TRƯỜNG ĐẠI HỌC CẦN THƠ THÔNG TIN & TRUY N …s1.downloadmienphi.net/file/downloadfile8/193/1337345.pdf · CHỈNH LƯU 3 PHA MẠCH TIA CÓ ĐIỀU KHIỂN ... Mạch

TRNG I HC CN TH

KHOA CNG NGH THNG TIN & TRUYN THNG B MN H THNG MY TNH & TRUYN THNG

GIO TRNH

TH NGHIM IN T CNG SUT

BIN SON: ON HA MINH

1

THNG TIN V TC GI

PHM VI V I TNG S DNG CA GIO TRNH 1. THNG TIN V TC GI

H v tn: ON HA MINH Sinh nm: 1956 C quan cng tc: B mn: H thng my tnh v truyn thng (HTMT&TT) ( ging dy trn 15 nm b mn Vin thng & T ng ha, chuyn sang b mn HTMT&TT t 2008) Khoa: Cng ngh thng tin v truyn thng. Trng: i hc Cn Th a ch email lin h: [email protected]

2. PHM VI V I TNG S DNG CA GIO TRNH

Gio trnh c dng tham kho nhng ngnh: K thut in, in t, T ng ha ca cc trng i hc k thut.

T kha: Linh kin cng sut, chnh lu, n p mt chiu, iu khin cng sut, bin tn gin tip, bin tn trc tip, lp trnh m phng, MATLAB, PSIM, mch to xung kch.

Yu cu kin thc trc khi hc v mn ny: hc l thuyt v in t cng sut.

Cha xut bn

2

mailto:[email protected]

CH AN TON IN

Tt c cc mch th nghim u s dng trc tip ngun in xoay chiu 220V. Do

khi thc tp sinh vin phi lun cnh gic gi an ton v ngi ln thit b th nghim. bo m an ton sinh vin phi tuyt i chp hnh cc qui nh sau y: 1. Khng c chm vo mch in khi m ngun cp in. 2. Khi mc in xong, phi bo co cho cn b hng dn kim tra, c s ng ca

cn b hng dn mi c m ngun cp in. 3. Khi o in p, dng in hoc xem dng sng cn phi:

S dng ng giai o.

t que o ng ch, ng cc.

Khi xem dng sng nhng im c in th cao phi dng b in cc (probe) c gim p.

4. Sp xp thit b v dy dn in ngn np, gn gng, thao tc chnh xc, tp trung lm bi, khng a gin.

5. Khng c di di cc thit b th nghim t bi ny sang bi khc. 6. Khi thc tp xong phi tt in, sp xp gn gng cc thit b trc khi ra v. Sinh vin s chu trch nhim v cc s c v bi thng thit b h hng nu khng

chp hnh ng cc qui nh trn.

3

MC LC THNG TIN V TC GI............................................................................................................2

1. THNG TIN V TC GI....................................................................................................2

2. PHM VI V I TNG S DNG CA GIO TRNH .............................................2

CH AN TON IN ...............................................................................................................3

MC LC.......................................................................................................................................4

LI NI U ................................................................................................................................7 U

BI 1: KHO ST LINH KIN CNG SUT C BN............................................................8

1.1. MC CH..........................................................................................................................8

1.2. KIN THC NN...............................................................................................................8

1.2.1. BJT cng sut: ...............................................................................................................8

a) Ti t chn E ..............................................................................................................8

b) t ti chn C ..............................................................................................................9

c) iu khin gin tip ........................................................................................................9

1.2.2. MOSFET cng sut:....................................................................................................10

1.2.3. SCR .............................................................................................................................10

a. K hiu ..........................................................................................................................10

b. Khi phn cc thun: ......................................................................................................11

c. Khi phn cc nghch:.....................................................................................................11

d. Tm li: .........................................................................................................................11

1.2.4. TRIAC.........................................................................................................................11

1.3. THC HNH: ...................................................................................................................12

1.3.1. BJT: ............................................................................................................................12

1.3.2. MOSFET ....................................................................................................................12

1.3.3. SCR .............................................................................................................................13

A. Mc mch nh hnh sau: (Hnh 1.20):..........................................................................13

B. Mc mch nh hnh sau (Hnh 1.21): ...........................................................................13

1.3.4. TRIAC.........................................................................................................................14

A. Mc mch nh hnh sau (Hnh 1.22):...........................................................................14

B. Mc mch nh hnh sau (Hnh 1.23): ...........................................................................14

1.4. THIT B: ..........................................................................................................................15

1.5. TI LIU THAM KHO:.................................................................................................15

BI 2: M PHNG LINH KIN CNG SUT C BN.........................................................16

2.1. MC CH........................................................................................................................16

2.2. NI DUNG ........................................................................................................................16

2.2.1. DIODE: .......................................................................................................................16

4

2.2.1.1. M hnh ton hc [6]:...........................................................................................16

2.2.1.2. Thc hnh:............................................................................................................17

2.2.2. TRANSISTOR ...........................................................................................................17

2.2.2.1. M hnh ton hc [6]:...........................................................................................18

Trong m hnh Ebers-Moll c bn (hnh 3.c), cc dng in I , IC B, IE c xc nh bi cc biu thc sau: ..............................................................................................................18

2.2.2.2. Thc hnh: [1], [3], [7], [8], [9], [10], [11] ..........................................................19

2.2.3. MOSFET (Metal Oxide Semiconductor Field Effect Transistor)...............................20

2.2.3.1. E-MOSFET transistor [2], [12] ............................................................................20

2.2.4. THYRISTOR (SCR) [2], [10].....................................................................................21

2.2.4.1.Cc thng s k thut c bn ca SCR l: ............................................................22

2.2.4.2. Thc hnh [1], [3], [6], [7], [8], [9], [10], [11] ....................................................22

2.2.5. TRIAC [2], [12]...........................................................................................................22

2.2.5.1. Cc thng s k thut c bn ca TRIAC l:.......................................................23

2.2.5.2. Thc hnh:............................................................................................................23

2.3. TI LIU THAM KHO:.................................................................................................23

BI 3: CHNH LU MT PHA C IU KHIN ...................................................................24

3.1. MC CH........................................................................................................................24

3.2. CC KIN THC LIN QUAN ......................................................................................24

3.2.1. Sinh vin n li:...........................................................................................................24

3.2.2. Sinh vin tm hiu v gii thch nguyn tc hot ng ca mch to xung kch:............24

3.3. THC HNH: ...................................................................................................................24

3.3.1. Kho st Board mch to xung kch: ..........................................................................24

3.3.2. Kho st nguyn tc iu khin gc m: ....................................................................26

3.3.3. Kho st chnh lu cu dng 4 diode cng sut:.........................................................27

3.3.4. Kho st chnh lu cu, bn iu khin.......................................................................27

3.3.5. Chnh lu cu 1 pha iu khin hon ton ..................................................................28

a. Mc ti R ( bng n):...................................................................................................28

b. Mc ti R-L (gm n v cun cm ni tip): ..............................................................28

3.4. THIT B TH NGHIM...................................................................................................28

3.5. TI LIU THAM KHO:.................................................................................................29

BI 4: LP TRNH M PHNG MCH CHNH LU BNG MATLAB..............................30

4.1. MC CH........................................................................................................................30

4.2. KIN THC NN.............................................................................................................30

4.3. THC HNH ....................................................................................................................30

4.3.1. Chnh lu 3 pha mch tia khng iu khin................................................................30

a. Chng trnh mu 1:......................................................................................................31

5

b. Cu hi: .........................................................................................................................33

4.3.2. CHNH LU 3 PHA MCH TIA C IU KHIN................................................34

a. Chng trnh mu 2:......................................................................................................34

b. Cu hi: .........................................................................................................................36

4.4. TI LIU THAM KHO..................................................................................................38

BI 5: M PHNG MCH CHNH LU MT PHA C IU KHIN BNG PSIM .........39

5.1. MC CH:......................................................................................................................39

5.2. KIN THC NN:...........................................................................................................39

5.3. THC HNH: ..................................................................................................................41

5.3.1. Mch chnh lu iu khin mt pha na chu k: ........................................................41

5.3.2. Mch chnh lu iu khin mt pha hai na chu k: ..................................................42

5.4. TI LIU THAM KHO:.................................................................................................43

BI 6: N P MT CHIU........................................................................................................44

6.1. MC CH........................................................................................................................44

6.2. S LC V L THUYT.............................................................................................44 T

6.2.1. n p tuyn tnh ..........................................................................................................44

6.2.2. n p ngt m .............................................................................................................45

6.3. PHN THC HNH ........................................................................................................47

6.3.1. n p tuyn tnh ..........................................................................................................47

6.3.2. n p ngt m: ............................................................................................................49

6.3.2.1. Vi mch KA3842 c s chn: .........................................................................50

6.3.2.2. Sinh vin kho st mch v thc hin cc cng vic sau:....................................50

6.4. THIT B TH NGHIM:..................................................................................................51

6.5. TI LIU THAM KHO:.................................................................................................51

BI 7: IU KHIN CNG SUT AC......................................................................................52

7.1. MC CH:.......................................................................................................................52

7.2. S LC L THUYT: ..................................................................................................52

7.3. CU HI V THC HNH............................................................................................53

A. Cu hi l thuyt : ............................................................................................................53

B. Cu hi thc hnh :...........................................................................................................54

7.4. THIT B TH NGHIM:.................................................................................................56

7.5. TI LIU THAM KHO:.................................................................................................56

BI 8: BIN TN GIN TIP....................................................................................................57

8.1. MC CH.......................................................................................................................57

8.2. S LC V L THUYT BIN TN ........................................................................57

8.2.1. Phn loi ......................................................................................................................57

8.2.2. Cu to: .......................................................................................................................57

6

a. B chnh lu v mch trung gian mt chiu:.................................................................58

b. B nghch lu p ...........................................................................................................58

8.2.3. Phng php iu khin b nghch lu p :................................................................60

a. Phng php iu ch rng sin (sin PWM) .............................................................60

b. Phng php iu ch rng xung vung (Square PWM) ........................................60

c. Phng php iu ch rng xung ti u (Optimum PWM) .....................................61

8.2.4. Gii thiu v bin tn SIEMENS G110 ......................................................................61

a. Gii thiu chung ............................................................................................................61

b. S lc cu to. .............................................................................................................62

c. S dng.........................................................................................................................63

8.3. CU HI V THC HNH............................................................................................65

A. Cu hi l thuyt ..............................................................................................................65

B. Phn thc hnh trn b bin tn dng BJT cng sut v mch to xung kch dng vi iu khin 89C51. .........................................................................................................................65

C. Phn thc hnh trn b bin tn Siemens G110. ..............................................................66

1. iu khin G110 t cc DIN.........................................................................................66

2. iu khin G110 t BOP ..............................................................................................66

8.4. THIT B TH NGHIM...................................................................................................67

8.5. TI LIU THAM KHO:.................................................................................................68

BI 9: BIN TN TRC TIP ...................................................................................................69

9.1. MC CH........................................................................................................................69

9.2. S LC L THUYT ...................................................................................................69 T

9.2.1. Mch cng sut: ..........................................................................................................69

9.2.2. Mch iu khin (mch to xung kch):......................................................................69

9.3. CU HI V THC HNH............................................................................................71

A. Cu hi l thuyt: .............................................................................................................72

B. Cu hi thc hnh.............................................................................................................73

1. Kho st mch to xung kch: .......................................................................................73

2. Kho st mch cng sut:..............................................................................................73

9.4. THIT B TH NGHIM:.................................................................................................74

9.5. TI LIU THAM KHO:.................................................................................................74

7

LI NI U

Nm 2001, B mn Vin thng v iu khin t ng, Khoa Cng ngh thng tin & truyn thng, Trng i hc Cn Th, thc hin thit k li cc bi th nghim in t cng sut. Cc bi th nghim ny c thit k bao gm thit b th nghim v gio trnh, phc v cho cc chuyn ngnh in t, Vin thng, T ng ha, K thut in,

Gio trnh th nghim in t cng sut c thc hin ln ny l s b sung v ci tin gio trnh th nghim in t cng sut nm 2001. Gio trnh c bin son gm 9 bi thc tp cho hc phn 2 tn ch, thi lng l 60 tit thc tp, mi bi c thc hnh vi thi gian 6 tit, 6 tit cn li dnh cho kim tra hc phn. Tuy nhin, ta cng c th chn ra 5 bi cho hc phn 1 tn ch.

