Dien Tu Cong Suat - Doan Quang Vinh

8/3/2019 Dien Tu Cong Suat - Doan Quang Vinh

1/196

IN T CNG SUT

Ti liu tham kho in t cng sut L Vn Doanh Gio trnh in t cng sut Nguyn Vn Nh

in t cng sut Nguyn Bnh

[email protected]

0903 586 586


2/196

CH

NG 1MU CC LINH KIN IN T CNG SUT

1.1 Khi nim chung

in t Cng sut ln

Cc linh kin in t cng sut c s dngtrong cc mch ng lc cng sut ln


3/196

S khc nhau gia cc linh kin in t ng dng

(in tiu khin) v in t cng sut

Cng sut: nh ln Chc nng: iu khin ng ct dng in cng sut ln

IB

IC

Thi im Cng sut

ng lciu khinCc linh kin in tcng sut ch lmchc nng ng ctdng in cc van


4/196

Transistoriu khin: Khuych i

Transistor cng sut: ng ct dng in

B

IC

U

R

ab

A

A

UCE = U - RIC

UCE = UCE1

UCE1U

IB2 > IB1

IB1 > 0

IB = 0

UBE < 0 UCE

IB2IB

R

U

uCE

CiB

B

uBE

EiE

iC


5/196

c tnh Volt Ampe ca van cng sut l tng

i

u

iu khin

u

i

ac

b

d


6/196

i tng nghin cu ca in t cng sut

Cc b bin i cng sut Cc b kha in t cng sut ln

Chnh lu

Nghch lu

BBin pmt chiu(BXA)

BBin pxoay chiu (BAX) Bin tn


7/196

1. 2. Cc linh kin in t cng sut1.2.1 Cht bn dn - Lp tip gip P - NCht bn dn:

nhit bnh thng c dn in nm gia cht dn in v cht cch in

Loi P: phn t mang in l l trng mang in tch dng

Loi N: phn t mang in l cc electron mang in tch m

+

++

+

+

+++

-- -+

-- -

-- -

Min bo ha- Cch in

P N

+

++

+

+

+++

+

+

+

--- -+

--- -

--- -

P N

J


8/196

Phn cc ngc

+

++

+

+

+++

-- -+

-- -

-- -

Min bo ha- Cch in

P N

+-

+

+

+

-

--

Min bo ha - Cch in

P N

+-


9/196

Phn cc thun

+

++

+

+

+++

-- -+

-- -

-- -

Min bo ha- Cch in

P N

-+

-+

i


10/196

1.2.2 Diode

Cu to, hot ng

R: reverse ngcF: forward thun

NPKatode

KA

Anode

iR

uR

iF

uF

KA

Hng ngc

Hng thun


11/196

c tnh V A

Diode l tng

u

iNhnh thun m

Nhnh ngc ng

Diode thc t

UTO: in p ri trn diode

in tr thun trong diodeF

FF

dI

dUr =

in tr ngc trong diode

R

R

R

dUr

dI=

UBR: in p nh thng

Hai trng thi: m ng

U[BR]

IR [mA]

UF [V]UR [V]

1 1,5800 400 0

50

100

30

20

URRM

Tj

= 30 Co

oTj

= 160 C

IF [A]

URSM

Nhnh thun m

Nhnh ngc ng


12/196

c tnh ng ca diode

UK: in p chuyn mch trr: Thi gian phc hi kh nng ng irr: Dng in chuyn mch phc hi

=rrt

rrr dtiQ0

: in tch chuyn mch

Qu p trong

L

+

UK

-

S

I

iF

irr

iR

iF

ngS

trr 0,1 irrM

irrM

iR

iF=I

tO

irr Qr

t

uR

uF

Uk

uRM

uR = UkO


13/196

Bo v chng qu p trong

R C

LuR

V

Uk

irr

iL

iRC

- +

V

O t

irr iRC

O

Uk

t

M ng

L

R k

di

u U L dt= RCrrL iii +=


14/196

Cc thng s chnh ca diode

in p:

Gi tr in p nh thng UBR Gi tr cc i in p ngc lp li:URRM Gi tr cc i in p ngc khng lpli: URSM

Dng in - nhit lm vic

Gi tr trung bnh cc i dng inthun: IF(AV)M

Gi tr cc i dng in thun khnglp li: IFSM

U[BR]

I

R

[mA]

UF [V]UR [V]

1 1,5800 400 0

50

100

30

20

URRM

Tj

= 30 Co

oTj

= 160 C

IF [A]

URSM

Nhnh thun m

Nhnh ngc ng


15/196

Diode thc t: IDB30E60 Infineon Technologies


16/196

1.2.3 Transistor lng cc (BT)

Cu to, hot ng

R

U

uCE

CiB

B

uBE

EiE

iC

R

U

uEC

CiB

B

uEB

EiE

iC

N

N

PB

C

E

P

P

NB

C

E

(Bipolar Transistor)


17/196

c tnh Volt Ampe

Min m bo ha

Min ng bo ha

M

ng

c tnh ngoi IC = f(UCE)

c tnh iu khin IC = f(IB)

B

IC

UR

ab

AA

UCE = U - RIC

UCE = UCE1

UCE1U

IB2 > IB1

IB1 > 0

IB = 0

UBE < 0 UCEIB2

IB


18/196

ICE

ICE0ICERICES

ICEU

UCE0 UCE

UBR(CEU)

UBR(CES)

UBR(CER)

UBR(CE0)IB = 0

UCER

UCES

UCEU

RB

-IB UBE

+

-

RB

-IB UBE

+

-+

- ICEU

b) c)

a)

