n mn hoc in t cng sut-Truyn ng in

Trng i hc s phm k thut Hng yn n mn hc

Khoa in in t

MC LC trangCHNG I Gii thiu mt s van ban dn cng sut......................51.1. Diode cng sut ...............51.2. Transistor cng sut ........71.3 . Mosfet cng sut .................81.4 . Thyristor .............................12.CHNG II Tng quan v mach nghich lu mt pha..........................................142.1. Tng quan v nghich lu.......................................................................................142.2.Nghch lu c lp.................................................................................................142.2.2 .Nghch lu c lp ngun p mt pha qua my bin p im gia..................152.2.3. Nghch lu c lp ngun p cu 1pha..............................................................182.2.4.Nghch lu c lp ngun dng cu 1 pha..........................................................21CHNG III Tinh toan va thit k mach...............................................................253.1.Tnh ton my bin p.............................................................................................253.2.Mosfet cng sut IRF3205......................................................................................263.3.Thit k mch iu khin........................................................................................283.4. Mch lc................................................................................................................333.5. Mch cch ly ........................................................................................................343.6. Nguyn l hot ng ca ton h thng................................................................36Hng pht trin ca ti.......................................................................................38Kt lun ......................................................................................................................39 Ti liu tham kho.

NHN XET CUA GIAO VIN.......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Hng Yn, thng 11 nm 2012

Giao vin hng dn

NGUYN TRUNG THNHLI 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: Nghin cu 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 NGUYN NH HNG 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! N MN HCSinh vin thc hin : 1. Nguyn Danh Sch2. Trn Vn Thng3. Trng c ThnhLp

: 602101Kho hc

: 2010 - 2013Ngnh o to : K Thut inTn ti: Nghin cu ch to mch nghch lu mt pha S liu cho trc:

- Cc trang thit b o, kim tra ti xng thc tp, th nghim TCS.- Cc ti liu, gio trnh chuyn mn.

Ni dung cn hon thnh:1. Lp k hoch thc hin

2. Phn tch mch nghch lu mt pha ngun dng v ngun p.

3. Thit k, ch to mch nghch lu mt pha m bo yu cu:- S = 300VA; 4. Sn phm ca ti m bo tnh cng nghip v c tnh kh thi trong thc tin.5. Trnh by quyn thuyt minh theo yu cu: font times new roman; l phi 2.5cm; l tri 3cm; cch trn 2cm, cch di 2cm; mc cc chng (phn) ch vit hoa c 13, cc mc chnh ch thng in m, ni dung chnh ch 13. Cu trc thuyt minh theo yu cu hin hnh ca b mn.

Gio vin hng dn:

Nguyn Trung Thnh Ngy giao ti: 21-9-2012 Ngy hon thnh:

CHNG IGII THIU MT S VAN BAN DN CNG SUT

Cc phn t bn dn cng sut u c nhng c tnh c bn chung,o lcc 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 Diode cng sut a)cu tao

Diode cng sut l phn t bn dn c mt tip gip PN. Din tch b mt tip gip c ch to ln hn so vi diode thng thng, c th t ti hng trc mm2. Mt dng in cho php ca tip gip c 10A/mm.2 Do vy dng in nh mc ca mt s loi diode c th t ti hng trm ampe, nh PK200, thm ch hng nghn ampe nh BB2-1250. Cu to v k hiu ca diode cng sut c m t nh hnh 1.1

Hnh 1.1: Cu trc v k hiu ca diode cng sut

b)c tnh vn ampe:

Hnh 1.2 c tinh vn-ampe cua diode

c tnh V-A ca diode gm 2 nhnh, nhnh thun(1) nm gc phn t th

nht ng vi UAK ( 0, nhnh ngc (2) nm gc phn t th ba ng vi

UAK ( 0 hnh1.2.2-4.

-Trn ng c tnh thun ca diode nu in p UAK c tng dn t 0 n vt qu gi tr UD0 ( 0,6 0,7V, gi l in p ri trn diode theo chiu thun, th dng in i qua diode c th t ti gi tr rt ln, nhng in p ri trn diode hu nh khng i.

-Trn ng c tnh ngc diode nu in p UAK c tng dn t 0 n gi tr Ungmax th dng in qua diode c gi tr rt nh, gi l dng d. Cho n khi UAK t n gi tr ln hn Ungmax th dng in qua diode tng t ngt, nh vy kh nng cn tr dng in ca diode theo chiu ngc b ph v. y l hin tng diode b nh thng.