Ti xin chn thnh cm n qu thy c trong B mn Vin thng & K thut iu khin, Khoa Cng ngh thng tin & Truyn thng, hin nay l B mn Vin thng v B mn T ng ha, khoa Cng ngh, tham gia thc hin cc bi th nghim nm 2001.

Cm n ThS. Phm vn Tn, ThS. Nguyn Hong Dng, TS. Trn Thanh Hng v qu thy, c khc c nhiu ng gp hon thnh gio trnh ny.

Cn Th, ngy 18 thng 2 nm 2009

ON HA MINH

8

Bi 1: Kho st linh kin cng sut c bn

BI 1: KHO ST LINH KIN CNG SUT C BN Tham gia thc hin: KS. Trng Vn Tm

1.1. MC CH

Kho st cc linh kin cng sut: BJT, MOSFET, SCR v Triac. Trong lnh vc in t cng sut, cc linh kin ny c dng nh cc chuyn mch (switch). V vy, ta ch kho st chng trong hai ch ng (dn) v ngt (ngng dn), ring vi SCR v Triac ta s kho st thm cc c tnh c bn nh in th phn cc, dng kch, gc m (iu khin pha)

Qua bi thc hnh ny, sinh vin s hiu r hn nguyn l hot ng ca cc linh kin cng sut, t , c th ng dng chng trong thc t.

1.2. KIN THC NN lm tt bi th nghim ny, sinh vin phi t n tp kin thc nn trong cc gio

trnh l thuyt hc. y l cc linh kin quen thuc, nn trong cc phn sau y ch nhc li mt s vn c bn.

1.2.1. BJT cng sut: V cu to, nguyn l hat ng c bn vn ging nh BJT cng sut nh. Sau y

l cc c tnh ring ca BJT cng sut m ta cn lu :

B

C

II

= H s khuch i dng in ca BJT cng sut thng kh nh (khong

vi chc). Khi dng BJT nh mt chuyn mch, cc im cn quan tm l: thi gian chuyn

mch (thi gian chuyn t trng thi dn bo ha sang trng thi ngng dn v ngc li) cng ngn cng tt; trng thi ng, mch kch phi to dng IB ln (trong thc t I

B

ln t 2 n 5 ln IB BSAT) bo m BJT dn in tt. Tt nhin, ta phi thit k sao cho BJT hot ng khng vt qu cc nh mc.

BJT l lai linh kin cng sut c th kch ngt. V d: a) Ti t chn E (Hnh 1.1)

=C

CECE I

VR - Khi SW v tr 1 (ni mass), BJT ngng dn (ngt):

BJT nh mt SW v tr h (OFF, ) v Vo= 0, I = 0. L

C

CECE I

VR = - Khi SW v tr 2, BJT chuyn sang trng thi dn :

0, thc t t 0.1V 0.2V) th RKhi BJT dn bo ha (VCE CE 0 (BJT nh mt SW ng mch - ON), V0 Vi

Gio trnh th nghim in t cng sut Trang 8


IC # IL

2 1

Vi

RL

VoIL

RB

SW

Hnh 1.1

B+

- Vic iu khin nh trn c bt li l B+ phi ln hn VCC nu khng th BJT

khng bo ha tuyt i (phi phn cc thun c ni BC v BE). ci thin ta c th: b) t ti chn C (Hnh 1.2)

- c) iu khin gin tip (Hnh 1.3):



* R3 ni B+ Q3, Q2, Q1 dn bo ha, SW trng thi ON * R3 ni mass Q3, Q2, Q1 ngng, SW trng thi OFF Trong hai trng hp trn B+ ch cn khong vi volt

1.2.2. MOSFET cng sut:

Bi th nghim ny kho st MOSFET loi tng (E-MOSFET) ch to di dng V-MOSFET (Vertical MOSFET) hay D-MOSFET (Double-diffused MOSFET)

MOSFET knh N dn khi VGS > V > 0 v VGS(th) DS > 0. MOSFET knh P dn khi VGS < VGS(th)< 0 v VDS < 0. MOSFET knh N do VGS > 0 nn ti thng phi mc cc D khi s dng

MOSFET nh mt chuyn mch (Hnh 1.4). MOSFET c u dim l khi bo ha l VDS xung rt thp nn cng sut tiu tn

bn trong (di dng nhit) nh hn nhiu so vi BJT Ch : BJT c iu khin bng dng in IB, cn FET th c iu khin

bng in p VGS v in p ny ty thuc FET nn phi tht cn thn trnh ID vt qu IDMAX m FET c th chu c.

1.2.3. SCR a. K hiu (Hnh 1.5)



b. Khi phn cc thun: VA >V (Hnh 1.6) K

- SCR khng dn in khi VAK cn nh, khi tng VAK (bng cch tng VAA) n

tr s VBO (in th quay v) th SCR chuyn sang trng thi dn, lc ny VAK gim xung cn khong 0.7V v hot ng nh Diode chnh lu. in p VBO thng kh ln (t vi chc volt n vi trm volt ty SCR).

- Thc t ngi ta thng to dng kch IG SCR c th dn in ngay m khng ch in th cao. Dng kch IG ti thiu v ti a ty thuc vo mi SCR nhng ni chung cc dng ny cng ln (t vi mA n vi chc mA) khi SCR c cng sut cng ln.

- Khi SCR dn, nu ta b dng kch th SCR vn tip tc dn in (khng th tt SCR bng cc cng). c. Khi phn cc nghch: VA V Khi VT2 T1, Triac dn in t T2 sang T1 khi kch bng dng cng IG dng (VGT1>0)

Khi VT1 >VT2, Triac dn in t T1 sang T2 khi kch bng dng cng m.

Khi Triac VT2T1# 0,7V Nh vy Triac dng trong in xoay chiu thun li hn SCR. Cng nh SCR, dng

cng ti thiu v ti a cng tu thuc vo mi Triac.



1.3. THC HNH: 1.3.1. BJT:

Ta kho st mt cng tc in t dng BJT. Mch thc hnh nh hnh sau (Hnh 1.8):

a) Bt SW v v tr mass. o in th ca cc chn Q1, Q2, Q3. Gii thch kt qu. b) Bt SW v v tr +5V. Lp li cu 1.

LRV0c) Bt SW v v tr +5V. o V0 suy ra I ( I # ) ca QC C 1

d) Bt SW v v tr +5V. o VCE suy ra RCE ca Q1 1.3.2. MOSFET:

Mch thc tp c dng (Hnh 1.19):

Hnh 1.19 a) o VD chnh VR xc nh in th thm VGS(th) b) o VD chnh VR n khi MOSFET bo ha. Xc nh th s ti thiu ca VGS

lm FET bo ha. Suy ra IDSAT . So snh VDS(SAT) vi VCESAT ca BJT. Nhn xt.

ViTi

vi

RG

47

470/5W 47K

VR 10K

47K

VD

0.33



1.3.3. SCR A. Mc mch nh hnh sau: (Hnh 1.20):

a) Ln lt bt SW v v tr 1, 2, 3 quan st led (c mc song song vi ti, khi SCR dn led chy sng). Gii thch kt qu.

b) t SW v v tr 2 quan st ti, xong bt v v tr 1. Nhn xt gii thch. c) i cc ca ngun V , lp li cu a, gii thch kt qu. i

B. Mc mch nh hnh sau (Hnh 1.21): a) Chnh VR quan st ti. Gii thch. b) Chnh VR , dng dao dng nghim quan st in p hai u ti, v li dng

sng mt v tr no ca VR khi SCR dn. Gii thch. c) Ti sao bn k m SCR khng dn. d) Chc nng ca diode D1. e) Lm cch no tng cng sut ca SCR trong mch in xoay chiu?

Hnh 1.21



1.3.4. TRIAC A. Mc mch nh hnh sau (Hnh 1.22):

a. Ln lt bt SW v v tr 1, 2, 3 quan st led v gii thch kt qu. b. t SW v v tr 2 quan st ti, xong bt v v tr 1. Nhn xt gii thch. c. i cc ca ngun VI, lp li cu a v b, gii thch kt qu.

B. Mc mch nh hnh sau (Hnh 1.23):

Ti VR

2,2K

50K

47

Hnh 1.23

a. Gii thch nguyn tc hot ng ca mch (nu r chc nng cc linh kin trong mch iu khin pha).

, quan st ti, v li dng sng hai u ti. b. Chnh VRc. Th nu vi ng dng ca mch ny.



1.4. THIT B: 1. 01 Mch th nghim (board ln). 2. 01 oscilloscope 3. 01 VOM

1.5. TI LIU THAM KHO: [1]. Cc bi ging v gio trnh IN T CNG SUT B Mn Vin Thng & K

thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT. [2]. TRNG VN TM - LINH KIN IN T Gio trnh B Mn Vin

Thng & T ng Ha - Khoa cng Ngh Thng Tin & Truyn thng HCT 2001. [3]. TRNG VN TM - MCH IN T Gio trnh B Mn Vin Thng &

T ng Ha - Khoa cng Ngh Thng Tin & Truyn thng HCT 2001.


Bi 2: M phng linh kin cng sut c bn

BI 2: M PHNG LINH KIN CNG SUT C BN 2.1. MC CH

c tnh hot ng ca linh kin c m t mt cch r rng nht thng qua c tuyn ca n. c tuyn ca cc linh kin in t ch ph thuc vo loi linh kin m khng ph thuc vo cng sut ca n v chng ta cng bit trong cc mn l thuyt linh kin in t v in t cng sut. c tuyn ca mt linh kin c th xy dng t thc nghim hoc v ra t m hnh ton hc ca n. Tuy rng linh kin cng sut hot ng ch yu hai ch ngt (ngng dn) v ng (dn bo ha), nhng vic v c tuyn ca linh kin gip cho sinh vin nm c c tnh hot ng ca linh kin, t s dng chng tt hn trong cc mch cng sut. V vy, ni dung ch yu ca bi ny l v c tuyn ca cc linh kin in t c bn t cc m hnh ton hc ca n, vi s tr gip ca my tnh. Bi thc tp ny cn gip cho sinh vin nm c cc nguyn tc c bn ca vic m phng linh kin hay mch in t bng my vi tnh.

2.2. NI DUNG 2.2.1. DIODE: c tuyn biu din s ph thuc ca dng in I [A] qua diode vo in p V[V]

gia anode A v cathode K ca diode. Qui c: chiu dng ca I l chiu t anode n cathode, tng ng vi chiu

dng ca in p hng v anode. Hnh 2.1 m t cu to (a) v k hiu ca diode (b) .

Phan cc thuan: U > 0, I > 0 Phan cc nghch: U < 0, I < 0

P N

A

K

(a)

A

K

I

V

(b)

+

Hnh 2.1

2.2.1.1. M hnh ton hc [6]:

= 1exp

tS V

VIIe

kTVt = vi c gi l nhit in th.