O

0 H mch B E (IB = 0) R Mch B E theo hnh b) S Ngn mch B E (RB 0) U Mch B E theo hnh c)


19/196

Qu trnh qu ca transistor

iB

IB

0.9IB

O t

0.1IB

0.1IC

uCE

td tr

iCts

tofftonO

tf

0.9IC IC0.1IC


20/196

Mch tr gip ng m

(in t cng sut Nguyn Bnh)

Cc thng s chnh

in p:

Gi tr cc i in pcolector emitor UCE0M khi

IB = 0

Gi tr cc i in pemitor baz UEB0M khi IC

= 0

Dng in: Gi tr cc ica cc dng in IC, IB, IE


21/196

Transistor thc t - MJW3281A (NPN) ON Semiconductor


22/196

1.2.4 Transistor trng MOSFET

(Metal Oxid Semiconductor Field Effect Transistor)

N iD

D

OXID

GS

uGS

P

N

G

D iD

uDS

SuGS

N

D

OXIDGS

P

N

G

D

S


23/196

c tnh ng

RGon

UG

offCGS uGS

G

CGD D

iD

CDS

R

uDS U

+

-+

-

S

GS

UGS(th)0.1UG

UG

0.9UG

t

0.9U

U

tr

td(on)

ton

td(off)

uDSiD

tf

toff

0.9U

0.1U


24/196

MOSFET thc t - 19MT050XF International Rectifier


25/196

1.2.5 Transistor lng cc cng cch ly - IGBT

Insulated Gate Bipolar Transistor

C

G

E

G

C

E


26/196

c tnh ng

Gon

UG

RG

iC

C

E

uCEuGE

off

R

U

uGE

0.1UCM

UGE(th)

UG0.9UG

tuCE

0.1ICM

U

td(on)

tr

ton

td(off)

tf

toff

ICT

iC

ICM

0.1ICM

0.9ICM


27/196

IGBT thc t1MB-30-060 Fuji Electric


28/196

1.2.6 Thyristor

Cu to Hot ng

A

iG

i2

i1i

G

K

uAK

u

R

A

K

G PP

P

N

NN

J3J2

J1

A

K

G

N

P

N

P


29/196

iu kin m Thyristor

UAK > 0

Xung iu khin a vo cc iu khin.

iu kin ng Thyristor

t in p ngc ln A K

uD

iD

iG

iR

uR

uT

iT

uG

A K

Hng ngc

Hng thun

Trng thi: M ng Kha

T: Thun D: Kha

R: Ngc

K hiu


30/196

c tnh Volt - Ampe

Thyristor l tng

u

i Nhnh thun m

Nhnh ngc

ngThyristor thc t

Ba trng thi: ng m kha

Nhnh kha

kha

UBR: in p ngc nh thngUBO: in p t m ca thyristorUTO: in p ri trn Thyristor

IH: Dng duy tr (holding)

IL: Latching

Cc thng s chnh

Tng t nh diode.URRM = UDRM

Nhnh thun m

Nhnh kha

kha

Nhnh ngc ng

IG = 25 mA

IG = 0

IG = 0

IG = 25 mA

IN

IL

U[TD]

U[BR]

U[BR]

[V]UR

[V]UDUT

IR-110

-210

-310

[A]

[A]

ID

IT10

102

10-3

10-2

10-1

1

110101023

32

1010101


31/196

c tnh iu khin ca thyristor:

iG

U

R

uG

UG[V]

40

30

20

UGT

OIGT

1 IG[A] 2

(PGM)=/6

UG=U-RIG

(PGM)=/12

-400C

iG

2

IG

t

iG

t0


32/196

c tnh ng

M thyristor

Tn thtcng sut khi mthyristor


33/196

Kha thyristor

G

A

J1

J2

J3

P

N

P

N

iC

+

K

-

iC

C

uD

uD

tO

tO

iC


34/196

ng thyristor

Bo v qu p trong Thi gian ng thyristor Gc an ton

toff


35/196

Thyristor thc t - 22RIA SERIES International Rectifier


36/196

1.2.7 GTOGate Turn Off Thyristor

J1

J2J3

G

iRG K

A

P

N

PN

uRG

uFGiRG

iFG

ir(iD)

ur(uD)

A

K

G


37/196

c tnh ng

M GTO

uD

tgd

tgr

UD 0.9UD

ir

0.1UD

t

O

O

tgt

iFG

IFG10

0.2IFG


38/196

ng GTO

I

iD

iT

L

uD

iRG

uRG

iT

tgstgf uD

ITQ

0.9IT

UDP

IT=I

O t

tgq ttq

O

uRG iRG

iRG

QGQ

uRG

IRG

Mch tr gip


39/196

GTO thc t - FG3000FX-90DA Misubishi Electric


40/196


41/196

1.2.8 Triac

Hng ngc

Hng thun

in p thunin p kha

Dng in thunDng in kha

Dng in thun

Dng in kha

in p thun in p kha

Dng in v in pcc iu khin


42/196

Nhnh m

Nhnh kha

Nhnh kha

Nhnh m

UD > 0

UG > 0; IG > 0

UG < 0; IG < 0

UDR > 0

UG > 0; IG > 0

UG < 0; IG < 0

c tnh Volt - Ampe


43/196

Triac thc t - 2N6344 - ON Semiconductor


44/196

CHNG 2: MT S KHI NIM C BNTRONG IN T CNG SUT


45/196

2.1 Nng lng tch ly vo cun khng

v gii phng t cun khng

[ ]

1

0

1 1

0 0

0 1

( ) ( )

0 1 1 0 1 0

( ) ( )

( , );

( , ) ( ) ( ) ( ) ( )L L

L L

t

L L

L L L

t

t i t

L L L L L L L

t i t

d diu dt Q t t u Ldt dt

Q t t d L di t t L i t i t

= = =

= = = =

t0

t0


46/196

2.2 Nhp v s chuyn mch

Nhp l khong thi gian gia hai ln lin tip thay i trng thi calinh kin in t cng sut trong mch. Tn ca nhp l tn ca linhkin ang dn in.