-Trong nhng tnh ton thc t ngi ta thng dng c tnh gn ng tuyn tnh ha ca diode. Biu thc ton hc ca ng c tnh ny l:

u = UD0 + iDRDTrong : UD0(V); ID (A); RD (().

-c tnh V-A ca diode thc t l khc nhau, n ph thuc vo dng in cho php v in p ngc m diode chu c. Theo c tnh l tng th in tr tng ng ca diode bng 0 theo chiu thun v bng theo chiu ngc.1.2 Tranzisto cng sut ( 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; Vcc = ( 1 1,5 ) a)Cu to transistor ngc NPN

Hinh 1.3 Cu tao transistor ngcb) Cu to transistor thun PNP

Hinh 1.4 Cu tao transistor thunCng sut tn tht trong Tranzistor 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 Tranzistor khng c vt qu 200oC. gim nh nng lng tn tht do Tranzistor 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 Tranzistor lm vic cc iu kin sau :

f > 5 kHz hoc VC 60V, IC > 5A

1.3 MOSFET cng sut

MOSFET, vit tt ca "Metal-Oxide Semiconductor Field-Effect Transistor" trong ting Anh, c ngha l "transistor hiu ng trng Oxit Kim loi - Bn dn", l mt thut ng ch cc transistor hiu ng trng c s dng rt ph bin trong cc mch s v cc mch tng t. Vi nhng Mosfet cng sut thng c s dng nh nhng chuyn mch in t cng sut ln

+)Transistor MOSFET c xy dng da trn lp chuyn tip Oxit Kim lo v bn dn ( v d Oxit Bc v bn dn Silic).Lp bn dn c 2 loi nn c 2 loi MOSFET: NMOSFET hay PMOSFET. Thng thng cht bn dn c chn l silc nhng c mt s hng vn sn xut cc vi mch bn dn t hn hp ca silc v germani (SiGe), v d nh hng IBM. Ngoi silc v germani cn c mt s cht bn dn khc nh gali asenua c c tnh in tt hn nhng li khng th to nn cc lp oxide ph hp nn khng th dng ch to cc transistor MOSFET.

+) MOSFET c chia lm hai loi: -MOSFET knh lin tc v MOSFET knh gin on. -Mi loi knh lin tc hay gin on u c phn loi theo cht bn dn l knh N hay P. Ta xt cc loi MOSFET knh N v suy ra cu to ngc li cho knh P. 1.3.1 Cu to v k hiu ca MOSFET knh lin tca)Cu to v k hiu

Hinh 1.5 Cu tao MOSFET knh lin tc

b)c tnh

Hinh 1.6 c tnh ra MOSFET knh lin tc

1.3.2 Cu to v k hiu ca MOSFET knh gin ona)Cu to v k hiu

Hinh 1.7 Cu to ca MOSFET knh gin onb)c tnh

Hinh 1.8 c tnh ra ca MOSFET knh gin on1.3.3 Hot ng

Khi phn cc cho G c UGS>0V, cc in tch dng cc G s ht cc in t ca nn P v pha gia ca hai vng bn dn N v khi lc ht ln th s in t b ht nhiu hn, ni lin hai vng bn dn N v knh dn c hnh thnh.

Khi c dng in ID i t D sang S, in p phn cc cho cc G cng tng th dng ID cng ln. in p UGS ln to thnh knh dn in gi l in p ngng UGS(T) hay UT. Khi UGS 0, cn phn c tnh ngc nm gc phn t th ba vi UAK < 0.

a>Trng hp IG = 0:

*Khi UAK < 0 th tip gip J1 v J3 b phn cc ngc cn J2 phn cc thun, khi dng in qua thyristor rt nh. Gi l dng in d.

-Nu thc hin tng UAK n gi tr nh hn Ung,max th dng in qua thyristor cng vn rt nh. Nu c tip tc tng n gi tr UAK > Ung,max th x sy ra hin tng thyristor b nh thng, dng in qua thyristor x tng ln rt ln, qu trnh ny khng o ngc li c.

*Khi UAK > 0 khi tip gip J1 v J3 c phn cc thun cn J2 b phn cc ngc, lc ny dng in qua thyristor cng rt nh, gi l dng in d.

