tch hot ng ca

mch nghch lu nn sau y l mch nguyn l:

1/ s nguyn l .

ti : Mch nghch lu


11/14


2/ Phn tch nguyn l hot ng .

u tin khi cp ngun cho IC 4047 th IC 4047 pht ra 2 xung vi 2 na chu

k ngc pha nhau ti chn 10 v 11. tn s hot ng l 50hz th ta cn phi

tnh ton theo cng thc T=2,48RC. Chn R= 47K , C= 0,1uF.

Tn hiu xung vung c xut ra trn cc chn 10, 11 s i qua in tr R=

47K ti IC LM358 c tc dng khuyech i m vi h s K=1. Nhim v chnh

ca IC ny l gim tr khng u vo cho b phn cng sut , n nh ch

lm vic pht xung ca IC4047 .

Na chu k xung th nht m IC4047 to ra chn 11 mc 0, chn 10 mc

1 th kch cho Q1 dn lm xut hin dng in qua cun bin p. Na chu k sau

chn 11 mc 1 cn chn 10 mc 0 th kch cho Q3 dn lm xut hin dng

in chy qua cun bin p

Cp IRF Z44 c thay nhau ng m lin tc nh vy nh nhng kha in t

vi tn s f=50hz ca b pht xung. T s ng ngt ny dng in qua bin p

ti : Mch nghch lu


12/14


thay i theo tn hiu xung vung. chu k dng cun L1 phn s cp ca

bin p c cp ngun, chu k m cun L2 phn s cp c cp ngun .

Cc cun L1,L2 ca bin p s xut hin dng cm ng sang cun th

cp(220v) ca bin p to cng sut cp cho ti bn ngoi .

3, mch layout

Kt qu thu hoch.

Cc gi tr o thc t nh sau:in p th cp bin p khng ti l VAC, 50Hzin p th cp bin p c ti l 230VAC, 50Hz

Tn s u ra o c

ti : Mch nghch lu


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ti : Mch nghch lu

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