Chuyn mch l trng thi in t xy ratrong mch b bin i, c c trngbng vic dng in trong mt nhnhchuyn sang mt nhnh khc trong khi

dng in tng chy ra t nt gia hainhnh vn khng i.

Nhnh chnh Nhnh phLinh kin TCS chnh Linh kin TCS ph


47/196

Nhnh chnhNhnh chnh

Nhnh chnh

Nhnh ph in p chuyn mch Chuyn mch ngoi Chuyn mch t nhin Chuyn mch trong Chuyn mch trc tip Chuyn mch gin tip

Chuyn mch nhiu tng Thi gian chuyn mch Gc chuyn mch Chuyn mch tc thi


48/196

2.3 Cc ng c tnh

c tnh ngoi (c tnh ti): Mi quan h gia in p u ra vdng in u ra ca b bin i

c tnh iu khin: Mi quan h gia in p u ra v i lng

iu khin ca b bin i

2.4 H s cng sut ca b bin i

SP=

P: Cng sut hu cngS: Cng sut biu kin

H s cng sut PF (Power Factor)


49/196

P = mUI(1)

cos(1)

m: s phaU: Gi tr hiu dng in p iu ha ca phaI(1): Gi tr hiu dng ca thnh phn bc 1 dng in pha

(1): Gc chm pha ca thnh phn bc 1 dng in pha so vi in p

S = mUI

I: Gi tr hiu dng dng in pha

=

=1

2

)(

2

n

nII

2 2 2 2 2 2 2 2 2 2

( ) (1) ( )

1 2

n n

n n

S m U I m U I m U I

= =

= = +

2 2 2 2 2 2 2 2 2 2 2 2 2 2

(1) (1) (1) (1) (1) (1) (1)cos sinS m U I m U I m U I P Q = = + = +

mUI(1): Cng sut biu kin ca thnh phn bc 1Q(1): Cng sut phn khng ca thnh phn bc 1


50/196

2 2 2 2

(1)

2

( )

2

n

n

S P Q D

D mU I

=

= + +

=

D: Cng sut phn khng bin dng

(1)2 2 2

(1)

(1)

cosP

P Q DI

I

= =

+ +

=

mo dng tng THD (Total Harmonic Distortion)

H s mo dng DF (Distortion Factor)

H s cng sut PF (Power Factor)

2( )

2

(1)

n

n

I

I

THDI

==


51/196

CHNG 3: THIT B CHNH LU


52/196

Chc nng:

Bin i dng in xoay chiu thnh dng in mt chiu

ng dng

Cp ngun cho cc ti mt chiu:ng cin mt chiu, b npaccu, min phn, my hn mt chiu, nam chm in, truyn tiin mt chiu cao p,

3.1 KHI NIM CHUNG

3 2 c im ca in p v dng in chnh lu


53/196

3.2 c im ca in p v dng in chnh lu

3.2.1 in p chnh luud: Gi tr tc thi ca in p chnh lu Bao gm c thnhphn xoay chiu u v thnh phn mt chiu Gi tr trung bnhca in p chnh lu Ud

dd Uuu +=

S xung p mch ca sngin p chnh lu:

(1)fp

f

=

f(1): Tn s ca sng iu

ha bc 1 thnh phn xoaychiu ca ud f: Tn sin p li

3 1 2 Dng in chnh lu


54/196

3.1.2 Dng in chnh lu

id: Gi tr tc thi ca dng in chnh lu Sng dng in chnh lu

Id: Gi tr trung bnh Thnh phn mt chiu ca sng dng in chnh lui: Thnh phn xoay chiu ca dng in chnh lu

d di i I= +

Xt h thng chnh lu ti R,L,E:

( )d L d d di

u L u Ri E dt

= = +

0; 0dd d Ldiu Ri E udt

> + > >

0; 0dd d Ldi

u Ri E u

dt

= + = =

0; 0dd d Ldi

u Ri E udt

< + < Tng t khi gi thit V3 m. V1 m Nhp V1

Khng hp l


59/196

Nhp V1 1 < < 2:

1 2 2 1 3 3 1

1 1 2 3

0; ;

; ; 0

V V V

d d V d V V

u u u u u u u

u u i i I i i

= = =

= = = = =Nhp V2 2< < 3:

2 1 1 2 3 3 2

2 2 1 3

0; ;

; ; 0

V V V

d d V d V V

u u u u u u u

u u i i I i i

= = =

= = = = =Nhp V3 3 < < 4:

3 1 1 3 2 2 3

3 3 1 2

0; ;

; ; 0

V V V

d d V d V V

u u u u u u u

u u i i I i i

= = =

= = = = =


60/196

Nhp Vn:

1 1

1

0; ;

; ; 0

Vn V n Vm m n

d n d Vn d V Vm

u u u u u u u

u u i i I i i

= = =

= = = = =

Qu trnh chuyn mch ti cc thi

im 2:in p chuyn mch l uk = u2 u1

Tng t ti cc thi im 3, 4:in p chuyn mch ln lt l

u3 u2 v u1 u3

Chuyn mch t nhin

p= mS xung:

3.3.2 Chnh lu hnh tia c iu khin


61/196

Tn hiu

iu khinuc

Khu pht xung


62/196

Thi im chuyn mch t nhin

Gc iu khin : tnh t thi im chuynmch t nhin n thi im pht xungm thyristor.

