N TT NGHIP

N TT NGHIP

B GIO DC V O TO CNG HA X HI CH NGHA VIT NAMTRNG I HC BCH KHOA HN c lp T do Hnh phc ----------------------------------- -----------------------

NHIM V N TT NGHIPH v tn sinh vin: ...PHAN TNG LM......................S hiu sinh vin:.20109561 ..Kha ..........55...........Khoa/Vin..........in...............Ngnh................................................

1. u thit k:............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

2. Cc s liu ban u:..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

3. Ni dung cc phn thuyt minh v tnh ton:....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................4. Cc bn v, th ( ghi r cc loi v kch thc bn v ):..............................................................................................................................................................................................................................................................................................

5. H tn cn b hng dn:..............................................................................................................................................................................................................................................................................................

6. Ngy giao nhim v n:...............................................................................................

7. Ngy hon thnh n: ...................................................................................................

Ngy.thng.nm Trng b mn Cn b hng dn ( k, ghi r h, tn) ( k, ghi r h, tn)

Sinh vin hon thnh v np n tt nghip ngy..thng.nm 2014

Ngi duyt Sinh vin ( k, ghi r h, tn) ( k, ghi r h, tn)

N TT NGHIP

5

LI CAM OANEm xin cam oan bn n tt nghip: Nghin cu, thit k b Ngun n p - n dng ny do em t thit k vi s hng dn ca Ts. Nguyn Hng Quang. Cc s liu v kt qu thc nghim l hon ton ng vi thc t. hon thnh n ny em ch s dng nhng ti liu c ghi trong danh mc ti liu tham kho v khng sao chp hay s dng bt k ti liu no khc. Nu pht hin c s sao chp em xin chu hon ton trch nhim.

MC LCTable of Contents327DANH MC HNH V7DANH MC BNG9LI M U10Chng 111KHI NIM V NGUN P, NGUN DNG111.1.Khi nim ngun p111.1.1.Mch Buck-Converter111.2.Khi nim ngun dng131.2.1.Ngun dng s dng op-amp13Chng 215TNH TON THIT K MCH LC152.1.Tnh ton mch Buck-Converter152.1.1. Tnh ton Mosfet152.1.2. Cun cm L172.1.3. T lc u ra CO182.1.5. Diode192.2.Tnh ton mch ngun dng212.2.1. in tr RS212.2.2. in tr R1, R2222.2.3. in tr RB222.2.4. in tr RF v t CF232.2.5. Transistor NPN232.2.6. Operational Amplifier24Chng 325THIT K MCH IU KHIN253.1. Phng php iu khin253.2. Mch iu khin263.2.1. Tng quan v Ic Atmega8263.2.2. Cu trc Atmega8263.2.3.Cng vo ra I/O273.2.4.ADC ca Atmega8273.2.5.Timer/Counter293.3.LCD323.4.Ir 2110333.5.Ic LM 358353.6.Ic ACS 712363.7.Ngun cung cp373.8.Mch tng qut38Chng 442KT QU M PHNG THC NGHIM424.1. Kt qu m phng424.2.Mch ngun dng434.3. Mach Thit k44KT LUN46Ti liu tham kho47PH LC48

32DANH MC HNH VHnh 1.1: Mch ngun kiu Buck-Converter.10Hnh 1.2: (a) Cu trc mch buck c bn , (b) kha v tr 1, (c) kha v tr 2, (d) th in p trn cun cm theo thi gian, (e) th dng in qua cun cm theo thi gian......11Hnh 1.3:S mch ngun dng s dng op-amp13Hnh 2.1: S nguyn l mch Buck-Converter...14Hnh 2.2: S in p qua cun cm...16Hnh 2.3: S dng in qua cun cm.......16Hnh 2.4: Dng in p trn t lc CO....17Hnh 2.5: Diode 1n4148..19Hnh 2.6: Mch ngun dng s dng op-amp....20Hnh 3.1: th thay i rng xung PWM ......24Hnh 3.2: S cu trc ca Atmega8...25Hnh 3.3: Thanh ghi ADMUX26Hnh 3.4: Thanh ghi TCNT1...29Hnh 3.5: Thanh ghi TCCR1...29Hnh 3.6: Thanh ghi OCR1A v OCR1B...30Hnh 3.7: LCD16x231Hnh 3.8: IC Ir 2110 v cu trc bn trong32Hnh 3.9: S logic quan h u vo u ra ca Ic Ir2110.33Hnh 3.10: S mch boostrap34Hnh 3.11: Cu trc bn trong LM35835Hnh 3.12: Ic ACS 71236Hnh 3.13: Mch Ngun LM78xx..37Hnh 3.14: Mch ngun LM2576...37Hnh 3.15: Hnh mch buck-converter38Hnh 3.16: S khuch i thut ton..39