-Nu ta thc hin tng UAK n gi tr ln hn in p thun ln nht Uth,max th x sy ra hin tng in tr tng ng A- K t ngt gim xung v ng in d dng chy qua thyristor, v gi tr ca n ch ph thuc vo in tr mch ngoi. Nu khi dng qua thyristor ln hn dng uy tr Idt th thyristor x dn dng trn ng c tnh thun ( ging nh diode). c tnh thun c c trng bi tnh cht dng in c th thay i ln nhng in p ri trn thyristor gn nh khng i.

b> Trng hp IG > 0 .

*Khi UAK > 0 nu t vo cc iu khin dng IG > 0 th qu trnh chuyn im lm vic ln ng c tnh thun x xm hn. Nu dng iu khin cng ln th qu trnh chuyn im lm vic ln ng c tnh thun x cng xm hn vi UAK nh hn.

*Khi UAK < 0 th qu trnh sy ra cng tng t trng hp IG = 0.

CHNG IITNG QUAN V MACH NGHICH LU MT PHA2.1. Tng quan v nghch lu.

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: nghch lu v c ban c chia lm hai loi:- Nghch lu lm vic ch ph thuc vo li xoay chiu.

- 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 < ( 0 th ngun cung cp nng lng cho ti(cc thyristor dn dng)

- Khi is 0 v tng chy theo chiu t AB.

Giai on t t = 0 n t1 l giai on hon nng lng.

Khi t = T/2 cho xung m T2 v T4 , T1 v T3 b kho li, dng ti chy qua D2 v D4

khin cho T2 v T4 va kp m b kho li. Khi t = t3, i = 0, T2 v T4 s m li , i < 0

chy theo chiu t BA. Dng ti i bin thin theo quy lut hm m gia hai gi tr Im

v -Im. Cc xung iu khin Thyristor thng l xung chm.

* Biu thc ca dng ti i:

+ Khi bt u cho xung m T1 v T3 ta c phng trnh:

Di dng ton t Laplace ta c:

Trong i(0) = -Im v =R/L

Do

+ Khi cho xung m T2 v T4 ta c phng trnh

2.2.4.Nghch lu c lp ngun dng cu 1 pha :Nghch lu dng l thit b bin i ngun dng mt chiu thnh dng xoay chiu c tn s ty .

c im c bn ca nghch lu dng l ngun mt chiu cp ngun cho b bin i phi l ngun dng, do in cm u vo (Ld) thng c gi tr ln v cng m bo dng in l lin tc.

a) Nguyn l lm vic:

S d nghch lu dng mt pha c trnh by nh trn hnh (s cu) v hnh (s c im trung tnh).

*) Xt s cu: Cc tn hiu iu khin c a vo tng i tiristor T1, T2 th lch pha vi tn hiu iu khin a vo i T3, T4 mt gc 1800.

in cm u vo ca nghch lu ln (Ld = ), do dng in u vo c san phng, ngun cp cho nghch lu l ngun dng dng dng in ca nghch lu (iN) c dng xung vung.

Khi a xung vo m cp van T1, T2, dng in iN = id = Id. ng thi, dng qua t C tng ln t bin, t C bt u c np in vi du + bn tri v du - bn phi. Khi t C np y, dng qua t gim v khng.

Do iN = iC + iZ = Id = const, nn lc u dng qua ti nh v sau dng qua ti tng ln. Sau mt na chu k (t = t1) ngi ta a xung vo m cp van T3, T4. Cp van T3, T4 m to ra qu trnh phng in ca t C t cc + v cc -. Dng phng ngc chiu vi dng qua T1 v T2 s lm cho T1, T2 b kha li. Qu trnh chuyn mch xy ra gn nh tc thi. Sau , t C s c np in theo chiu ngc li vi cc tnh + bn phi v - bn tri. Dng nghch lu iN = id = Id nhng i du. n thi im (t = t2) ngi ta a xung vo m T1, T2 th T3, T4 s b kha li v qu trnh c lp li nh trc. Nh vy, chc nng c bn ca t C l lm nhim v chuyn mch cho cc tiristor. thi im t1, khi m T3, T4, tiristor T1, T2 s b kha li bi in p ngc ca t C t ln.