Phm vi ca gc iu khin :


63/196

Gi tr trung bnh in p chnh lu


64/196

coscossin 0dim

di Um

mUU ==

0 sinm

di

mUU

m

=

Udi0: Gi tr trung bnh in p chnh lu khng iu khin.

20 2

3 3 3 3 6sin 1.17

3 2 2

m mdi

U U UU U

= = = =

m = 3

2

2

sin2

m

di m

m

mU U d

+ +

+

=

C t h


65/196

Cc ng c tnh

c tnh iu khin: c tnh ngoi (c tnh ti):

u ra: Ud u vo:

0

cosdi di

U U =

Chchnh lu

Chnghch lu


66/196

6 2

< < c dng lin tc: trong ti phi c L

3.3.3 Ch lm vic chnh lu v nghch lu ph thuc Ch lm vic chnh lu

Ch lm vic nghch lu

d dU I=

ch nghch lu ph thuc2

>


67/196

Trong ti phi c E Eo chiu2

> dE U >

iu kin c nghch lu ph thuc

Gc an ton


68/196

0 <

Ch

chnh lu

Ch

nghchlu

offt =

3.3.4 Chnh lu hnh tia 3 pha c diode V0


69/196

dV uu =0

V0 s m khi trong trng hpkhng c V0 th ud < 0

V0 chhot ng khi

2 m


70/196

Chen vo gia cc nhp V1, V2, V3 l cc nhp V0:

0 1 1 2 2 3 3

0

0; ; ;d V V V V

d V d

u u u u u u u ui i I

= = = = == =


71/196

coscossin 0di

mdi U

m

mUU ==

0 sinm

dimUU

m

=

2 m

2 2m m

+

0

2

1 sin( )

sin2

2sin

mdi di

m

mU mU d U

m

+

= =

0 sinm

di

mUU

m

=

nh hng ca diode V0


72/196

Khng c ch nghch lu Diode V0 lm tng hiu sut ca b chnh lu

d dU I

mUI=

U, I: gi tr hiu dng ca in p v dng in pha

1

2

VdI I

= 1 02V Vm =

Diode V0 lm gim gi tr hiu dng thnh phn xoay chiu ca in

p chnh lu


73/196

3.4 Chnh lu hnh cu trong ch dng lin tc


74/196

Thit b chnh lu su ni hnh cu v thc cht l hai b chnh luhnh tia mc ni tip

N

hmKATODE

NhmANODE

NhmANODE

NhmKATODE

3.4.1 Chnh lu hnh cu 3 pha iu khin hon ton

S


75/196

S

Dng in trong cc pha:


76/196

i1 = iV1 iV4; i2 = iV3 iV6; i3 = iV5 iV2

Gi tr trung bnh in p chnh lu:

p = 2m

di diA diK U U U=

2

sin cos

diA diK U U

m U

m

=

=

Trong trng hp m = 3

0

0

cos

2 2

sin

di di

di

U U

mU

U m

=

=

0

3 62.34di

UU U

= =


77/196

Gin ng ct Xung iu khin:

3.4.2 Chnh lu hnh cu bn iu khin


78/196

0 0

3 6cos2

3 6 1 cos 3 6;

2 2

diA

diK di di di

UU

U UU U U U

=

+= = =

3.4.3 Chnh lu hnh cu iu khin hon ton c diode V0


79/196

Diode V0 s hot ng khi

623;)

6sin(1

2

0

+

= didi

UU

Tc dng: - Gim nhp nh ca in p v dng in ti- Tng hiu sut- Khng cho php ch nghch lu ph thuc

0

3 6di

UU

=

3.4.4 Chnh lu cu mt pha iu khin hon ton


80/196

1 2

1

2

sin

sin2

sin( )2

m

m

m

u U u u

Uu

Uu

= =

=

=

1 4 2 3

d dA dK

V V V V

u u u

i i i i i

=

= =


81/196

0

0

cos

2 2 0.9

di di

di

U U

UU U

=

= =

Gi tr trung bnh in p chnh lu


82/196

0

0

1 cos

2

2 2

di di

di

U U

UU

+=

=

3.4.5 Chnhlu cu mtpha bn iukhin

So snh gia hai phng n: iu khin hon ton v bn iu khin


83/196

nh m ca sng in p chnh lu b ct nhp nh Khng th lm vic ch nghch lu Hiu sut b bin i cao hn.

3.5 Dng in lin tc v gin on ca chnh lu p xung


84/196

3.5.1 Thit b chnh lu ch dng in gin onS xut hin ca dng in gin on

Ti R: 0 0d di u

Ti R,L: 0d dU RI= >

vi cc m ch dng lin tc Ud< 0s xut hin dng in gin on

Trong nhp 0:

Trong nhp 0:

Ti L, E: dU E= vi cc m ch dng lin tc Ud< E

s xut hin dng in gin onTrong nhp 0:

0;d Vi i

u u u= =

0;d Vi iu u u= =

;d Vi iu E u u E = =

; IN MAX

3.5.2 Phn tch dng in chnh lu ca chnh lu p xung,khng c V0


85/196

p = 1 Dng in lun gin on

Vi p > 1:

Chnh lu hnh tia c iu khin m pha. p = m. Um l bin in p pha

Chnh lu hnh cu iu khin hon ton

m pha. p = 2m. Um l bin in pdy (tr trng hp m = 1)