-19 l dng in r; T l nhit tuyt i; e = 1,59.10 Coulomb; Trong : IS

v k = 1.38.10-23 (hng s Boltzmann). = 1,2mA i vi diode Germanium. IS = 0,2nA i vi diode Silicon. IS

nhit bnh thng T = 3000K, Vt = 0,026 Volt



Khi phn cc thun, dng in qua diode tng nhanh, v th phi hn ch dng in qua diode n khng b nh thng. Khi diode dn din, in p phn cc thun V=0,3 Volts i vi diode Ge v V=0,7 Volts i vi diode Si. Do , V/Vt > 10 v exp(V/Vt) >>1.

tS V

VexpII Suy ra:

Cng thc trn ch ng khi dng in qua mi ni kh ln. Vi dng in nh (vi mA tr xung) dng in qua diode l:

I Is[exp(V/Vt)-1]

Trong : =1 i vi diode Ge, =2 i vi diode Si Trong th nghim, mch phn cc v c tuyn ca diode nh sau:

2.2.1.2. Thc hnh: 1) D vo m hnh ton hc, hy vit chng trnh v c tuyn I-V ca diode bng

ngn ng MATLAB (hoc ngn ng tu ) vi V bin thin t -10V n 0.7V cho diode Si nhit bnh thng. Chy th chng trnh v so snh kt qu m phng c vi c tuyn l thuyt hc. Da vo c tuyn v c, hy ghi li cc i lng: I khi phn cc ngc v V khi phn cc thun. [1], [6] S

2) Dng phn mm Multisim V6.20 hoc 5.12 (Electronics WorkBench) v c tuyn ca diode v so snh vi kt qu cu 1. [3], [7], [8], [9] Cho nhn xt.

2.2.2. TRANSISTOR Cu to, k hiu v mch tng ng Ebers-Moll ca transistor NPN ln lt c

trnh by trong hnh 2.2 (a), (b), (c).

(a)

IC

IR VBC

BE

IB

IF IEC

(ICS)

(IES)

IE

V

E

C

B

ICC

N

N

P

C

B C

B

Hnh 2.2

E

E E

(b) (c)



2.2.2.1. M hnh ton hc [6]:

, I , ITrong m hnh Ebers-Moll c bn (hnh 3.c), cc dng in IC B E c xc nh bi cc biu thc sau:

Ic = IF ES[exp (VBE/Vt)-1]-ICS[exp(VBC/Vt)-1] IE = -IES[exp(VBE/Vt)-1]+I [exp (VS BCV/vt)-1] IB = -(I +I ) C E

Trong : IES: dng in bo ha ngc ca diode B-E ICS: dng in bo ha ngc ca diode B-C F v ln lt l li dng in thun v ngcR ch tn hiu ln ca

BJT cc nn chung. Hai ngun dng in ICC v IEC c iu khin bi IF v IR nh sau:

I =IF CC/FI =IR EC/RICC= IF ES[exp(VBC/Vt)-1]= I F FIEC= IR CS[exp(VBC/Vt)-1]= I R R

ITa c: F ES = IR CS = I (dng bo ha ca BJT) SSuy ra:

=I / [exp(V IF S R BE/Vt)-1] =I / IR S R [exp(VBC/Vt)-1]

IEC=I [exp(VS BC/Vt)-1] ICC=I [exp(VS BE/Vt)-1]

Da vo kt qu ny, ta c th biu din transistor theo m hnh vn chuyn (transport model) nh trong hnh 2.3.a .

IC

IEC/R BC

VBE

IB

CC

V

I /IEC

S

F

(I /R)

S(I /F)

IE

E

C

ICC

(a)

IC

IEC

B

/R

IB

ICC/F (IS/F)

IE

E

C

B ICC -IEC

Hnh 2.3

(b)



v Ni chung cc tham s F R thng khng c dng m hnh ha

transistor, ngi ta thay th bng cc tham s thn thin hn, l: =F F/(1- ) v F R= /(1-R R)

v F R ln lt l li dng in thun v li dng in ngc ca transistor mc cc E chung. M hnh Ebers-Moll c th c thay i bng cch thay th ICC v IEC bi mt ngun dng duy nht c biu thc nh sau: ICT = I ICC EC = I [exp(VS BE/V ) - exp(VT BC/V )] T

M hnh ny c trnh by trong hnh 2.3.b.

2.2.2.2. Thc hnh: [1], [3], [7], [8], [9], [10], [11]

1) Da vo m hnh ton hc, hy vit chng trnh v c tuyn ng vo vi VBE bin thin t 0 n 0.7V ca BJT loi Silicon bng ngn ng MATLAB (hoc ngn ng tu ), nhit bnh thng. Chy th chng trnh v so snh kt qu m phng c vi c tuyn l thuyt hc.

2) D vo m hnh ton hc, hy vit chng trnh v c tuyn ng ra vi VCE bin thin t 0 n 24V ca BJT loi Silicon bng ngn ng MATLAB (hoc ngn ng tu ), nhit bnh thng. Chy th chng trnh v so snh kt qu m phng c vi c tuyn l thuyt hc.

3) D vo m hnh ton hc, hy vit chng trnh v c tuyn truyn ca BJT loi Silicon bng ngn ng MATLAB (hoc ngn ng tu ), nhit bnh thng, vi VCE bin thin t 0 n 24V v VBE bin thin t 0 n 0.7V . Chy th chng trnh v so snh kt qu m phng c vi c tuyn l thuyt hc.

4) Dng phn mm Multisim V6.20 hoc 5.12 (Electronics WorkBench) v c tuyn ng vo v c tuyn ng ra ca BJT, so snh vi kt qu cu 1, cu 2 v cu 3. Cho nhn xt.

Gi :

Da vo m hinh cu trc ny ta tm c: = I (VIC S BE/Vt)-exp(VBC/Vt)]-I / [exp(VS R BC/Vt)-1]

I = I / [exp(VB S R BC/Vt)-1]+ I / [exp(VS R BE/Vt)-1] =I [(VIE S BE/Vt)-exp(VBC/Vt)]-I / [exp(VS R BE/Vt)-1]

Phng trnh c tuyn ng vo ca transistor: =f(VIB BE)|VCE

I = I / [exp(VB S R BC/Vt)-1]+ I / [exp(VS R BE/Vt)-1] Thay VBC=VBE-VCE, suy ra: I = I / [exp(VB S R BC/Vt)-1]+ I / {exp(VS R BE--VCE)/Vt]-1}

Phng trnh c tuyn ng ra ca transistor: I =f(VC CE)|IB I = I (VC S BE/Vt)-exp(VBC/Vt)]-I / [exp(VS R BC/Vt)-1] Thc t VBE


I = I (VC S BE/Vt)-exp(VBC/Vt)]-I / [exp(VS R BC/Vt)-1] Thay VBC=VBE-VCE ta c: I = I {(VC S BE/Vt)-exp[(VBE-VCE)/V ]}-I / {exp[(Vt S R BE-VCE)/Vt]-1}

2.2.3. MOSFET (Metal Oxide Semiconductor Field Effect Transistor)

MOSFET c 2 loi: loi him (DE-MOSFET: Depletion-type MOSFET) v loi tng (E-MOSFET: Enhancement-type MOSFET).

Trong bi thc hnh ny ta ch kho st loi tng (E-MOSFET)

2.2.3.1. E-MOSFET transistor [2], [12] Cu to cn bn

E-MOSFET c hai loi: loi knh N v loi knh P. M hnh 2.4 m t cu to, k hiu v hnh dng ca hai loi E-MOSFET knh N

v knh P.

Hnh 2.4

Hot ng Khi VGS0 mt in trng c to ra vng cng. Do cng mang in tch dng nn ht cc in t trong nn P _ (l ht ti in thiu s ) n tp trung mt i din ca vng cng. Khi VGS ln, lc ht mnh cc in t n tp trung nhiu v to thnh mt thng l tm thi ni lin gia hai vng ngun S v thot D. in th VGS m t dng in thot ID bt u tng c gi l in th thm cng ngun VGS(th). Khi VGS tng ln hn VGS(th), dng in thot ID tip tc tng nhanh..

Dng in thot I c xc nh theo tng iu kin sau: DID=0 ,VGSVth and VGS-VDS>VthID=(/2)(VGS-V )2 ,Vth GS>V and Vth GS-VDS


Thc hnh [1], [3], [6], [7], [8], [9], [10], [11]

1) Xy dng m hnh ton hc, vit chng trnh v c tuyn ng ra ca MOSFET

knh N bng ngn ng MATLAB (hoc ngn ng tu ), nhit bnh thng, vi VDS bin thin t 0 n 24V v VGS = -2V; -1V; 0V; 1V; 2V; 3V; 4V; 5V; 6V. Chy th chng trnh v so snh kt qu m phng c vi c tuyn l thuyt hc.

2) Xy dng m hnh ton hc, vit chng trnh v c tuyn truyn ca MOSFET knh N bng ngn ng MATLAB (hoc ngn ng tu ), nhit bnh thng, vi VGS bin thin t 0 n 10V v VDS= 24V. Chy th chng trnh v so snh kt qu m phng c vi c tuyn l thuyt hc.

3) Dng phn mm Multisim V6.20 hoc 5.12 (Electronics WorkBench) v c tuyn ng ra v c tuyn truyn ca MOSFET, so snh vi kt qu cu 1 v cu 2. Cho nhn xt.

2.2.4. THYRISTOR (SCR) [2], [10]

SCR vTriac l cc linh kin iu khin khng th kch ngt. Cng dng quan trng ca n l iu khin cng sut trn ti. Trong trng hp ny chng ng vai tr nh mt kha in t, nn ch c 2 trng thi dn (ng) v kha (ngt). SCR iu khin cng sut DC, TRIAC iu khin cng sut AC. Tuy nhin, ta cng c th dng 2 SCR hoc kt hp SCR vi mt s Diode iu khin cng sut AC.

Cu to, k hiu, hnh dng thc t v c tuyn vo ra ca SCR c trnh by trong hnh 2.5.

Hnh 2.5

Ta thy, SCR ch dn in mt chiu. - Kch ng (m): VAK > 0, IG > 0



- SCR kha ta khng th kch bng dng IG. SCR kha phi tha iu kin sau: V 0 . AK

2.2.4.1.Cc thng s k thut c bn ca SCR l: - Dng in thun nh mc: In (A)

(V) - in p ngc cc i Vinmax- in p ri V (V)

(V) - in p iu khin VG- Dng in iu khin IG (mA). - Tc d tng dng in di/dt (A/s) - Tc d tng in p dv/dt (V/s) - Dng in r ICO (mA) 2.2.4.2. Thc hnh [1], [3], [6], [7], [8], [9], [10], [11] 1) Xy dng m hnh ton hc, vit chng trnh v c tuyn truyn ca SCR bng

ngn ng MATLAB (hoc ngn ng tu ), nhit bnh thng. Chy th chng trnh v so snh kt qu m phng c vi c tuyn l thuyt hc.

2) Dng phn mm Multisim V6.20 hoc 5.12 (Electronics WorkBench) v c tuyn ng ra v c tuyn truyn ca SCR, so snh vi kt qu cu 1. Cho nhn xt.

2.2.5. TRIAC [2], [12] Cu to, k hiu, hnh dng thc t v c tuyn vo ra ca TRIAC c trnh by

trong hnh 2.6.

Hnh 2.6

- Triac dn c 2 chiu. - Triac c kch ng (dn) bng dng in IG

- a Triac t trng thi dn sang trng thi kha phi c 2 iu kin l : IG=0 v in p ngun i chiu.

Triac c th c kch ng trong 4 trng hp sau : a/. VD>0, VG>0, I >0 (chiu dng l chiu mi tn) G

>0, V


2.2.5.1. Cc thng s k thut c bn ca TRIAC l: - Dng in nh mc: In (A) - in p in mc Vn (V) - in p ri V (V)

(V) - in p iu khin VG- Dng in iu khin IG (mA). - Tc d tng dng in di/dt (A/s) - Tc d tng in p dv/dt (V/s) - Dng in r ICO (mA) 2.2.5.2. Thc hnh: 1) Xy dng m hnh ton hc, hy vit chng trnh v c tuyn truyn ca

TRIAC bng ngn ng MATLAB (hoc ngn ng tu ), nhit bnh thng, vi VGS bin thin t 0 n 10V v VDS= 24V. Chy th chng trnh v so snh kt qu m phng c vi c tuyn l thuyt hc.