DANH MC BNGBng 2.1: Thng s hot ng ca mosfet..15Bng 2.2: Thng s hot ng ti a ca Irf 3205..17 Bng 2.3: Thng s diode 1N414819 Bng 2.4: Thng s hot ng ca Transistor TIP4122Bng 3.1: Bng chn in p tham chiu cho ADC...27Bng 3.2: Bng chn in p tham chiu...28Bng 3.3: Chc nng cc bit CS12,CS11,CS10.29Bng 3.4: Cc bit WGM v ch hot ng ca T/C130Bng 3.5: Chc nng cc chn ca LCD31Bng 3.6: Thng s hot ng ca Ir 211033Bng 3.7: Chc nng hot ng ca tng chn..33

LI M U

Trong lnh vc k thut in hin i ngy nay, vic ch to ra cc b chuyn i ngun c cht lng in p cao, kch thc nh ngn cho cc thit b s dng in l ht sc cn thit. Qu trnh x l bin i in p mt chiu thnh in p mt chiu khc gi l qu trnh bin i in p DC-DC. Cu trc mch ca cc b bin i DC-DC vn khng phc tp nhng vn iu khin nhm t c hiu sut bin i cao v m bo n nh lun l mc tiu ca cc cng trnh nghin cu.Vic a kin thc vo thc tin khng cn qu xa l i vi sinh vin ang theo hc ti cc trng i hc c bit l cc trng k thut. Trong hc phn n tt nghip ny, em thc hin ti: Thit k mch ngun n p, n dng ng dng trong th nghim v cng nghip. ti ny gip em hiu r hn v vi iu khin v mt s kin thc v in t cng sut. ng thi tch ly kin thc c bit l trong qu trnh lm mch thc t song do thi gian v kin thc c hn, nn mch thit k cn nhiu thiu st. . Em xin chn thnh cm n ging vin:T.S Nguyn Hng Quang (b mn t ng ha x nghip cng nghip) quan tm hng dn tn tnh v to iu kin chng em hon thnh n tt nghip. Em rt mong nhn c s gp ca qu thy c em c th hon thin v nng cao cht lng ca ti tt nghip ny mt cch tt nht.Em xin trn thnh cm n!H Ni, ngy 29 thng 05 nm 2010 Sinh vin thc hin Phan Tng Lm

Chng 1KHI NIM V NGUN P, NGUN DNG1.1. Khi nim ngun pTrong tt c cc thit b in t vn ngun cung cp l mt trong nhng vn quan trng nht quyt nh n s lm vic n nh ca h thng, ca thit b. Hu ht cc thit b in t u s dng cc ngun in mt chiu c n p, n dng vi chnh xc v n nh cao. c c nh vy ta cn phi dng cc loi mch ngun n nh. Ngy nay ngi ta thng dng cc loi ngun p c tnh n nh cao nh: Mch ngun kiu Buck: hay cn gi l mch ngun gim p, cho in p u ra nh hn in p u vo. Mch ngun kiu Boots: hay cn gi l mch ngun tng p, cho in p u ra ln hn in p u vo. Mch ngun kiu Flyback: kiu ngun ny cho in p u ra c th nh hoc ln hn in p u vo. T mt u vo c th chia lm nhiu u ra. Mch ngun kiu Push-Pull: l kiu ngun y ko. Cho in p u ra ln hoc nh hn in p u vo.Vi yu cu v thit k, m bo tnh nh gn, n nh v in p, dng in em chn mch ngun thit k l mch ngun kiu Buck.1.1.1. Mch Buck-Converter

Hnh 1.1: Mch ngun kiu Buck-ConverterB bin i ngun DC-DC Buck-Convert l b bin i ngun gim p, dng sng dng in, in p u ra cho trn hnh 1.2.Vg l in p ngun mt chiu u vo v V l in p mt chiu u ra

Hnh 1.2: (a) Cu trc mch buck c bn , (b) kha v tr 1, (c) kha v tr 2, (d) th in p trn cun cm theo thi gian, (e) th dng in qua cun cm theo thi gian. Trong khong thi gian 0< t do hiu ng in t trng lm cho in tr RDS gim, in p UGS cng ln th in tr RDS cng nh.Vi in p max ri trn cun cm l Umax=24 (V) do gi tr in p ta cn la chn cho van s l: Uvan > K . UL . y K thng bng t 1,7 2,2=> Uvan= 2,2 . 24 =52.8 (V). M Ilmax=0.096 (A) => ta chn van chu c dng l 0.11 (A). Tn s ng ct ca van tha mn f=25 kHz.=> Chn Mosfet Irf 3205:nh NghaGi trn v

in p gia D v S55V

in tr gia cc D v S khi m0.0008

Dng qua DS110A

Bng 2.1: Thng s hot ng ca mosfetK hiuThng sTi an v

ID TC=25oCDng in lin tc qua cc D, khi =10V110A

ID TC=100oCDng in lin tc qua cc D, khi =10V80A

IDMDng xung qua cc D390A

PD TC=25oCCng sut tiu tn200W

H s khng cung cp1.3W/ oC

VGSin p gia cc Cng v cc Ngun20V

EASNng lng xung thc l480MJ

IARDng thc l59A

EARNng lng thc l lp li20MJ

dv/dtTc bin thin in p5.0V/ns

TJ,TSTGS hot ng lin tc v di nhit d tr-55 175oC

Nhit hn, trong vng 10s300oC

S gia tng mmen10

Bng 2.2: Thng s hot ng ti a ca Irf 32052.1.2. Cun cm LKhi Mosfet m (hnh 1.2): uL= L = Vin Vo (2.1)Khi Mosfet kha (hnh 1.2): uL= L = -Vo (2.2)Vi gi thit Vo= const dng qua cun cm L trong c 2 phng trnh (2.1) v (2.2) u c dng tuyn tnh. Trong ch xc lp gi tr trung bnh ca in p trn cun cm trong mt chu k ng ct TS phi bng khng.UL===0 (2.3)