Z =

Gc bt u:

p = 1:

2Z

p

= + p > 1:

Ti tng qut R, L, E:


86/196

sin (1)dd mdi Ri L E U d

+ + =

sin( )

1

( ) sin( )

Z

Z

md

md Z Z

Ui

Z

Ee

R

U

i eZ

=

+

+

(2)

2 2 2

arctg

Z R L

L

R

L

R

= +

=

= 0di iu kin:

Dng in gin on:

IN Z MAX


87/196

IN Z MAX <

p dng vo (2)

2 2

2( ) ( ) sin( )

1 ( ) sin( )

md Z d K Z

p pmd Z Z

Ui iZ p

UEe i e

R Z

= = +

+

(5)

Suy ra2

2

2

sin( ) sin( )( ) ( )

1

p

Z Z

d Z d K m

p

e Epi i U

ZZ e

+ = =

(6)

3.5.3 Dng in chnh lu ca chnh lu p xung,

di d V0


90/196

c diode V0

3.6 Hin tng trng dn


91/196

1 2V V d di i i I


92/196

1 2V V d d i i i I + = =

2 1

2 1

V V

K

di di L u u

dt dt

=

2 1 sin

2 sin

k km

km m

u u u U

U Um

= =

= bin in p dy gia hai pha k nhau

2

2

0

sin2

Vi

kmV

K

Udi dL

=

( )2 cos coskmVU

i


93/196

( )

( )

2 cos cos2

cos cos

2

kmVK

km

kmkm

K

i L

I

UI

L

=

=

=

)cos cosd kmI I = +

arccos cos d

km

II

=

gc trng dn

22

Vd k

diu u L d


94/196

2

1 2

2

d ku u L dt

u u

=

+=

( )cos coskm di I I

0du =


95/196

( )cos coskm di I I = km

km

K

UI

L

=

( )1 2

3 4 1

cos cos2

kmV V

V V d V

Ii i

i i I i

= =

= =

)2 cos cosd kmI I = + 2

arccos cos d

km

I

I

=

St p do trng dn Ud

U R I


96/196

d dU R I =

2

kpXR

=

Chnh lu hnh tia ba pha Chnh lu cu 3 pha

kpXR

=

Chnh lu cu mt pha

Ud: St p do Lk

c tnh ngoi khi xt n st p v dng in gin on


97/196

Ud: St p do Lk.Udr= Rk.Id: St p trn RkUdF: St p trn van

nh hng n gc an ton ca thyristor:


98/196

M + + =

( )cos cosdMkm

I

I = +

Chnh lu hnh cu 3 pha, tia ba pha

Chnh lu hnh cu mt pha

( )2

cos cosdM

km

I

I

= +

Xc nh gi trin p chnh lu cc i

1


99/196

( )01

di c dM d M drM dFM U c U U U U b

= + + +

cc: hng s d tr cho iu khin cc = 1.04 1.06

b: hng s d tr ca li in 5% b = 0.95

3.7 Chnh lu c o chiu dng in - bn gc phn t


100/196

Nguyn l iu khin:

iu khin ring:

Tng b chnh lu lm vic c lp,trong khi b chnh lu cn likhng lm vic.

iu khin chung

Xung iu khin cng mt lc c a


101/196

g g vo c hai b, trong c mt bciu khin vi gc < /2, lm vic ch chnh lu. Cn b th hai c

iu khin vi gc

>/2, chch.

khng c dng ngn mch gia hai bchnh lu:

UdI + UdII 0

( )0 0

0

.cos .cos 0

cos cos 0

di I di II

di I II

I II

U U

U

+

+

+


102/196

Tuy nhin:udI + udII 0 dng in tun hon

Hn ch dng tun hon:lp thm cun khng cn bng

3.8 My bin p ng lc

3 8 1 Dng in


103/196

3.8.1 Dng in

iS = IS(AV) + iS

NP: s vng dy cun s cpNS: s vng dy cun th cp

iP

.NP

= iS

.NS

3)(

dAVS

II =

Gi s NP = NS = N

dIi i i= =


104/196

1 1 1

2 2 2

3 3 3

3

3

3

S S P

dS S P

dS S P

i i i

I

i i i

Ii i i

= =

= =

= =

1 3 1

2 1 2

3 2 3

P P

L P P

L P P

i i i

i i ii i i

=

= =

3.8.2 Cng sut biu kin ca my bin p

P SS SS K P+


105/196

2

P StN t tN S K P= =

StN: Cng sut biu kin nh mc my bin p

SP: Cng sut biu kin cun dy s cpSS: Cng sut biu kin cun dy th cpPtN: Cng sut hu cng nh mc ca my bin p

i vi my bin p /Y

2 / 32

0

1

2 3

dS d I I d

= =

( ) ( )2 / 3 2

2 2

0 2 / 3

212 / 3 / 3

2 3

d P d d I I d I d

= + =

3 33 2

S S SN S dN S U I U I S U I U I

= =


106/196

3 2 P PN P dN S U I U I = =

Vi chnh lu tia ba pha: 03 6

2diU U

=

0

0

2 2

3 3

2 2

3 3 3 3

S di dN dN

di dN dN

S U I P

S U I P

= =

= =

2 23 3 3

1.352

tN dN dN S P P

+= =

3.9 Cc nguyn tc iu khin chnh lu

Xung iu khin a vo thyristor lc in p t ln thyristor dng


107/196

Xung iu khin a vo thyristor lc in p t ln thyristor dng Phi bit c khi no in p t ln thyristor dng Phi c in p ng b: ng b vi in p kha t ln thyristor