2) Dng phn mm Multisim V6.20 (Electronics WorkBench) v c tuyn ng ra v c tuyn truyn ca TRIAC, so snh vi kt qu cu 1. Cho nhn xt.

2.3. TI LIU THAM KHO: [1]. Cc bi ging v gio trnh CAD B Mn Vin Thng & K thut iu khin -

Khoa cng Ngh Thng Tin & Truyn thng HCT. [2]. Cc bi ging v gio trnh IN T CNG SUT B Mn Vin Thng & K

thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT. [3]. NGUYN CH NGN - Gio trnh THIT K M PHNG MCH V V

MCH IN - B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT 2003.

[4]. TRNG VN TM - LINH KIN IN T Gio trnh B Mn Vin Thng & T ng Ha - Khoa cng Ngh Thng Tin HCT 2001.

[5]. TRNG VN TM - MCH IN T Gio trnh B Mn Vin Thng & T ng Ha - Khoa cng Ngh Thng Tin HCT 2001.

[6]. M. BIALKO, R. CRAMPAGNE, D. ANDREU BASIC METHODS FOR MICROCOMPUTER AIDED ANALYSIS OF ELECTRONIC CIRCUITS Prentice Hall 1995.

http://www.vocw.edu.vn/content/m10373/latest/[7]. [8]. http://www.electronicsworkbench.com/index.html

http://www.box.net/shared/rma8ut6x4s[9]. [10]. http://www.powersimtech.com

www.mathworks.com[11]. http:// [12]. Zainal Salam POWER ELECTRONICS AND DRIVES Version 3

UTM.JB 2003


http://www.vocw.edu.vn/content/m10373/latest/http://www.electronicsworkbench.com/index.htmlhttp://www.box.net/shared/rma8ut6x4shttp://www.powersimtech.com/http://www.powersimtech.com/

Bi 3: Chnh lu mt pha c iu khin

BI 3: CHNH LU MT PHA C IU KHIN Tham gia thc hin: KS Ng Trc Hng

3.1. MC CH - Kho st mch chnh lu khng iu khin dng Diode cng sut. - Kho st mch chnh lu dng SCR. - Kt hp SCR v Diode chnh lu v iu khin cng sut ng ra bng cch

thay i gc m (gc tr) .

3.2. CC KIN THC LIN QUAN 3.2.1. Sinh vin n li: - Cc nguyn tc cu to ca diode v SCR, cc mch chnh lu dng diode v

SCR. - Nguyn tc iu khin gc m. - Chnh lu mt pha bn iu khin. - Chnh lu mt pha iu khin hon ton.

3.2.2. Sinh vin tm hiu v gii thch nguyn tc hot ng ca mch to xung kch: Board to xung kch dng to v cp xung kch cho board cng sut ti nhng thi

im mong mun. Hot dng ca n c m t bng gin dng sng tn hiu trong hnh 3.1. S mch th nghim c trnh by trong hnh 3.2 cui bi th nghim ny.

3.3. THC HNH: 3.3.1. Kho st Board mch to xung kch: Ni board mch kch xung vo Board cng sut bng dy BUS 4 si. a. Quan st v v li dng sng ca TP3 v TP6 trn cng mt th. iu chnh

VR1, cho nhn xt. b. Quan st v v li dng sng ca TP3 v TP8 trn cng th, iu chnh VR1,

cho nhn xt. c. o v v li dng sng ca TP3 v TP9 trn cng th. iu chnh VR2, cho

nhn xt. d. Trng hp cu c. khc vi trng hp cu b. v thi im kch xung nh th no?



TP3

Tn hiu ng vo

TP4

Qua so snh

TP5

Qua mch vi phn

TP6

Qua a hi n n

TP7

Qua mch to xung Cng EXOR

TP8

Qua mch chn xung, Xung kch bn k dng

TP9

Xung kch bn k m

Hnh 3.1: Gin dng sng to tn hiu



Hnh 3.2: Mch to xung kch TRAC

3.3.2. Kho st nguyn tc iu khin gc m: Rp mch nh hnh 3.3:

R6

R1

U3MOC3021

1

2

64

R4

R1

D

U1MOC3021

1

2

64

Q1

SCR

Q4

SCR

DD

U2MOC3021

1

2

64

U4MOC3021

1

2

64

R3E

CR2

R2

R5

TP2

1

Q2

SCR

D

TP1

1

R1

Board Tai

C

R2Q3

SCRE

D3

Dm

Hnh 3.3

a. iu chnh gc m = /2 - V li dng sng in p AC ( nn ly ng vo trn mch to xung, ti im TP3),

xung kch v ng ra Vo theo cng trc thi gian. - Tnh cng sut trn ti.

b. Thay i gc m bng cch chnh bin tr VR1, quan st sng ca n, cho nhn xt v cng sut trn ti theo gc m .



3.3.3. Kho st chnh lu cu dng 4 diode cng sut: Mc mch nh hnh 3.4:

Board ti

A

B

TP1

TP2 5K

220K Vo

Vin

Hnh 3.4

Dng Oscilloscope quan st dng sng trn TP1 v TP2- V li dng sng V v Vin o theo cng trc thi gian. - Tnh cng sut trn ti, so snh cng sut vi cu 2.3.1.

3.3.4. Kho st chnh lu cu, bn iu khin Mc mch nh hnh 3.5 :

a. h Dm, ni ti R (bng n 75W) bng /3 v /3+ (tng ng vi xung kch

-

b. 1 v T2 l 2/3 v +2/3

c. n cm ni tip). rn ti).

v T2. Quan st dng sng trn t

g ca Dm.

D1

R6

R1 R4

D

U1MOC3021

1

2

64

Q1

SCRU2MOC3021

1

2

64

R3E

R2

R5

TP2

1

D2

Q2

SCR

TP1

1

Board Tai

C

D

D3

Dm

Hnh 3.5

- iu chnh gc m ca T1 v T2 ti TP8 v TP9). V li dng sng in p AC ( nn ly ng vo trn mch to xung, ti im TP3), xung kch ca T1 v T2, v in p ng ra Vo Tnh cng sut trn ti.

Thay i gc m ca T- Cho nhn xt v sng ca n. - Tnh li cng sut trn ti. Mc ti R-L (gm n v cu- Lp li cu a v b ( khng cn tnh cng sut t-Ni Dm vo mch, thay i thi im kch xung ca T1i v nu nhn xt. - Cho bit cng dn



3.3.5. Chnh lu cu 1 pha iu khin hon ton Mc mch nh hnh 3.6 :

R6

R1

U3MOC3021

1

2

64

R4

R1

D

U1MOC3021

1

2

64

Q1

SCR

Q4

SCR

DD

U2MOC3021

1

2

64

U4MOC3021

1

2

64

R3E

CR2

R2

R5

TP2

1

Q2

SCR

D

TP1

1

R1

Board Tai

C

R2Q3

SCRE

D3

Dm

Hnh 3.6

a. Mc ti R ( bng n):

a.1. Chnh gc m ca T1, T2 l /3 v +/3 , xung kch T- V li dng sng Vin 1, T2 v Vo. Tnh cng sut.

a.2. Thay i gc m l 2/3 v +2/3 - Lp li cu a.1. Nhn xt sng ca n

b. Mc ti R-L (gm n v cun cm ni tip): h Dm, b.1. Lp li cu a.1. Cho nhn xt dng sng va v c g khc vi cu a.1, cho

bit nh hng ca cun cm va mc vo? b.2. Lp li cu a.2. Cho nhn xt so vi cu b.1 b.3. Ni Dm vo mch, thay i thi im kch xung ca c 2 bn k (thay i gc m),

dng Oscilloscope quan st dng sng trn ti, cho nhn xt . Dng sng trn ti c g khc so vi trng hp h Dm? Gii thch? (Dng thm hnh v).

3.4. THIT B TH NGHIM 1) 01 mch to xung iu khin (board nh). 2) 01 mch cng sut (board ln). 3) 01 board ti. 4) 01 oscilloscope. 5) 01 VOM. 6) Dy ni mch.



3.5. TI LIU THAM KHO: [1]. Cc bi ging v gio trnh IN T CNG SUT B Mn Vin Thng &

K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT. [2]. NGUYN VN NH - GIO TRNH IN T CNG SUT I NXB i

hc Quc gia TP HCM 2002. [3]. TRNG VN TM - LINH KIN IN T Gio trnh B Mn Vin

Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT 2001.

[4]. TRNG VN TM - MCH IN T Gio trnh B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT 2001.

[5]. CYRIL W. LANDER POWERS ELETRONICS McGraw-Hill, London 1987.

[6]. Zainal Salam POWER ELECTRONICS AND DRIVES Version 3 UTM.JB 2003


Bi 4: Lp trnh m phng mch chnh lu bng Matlab

BI 4: LP TRNH M PHNG MCH CHNH LU BNG MATLAB

4.1. MC CH

- Bit cch xy dng m hnh tan hc m phng mch in t, c bit l mch in t cng sut.

- Nm vng nguyn tc hat ng ca mch chnh lu khng iu khin v c iu khin.

- Thy r dng in p v dng in ng ra, c bit khi ti c cm khng. - Rn luyn k nng xy dng phn mm m phng. - Cng c cc kin thc v k nng hc trong bi 2.

4.2. KIN THC NN - Sinh vin t n tp l thuyt v mch chnh lu khng iu khin v c iu

khin; mt pha v 3 pha. - Gi s cc linh kin cng sut c dng l l tng v ng vai tr ca mt cng

tc (khi ng in th gia 2 cc chnh bng 0, khi ngt dng in qua n bng 0). - Khi m phng mch chnh lu bng MATLAB, ta khng th s dng cc khi dng

sn trong th vin SIMULINK. V vy, ta phi xy dng m hnh ton hc cho mch in (cc phng trnh ca dng in v in p), t vit chng trnh m phng.

4.3. THC HNH

Trong bi ny, sinh vin s m phng mch chnh lu 3 pha, vi ngun in 3 pha l tng c cc in p pha lch nhau 1200, nh sau:

u1 = um sin(x), vi x = t = 2Ft u2 = um sin(x-2/3)

u3 = um sin(x-4/3) Cc linh kin cng sut c gi thit l l tng, hot ng 2 trng thi: ng (in

tr gia 2 cc chnh bng 0, in p ri bng 0), ngt (in tr gia 2 cc chnh bng ).