Hnh 2.2: S in p qua cun cm

Hnh 2.3: S dng in qua cun cmT (2.3) suy ra: vi D l tham s iu chnh (2.4)Imin v Imax l cc gi tr nh nht v ln nht ca dng in qua cun cm, ta c:

Vi gi tr thng c chn khong t 10% - 20% .Ta chn .Vi in p VMAX = 22V:36 uH.Vi in p VMIN = 0.1 V:

Chn gi tr cun cm L= 36 H2.1.3. T lc u ra COLng in tch trong t c tnh theo cng thc (2.5)

Hnh 2.4: Dng in p trn t lc CO.Hnh 2.4 m t hnh dng dng in v in p trn t, t ta c: (2.6)Hay:

(2.7) Th 2 phng trnh (2.6) v (2.7) vi nhau ta c:

(2.8) C = 2.5 uFChn C= 3.3 uF.2.1.4. T lc u vo Dng in gn sng c tnh vo t u vo:

in p u vo gn sng ca t u vo:

Chn gi tr tr khng (ESR) ca t u vo l : ESR= 0.12 () Gi tr t lc u vo ca mch Buck-Converter c xc nh l:

Chn gi tr t in u vo mch Buck-Converter l 220uF 25V2.1.5. DiodeTrong cc b ngun xung th u ra ca bin p xung, ta phi dng diode xung chnh lu, diode xung l diode lm vic tn s cao khong vi chc kHz. Diode xung trong mch c nhim v khp mch cung cp dng qua ti khi m van Mosfet ng ct. V Mosfet ng ct vi tn s cao nn chng ta phi chn diode xung m bo nhim v khp kn mch nhiu ln m khng b hng. Vi D= ta xc nh c dng c tnh qua diode:ID= (1-D).Iti=(1-).0,1=0.008 (A).Ta cn chn diode c gi tr dng in ln hn 0.05 (A) v in p ln hn 24 (V) v tha mn tn s 25 kHz. Chn diode 1N4148.

Hnh 2.5: Diode 1n4148.

Bng 2.3: Thng s diode 1N4148.2.2. Tnh ton mch ngun dng

Hnh 2.6: Mch ngun dng s dng op-ampThng s thit k mch ngun dng: Vin = 0-5 Vdc Vop-amp = 12V IOUTPUT = 0-500 mA2.2.1. in tr RSin tr Rs l in tr cm ng nm ni tip vi ti, c chc nng phn p to ra in p t l vi dng in qua ti. in p ny c a v u o (IN-) ca op-amp nhm thc hin chc nng phn hi. Thng qua , op-amp s iu khin dng in u ra thng qua mt BJT. Nh vy in p a v chn u vo khuch i o s bng vi in p a vo chn khuch i khng o nhm thc hin chc chuyn i V-I.Khi gi tr ca in tr Rs s c tnh nh sau:Rs = = 200 m2.2.2. in tr R1, R2Bng cch hn ch ti a in p u khuch i o (IN-) l 100mV, do in p u vo khuch i khng o ca op-amp cng c gii hn l 100mV. Vi in p u vo Vin = 0-5 Vdc ta thc hin phn p cp cho u vo khng o (IN+) vi mt gi tr in p l 100mV. Khi gi tr ca cc in tr R1 v R2 c tnh ton nh sau:in tr R2 c gi tr c trn da trn mong mun dng in u vo v in p u vo ca IN+:

in tr R1 c tnh ton da trn gi tr ca in tr R2 v in p u vo 5V:

100mV=5V R1 = 49 kVi in p trn chn IN+ bng vi in p trn RS quan h chuyn i gia in p sang dng in c th hin nh sau:

Gain = 2.2.3. in tr RBRB l in tr dng kch cho BJT hot ng nhm to ra gi tr dng in trn cc E ca transistor. Vi h s =100 ca BJT. Tip41 s ko mt gi tr dng in khong 5mA trn cc B khi gi tr dng in IO t gi tr 500mA. RB c tnh nh sau:

2.2.4. in tr RF v t CFCc thnh phn phn hi RF v CF cung cp nng lng b nng lng cho mch m bo s hot ng n nh trong thi gian u vo hoc ti qu . Cc thnh phn ny lm vic bng cch loi b h s khuch i ca BJT t vng iu khin tn s cao nht bng cch a tn hiu phn hi trc tip v u vo o t u ra ca b khuch i thng qua CF thay v cc Emiter ca BJT thng qua RF. Tn s ca mch da vo hng s thi gian RC thng qua t CF v in tr RF. Gi tr ca t in v in tr trong mch c la chn da trn tn s bng thng ca op-amp, tn s c la chn trn 100 kHz phn ng khng b tt dn. Gi tr ca in tr RF nn ln hn rt nhiu so vi in tr ti nhng khng c qu ln, nn cc u vo op-amp c dng bias chy qua n to ra mt in p offset ln.2.2.5. Transistor NPNTransistor NPN Tip41 c chn cho thit k mch ngun dng vi dng collector lin tc l 6A v in p maximum Collector-Emitter l 40V. Vic ta la chn transistor c gi tr v in p v dng in hot ng ln hn so vi gi tr tnh ton trong thit k s tiu tan nhit hiu qu hn, v cho php mch thit k hot ng bn ngoi khng cn tn nhit. transistor Tip41 c in p Base-Emitter l 5V v dng in ti cc Base IB = 2A

Bng 2.4: Thng s hot ng ca Transistor TIP412.2.6. Operational Amplifier p ng c yu cu thit k op-amp cn c in p offset thp, nhit tri thp. B khuch i thut ton LM358 l mt thit b chnh xc cao vi in p offset l 2V v 7V/C tri dt nhit , LM358 cung cp in p offset thp v gn nh khng tri qu nhit . in p thp offset v tri dt thp s lm gim li b p trong h thng lm cho cc thit b kim sot cc c im DC mt cch chnh xc.

Chng 3THIT K MCH IU KHIN

3.1. Phng php iu khinS dng phng php PWM (pulse width Modulation): l phng php thay i rng xung vung , tc l thay i rng sn dng hoc sn m ca xung m khng lm thay i tn s ca xung. Dng phng php PWM iu khin vic ng, m ca cc van (Mosfet) trong b bin i DC-DC gim p. Vic thay i rng xung iu khin dn n thay i thi gian ng, m ca van (Mosfet) do lm thay i in p u ra ca b bin i. c xung PWM chnh xc iu khin Mosfet th y ta dng phng php iu khin vng kn s dng vi iu khin kt hp vi s phn hi p u ra x l tnh ton cho ra xung PWM thch hp.

Hnh 3.1: th thay i rng xung PWM.3.2. Mch iu khin3.2.1. Tng quan v Ic Atmega8Atmega8 l vi iu khin thuc h Mega AVR do hng Atmel sn xut. Atmega8 l chip vi iu khin 8 bit vi cu trc lnh n gin ha RISC, mt kiu kin trc ang th hin u th trong cc b vi x l. So vi cc chip iu khin 8 bits khc, Atmega8 c nhiu c tnh hn hn, hn c trong tnh ng dng v c bit l v chc nng: Gn nh chng ta khng cn mc thm bt k linh kin ph no khi s dng AVR, thm ch khng cn ngun to xung clock cho chip. Thit b lp trnh cho AVR rt n gin, c loi mch np ch cn vi in tr cng c th lm c, mt s AVR cn h tr lp trnh on chip bootloader khng cn mch np Bn cnh lp trnh ASM, cu trc ca AVR cn tng thch vi ngn ng C. Ngun ti nguyn v scoure code, application note rt ln trn internet.3.2.2. Cu trc Atmega8Ic Atmega8 c cu trc Harvard, trong c ng truyn cho b nh d liu (data memory bus) v ng truyn cho b nh chng trnh (program memory bus) c tch ring.Data memory bus ch c 8 bit v c kt ni vi hu ht cc thit b ngoi vi vi register file. Trong khi program data bus c rng 16 bit v ch phc v cho cc instruction registers.

Hnh 3.2: S cu trc ca Atmega8.3.2.3. Cng vo ra I/OVi iu khin Atmega8 c 23 ng vo ra v chia lm 4 nhm 8 bit mt. Cc ng vo ra ny c rt nhiu tnh nng v c th lp trnh c. Chng ta c thanh ghi v mt a ch cng i vi mi cng l: thanh ghi d liu cng PORT v thanh ghi d liu iu khin cng DDR. V cui cng l a ch chn vo cng PIN. Thanh ghi DDRx: y l thanh ghi 8 bit v c tac dng iu khin hng cng PORTx. Nu nh 1 bit trong thanh ghi ny c set th bit tng ng trn PORTx c nh ngh nh mt cng ra. Ngc li nu bit khng c set th bit tng ng tn PORTx c nh ngha l cng vo. Thanh ghi PORTx: y l thanh ghi 8 bit n l thanh ghi d liu cng Px v trong trng hp cng c nh ngha l cng ra th khi ta ghi mt bit ln thanh ghi ny th chn tng ng trn PORT s c cng mc logic. Trong trng hp cng c nh ngha l cng vo th thanh ghi ny s mang d liu iu khin cng. Thanh ghi PINx: y l thanh ghi 8 bit cha d liu vo ca PORTx v n ch c th c m khng th ghi vo c.3.2.4. ADC ca Atmega8Ic Atmega8 ca Atmel c tch hp sn b chuyn i ADC vi phn gii 10 bit c tt c 8 knh trn Atmega8. ADC trn AVR c nui bng in p ring chn AVCC. m bo sai s cho ngun nui ADC ta s dng lc nhiu cho ngun mt cch k cng. in p tham chiu cho ADC ta c th s dng 3 ngun: dng ngun in p tham chiu ni c nh 2.56V, dng in p AVCC hoc in p c trn chn VREF.C 4 thanh ghi ADC trn AVR trong c 2 thanh ghi cha gi liu sau khi chuyn i, v 2 thanh ghi iu khin v cha trng thi ca ADC. ADMUX: l thanh ghi 8 bit iu khin vic chn in p tham chiu knh v ch hot ng ca ADC.