S khi ca khu pht xung biu khin:

ng bub

So snh

uc

Khuych iv p.p

iG1, iG2, iG3

3.9.1 Nguyn tc thng ng tuyn tnh

in p ng b l in p rng ca


108/196

. cK u=

( )0 0cos cos .di di di cU U U K u= =

ub1

ub2

ub3

uC

uC

uC

3.9.2 Nguyn tc arccos:

i b l t i


109/196

in p ng b l mt ng cosin

max cosbu U =

max

max

cos

arccos

b c

c

u u U

u

U

= =

=

0 0max

cos cdi di diu

U U UU

= =

Umaxub

uAK


110/196

uc


111/196

Chng 4: B bin i

v b khamt chiu

4.1 Khi nim chung Phn loi


112/196

4.2 B kha mt chiu

ng ct dng in mt chiu


113/196

S nguyn l s dng GTO

a) V

U

V0 L

R

iZ

Z

iG

iV0

iV

LR

0

0

iG

iV

iV0

t

RL

ngCt

Khi s dng thyristor:

M - ngNG

NG


114/196

M ng

ng Ct

CTS

BCM

S

S

PS

Z

V0

OS

OS

S

PS

t

4.3 Phn loi thit b bin i mt chiu

4.3.1 Phn loi theo phng php bin iCh h l


115/196

Trc tip b bin i xung Gin tip

4.3.2 Phn loi theo chc nng bin i

Gim p mc ni tip Tng p mc song songiu khin xung gi trin tr

4.3.3 Phn loi theo phng php iu khin

Tn s xung rng xung Hai gi tr

Nghch luChnh luc iu khin

U UZ

4.4 Nguyn l lm vic ca cc b bin i xung

4.4.1 B bin i gim p mc ni tip


116/196

Nguyn l lm vic

Nhp S:uZ = U

iZ = iS: tng theo ng conghm m v gi tr (U - E)/R

Nng lng t ngun U,mt phn tch ly vocun L, phn ln npcho E, phn cn li tiu

tn trn RNhp S ko di trong khon thi gian T1. Kt thc khi tn hiu ct a vo kha S.

uc

S

iS

U

iV0

V0

R

L

uZ

iZZ

uZ

0

0

S V0 S V0 S

U

UZi

tT1 T2T

iS iV0 IZ

iZ

iZMiZMIN

t

Nhp V0:

uZ = 0 u S V0 S V0 S


117/196

Z

iZ = iV0: gim theo ng conghm m v gi tr -E

/R

Nng lng trc y tchly trong cun L c giiphng, phn ln np cho

E, phn cn li tiu tntrn R

Nhp V ko di trong khon thi gian T2. Kt thc khi tn hiu ng a vo

kha S.

uc

S

iS

U

iV0

V0

R

L

uZ

iZ

Z

uZ

0

0

S V0 S V0 S

U

UZi

tT1 T2T

iS iV0 IZ

iZ

iZMiZMIN

t

Gi tr trung bnh in p trn ti


118/196

zUUT

TUZi ==

1

z: t s chu k

0 z 1

0 Uzi U

Ziz

U EI

R

=

uc

S

iS

U

iV0

V0

R

L

uZ

iZZ

uZ

0

0

S V0 S V0 S

U

UZi

tT1 T2T

iS iV0 IZ

iZ

iZMiZMIN

t

4.4.2 B bin i tng p mc song song

Nguyn l lm vicu


119/196

Nhp S:

uZ = 0

iZ = iS; tng theo ng conghm m, v gi tr E/R

Nng lng t ngun E

c tch ly phn lnvo cun L, phn cn litiu tn trn in tr R

Nhp S ko di trong khong thi gian T1. Nhp kt thc khi tn hiu ct a vo S

uc

iV0

V0

iS

S

iZ

Z

U

R

L

uZ

S V0 V0S S

T1 T2T

0U

UZi

t

uZ

iS iV0iZMIN

iZM

t

Nhp V0:

uZ = Uuc

S V0 V0S S


120/196

iZ = iV0; gim theo ngcong hm m, v gi tr

(E U)/R < 0

Nng lng t ngun Ecng vi nng lng tch ly trong cun L

nhp trc, tiu tn mtphn trn in tr R,phn ln cn li ctr v ngun U.

Nhp V0 ko di trong khong thi gian T2. Nhp kt thc khi tn hiu ng a

vo S.

iV0

V0

iS

S

iZ

Z

U

R

L

uZ

T1 T2T

0U

UZi

t

uZ

iS iV0 iZMINiZM

t

Gi tr trung bnh in p trn ti

uc


121/196

( )

2

1

1

Zi

TU U

TT T

UT

z U

= =

= =

=

Ziz

E UI

R

=

uc

iV0

V0

iS

S

iZ

Z

U

R

L

uZ

S V0 V0S S

T1 T2T

0U

UZi

t

uZ

iS iV0iZMIN

iZM

t

4.4.3 B bin i xung gi trin tr

S

uc

L

iZ

L

iS

SiR uc


122/196

Nguyn l lm vic

Nhp S:

iZ = iS: tng vi h s gc bng U/L

Nhp S ko di trong khong thi gian T1. Kt thc khi tn hiu ct a vo S.