4.3.1. Chnh lu 3 pha mch tia khng iu khin Xt trng hp ti R-L-E v gi s c th b qua tng tr ca ngun

Hnh 4.1: Chnh lu 3 pha mch tia khng iu khin ti thun tr. Ch chiu dng in p c qui c nh sau: + -



a. Chng trnh mu 1: function [i_d,u_d]=cl_diode_RLE(u,r,l,e,F) % cl_diode_RLE(u,r,l,e,F) m phng mch chnh lu tia 3 pha khng iu khin dng % diode, ti R-L-E, tnh in p v dng in chnh lu trn ti, v th ca cc i lng % ny vi cng thang o trn trn trc gc pha x = wt = 2Ft, w l tn s gc ca ngun 3 % pha. i s vo (input argument) u l gi tr hiu dng ca in p ngun, r v l gi tr % ca in tr v cun dy trn ti, e sc in ng trn ti hoc ngun dc trn ti, F l tn % s ca in p ngun. i s ra (Output argument) i_d l dng in qua ti , u_d l in % p trn ti. Cc th c v theo bin x = wt . V gi tr ca dng in rt nh so vi % in p, nn c th quan st dng sng ca dng in tt hn, trc khi v th, dng % in c nhn ln t 3 n 10 ln so vi gi tr tht. global R L E f u_m % Khai bo bin ton cc. if nargin < 4 error('Requires 4 or 5 input arguments.') elseif nargin >= 4 R=r;L=l;E=e; % Gn i s vo cho cc bin ton cc. u_m=sqrt(2)*u; % Tnh bin in p ngun 3 pha. % Khai bo vector bin gc pha x, x=wt. x1=[0:0.01:pi/6];x2=[pi/6+0.01:0.01:5*pi/6]; x3=[5*pi/6+0.01:0.01:9*pi/6];x4=[9*pi/6+0.01:0.01:13*pi/6]; x=[x1 x2 x3 x4]; % Khai bo in p ngun in 3 pha.

u_1=u_m*sin(x); u_2=u_m*sin(x-2*pi/3); u_3=u_m*sin(x-4*pi/3); % Mc nh bin tn s f =50, khi khng c i s vo F. if nargin==4

f=50; else f=F; end % Tnh dng in ti bng cch s dng hm ode15s gii phng

dtdid % trnh vi phn ud = Rid + L + E, nu L khc 0.

if L==0 i_d1=(u_m*sin(x1-4*pi/3)-E)/R;i_d2=(u_m*sin(x2)-E)/R; i_d3=(u_m*sin(x3-2*pi/3)-E)/R;i_d4=(u_m*sin(x4-4*pi/3)-E)/R; i_d=[i_d1 i_d2 i_d3 i_d4]; else [k_1,id1]=ode15s('phuongtrinh3',[0:0.01:pi/6],u_m/(R+2*pi*f*L)); [k_1,id2]=ode15s('phuongtrinh1',[pi/6+0.01:0.01:5*pi/6],

id1(length(id1))); [k_1,id3]=ode15s('phuongtrinh2',[5*pi/6+0.01:0.01:9*pi/6],

id2(length(id2))); [k_1,id4]=ode15s('phuongtrinh3',[9*pi/6+0.01:0.01:13*pi/6],

id3(length(id3))); i_d=[id1' id2' id3' id4']; end



i_d3=3*i_d; %Tng thang o ca dng in ln t 3 n 10 ln. for n=1:length(x) if (x(n)pi/6)&(x(n)5*pi/6)&(x(n)


% nh ngha phng trnh vi phn cho hm ode23s. global u R L E f u_m ham=(-i(1)*R/L+ u_m*sin(x)/L-E/L)/(2*pi*f); function ham=phuongtrinh2(x,i) % nh ngha phng trnh vi phn cho hm ode23s global u R L E f u_m ham(1)=(-i(1)*R/L+ u_m*sin(x-2*pi/3)/L-E/L)/(2*pi*f); function ham=phuongtrinh3(x,i) % nh ngha phng trnh vi phn cho hm ode23s global u R L E f u_m ham(1)=-i(1)*R/(2*pi*f*L)+ u_m*sin(x-4*pi/3)/(2*pi*f*L)-E/(2*pi*f*L);

b. Cu hi: 1. Hon thnh cc khong trng trong h phng trnh m t trng thi mch in

(hnh 4.1) sau y:

+ Khi 0 < x /6 v 9/6


4.3.2. CHNH LU 3 PHA MCH TIA C IU KHIN Xt trng hp ti R_L_E v gi s c th b qua tng tr ca ngun.

Hnh 4.2: Chnh lu 3 pha mch tia c iu khin ti R_L_E. Ch chiu dng in p c qui c nh sau: + -

a. Chng trnh mu 2:

function [i_d,u_d]=cl_diode_RLE_dk(u,r,l,e,al,F) % cl_diode_RLE_dk(u,r,l,e,al,F) m phng mch chnh lu tia 3 pha c iu khin dng % diode, ti R-L-E, tnh in p v dng in chnh lu trn ti, v th ca cc i lng % ny vi cng thang o trn trn trc gc pha x = wt = 2*pi*f*t, w l tn s gc ca % ngun in 3 pha. i s vo (input argument) u l gi tr hiu dng ca in p ngun, r % v l l gi tr ca in tr v cun dy trn ti, e sc in ng trn ti hoc ngun dc % trn ti, F l tn s ca in p ngun. i s ra (Output argument) i_d l dng in qua % ti , u_d l in p trn ti. Cc th c v theo bin x . V gi tr ca dng in rt % nh so vi in p, nn c th quan st dng sng ca dng in tt hn, trc khi v % th, dng in c tng ln t 3 n 10 ln so vi gi tr tht.

global R L E a f u_m % Khai bo bin ton cc. if nargin < 5 error('Requires 5 or 6 input arguments.') elseif nargin >= 5 R=r;L=l;E=e;a=al; %Gn gi tr cc bin theo gi tr ca cc i s vo. u_m=sqrt(2)*u; % Tnh bin ca in p ngun. % Khai bo bin gc pha x=wt=2*pi*t, t l thi gian. x1=[0:0.01:pi/6+a];x2=[pi/6+0.01+a:0.01:5*pi/6+a]; x3=[5*pi/6+0.01+a:0.01:9*pi/6+a];x4=[9*pi/6+0.01+a:0.01:13*pi/6]; x=[x1 x2 x3 x4]; % Khai bo in p ngun 3 pha. u_1=u_m*sin(x); u_2=u_m*sin(x-2*pi/3); u_3=u_m*sin(x-4*pi/3); % Gn gi tr mc nh cho bin tn s . if nargin==4



f=50; else f=F; end % Tnh dng in qua ti. if L==0 i_d1=(u_m*sin(x1-4*pi/3)-E)/R;i_d2=(u_m*sin(x2)-E)/R; i_d3=(u_m*sin(x3-2*pi/3)-E)/R;i_d4=(u_m*sin(x4-4*pi/3)-E)/R; i_d=[i_d1 i_d2 i_d3 i_d4]; else [k_1,id1]=ode23s('phuongtrinh3',[0:0.01:pi/6+a],u_m/(R+2*pi*f*L)); [k_1,id2]=ode23s('phuongtrinh1',[pi/6+0.01+a:0.01:5*pi/6+a],id1(length(id1))); [k_1,id3]=ode23s('phuongtrinh2',[5*pi/6+0.01+a:0.01:9*pi/6+a],id2(length(id2))); [k_1,id4]=ode23s('phuongtrinh3',[9*pi/6+0.01+a:0.01:13*pi/6],id3(length(id3))); i_d=[id1' id2' id3' id4']; end for k=1:length(i_d) % Nu gi tr m th cho bng zero. if i_d(k)


plot(x,u_d,'b',x,i_d3,'r'); grid on xlabel('x'),ylabel('u_d i_d'); legend('u_d','3*i_d'); subplot(313); plot(x,u_v1,'b',x,10*i_v1,'r'); grid on xlabel('x'),ylabel('u_D_1 i_D_1'); legend('u_D_1','10*i_D_1'); end;

b. Cu hi: 1. Hon thnh cc khong trng trong h phng trnh m t trng thi mch in

(hnh 3.1) sau y: + Khi 0 < x /6 + v 9/6 +


Trng hp c hin tng trng dn ti R_L v cm khng ca ngun LC khng th b qua (LC 0).

Hnh 4.3: Chnh lu 3 pha mch tia c iu khin ti R_L, L 0. C Ch chiu dng in p c qui c nh sau: + -

Cu hi:

6. Hin tng trng dn l g? 7. M PSIM, lp rp mch nh hnh 4.3 (phi thm vo mch to xung kch mc

thm cc ampere k v volt k vo cc v tr cn o dng in v in p) v chy chng trnh m phng trn PSIM ln lt vi cc thng s:

= 0.001 H. R=10, L= 0.01 H, = /3 rad, LCSo snh kt qu vi cu 4.2.4 v cho nhn xt.



4.4. TI LIU THAM KHO: [1]. Cc bi ging v gio trnh IN T CNG SUT B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT. [2]. Cc bi ging v gio trnh CAD B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT. [3]. NGUYN CH NGN - Gio trnh THIT K M PHNG MCH V V MCH IN - B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT 2003. [4]. NGUYN VN NH - GIO TRNH IN T CNG SUT I NXB i hc Quc gia TP HCM 2002. [5]. TRNG VN TM - MCH IN T Gio trnh B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT 2001. [6].M. BIALKO, R. CRAMPAGNE, D. ANDREU BASIC METHODS FOR MICROCOMPUTER AIDED ANALYSIS OF ELECTRONIC CIRCUITS Prentice Hall 1995.

www.powersimtech.com[7]. http:// [8]. http:// www.mathworks.com[9]. http://www.vocw.edu.vn/content/m10373/latest/ [10]. http://www.electronicsworkbench.com/index.html [11]. http://www.box.net/shared/rma8ut6x4s


http://www.powersimtech.com/http://www.powersimtech.com/http://www.vocw.edu.vn/content/m10373/latest/http://www.electronicsworkbench.com/index.htmlhttp://www.box.net/shared/rma8ut6x4s

Bi 5: M phng mch chnh lu mt pha c iu khin bng Psim

BI 5: M PHNG MCH CHNH LU MT PHA C IU KHIN BNG PSIM

5.1. MC CH:

Dng phn mm PSIM m phng mch chnh lu iu khin mt pha na chu k v mch chnh lu iu khin mt pha hai na chu k. So snh vi kt qu trong bi 3 v bi 4. T cng c c kin thc v vic iu khin ng ngt cc linh kin cng sut ni chung v mch chnh lu c iu khin ni ring. ng thi hnh thnh c phng php v k nng vit chng trnh m phng cng nh s dng cc phn mm m phng c sn.

5.2. KIN THC NN:

- Sinh vin t n tp l thuyt v mch chnh lu khng iu khin v c iu khin; mt pha v ba pha [1], [4].

- Gi s cc linh kin cng sut c dng l l tng v ng vai tr ca mt cng tc (khi ng in th gia 2 cc bng 0, khi ngt dng in qua n bng 0).

- Phn mm PSIM ca Powersim Inc [6]. PSIM l mt phn mm ng gi chuyn dng cho vic m phng mch in t cng sut v iu khin m t. N c cc u im l tc nhanh, giao din thn thin vi ngi dng v c chc nng x l hin th dng sng ca tn hiu. Bao gm 03 chng trnh: chng trnh v s mch in SIMCAD; chng trnh m phng PSIM; chng trnh x l v hin th dng sng SIMVIEW. Mt mch in c trnh by bi PSIM gm 04 khi: mch cng sut, mch iu khin, cm bin v cc b iu khin switch.

- m phng mt mch in hoc mt h thng iu khin, ta tin hnh cc bc sau: Khi ng PSIM (Theo s ch dn ca ging vin): Mt giao din m phng SIMCAD xut hin, nh hnh 5.1:



Hnh 5.1

Trn menu, t File ta chn New (thc hin mch in mi) hoc Open ( m project c lu di dng file c phn m rng l .sch). Cc thao tc c bn thc hin mt mch in mi:

o Chn linh kin, ngun tn hiu v cc thnh phn khc t Elements trn menu hoc trn thanh cng c pha di mn hnh ( nhp chut tri vo phn t mun chn. Sau nhp chut vo v tr mun t phn t trn ca s thit k, c th quay phn t chn t Rotate trn menu Edit hoc nhp chut tri vo biu tng tng ng trn menu bar).

o Thc hin cc ng mch ni cc linh kin v cc thnh phn khc: chn Wire trn menu Edit hoc biu tng tng ng trn menu bar, sau r chut gia cc im mun ni.

o t cc tham s ca cc linh kin: nhp chut tri vo biu tng mi tn trn menu bar, ri nhp chut tri vo thnh phn mun t tham s, sau chn Attributes trn menu Edit (hoc n phm tt F4), mt ca s con hin ra, cho php ta nhp cc tham s cn thit. Ch cc tham s v n v tnh ca cc linh kin.

o Dn nhn: chn Label trn menu Edit (hoc n phm tt F2) , nu cn. o Chy chng trnh m phng: chn Run Simulation trn menu Simulate,

hoc n phm tt F8, hoc nhp chut trn biu tng tng ng trn menu bar. ch mc nh (Auto-Run SIMVIEW), mt ca s con Data Display Selection hin ra cho php ta chn cc bin cn hin th lit k sn (theo cc thit b v in p c trong mch in). Nu mun hin th

Quay Ni dy dn Dn nhn Chy PSIM

Chy SIMVIEW

Chn phn t trong mch

Ca s thit k



th ca mt i lng (bin) no , ta cn phi t thit b o lng tng ng vo v tr trn mch in.

o Sinh vin cn tham kho trc v PSIM trong cc ti liu [6]. 5.3. THC HNH:

5.3.1. Mch chnh lu iu khin mt pha na chu k: a. M phn mm PSIM v v mch chnh lu mt pha bn iu khin hnh 5.2:

Hnh 5.2: Mch chnh lu iu khin mt pha na chu k.