Hnh 3.3: Thanh ghi ADMUX.Bit 6 v bit 7: l bit la chn in p tham chiu cho ADCBit 5 ADLAR: l bit cho php hiu chnh kt qu chuyn i ADC.Cc bit t bit 4 n bit 0: l 5 bit cho php chn knh, ch hot ng v h s khuch i cho ADC

Bng 3.1: Bng chn in p tham chiu cho ADC ADCSRA: l thanh ghi chnh iu khin hot ng v cha trng thi cc module ADCL v ADCH: l hai thanh ghi cha gi tr ca qu trnh chuyn i, v bit ADLAR trong thanh ghi ADMUX quy nh cch m m kt qu c ghi vo.ADLAR=0:

ADLAR=1: SFIOR: thanh ghi cha chc nng c bit, 3 bit cao trong thanh ghi ny quy nh ngun kch cho ADC nu ch auto trigger c s dng. l cc bit ADTS2:0 cc loi ngun kch ny c trnh by trong bng.

Bng 3.2: Bng chn in p tham chiu3.2.5. Timer/CounterTimrer/counter l cc module c lp vi CPU. Chc nng chnh ca cc b Timer/counter nh tn gi ca chng l nh thi gian v m s kin. Trn cc chip AVR cc b timer/counter cn c chc nng to to ra cc xung iu rng PWM. Cc b Timer/counter c chia theo rng thanh ghi cha gi tr nh thi hay gi tr m ca chng. Trn chip Atmega8 c 2 b timer/counter 8 bit v 1 b timer/Counter 16 bit. Ch hot ng v phng php iu khin ca tng timer/counter cng khng hon ton ging nhau.Timer/Counter1: l b T/C 16 bit, a chc nng. y l b T/C rt l tng cho lp trnh o lng v iu khin v n c phn gii cao v c kh nng to xung iu rng PWM.C kh nhiu thanh ghi lin quan n T/C1. V T/C1 l thanh ghi 16 bit trong khi b nh d liu ca AVR l 8 bit nn i khi cn dng nhng cp thanh ghi 8 bit to thnh 1 thanh ghi 16 bit, 2 thanh ghi 8 bit s c k hiu l L v H trong L l thanh ghi 8 bit thp, H l thanh ghi 8 bit cao ca gi tr 16 bit chng ta to thnh. TCNT1H v TCNT1L: l 2 thanh ghi 8 bit to thnh thanh ghi 16 bit (TCNT1) cha gi tr vn hnh ca T/C1. C 2 thanh ghi ny cho php ghi gi tr mt cch trc tip.Hnh 3.4: Thanh ghi TCNT1 TCCR1A v TCCR1B: l 2 thanh ghi iu khin hot ng ca T/C1. Tt c cc ch hot ng ca T/C1 u c xc nh thng qua cc bit trong 2 thanh ghi ny, v 2 thanh ghi ny hon ton c lp. Cc bit trong 2 thanh ghi ny bao gm bit chn ch hay chn dng song (WGM), cc bit quy nh dng ng ra (COM) , cc bit chn gi tr chia chu k xung nhp (CS).

Hnh 3.5: Thanh ghi TCCR1 Chc nng cc bit CS12,CS11,CS10:

Bng 3.3: Chc nng cc bit CS12,CS11,CS10

OCR1A v OCR1B: l thanh ghi so snh, gi tr ca thanh ghi TCNT1 lin tc c so snh vi gi tr ca thanh ghi OCR1A v OCR1B. Do ng dng ny c dng trong phn iu chnh rng xung PWM.

Hnh 3.6: Thanh ghi OCR1A v OCR1B.

ICR1 (Input Capture Register 1): gi tr ca thanh ghi ny dng cp nht gi tr TOP ca T/C1. Dng trong to tn s PWM.Cc bit WGM v ch hot ng ca T/C1:

Bng 3.4: Cc bit WGM v ch hot ng ca T/C1

3.3. LCDLCD l loi mn hnh tinh th lng nh dng hin th cc dng ch hoc s trong bng m ACII2. LCD 16x2 iu khin bi chip HD44780U ca hng Hitachi. i vi cc LCD khc bn cn tham kho datasheet ring ca tng loi. Tuy nhin, HD44780U cng c coi l chun chung cho cc loi Text LCD.