URP

SRp

U

c

T1 T2

T

iS iR iZMINiZM

t0

iZ =iS+iR

iZ

L

iS

SiR

Rp

uc


123/196

Nhp 0

iZ = iR; gim theo ng cong hm m v gi tr U/Rp.Nhp 0 ko di trong khong thi gian T2. Kt thc khi tn hiung c avo S

U

T1 T2

T

iS iR iZMINiZM

t0

iZ =iS+iR

Xc nh gi trin tr tng ng ReiiZ

L

iS

SiR uc


124/196

eip

ZZpZ

R

U

TTR

UITIRTUI ===

2

2

2

( )2 1ei p pT

R R z RT

= = 0 ei pR R

Rp

U

T1 T2

T

iS iR iZMIN iZM

t0

iZ =iS+iR

4.5 B chuyn mch

4.5.1 Mch LC V iV

C


125/196

U

dt

diLidt

C

u

t

C =++ 0

1)0(

(0)sin (0) cosC v v

U ui t i t

LC

= +

v: tn s gc ca mch LC 1

vLC

=

C uC

i

L

t = 0

uC(0)

0

uCi

t

U

t = 0

L

i

uC C Ot

uC(0)=0

uC

iU

2U

SC

1t


126/196

[ ]

0

1(0)

(0) cos (0) sin

C C

C v v

u u idt C

LU u U t i t

C

= + =

= + +

4.5.2 Phn tch b chuyn mch ca b bin i xung p


127/196

uc

S

iS

U

iV0

V0

R

L

uZ

iZZ

iiV1

V1C

uCiC

uV1

V2

V3L1

U V0

Z

iZ

uZ

iiV1

V1

C

uCiC

uV1V2

V3L1

UV0

Z

iZ

uZt

V0

T

T1 T2

V1V3

V1 V2 V0

K1U

U

uZ

t2

0 t1 t3 t4 t5 t6 t7

QK


128/196

Nhp V0 (0, t1)

iZ = iV0, uV0 = 0, uZ = 0

Gi thit uC = U

uV2 = 0; uV1 = U

iC = iV1 = iV2 =0

0

0

0

0

U

U

U

-K1U

K1U

uC iC

IZ

iV1

uV1

t0V1

uV2 iV2

t0V2

t

IZ

iZ iV2

iV0

iiV1

V1

C

uCiC

uV1V2

V3L1

UV0

Z

iZ

uZt

V0

T

T1 T2

V1V3

V1 V2 V0

K1U

U

uZ

t2

0 t1 t3 t4 t5 t6 t7

QK


129/196

Nhp V1, V3 (t1, t3)

Ti t1a xung iu khin m V1

uZ = U; uV0 = -uZ = -U V0 ng li

iZ = iV1

1cos ( )C vu U t t =

1sin ( )C vUi t tL

C

=

0

0

0

0

U

U

U

-K1U

K1U

uC iC

IZ

iV1

uV1

t0V1

uV2 iV2

t0V2

t

IZ

iZ iV2

iV0

iiV1

V1

C

uCiC

uV1V2

V3L1

UV0

Z

iZ

uZt

V0

T

T1 T2

V1V3

V1 V2 V0

K1U

U

uZ

t2

0 t1 t3 t4 t5 t6 t7

QK


130/196

uV1 = 0

iV1 = IZ - iCuV2 = -uC

iV2 = 0

Ti t = t3, dng iC = 0; V3 ng li

uC(t3) = -K1U; K1 = 0.7 0.9

0

0

0

0

U

U

U

-K1U

K1U

uC iC

IZ

iV1

uV1

t0V1

uV2 iV2

t0V2

t

IZ

iZ iV2

iV0

iiV1

V1

C

uCiC

uV1V2

V3L1

UV0

Z

iZ

uZt

V0

T

T1 T2

V1V3

V1 V2 V0

K1U

U

uZ

t2

0 t1 t3 t4 t5 t6 t7

QK


131/196

Nhp V1 (t3, t4)

Tt c cc i lng gi nguyn gi trti thi im t = t3

0

0

0

0

U

U

U

-K1U

K1U

uC iC

IZ

iV1

uV1

t0V1

uV2 iV2

t0V2

t

IZ

iZ iV2

iV0

iiV1

V1

C

uCiC

uV1V2

V3L1

UV0

Z

iZ

uZt

V0

T

T1 T2

V1V3

V1 V2 V0

K1U

U

uZ

t2

0 t1 t3 t4 t5 t6 t7

QK


132/196

Nhp V2 (t4, t6)

Ti t = t4a xung iu khin vo V2 m V2

uV2 = 0

in p ngc trn C t ln V1ng V1

4

4

4 1

1( )

( )

t

C Z C C Z

t

Z

i I u u t I dt C

It t K U

C

= = +

=

0

0

0

0

U

U

U

-K1U

K1U

uC iC

IZ

iV1

uV1

t0V1

uV2 iV2

t0V2

t

IZ

iZ iV2

iV0

iiV1

V1

C

uCiC

uV1V2

V3L1

UV0

Z

iZ

uZt

V0

T

T1 T2

V1V3

V1 V2 V0

K1U

U

uZ

t2

0 t1 t3 t4 t5 t6 t7

QK


133/196

Nhp V2 (t4, t6)

iV2 = IZuV1 = uC

iV1 = 0uZ = U uC = -uV0

Ti t = t6, uZ = 0 V0 m, V2 ng li Bt u nhp V0

uZ(t6) = 0uC = U

0

0

0

0

U

U

U

-K1U

K1U

uC iC

IZ

iV1

uV1

t0V1

uV2 iV2

t0V2

t

IZ

iZ iV2

iV0

Np in cho t C khi bt u lm vic

M V2 trcng t C trc tip vo ngun U qua mt in tr hn ch dng

X h th C L


134/196

Xc nh cc thng s C v L

V1 s dng khong (t4, t5) phc hi kh nng kha

(t5 t4)MIN = toffV1

115 4

1

( )ZM offV

Z

I tK UCt t C

I K U = =

V2 s dng khong (t1, t2) phc hi kh nng kha (t2 t1)MIN = toffV2

22

2 1 2

4( )