Hnh 1.1 S mt pha c im trung tnh v biu xung ca s cu mt pha.

Khong thi gian duy tr in p ngc t1 t1 = tk toff; toff l thi gian kha ca tiristor hay chnh l thi gian phc hi tnh cht iu khin.

.tk = l gc kha ca nghch lu.

b) nh hng ca in cm u vo Ld i vi ch lm vic ca nghch lu:

Dng in vo ca nghch lu (id) nh hng ln i vi ch lm vic ca n. Dng u vo ph thuc vo gi tr ca in cm Ld.

Hnh 1.2 nh hng ca in cm Ld i vi ch lm vic ca nghch lu.

a) Ld = ; b) Ld hu hn nhng dng Id l lin tc; c) Dng Id gin on.

Nu in cm vo ln , dng in c san phng, ngun vo thc cht l ngun dng. Dng dng qua tiristor l dng xung ch nht, do dng in ca nghch lu cng l dng xoay chiu dng xung ch nht, v thi gian kha (tk) ca nghch lu l ln nht. Khi in cm u vo chim mt gi tr trung bnh no m vn m bo dng l lin tc , lc ny dng sng in nhp nh do vn cha cc sng iu ha bc cao. Dng in p gn vi hnh sin hn, nhng thi gian kha ca tiristor b gim xung.

Khi dng in vo l gin on, gi tr in cm khng duy tr ngun l ngun dng th thi gian tk l b nht.

i vi nghch lu dng in, quan trng nht l qu trnh chuyn mch ca tiristor. Ph ti lun nh hng n qu trnh chuyn mch, do vy m bo nghch lu lm vic tin cy th thi gian tk phi ln, tc l ngun u vo phi lun lun m bo l ngun dng.

c) nh hng ca ph ti i vi vi ch lm vic ca nghch lu:

Ta xt trng hp Ld = (in cm v cng ln). S trn hnh 3.2 c th thay th bng s hnh 3.4a.

Hnh1 .3 a) S thay th ca nghch lu dng mt pha.

b) nh hng ca ti i vi in p.

Ta c phng trnh ca in p trn ti:

.

T phng trnh trn ta thy in p trn ti bin thin theo quy lut hm m c s e. Khi thay i ph ti nh gim dng ti, dng qua t s t thay i v (ngun dng), do in p trn ti s c dng l nhng ng gn tuyn tnh (ng 1 trn hnh 3.4b), gc kha = .tk /2., vi tk l thi gian kha ca nghch lu.

Nghch lu dng khng c kh nng lm vic ch khng ti, v nu Rt th Ut v id . Trn thc t khi Rt ln v cng th in p trn ti cng tin n gi tr rt ln, do qu trnh chuyn mch khng th thc hin c, cng nh khng c thit b bn dn no chu ng ni qu in p ln nh vy.

Ngc li, khi tng ph ti (tng ng vi vic gim gi tr Rt), lc ny dng np cho t s gim, ngc li dng phng ca t qua ti s tng ln. iu dn n gim nng lng tch tr trong t, dng in p trn ti s c dng gn vi hnh ch nht, nhng gc cng gim ng k v nh hng n qu trnh chuyn mch ca nghch lu (ng 2 hnh 3.4b).

Thi gian tk l thi gian duy tr in p ngc t ln tiristor. Gc kha ca nghch lu ph thuc vo tn s, ph ti v t chuyn mch.

tha mn iu kin lm vic ca nghch lu th min > .toff.

CHNG III

TNH TON V THIT K SN PHM.S dung s nguyn ly mach nghich lu c lp ngun ap mt pha s dung may bin ap im gia vi s n gian,d thit k .lp giap va chi phi thp.3.1.Tnh chn my bin p mt pha tn s 50HzMy bin th c th thay i hiu in th xoay chiu, tng th hoc h th, u ra cho 1 hiu in th tng ng vi nhu cu s dng. My bin p c s dng quan trng trong vic truyn ti in nng i xa. Ngoi ra cn c cc my bin th c cng sut nh hn, my bin p (n p) dng n nh in p trong nh, hay cc cc bin th, cc xc, ... dng cho cc thit b in vi hiu in th nh (230 V sang 24 V, 12 V, 3 V, ...). trong mch ny ta la chn my bin p im gia v so snh v mt kinh t v mt k thut phng n la chn ny l ti u