- Thit lp cc gi tr ph hp. - V li trn bi phc trnh dng sng in th ti ud, dng sng dng in ti id. - Gii thch dng sng ud, id. - Da vo th dng sng in p ti, tnh gi tr in p trung bnh gia 2 u ti

b. Thay i V1 thay i gc kch . V li trn bi phc trnh dng sng ng vi gc kch = 2/3 (V1 = 120 Volt).

c. Thit lp L=0.05H. V li trn bi phc trnh dng sng ud, id. So snh vi dng sng cu a v gii thch.



5.3.2. Mch chnh lu iu khin mt pha hai na chu k: a. V mch chnh lu iu khin mt pha hai na chu k nh sau (Hnh 5.3):

Hnh 5.3: Mch chnh lu iu khin mt pha hai na chu k.

- Thit lp cc gi tr ph hp. - V li trn bi phc trnh dng sng in th ti ud, dng sng dng in ti id. - Gii thch dng sng ud, id.

b. Thay i V2 thay i gc kch . V li trn bi phc trnh dng sng ng vi gc kch = /3 (V2 = 120 Volt).

c. Thit lp L = 0H. V li trn bi phc trnh dng sng ud, id. So snh vi dng sng cu a v gii thch.



5.4. TI LIU THAM KHO: [1]. Cc bi ging v gio trnh IN T CNG SUT B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT. [2]. Cc bi ging v gio trnh CAD B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT. [3]. NGUYN CH NGN - Gio trnh THIT K M PHNG MCH V V MCH IN - B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT 2003. [4]. NGUYN VN NH - GIO TRNH IN T CNG SUT I NXB i hc Quc gia TP HCM 2002. [5]. TRNG VN TM - MCH IN T Gio trnh B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT 2001. [6]. http:// www.powersimtech.com

http://www.vocw.edu.vn/content/m10373/latest/[7]. http://www.electronicsworkbench.com/index.html[8]. http://www.box.net/shared/rma8ut6x4s[9].


http://www.powersimtech.com/http://www.vocw.edu.vn/content/m10373/latest/http://www.electronicsworkbench.com/index.htmlhttp://www.box.net/shared/rma8ut6x4s

Bi 6: n p mt chiu

BI 6: N P MT CHIU Tham gia thc hin: KS. Trng Vn Tm

6.1. MC CH:

Gip cho sinh vin thu hiu nguyn l hot ng ca cc loi n p DC, rn luyn k nng thc hnh, hnh thnh kh nng thit k v lp rp cc loi n p DC theo yu cu thc t.

6.2. S LC V L THUYT

Mch n p mt chiu cn c gi l mch bin i DC-DC, y l mt mch bin i t in p mt chiu ny thnh in p mt chiu khc.

Thng thng, ngi ta chia n p mt chiu ra lm 2 loi: - n p tuyn tnh, - n p ngt m (switching regulator).

D l loi no, mt mch n p cng phi t 2 chc nng: - n nh in p ng ra khi in p ng vo thay i v khi dng ti thay i. - Gim n mc thp nht sng d ng ra.

6.2.1. n p tuyn tnh Trong bi th nghim ny ta kho st mch n p tuyn tnh dng ni tip. S khi

nh sau:

C1: T lc ng vo C2: T lc ng ra

n p + vi-

vo+ - RL

Hnh 6.1

+ - AV

Cng sut n p

Kch

So snh

Chun

Ly mu C1

+

-

+ vi

Cha n p

C2-

+

vo n p

RL

IL

Hnh 6.2 Gio trnh th nghim in t cng sut Trang 44

Bi 6: n p mt chiu

- Cng sut n p: Thng l mt transistor cng sut ln, hot ng nh mt in tr thay i.

- So snh: So snh in th ly mu v in th chun to thnh in th iu khin VDK iu khin mch kch to dng kch cho cng sut.

- Chun: To in th chun Vref cho mch so snh (thng dng zener). - Ly mu: Ly mt phn in th ng ra so snh vi in th chun (in th ly mu

thay i theo in th ng ra vo). Nguyn tc hot ng: vo=vi-AV

Gi s khi vo thay i (v l do no ), in th ly mu thay i theo trong khi in th chun khng i nn ng ra VDK ca mch so snh thay i, in th VDK ny iu khin mch kch v cng sut thay i hot ng (chy mnh/chy yu) thay i A sao cho vV o n nh. Mch cn bn c dng:

R3

VR

R4

R2

Q1

Q2

Q3

R1

RL

IL+

-

voC3

D

C2

C1

+

+

- -

R

+

vi

Hnh 6.3

Q1: Cng sut ; Q2: Thc (kiu darlington) ; Q3: So snh Zener D: to in th chun R3, R4,VR: Ly mu C2: Gim sng d ng ra

chy thng v thng trc qua QDo dng ti IL 1 nn Q1 phi c cng sut ln v phi c gii nhit cn thn. Mch thng c mt in tr R cng sut ln chia bt dng qua Q1

6.2.2. n p ngt m - Tuy c rt nhiu dng, nhng a s u dng phng php bin iu rng xung. - Nguyn l chung vn nh mch n p tuyn tnh nhng thay mch khuch i kch

bng mt mch dao ng to sng vung. Tn hiu ra ca mch dao ng kch vo transistor cng sut n p (thng l BJT hoc MOSFET cng sut ln), mc cao ca


Bi 6: n p mt chiu

xung vung lm transistor bo ha, mc thp lm transistor ngng. Nh vy cng sut n p hot ng nh mt chuyn mch (switch).

- Dao ng to xung vung c th l a hi (cng sut c lp vi mch dao ng) hoc thng dng hn l dao ng blocking (cng sut tham gia vo mch dao ng) do cch ly c mass in.

Cng sut n p

Dao ng to xung vung

So snh

Chun

Ly mu Ci

+

-

+ vi

+ - AV

Co

-

+

voRL

IL

-

SW

vi vo

vo

0 Tx

T

Hnh 6.4

- Khi cha mc t lc ng ra, v0 c dng xung vi bin nh bng vi khi SW

trng thi ON v v0=0 khi SW trng thi OFF. Tr trung bnh ca v0 l

Ta thy: thay i tr trung bnh ng ra vTT

vv xio =

o ta c th: - Thay i thi gian SW trng thi ON (Transistor dn bo ha) - Thay i tn s ca mch dao ng (Tc thay i chu k T) - Hoc thay i c hai Thc t, tin vic thit k v kim sot, thng ngi ta gi nguyn tn s dao ng

(thc t trong my thu hnh, monitor my tnh. Ngi ta dng xung qut ngang a v


Bi 6: n p mt chiu

gi cho tn s dao ng bng vi tn s qut ngang), tn hiu ly mu ch lm thay i rng ca xung vung tc thay i thi gian dn-ngng ca transistor cng sut, tc Tx.

- n nh vo, th d khi vi cao ngi ta gim Tx, khi vi gim ngi ta tng Tx. - Mch thng c thit k tn s kh cao (hn 10KHz) nn t lc ng ra khng

cn ln m vn bo m c vic gim ti a sng d (vo gn l tng). - to ra nhiu loi in p khc nhau, nht l cch ly c mass in v mass my

(chng git), ngi ta thng thit k b ngun c bin p xung. Ty theo tn s hot ng ca mch v s vng cun s cp, th cp m ta c c cc in p khc nhau theo yu cu.

+ -

B1D

+ -

B2D

SW

B+

OSC

Hnh 6.5

6.3. PHN THC HNH

6.3.1. n p tuyn tnh Mch dng thc tp c dng:

R4

VR

R5

R3

Q1

Q2

Q3

R1

RL

IL

+

-

voCo

D

C

Ci

+

+

-

-

+

vi

+ vo

R2

1,8K

2200F 2200F

100F100K

560 1K

1K

2,2K

Hnh 6.6

Vi vi c cp t mt ngun thay i bn ngoi a/ Gii thch vn tt nguyn l hot ng ca mch (khi vi v I thay i) Lb/ Cp vI = +18V, o in th ng ra v , chnh Vo R theo hai chiu. Nhn xt v gii thch.


Bi 6: n p mt chiu

c/ Chnh VR vo=+12V, cho vi thay i t +15V +20V, o vo, lp bng theo mu sau v v th vo=f(vi). Nhn xt.

Vi +15V +16V +17V +18V +19V +20V

vo

d/ Cp vi=+18V, o vo khi thay i I (bng cch thay i RL L)

RL R1(100) R2(50) R3(100/3) R4(25)

IL vo

V th vo=f(I ). Nhn xt. Le/ Khng mc t C vo mch, quan st sng d ng ra. Lp li th nghim. Khi mc t

C vo mch. Nhn xt v gii thch. f/ Gi s khng mc Co vo mch, vo b nh hng g? Gii thch?


Bi 6: n p mt chiu

6.3.2. n p ngt m: Mch thc hnh hnh 6.7

Ghi ch quan trng: * Trong mch c 2 mass, mt mass in v 1 mass my. Sinh vin khi lm thc tp phi

tht cn thn, trnh b in git. * Trong bi thc tp dng SCR v E-MOSTFET knh N vi s chn nh sau:

SCR

K794

G D S

+300V 7 8

5 9

B1

100F/100V

+

-

RL1

47K

/2W

272/

1K

B2

+

-

RL2

10

11

13

15

4

3

2

1

5

6

7

8

+

- .001

1K

47

47K

.33

/2W

K794

47K/2W

47K/2W

100

3

272/

1K

.1 1K

Vz=18V

1

100F/25V

+

-

1M 100p

.22

100K

3.3K

.KA

3842

out

Vcc

18K

5K

47

22K .0022

47

.1

220VAC

+

- C1

+

-

+

-

Hnh 6.7


Bi 6: n p mt chiu

6.3.2.1. Vi mch KA3842 c s chn:

7 Vcc

5

RT/C

IC KA3842 l IC dao ng iu khin mch ngun Switching c s dng rt nhiu trong cc mch ngun monitor my tnh. IC ny hot ng theo kiu bin iu rng xung (pulse width modulation). IC c kh nng to ngun chun Vref=+5V ti chn 8, mch so snh cm nhn v in p kho mch bin iu rng xung bn trong. Chn 4 mc R, C nh tn s dao ng, xung bin iu rng c thc hin bi mch FF RS cp cho mch khuch i Push-Pull thng qua cng OR.

Khi m my, chn 7 c cp ngun t in th 300V khi ng mch, sau

in th cm ng ly t cun 1-3 s uc chnh lu cp ngun n nh cho IC3842. Cun 1-3 cn c dng ly mu ng ra a v mch so snh (chn 1-2). Zener 18V v SCR gi vai tr bo v khi in p vt qu cao.

6.3.2.2. Sinh vin kho st mch v thc hin cc cng vic sau: 1. h cng sut ngun, kho st IC3842 a/ o in p DC chn 7 khi mch hot ng n nh. Lc ny zener 18V v SCR

dn hay ngng?