Hnh 3.7: LCD 16x2S d chn ca LCD 16x2:

Bng 3.5: Chc nng cc chn ca LCD.3.4. Ir 2110IR2110 l IC chuyn dng iu khin Mosfet v IGBT ca hng IR International Rectifier, IC ny c mt knh Output high side v Output low side, thng c ng dng trong cc mch van s dng iu khin pha high side. Hai tc dng quan trng ca IR2110 m c ng dng rng ri l:- Lm cho tn hiu ra hai chn HO v LO khng trng trng thi, trnh vic hai van trn cng mt nhnh trng dn gy ngn mch ngun.- Kt hp vi mch Bootstrap ko in p ln iu khin pha high side. Nguyn l hot ng ca IC IR2110 nh sau:+ Nhn tn hiu iu khin t hai chn u vo s 10 l (HIN) v s 12 l (LIN/) a tn hiu iu khin ra chn s 7 (HO) v chn s 5 (LO). Tn hiu chn HO iu khin pha high side cn tn hiu chn LO iu khin pha low side.+ Chn HO v LO khng bao gi cng mc tn hiu logic, th hin r trong th di y.

Hnh 3.8: IC Ir 2110 v cu trc bn trong

Hnh 3.9: S logic quan h u vo u ra ca Ic Ir2110.nh nghaGi trn v

in p hot ng500V

Dng in ra2/2A

in p ra10 20V

Thi gian m/kha120 v 94Ns

Thi gian cht10nsNs

Bng 3.6: Thng s hot ng ca Ir 2110Th t chnK hiuChc nng

1LOCng ra iu khin pha low side

2COMNi t

3VCCin p cung cp

5VSNgun phn hi pha high side

6VBNgun ko cho pha high side.

7HOCng ra iu khin pha high side.

9VDDin p cung cp mc logic

10HINiu khin pha high side, tch cc cao.

11SDQuyt nh mc tn hiu logic cho tn hiu u ra

12LINiu khin pha low side, tch cc thp.

Bng 3.7: Chc nng hot ng ca tng chnMch Bootstrap l mt mch in t kt hp gia mt it v t in thng c dng kch p iu khin Mosfet v IGBT pha high side. Q1 v Q2 lun trng thi lm vic i nghch nhau. Khi Q1 trng thi On th Q2 trng thi Off v ngc li. khi Q1 ang trng thi Off chuyn sang trng thi On th chn S ca Q1 ang chuyn t Ground sang in p cao. Do mun kch Q1 tip tc On th phi to in p UG1S1 c gi tr UG1S1 = USQ1 + V. Trong khi tn hiu ra ca vi iu khin ng ngt cc kha ch c in p +5V so vi Ground. Nn cn phi c mch li tri p v cch ly trong vic ng ngt pha high side Q1. Tuy nhin i vi pha low side Q2 th chn S lun c ni vi t do in p kch VG2S2 ch cn c gi tr V. Do vic ng ngt kha pha low side Q2 c iu khin d dng.

Hnh 3.10: S mch boostrap.3.5. Ic LM 358Ic LM 358 l Ic khuch i thut ton kp, bn trong c 2 b khuch i. Mi b khuch i c 3 chn: ng vo o (IN-), ng vo khng o (IN+), v ng ra.Khi in p +input cao hn input, ng ra mc cao (+VSS), ngc li ng ra mc thp (-VSS). Ic LM358 s dng cho cc thao tc tnh ton Analog. Gi l mch khuch i bi v vi s thay i ca cc linh kin bn ngoi nn LM358 c s dng nhiu trong cc bi ton khc nhau nh so snh, khuch i tn hiu, cng tr.. Vi mch Buck-Converter c iu khin phn hi ta s dng ic LM 358 vi vai tr l mt mch khuch i thut ton khuch i in p t 1V ln 5V a vo chn ADC ca vi iu khin. Cn vi mch ngun dng, ic LM 358 ng vai tr l mt mch so snh, so snh in p phn hi t cm bin in tr RS vi in p cho trc 100mV trn chn IN+ t cho gi tr in p ph hp m transistor.

Hnh 3.11: Cu trc bn trong LM358S chn: Chn 1: u ra A Chn 2: u vo nghch o A Chn 3: u vo khng nghch o A Chn 4: chn ni t cho Ic Chn 5: u vo khng nghch o B Chn 6: u vo nghch o B Chn 7: u ra B Chn 8: in p cung cp cho ic hot ng3.6. Ic ACS 712Ic ACS 712 l ic cm bin dng tuyn tnh da trn hiu ng hall. ACS xut ra mt tn hiu Analog VOUT bin i tuyn tnh theo s thay i ca ca dng in IP ly mu th cp DC trong phm vi cho. T CF c dng vi mc ch chng nhiu v c gi tr thay i c ph thuc vo tng mc ch s dngu im ca Ic ACS 712: ng tn hiu Analog c nhiu thp Thi gian tng dn ra p ng vi u vo l 5s. in tr dy dn trong l 1.2 m Ngun vn hnh n gin 5V nhy u ra t 63-190 mA in p u ra cc k n nh.