My bin p c cc thng s: Uv = 12V, Ur = 220V, f = 50HZ, S= 300WV th ta chn my bin p c N1=30(vng),N2=520(vng) Vi :N1 l s vng dy qun ca cun dy s cp N2 l s vng dy qun ca con dy th cp

T ta tnh c:N11=N12=N1/2=30/2=15(vng) Do my bin p im gia nn in p U1 = 2.U11 = 2.12 = 24( V )

Cng sut ca my bin p: S = .U2.I2

Trong : S l cng sut ca my bin p

U2 l in p ca cun th cp my bin p

I2 l dng in ca cun th cp my bin p

l hiu sut my bin p

Chn = 0,85 ta tnh c dng in th cp ca my bin p

I2 =S/(.U2 )= = 1.6 ( A )

p dng t s my bin p

I1 =

I1 = = 14,67( A )Cng sut ti a m ti chiu cl:

P1 = U1 . I1 = 24 .14,67 = 352 (W)

3.2. MOSFET cng sut IRF 3205 Nh tnh trn ta s chn MOSFET cng sut l IRF3205 v dng nh mc l:110A

Thng s nh trong bng:

a)Hnh dng

b)Thng s v c tnh

3.3.Thit k mch iu khin 3.3.1. Nhim v v chc nng ca mch iu khin :

*Nhim v

- iu chnh c rng xung trong na chu k dng ca in p t ln colector v emitor ca van .

- To ra c xung m c bin cn thit kho van trong na chu k cn li .

-Xung iu khin phi c bin v nng lng m v kho van chc chn .

-To ra c tn s theo yu cu .

-D dng lp rp, thay th khi cn thit, vn hnh tin cy, n nh .

-Cch ly vi mch ng lc

*Yu cu chung v mch iu khin l : - Mch iu khin l khu quan trng trong h thng, n l b phn quyt nh ch yu n cht lng v tin cy ca b bin i nn cn c nhng yu cu sau :

+)V ln ca dng in v in p iu khin:

Cc gi tr ln nht khng vt qu gi tr cho php. Gi tr nh nht cng phi m bo c rng cung cp cho cc van m v kho an ton. Tn tht cng sut trung bnh cc iu khin nh hn gi tr cho php .

+)Yu cu v tnh cht ca xung iu khin :

Gia cc xung m ca cc cp van phi c thi gian cht, thi gian cht ny phi ln hn hoc bng thi gian khi phc tnh cht iu khin ca van .

* Yu cu v tin cy ca mch iu khin :

Phi lm vic tin cy trong mi mi trng nh trng hp nhit thay i , c t trung...

+)Yu cu v lp rp v vn hnh :

S dng d dng , d thay th , lp rp . . . 3.3.2. Tnh ton mch iu khin:

to ra khi pht xung ta s dng vi mch CD4047B .Vi mch CD4047B mc ch chnh trong mch l to dao ng(xung vung),chnh bi xung to ra t IC ny nn IC CD4047B c chn to dao ng trong cc mch nghch lu.in p u ra t c dng sin hay khng l ph thuc phn ln vo xung tc ng vo cc chn iu khin ca cc van .Cc u ra n nh c tnh chun v i xng. V cng sut tiu th thp. Chnh nhng u im m ta chn vi mch CD4047B thit k mch iu khin cho mch nghch lu.a) Mch to xung

b)S chn ca vi mch

Cu trc bn trong ca vi mch nh sau

+)IC4047 c 14 chn trong :-Chn 1,2,3 l cc chn u vo(lm thay i c xung u ra)

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

-Chn 7 ni mass

-Chn 9 l chn khi ng li(ni mas) -Chn 10chn 11 l chn u ra - Chn 12 cho php kch m tr li khi n l xung dng

-Chn 13 hin th sng u ra (bnh thng khng cp g)-Chn 14 l chn cho ngun (+) vo cung cp cho ICc)Hot ng ca IC nh sauHot ng ca chn astable c php khi t u vo chn 5 mc cao hoc mc thp cua chn 4 hoc cua 2 chn.

rng ca xung vung ca Q v 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

+)Ta tnh ton c c xung ra l 50Hz nh sau:

-Gin thi gian tin hiu vo,ra v cng thc tnh rng xung

Dng sng u ra

Thay s: V = 12 V V= 50% V

Vi f = 50 (hz)