T

29V 5V SET

Vref RESET 8

INTERNAL BIAS

LOGIC

2

1

3

4

GND

Vref

VFB

Comp

CS

Sense

UVLO

7

PWRVC

6

out

5

PWR GND

OSCILLATOR

22V

+

-

T>

R

S

1/3

C.S Comp

Vref ERROR Amp

1V

Hnh 6.8


Bi 6: n p mt chiu

b/ o in p DC ti chn 2. in p ny dng lm g? C thay i theo in p ng ra B1 v B2 khng? Ti sao?

c/ Quan st v v li dng sng chn s 4 d/ Quan st v v li dng sng ti ng ra (chn 6). Chnh bin tr 5K, dng sng

ng ra thay i nh th no? 2. Ni cng sut ngun vo mch

27.4a/ o B1 khi RL = K

b/ Thay i RL bng cch khng ni ri ni ln lt JP1, JP2, JP3, o B1, lp bng:

RL(K)

B1

IL = LR

B1

37.4

47.4

57.4

27.4

V th B1 theo I . Nhn xt? Lc/ o B1, chnh VR=5K. Nhn xt v cho bit chc nng ca V . R

6.4. THIT B TH NGHIM:

1) 01 mch n p tuyn tnh (board nh). 2) 01 mch n p ngt m (boad ln). 3) 01 VOM. 4) 01 ocilloscope

6.5. TI LIU THAM KHO: [1]. Gio trnh TH NGHIM IN T CNG SUT B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT - 2001. [2]. Cc bi ging v gio trnh IN T CNG SUT B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT. [3]. NGUYN VN NH - GIO TRNH IN T CNG SUT I NXB i hc Quc gia TP HCM 2002. [4]. TRNG VN TM - MCH IN T Gio trnh B Mn Vin Thng & K thut iu khin - Khoa cng Ngh Thng Tin & Truyn thng HCT 2001. [5]. CYRIL W. LANDER POWERS ELETRONICS McGraw-Hill, London 1987. [6]. Zainal Salam POWER ELECTRONICS AND DRIVES Version 3 UTM.JB 2003

http://www.vocw.edu.vn/content/m10373/latest/[7].


http://www.vocw.edu.vn/content/m10373/latest/

Bi 7: iu khin cng sut AC

BI 7: IU KHIN CNG SUT AC

7.1. MC CH: - Bit cch dng Triac iu khin cng sut tiu th trn ti AC.

- Nm c nguyn tc to xung kch Triac v mi quan h gia gc m vi cng sut tiu th trn ti.

7.2. S LC L THUYT: - Triac l mt linh kin iu khin khng th kch ngt. Cng dng quan trng ca n l iu

khin cng sut AC trn ti. Trong trng hp ny Triac ng vai tr nh mt kha in t. S mch iu khin cng sut AC nh hnh 7.1 :

Mch to xung kch

VSVG

IG

A2 A1 VD

Ti VL

G

Hnh 7.1

VS

IG

VL

t

t

t

Hnh 7.2 V Triac dn c 2 chiu nn ch c 2 trng thi dn v kha. Triac c kch ng

(dn) bng dng in IG v a Triac t trng thi dn sang trng thi kha phi c 2 iu kin l : I =0 v in p ngun i chiu. G

Triac c th c kch ng trong 4 trng hp sau : a/. VD>0, VG>0, I >0 Gb/. V >0, V


- S mch iu khin cng sut AC dng Triac c trnh by trong hnh 7.3 cui bi th nghim ny.

Lu rng, xc nh gc tr v xung kch xut hin ng thi im, mch to xung kch cn phi c thng tin v pha ca in p ngun.

=V- Trng hp in p ngun c dng sin : VS Msint= V2 Ssin.

Vi VM : gi tr cc i,V : gi tr hiu dng,=t=2ft Sin p hiu dng trn ti l :

2

22 2VL=[ VS sin2d ]1/2

22sin

1Hay: VL=VS[ (-+ )]1/2

Ta thy, khi bin thin t 0-> th VL bin thin t VS->0. iu ny chng t cng sut tiu th trn ti ph thuc vo . 7.3. CU HI V THC HNH

A. Cu hi l thuyt : 1/. T s mch to xung kch v mch cng sut hnh 7.3 hy cho bit chc nng

ca cc linh kin sau y: U2, U3, U4, U5, D3, D4, D5, Q1, Q2, Q3, C3, C6 v R8 (VR 5K). 2/. Thng tin v pha ca in p ngun c ly v x l nh th no?



B. Cu hi thc hnh :

1. Mc ti R (bng n) vo mch iu khin cng sut AC, ly im t (mass) chung, dng oscilloscope xem v v li dng sng ti cc im : TP0, TP1, TP2, TP3, TP4, TP5, TP6, TP7 (tt c cng mt thang thi gian). Trong , TP5 c v trn cng mt th vi TP2 v TP5 cng c v trn cng mt th vi TP3 (cc thang gi tr ca cc th c v nh hnh 7.4 ), so snh v nhn xt.

- So snh dng sng TP0 vi TP2 v Tp4, t suy ra Q2 v U3 to xung kch ng trong bn k no?

- So snh dng sng TP0 vi TP3 v TP6, t suy ra Q3 v U4 to xung kch ng trong bn k no?



TP1

t

TP3TP5

t

TP9

t

TP7

t

TP6

t

TP2TP5

t

Hnh 7.4

2. Vi ti R, dng Oscilloscope quan st in p trn ti, c lng gc m, o in p hiu dng (hoc dng in hiu dng) trn ti, lp bng 1, nhn xt v so snh vi l thuyt. L

L

RV

P2

=

VL

00 300 600 900 1200 1500 1800

Hnh 7.5



3. Mc ti R_L vo mch iu khin cng sut AC, dng oscilloscope xem v v li dng sng in p trn ti, so snh vi trng hp ti tr, gii thch.

l in p gia 2 u R) . Nhn xt. 4. Vi ti R_L, lp li cu 2 (ch : VL 7.4. THIT B TH NGHIM:

1) 01 board th nghim (board ln). 2) 01 ti R-L. 3) 01 ti motor. 4) 01 oscilloscope. 5) 01 VOM.


http://www.vocw.edu.vn/content/m10373/latest/[7].



Bi 8: Bin tn gin tip

BI 8: BIN TN GIN TIP Tham gia thc hin: KS Trn L Trung Chnh

8.1. MC CH

Gip sinh vin nm c nguyn tc hot ng v mt s ng dng ca b bin tn dng nghch lu p. 8.2. S LC V L THUYT BIN TN

Bin tn dng chuyn i in p hoc dng in xoay chiu u vo t mt tn s ny thnh in p hoc dng in c mt tn s khc u ra. Bin tn c dng iu khin vn tc ng c xoay chiu theo phng php iu khin tn s, theo tn s ca li ngun s i thnh tn s bin thin. Ngoi vic thay i tn s cn c s thay i tng s pha. T ngun li 1 pha, thng qua bin tn ta c th mc ti l mt ng c ba pha. B bin tn cn c s dng rng ri trong k thut nhit in, chng hn nh cung cp nng lng cho l cm ng.

8.2.1. Phn loi - Phn loi da vo tng s pha ta c: bin tn 1 pha, 3 pha, m pha - Phn loi da vo cu trc mch in v nguyn tc hot ng ta c: bin tn gin

tip dng nghch lu p, bin tn gin tip dng nghch lu dng v bin tn trc tip. Trong bi ny ta s kho st bin tn gin tip dng nghch lu p. Bin tn trc tip

s c thc hin trong bi 9. 8.2.2. Cu to:

(Xem s nguyn l hnh 8.1)

Bin tn gin tip gm c: - B chnh lu : C chc nng chnh in p xoay chiu vi tn s c nh ng

vo. B chnh lu c nhiu dng: mch tia, mch cu, 1 pha hoc 3 pha - Mch trung gian mt chiu : gm cun cm Lf v t Cf dng lm phng in p

c chnh lu, to ra mt ngun p cung cp cho b nghch lu. - B nghch lu: c th l 1 pha hoc 3 pha. Qu trnh chuyn mch ca b nghch

lu p thng l qu trnh chuyn i cng bc. B nghch lu c chc nng bin ngun in mt chiu c chnh lu thnh ngun in xoay chiu m tn s c th iu chnh c

- Mch to xung kch iu khin nghch lu p: Cc b nghch lu p thng c iu khin theo k thut iu ch xung (PWM:

Pulse With Modulation) v qui tc kch ng i nghch



~ -

- ~

Id1f1

Lf

Cf

Id2

Ud2f1

Hnh 8.1 Mch to xung kch

Mch chnh lu

Mch nghch lu

a. B chnh lu v mch trung gian mt chiu: Chnh lu bn k khng iu khin (hnh 8.2)

Lf

330F/400V

.01F/400V

AC110/50Hz

Lf

330F/400V

Pha

Pha

Pha

Dy trung ha

(a) (b)

Hnh 8.2: (a) 1 pha (b) 3 pha

Trong bi th nghim ny ta s dng ngun in 1 pha.

b. B nghch lu p B nghch lu p 1 pha:

B nghch lu p dng BJT mc theo dng mch cu (Hnh 8.3.a) c 4 cng tc (BJT) v 4 diode mc i song.

Xung kch c a vo iu khin b nghch lu c cch ly bng bin th.



1N5408 1N5408

Ti

-

1N5408 1N5408

+280VDC

(a)

C2939

10

C2939

10

C2939

10

C2939

10

Uti

S1, S2

S3, S4

+

-

(b)

Hnh 8.3 (a) B nghch lu p 1 pha. (b) Gin kch ng cc cng tc v th p ti.



S1 S3 S5

S2 S6 S4

+ -

-

+

U

U/2

U/2

S1

S4

S3

S6

S5

S2

U11 U12 U13

J1 J2 J3

Hnh 8.4 : B nghch lu p 3 pha

8.2.3. Phng php iu khin b nghch lu p : Cc b nghch lu p thng c iu khin da theo k thut iu ch rng xung

(PWM) v qui tc kch ng i nghch. Qui tc kch ng i nghch m bo dng p ti c iu khin tun theo gin kch cng tc v k thut iu ch rng xung c tc dng hn ch ti a cc nh hng bt li ca sng hi bc cao xut hin pha ti.

Da vo phng php thit lp gin kch ng cc cng tc trong b nghch lu p, ta c th phn bit cc dng iu ch rng xung khc nhau nh sau.

a. Phng php iu ch rng sin (sin PWM) Gin kch ng cng tc b nghch lu da trn c s so snh 2 tn hiu c bn :

sng iu ch tn s cao v sng iu khin dng sin. Sng iu ch c th dng tam gic. Sng iu khin mang thng tin v ln tr

hiu dng v tn s sng hi c bn ca in p ng ra. Trong trng hp b nghch lu p 3 pha, 3 sng iu khin ca 3 pha phi to lch nhau 1/3 chu k ca n.

b. Phng php iu ch rng xung vung (Square PWM) Sng iu khin c dng ch nht, c chu k khng i trong mi na chu k.



c. Phng php iu ch rng xung ti u (Optimum PWM) nh hng ca mt s sng hi bt thp cha trong inn p ra c th c kh b

bng phng php iu ch rng xung ti u. Gin kch ng cc cng tc c thit lp trn c s phn tch hm ti u theo cc bin l gc kch ng cc linh kin. d. Phng php iu ch theo dng in

Gin kch ng cc cng tc c xc nh trn c s so snh dng in yu cu ca ti v dng in o c. e. Phng php iu rng

Cn gi l phng php iu ch rng xung n, l trng hp t bit ca phng php iu ch rng xung. Trong mi na chu k, p ra ch c mt xung in p. ln in p cho ti c iu khin bng cch thay i rng xung in p. Phng php ny ch p dng iu khin b nghch lu p 1 pha. f. Phng php iu khin theo bin

Gi tc l phng php iu bin. Phng php ny i hi in p ngun iu khin c. Cc cng tc trong cp cng tc cng pha c kch ng vi thi gian bng nhau v bng mt na chu k p ra.