Hnh 3.12: Ic ACS 712.Cc loi Ic ACS 712: ACS 712-5A: gii dng in o c t -5A n +5A. nhy 180-190 mA ACS 712-20A: gii dng in o c t -20A n +20A. nhy 96-104 mA ACS 712-30A: gii dng in o c t -30A n +30A. nhy 63-69 mA

3.7. Ngun cung cpNgun cung cp l mt b phn quan trng trong thit k. m bo h thng hot ng ta cn cung cp mt ngun p n nh. Ta s dng Ic chuyn dng cho to ngun nh Ic h LM 78xx, Ic h LM 2576, cung cp in p cho h thng. LM2576 l mt ic ngun tch hp ca mch ngun xung theo nguyn l buck-converter. Vi dng in nh mc u ra ti l 3A v c cc u in p ra c nh 3.3V, 5V, 15V. v in p bin i theo tng loi serial ca LM2576. y l loi ic ngun cung cp u ra n nh, hot ng n nh vi u tn nhit tt, gip ic hot ng tt trong iu kin cho php.S mch ngun cung cp nh hnh (3.15) v (3.16) ta s dng ic LM 2576 lm ngun Vcc cung cp in p cho vi x l, ngun dng, lcd cn ngun LM 7815 ta dng lm ngun cung cp cho mch op-amp khuch i thut ton v mch iu khin mosfet.

Hnh 3.13: Mch Ngun LM78xx.

Hnh 3.14: Mch ngun LM25763.8. Mch tng qutNguyn l ca Mch: Ngun pVi iu khin thc hin iu xung PWM ng m cho Mosfet ca mch Buck-Converter thng qua ic ir2110 c nhim v kt hp vi mch bootstrap iu khin xung PWM. in p u ra ca mch Buck-Converter c phn p qua mch khuch i thut ton phn hi v vi iu khin. Tn hiu in p phn hi v c so snh vi tn hiu in p mu USet nhm mc ch tnh ton iu xung PWM ra van Mosfet thng qua IC li van IR2110, gip in p u ra mch Buck n nh hn. Ngun dng:Ta s dng phng php chuyn i in p sang dng in, s dng tn hiu nh ca Op-amp LM358 iu khin cc Emitter ca Transistor. Tn hiu in p trn in tr RS c a v chn IN- ca op-amp so snh vi tn hiu in p trn chn IN+ iu chnh in p u ra kch transistor hot ng hay iu chnh dng Iout ca mch. Gi tr dng in c a v vi x l thng qua ic ACS 712-5AKt qu o in p ca mch Buck-Converter v gi tr dng in ca ngun dng s c hin th ln mn hnh LCD.

Hnh 3.15: Hnh mch buck-converterTrn Hnh ta thy c u ra ca mch Buck-converter c phn p bi R19-R21-R22-R23,nhng con tr ny c chc nng phn p,gim p a v Lm358, sau c Lm358 khuch i v a vo ADC ca VDK. mch ny ta cho in p u FeedBack( FB+) b hn 30 ln so vi in p ra trn mch buck,chn dng i qua bn con tr phn p l 10mA. Gi s in p u ra l 30v,vy u ra Feed-back l 1v: R19+R21+R22+R23R23= R19+R21+R22=3000-100=2900 ohmTa chn :R22=2k7 ohm, R19=R21=100 ohmu ra FB+ c a v b khuch i thut ton s dng mch tr, vi h s khuch i:K= = 5 (ln).Do in p u ra LM 358 l 5V v c a v ADC ca vi iu khin, thc hin chc nng c in p.

Hnh 3.16: S khuch i thut ton.Thut ton o in p v dng in: 114 if(i22)40 tam=22;41 vset=tam; 42 } y chng trnh c gi tr in p t thng qua knh ADC(0),sau lu vo bin Vset phc v chng trnh pha sau. T dng lnh 105 tr i l chng trnh chnh, y VDK ly gi tr ca in p ra v dng in thit t t ng FEEDBACK c qua ADC x l hin th ra LCD v iu xung ra iu khin Mosfet qua chn OCR1AChng trnh lp trnh cho vi iu khin (code) tham kho ph lc [1]Chng 4KT QU M PHNG THC NGHIM4.1. Kt qu m phng m phng mch in t cng sut ta c th s dng cc phn mm m phng nh Matlab, Psim, Tina, Proteus Trong cc phn mm , phn mm Psim c ng dng nhiu cho m phng mch in t cng sut trong cng nghip.Vi cc thng s:VIN= 24V, VOUT=22 V, IOUT= 1A, Tn s ng ct f= 25kHz. L= H. COUT= (F).Kt qu m phng trn phn mm PSIM

Hnh 4.1: Kt qu m phng in p trn cun cm L

Hnh 4.2: th in p ra ca Mch Buck-Converter

Hnh 4.3: th dng in u ra mch Buck-converter4.2.Mch ngun dngThng s: VIN = 0 5V IOUT= 0 500 mA th dng in vi ti u ra l 10