T = 0.02 (s)

4.4RC = 0.02RC = 4,5*10-3Chn t c C = 10-4, R=47kU Q v = 11 V3.4.Mch ng lc+)S nguyn l

Mch lc gm2 nhom van:Q1 ,Q2 v Q3,Q4 lp theo cch ghp song song nhm gia tng h s khuch i ca mch +)S xung iu khin n cc van

+)Tn hiu din p u ra

3.4.Mch cch ly:

Ta c in p u ra ti hai chn 10 v 11 ca 4047 l 9,5V .Dng in v in p lm vic ca IC nh, cn mch ng lc dng lm vic ln. cch ly gia mch iu khin v mch ng lc ta s dng PC817 c cu trc v thng s nh sauHnh dng

in p vo lm vic ca PC ln nht l 6V v th khi ni gia u ra Q v ca 4047 v PC ta ni qua in tr gy st p trn in tr. Suy ra ta chn R= 1 k.S lc v hot ng ca mch ny nh sau: Khi in p u ra chn 11ca 4047 l 4,8V qua diode v in tr c cp vo chn 1 ca Opto PC817 khi chn 3Opto c in p l 5,8V tc ng xung n mch lc v lm cho ti hot ng 3.6. Nguyn l hot ng ton h thng:a)S nguyn l

b)S board

c)Nguyn l hot ng- Khi c cp ngun 4047 s hoat ng to ra tn hiu ti xung ti hai chn 10 v 11 lch pha nhau 180 .Tn hiu xung ny s c cp vo chn 1 ca Opto PC817 lm cho PC817 hot ng. Tn hiu ra chn 3 ca PC817 i n kich m chn G ca Mosfet lm cho Mosfet hot ng nh vy dao ng to ra s iu khin cho Mosfet lin tc ng ngt to thnh dng in bin thin lin tc chy qua cun s cp => sinh ra t trng bin thin cm ng ln cc cun th cp => cho ta in p ra 220V ACHNG PHT TRIN CA TI

Mch nghch lu mt pha 12V sang 220V ngy nay c ng dng rng ri trong i sng sinh hot, n c kh nng cung cp in p u ra 220V n nh s dng cho cc thit b trong gia nh nh: qut, n, tivi... trong mt khong thi gian nht nh. Ty thuc vo cng sut mch, dung lng acquy m thi gian cung cp in cho cc thit b l nhiu hay t. Vi mch nghch lu n gii quyt phn no nhu cu v in nng ca con ngi, vai tr ca mch nghch lu th hin rt r khi in li b ct. Nhn chung mch nghch lu c vai tr kh to ln trong i sng. Thc hin an ny chng em thit k v ch to mch nghch lu cng sut b, ch yu dng cho cc thit b c cng sut nh nh n, qut.

Ti y ,nhom thc hin an chung em co y inh phat trin tai Nghin cu ch tao mach nghich lu mt pha co kha nng hoa vao li in , Chung em rt mong y kin ong gop va s giup cua cac thy c trong khoa.

KT LUN

Sau qu trnh thc hin bn n chng em thu c mt s kt qu nh sau:

- 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 pha. -Hon thin sn phm theo yu cu t ra c th:

in p ra dng cho ti 220 V: cng sut :300VATuy nhin an cua chung em con co nhc im la cha n inh c in ap ra khi tai ln.

Vi s c gng n lc ca mi thnh vin trong nhm chng em hon thnh n ca mnh theo ng thi gian. Mt ln na chng em xin gi li cm n ti cc thy c trong khoa in - in T, c bit l thy Nguyn Trung Thnh trc tip hng dn chng em trong vic hon thnh n. Chng em rt mong nhn c nhng kin nhn xt, gp ca cc thy c v cc bn bn n ca chng em hon thin hn.

Chng em xin chn thnh cm n!Ti liu tham kho1. V Minh Chnh Phm Quc Hi Trn Trng Minh

in t cng sut v truyn ng in _ NXB Khoa hc k thut

2. Nguyn Phng Tho Cng Thng

in t cng sut v truyn ng in _ Trng HSP K Thut Hng Yn

SVTH: Nguyn Danh Sch GVHD: Nguyn Trung Thnh

Trn Vn Thng

Trng c Thnh 14

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