B nghch lu p ba pha iu khin theo bin cn gi l b nghch lu 6 bc (six-step voltage inverter)

Trong bi ny s dng vi iu khin 89C51 to xung iu khin, n c lp trnh cung cp 3 tn hiu iu khin lch pha 1200 3 port P3.0, P3.1 v P3.2 v c th chn mt trong 3 tn s 40Hz, 50Hz, 100Hz cho dng in ra trn ti.

S chi tit ca b bin tn trong bi th ny c c in km theo board mch th nghim.

8.2.4. Gii thiu v bin tn SIEMENS G110

a. Gii thiu chung - Sinamics G110 l bin tn cho php thay i tn s nh mong mun iu khin

ng c AC 3 pha. Hin dng sn phm c nhiu model vi cng sut t 120W n 3KW. Model s dng trong bi th nghim c cng sut 2.2KW.

- Bin tn G110 l mt h vi x l v iu khin dng cng ngh IGBT ( Isolated Gate Bipolar Transistor). Sn phm c tin cy cao v linh hot trong cc ng dng. Vic s dng phng php bin iu rng xung c bit, vi tn s xung c th la chn cho php motor hoat ng tht yn tnh v nh nhng. Bn cnh , vi cc tnh nng bo v ton din gip bo v an ton cho chnh bin tn G110 v motor kt ni khi s dng.

- G110 c th s dng theo hai phng thc iu khin: + iu khin Analog dng mch tng t kt ni vi cc ng vo ca G110. + iu khin USS dng chun RS485.



b. S lc cu to.

BOP

DIN10

U,V,W,PE

L1,L2/N

Hnh 8.5: Hnh dng bin tn G110

- G110 vi gc nhn t nh (Hnh 8.6).

+ L1, L2: ni vi ngun in 220V.

+ PE (Protect Circuit): thng c ni vi

mass ca bin tn G110.

+ Led: dng hin th gip ngi s dng

bit c trng thi ca G110.

+ DC+, DC-: ng ra in th 1 chiu.

+ U, V, W: Kt ni vi ng c 3 pha. + DIN 10: Cc ng vo ca G110.

DIN10

Hnh 8.6



- S khi ca G110 (Hnh 8.7):

Hnh 8.7 c. S dng

G110 c th iu khin ng c bng nhiu cch: + Thng qua cc DIP trn G110 + Keypad + PC (mode USS).

- iu khin hot ng ca G110, ngi iu khin phi nhp vo cc tham s (Parameter). G110 s ly gi tr cc tham s ny, tnh ton v thc hin iu khin tng ng ng ra.



Cc tham s iu khin: - P0003: Cp truy nhp cc thng s.

1: Standard. 2: Extended. 3: Expert 4: Reserved

- P0010: Ci t ch chp hnh cho G110. 0: Ready 1: Quick Commissioning. 2: Inverter. 29: Download 30: Factory setting - P0100: Europe / North America. 0: kw/50hz. 1: Hp/60hz. 2: kw/60hz.

- P0700: Chn b iu khin: 1: BOP (Basic Operation Panel) 2: Terminal / Digital input 3: USS Interface

Tn Chc nng P0304 in th nh mc ca ng c P0305 Dng in nh mc ca ng c P0307 Cng sut nh mc ca ng c P0308 H s cng sut P0310 Tn s hot ng P0311 S vng quay trong 1 pht P0335 Chn ch lm mt cho motor P0640 Tham s v dng qu ti cho php P1000 La chn tn s t trc P1080 Tn s nh nht P1082 Tn s ln nht P1120 Thi gian tng n tn s ln nht P1121 Thi gian gim t tn s ln nht v

0 P1300 Chn ch iu khin P3900 Chn kt thc Quick

Commissioning

S dng BOP truy nhp vo cc tham s tng i n gin: 1. Nhn vo chn cc tham s. 2. Nhn n khi tham s cn hiu chnh hin th trn mn hnh. 3. Nhn hin th gi tr hin ti ca tham s. 4. Nhn hoc chn gi tr cn thit lp. 5. Nhn chp nhn gi tr va thay i. 6. Lp li t bc 2 cho cc thng s k tip.



8.3. CU HI V THC HNH A. Cu hi l thuyt

1. Cng sut ca mt dng in hnh sin ph thuc vo tn s ca n nh th no? 2. Tc quay ca mt motor AC thay i theo tn s ca ngun cp in nh th no? 3. T s mch hy cho bit cc xung iu khin S1, S2, S3, S4, S5, S6 lch pha

nhau nh th no ? 4. B bin tn gin tip dng nghch lu p khc vi bin tn gin tip dng nghch

lu dng im no? B. Phn thc hnh trn b bin tn dng BJT cng sut v mch to xung kch dng vi iu khin 89C51.

1. Mc ti R(bng n) vo mch bin tn theo kiu Y (u hnh sao): a. Chn tn s 40Hz, dng oscilloscope xem v v li dng sng xung iu khin

S1 ( ti JH1), S3 (ti JH9) v S5 (ti JH4) t cho bit phng php iu khin l phng php g?

b. Thay i tn s (theo trnh t nh sau: ngt in ngun, n nt x in X, m ngun in li, n nt chn tn) o in p hiu dng trn ti (trn mt pha xc nh). Lp bng :

Tn s (Hz) 40Hz 50Hz 100Hz

Vti(V) 2Pti= V /R ti

Cho nhn xt v s ph thuc ca cng sut vo tn s. c. Dng oscilloscope xem v v li dng sng in p ra trn ti trn mt pha

xc nh (ch : dng dy ly tn hiu cho oscilloscope c mch gim p) , nhn xt. 2. Mc ti R_L vo mch bin tn theo kiu Y, chn tn s 40Hz, dng

Oscilloscope xem v v li dng sng in p trn ti (trn mt pha xc nh) 3. Thay ti R_L bng motor 3 pha, thay i tn s v quan st tc quay ca

motor. Suy ra s ph thuc ca tc quay vo tn s ca ngun in cp cho motor. Lc khi ng motor, ngun cp in cho motor c tn s thp hay cao? Ti sao?



C. Phn thc hnh trn b bin tn Siemens G110. 1. iu khin G110 t cc DIN iu khin tc v chiu quay ng c t mch in kt ni t bn ngoi:

- Ci t cc tham s:

+ P0700=2 + P1000=2

- Tc ng ln cc SW ta s iu khin on/off v chiu quay ca ng c. Thay i tn s bng cch iu chnh bin tr.

* Sau khi motor hot ng, nhn gi phm trong khong 2s xem cc thng s ca ti ang hot ng: in th, tn s, dng din.

Yu cu: Lp bng thng k sau:

Tn s 0 20 30 40 50 in p

Cho nhn xt v mi quan h gia in p ng ra, tc ng c vi tn s c iu chnh.

2. iu khin G110 t BOP Thc hin ci t cc thng s cho bin tn nh sau:

P0003=1 // Cp truy cp cc tham s P0010=1 P0100=0 P0304=220V P0305=2.00A P0307=0.75kw P0310=50Hz P0311=1390 P0700=1 P1000=1 chn tn s setpoint t MOP P1080=0 Hz



P1082=50 Hz P1120=10 P1121=10 P3900=1 : Khi ng motor ( ON) Motor chy vi tn s 5Hz. : Dng Motor (OFF). : o chiu quay Motor. : Nhn gi Motor s tng dn n tn s t.( P1058 ) tn s hot ng

motor tng dn n 5Hz. cc thng s v motor trn nhng ta thay i thm mt s tham s: - Vn gi

P0003=3 P0010=0 P1040=30 thay i tn s MOP. P1058 = 20 thay i tn s JOG.

Thc hin ci t li 3 tham s: P0700=1 P0719=0 P1000=1 : Khi ng motor ( ON) Motor chy vi tn s 30Hz. : Dng Motor (OFF). : o chiu quay Motor. : Nhn gi Motor s tng dn n tn s t.( P1058 ) tn s hot ng

motor tng dn n 20Hz.

- Nhn gi trong khong 2-3s, sau nhn tip tng ln xem cc thng s hot ng ca motor. Mun tr v mode cc tham s th n gi trong khong 2-3s.

Yu cu: - Cho nhn xt v hot ng ca ng c, khi ta thay i tn s MOP v JOP. - Cho bit ngha ca 2 tham s MOP v JOP.

8.4. THIT B TH NGHIM

1. B bin tn dng BJT v mch kch dng vi iu khin 89C51. 2. B bin tn Siemens G110. 3. 01 Osciloocope 4. 3 ti R_L 5. 01 VOM ( hoc Ampere kim) 6. 01 motor 3 pha




http://www.vocw.edu.vn/content/m10373/latest/[7]. [8]. Ti liu km theo thit b bin tn Siemens G110.



Bi 9: Bin tn trc tip

BI 9: BIN TN TRC TIP Tham gia thc hin: ThS. Trn Thanh Hng - 2001

9.1. MC CH B bin tn trc tip (cycloconverter) to ra in p xoay chiu ng ra vi tr hiu

dng v tn s iu khin c, tr hiu dng v tn s in p ng ra lun nh hn hiu dng v tn s ca in p ngun. B bin tn loi ny c ng dng trong iu khin truyn ng ng c in xoay chiu.

Bi th nghim ny kho st bin tn trc tip vi ngun in xoay chiu mt pha bao gm: - Kho st mch to xung iu khin, thng qua sinh vin nm c phng

php v k thut to xung kch c th thay i gc iu khin. - Kho st mch cng sut, thng qua sinh vin hiu r hn nguyn l hot ng

ca b bin tn trc tip, hot ng ca linh kin cng sut (trong bi ny ta dng SCR); xc nh mi quan h gia tn s v cng sut, dng sng in p ra, trn cc loi ti khc nhau: ti thun tr, ti R-L, ti R-L-C.

9.2. S LC L THUYT T in th cung cp xoay chiu hnh sin vi tn s 50Hz/60Hz, ta c th to c

in th xoay chiu hnh sin vi tn s thay i c bng cch ct tng on in th cung cp ghp li sao cho in th trung bnh c dng hnh sin. Bin tn hot ng da vo nguyn tc ny c gi l bin tn trc tip.

Da vo hnh 9.1 ta c th thy nu in th cung cp cho bin tn trc tip cng c nhiu pha, th in th ct c c gi tr trung bnh cng gn vi sng sin mong mun.

kho st, ta c th chia bin tn thnh 2 b phn: mch cng sut v mch iu khin.

9.2.1. Mch cng sut: Hnh 9.2 trnh by s chi tit mch cng sut ca mt bin tn trc tip hai pha.

Hai pha in th lch pha nhau 1800 c to ra t in th 1 pha bng mt bin th c im gia. Hai SCR Q1 v Q2 hot ng nh 2 cng tc ct in th ca 2 pha to thnh bn k dng ca in th hnh sin mong mun (cung cp cho ti). Ngc li, 2 SCR Q3 v Q4 s to bn k m ca in th mong mun. Gc m ca cc SCR phi thch hp in th to ra c gi tr trung bnh thay i theo qui lut hnh sin (xem hnh 9.1.b).

9.2.2. Mch iu khin (mch to xung kch): cc SCR ct in th cung cp ng v tr, cn phi c mt mch iu khin

to nn cc xung kch cc SCR (cc tn hiu g1, g2, g3, v g4 trn hnh 9.2). iu khin cc SCR Q1 v Q2 ct 2 pha in th to bn k dng ca in p

ng ra, ta c th dng mch nh trn hnh 9.3. u tin mt in p cng pha vi pha 1 c i t

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