Hnh 4.4: s dng in u ra. 4.3. Mach Thit k

Hnh 4.5: S mch 3D

Hnh 4.6: S mch lp Bot

KT LUNVi ti thit k ngun p, ngun dng qua qu trnh tm hiu , em tng hp c kh nhiu lng kin thc c hc trong sch v, trn ging ng, v gip c c nhng kin thc lm vic qu bu. Mch ngun p ngun dng l nhng mch cng sut ng dng nhiu trong thc t, trong ging dy, do m i hi tnh chnh xc cng nh tnh linh ng cao trong thit k. hon thnh c n ny, ngoi s c gng n lc ca bn thn v s hp tc ca cc thnh vin trong nhm mnh, chng em cn nhn c s hng dn tn ty , s ch bo nhit tnh ca thy gio Nguyn Hng Quang, ngi gip chng em trong sut qu trnh lm n.Do thi gian v nng lc ca bn thn cn hn ch nn kt qu ca em chc chn cn c nhiu thiu st, em rt mong nhn c s ch bo v ng gp kin ca thy c v cc bn.Em xin chn thnh cm n!H Ni, Ngy 1 thng 7 nm 2014.

Ti liu tham kho

[1] Phm Quc Hi, Hng Dn Thit K in T Cng Sut, Nh Xut Bn Khoa Hc V K Thut, 2009.[2] V Minh Chnh - Phm Quc Hi - Trn Trng Minh, in T Cng Sut, Nh Xut Bn Khoa Hc V K Thut, 2007.[3] TI Precision Designs: Verified Design 1% Error, 0-5 V Input, 0-500 mA Output, Low-Side Voltage-to-Current (V-I) Converter.[4] Programmable DC Power Supply Flash Innovation Contest 2003 Project F2026[5] DC-DC Fundamentals 1-5 converter control[6] Buck-Converter Design Example Microchip[7]http://ic.ute.edu.vn/wpcontent/uploads/2012/11/Triet_BaiGiang_DienTuCongSuat_Ch6_DC-DC.pdf[8] Datasheet Atmega8[9] Datasheet LM358[10] Datasheet Ir2110[11] Datasheet ACS 712 5A[12] http://www.hocavr.com[13] http://www.dientuvietnam.net[14] http://www.banlinhkien.vn

PH LCChng trnh chy. 1 #include 2 #include 3 #include 4 #include 56 // Alphanumeric LCD functions7 #include 8 unsigned char str1[30];9 unsigned char str[30];10 float ADC1,ADC,dienap=0,dongdien=0,vin=12,ansi=0,ansv=0,errorv=0,vset=0,Iset=0;11 float anserrori=0,anserrorv=0,tam=0;12 unsigned long int i=0,dong=0,ap=0; 13 #define ADC_VREF_TYPE 0x001415 // Read the AD conversion result16 unsigned int read_adc(unsigned char adc_input)17 {18 ADMUX=adc_input | (ADC_VREF_TYPE & 0xff);19 // Delay needed for the stabilization of the ADC input voltage20 delay_us(10);21 // Start the AD conversion22 ADCSRA|=0x40;23 // Wait for the AD conversion to complete24 while ((ADCSRA & 0x10)==0);25 ADCSRA|=0x10;26 return ADCW;27 }2829 // External Interrupt 0 service routine30 interrupt [EXT_INT0] void ext_int0_isr(void)31 {32 // Place your code here3334}3536 // External Interrupt 1 service routine37 interrupt [EXT_INT1] void ext_int1_isr(void)38 {39 tam=(read_adc(0)*22)/1023; 40 if(tam>22)41 tam=22;42 vset=tam; // Place your code here4445}50 void main(void)51 {5253PORTB=0x00; 54DDRB=0xFF;5556PORTC=0x00; 57DDRC=0x00;5859PORTD=0x00; 60DDRD=0xFF;6162 TCCR0=0x00;63 TCNT0=0x00;6465 TCCR1A=0xA2;66 TCCR1B=0x19;67 TCNT1H=0x00;68 TCNT1L=0x00;69 ICR1=320;70 71 ASSR=0x00;72 TCCR2=0x00;73 TCNT2=0x00; 74OCR2=0x00;7576 // KHOI TAO NGAT NGOAI77 // INT0: On78 // INT0 Mode: Falling Edge (NGAT CANH XUONG)79 // INT1: On80 // INT1 Mode: Falling Edge (NGAT CANH XUONG)81 GICR|=0xC0; // Cho phep su dung INT1, INT082 MCUCR=0x0A; // Thiet lap che do ngat ngoai83 GIFR=0xC0; // Bat co ngat chung85 TIMSK=0x00;86 UCSRB=0x00;90ACSR=0x80; 91SFIOR=0x00;93ADMUX=ADC_VREF_TYPE & 0xff; 94 ADCSRA=0x83;95 SPCR=0x00;97TWCR=0x00;99 lcd_init(16);101102 // Global enable interrupts103 #asm("sei")104105 while (1)106 { 107 ADC1=read_adc(3); 108 Iset=((ADC1*5)/1023)/0.00022; 109 ADC=read_adc(1); 110 errorv=vset-(ADC*29.8)/1023;111 ansv=(errorv/vin)*100+ansv;112 OCR1A=ansv; 113 127 if(i