4 2

offVvtT

t t LC L

C

= = =

4.6 Nguyn tc iu khin b bin i xung p

rng xung thay i T1 Tn s xung thay i T Hai gi tr


135/196

4.6.1 Nguyn tc iu khin rng xung

Gi nguyn f = 1/T, thay i T1

BK

M

ucBCM

C

T T1 T2

0

ucM uP uc

t

4.6.2 Nguyn tc iu khin tn s xung

Gi nguyn T1, thay i T


136/196

f = 1/T M

BK

M

uc BCM

Khu

pht xung

Tr T1

4.6.3 Nguyn tc iu khin hai gi tr

iZt

i

iZM

ui1

ui2

ucM


137/196

B pht xung ng vai tr ca mt biu khin dng in

0

iZMIN

I'Z=IZ

ui1

ui2

iZ

ui1

ui2

ui1 ui2

uc

uc > 0

uc < 0

M

uc

BCM

V0

Z

iZ

4.7 Cc b bin i xung nhiu gc phn t


138/196

4.7.1 B bin i hai gc phn to chiu dng in


139/196

V

S1

US2

V0Z

uZ

iZ

4.7.2 B bin i hai gc phn to chiu in p

S1 V1

S1S2 V1V2

S1S2V2V1


140/196

)12(21 =

= zUT

TTUUZi

z > 0.5 Uzi > 0z < 0.5 Uzi < 0

U

S1

V2

uZ

iZ

V1

S2

Z

0

iZ

uZ

t

T1 T2 T

4.7.3 B bin i bn gc phn t

S2S1 S4S3S2S1V4V3 V1

V2S4S3

V2V1


141/196

V2

V1

S2

S1 S3

S4V4

V3

Z

iZ

uZU

S3S4

iZ

uZ

t

0

0

S2S1 S1V3

S2S1 S3V1

S3S4 S3V1

tiZ uZ

Ch 5 Thit b h h l


142/196

Chng 5: Thit b nghch lu


Bin i nng lng in mt chiu thnh nng lng in xoay chiu

Phn loi


143/196

Phn loi

Theo s lng pha:- Mt pha- Ba pha

- Nhiu pha

Theo s- Hnh cu- Hnh tia

Theo c im ngun- Ngun p- Ngun dng

5.2 S nguyn l

S1 S3

R

S2S1 S2S1S4S3

0

uZ


144/196

S nguyn l nghch lu cu mt pha

S nguyn l nghch lu tia v bn cu mt pha

S4 S2

uZU

0 = t

S1 S2

R

Ud

uZ

O

S1S2S1

Ud

= t

uZ

Ud

Ud

S1

S2

R

uZ

S1 S3 S5

S1S2S3

S4

S5S6

3


145/196

Nghch lu cu ba phati thun tr

Ud

S4 S6 S2

1 2 3

uZ1 uZ2 uZ3

Ud2

= t

uZ1

uZ2

uZ3

5.3 Nghch lu p

5 3 1 Dng cng sut hu cng v phn khng

Mang tnh cht ngun p: to ra in p xoay chiu. Dng in ura ph thuc vo ti.u vo ca nghch lu p l ngun in p mt chiu


146/196

5.3.1 Dng cng sut hu cng v phn khng

P = UdId

P > 0 Id > 0: c. nghch luP < 0 I

d

< 0: c. chnh lu

=

==m

n

ndd piUp1 Ud

id

-idS

VR

P = Ud.Id

p = Ud.id

1

2

3

p1

Z1

p2Z2

p3Z3

5.3.2 Nghch lu p cu mt pha

VR1S1 S3

VR3

iZZ

id

iVR1

iS1


147/196

: Gc d kin ng cc b kha

S: Gc thng dng ca cc b kha

R: Gc thng dng ca ccdiode ngc

VR2

S2S4

VR4

uZUd

L R

S1,S2

VR1,VR2

S3,S4

VR3,VR4

uZ

R

= t Ud

S

-UdO

2

Ud

S1

S2

Z

iZ

S1,S2

VR3,VR4


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Ud/R

-Ud/R

iZ

iS1 = iS2

O

Id

iVR3 = iVR4

iS3 = iS4 iVR1 = iVR2

O

O Z

iZ

VR3

VR4

,

S4

S3

Z

iZ

S3,S4

5.3.3 Nghch lu p tia mt pha


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Nhp S1:

uZ = ua = Ud

iS1 = id = iZ tng theo ng cong hm m

=


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Nhp VR2:

uZ = ub = -UdiVR2 = -id = iZ gim theo ng cong hm m

Ngt xung iu khin a vo S1. Do nh hng ca L trong ti, dngin trong cun th cp v qua dng trong cun s cp vn gichiu c. Dng trong cun s cp chy qua VR2 v qua na phi cacun s cp.

Nhp VR2 kt thc khi dng iVR2 gim v gi tr 0


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Nhp S2:

uZ = ub = -Ud

iS2 = id = -iZ tng theo ng cong hm m vi chiu ngc li

Xung iu khin a vo S2 ngay sau khi ngt S1. Khi VR2 ng,dng s chy qua S2.in p trn ti vn khng i, tuy nhin dng iZso chiu

Nhp S2 kt thc khi ngt xung iu khin a vo S2 v bt u a xungiu khin vo S1


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Nhp VR1:

uZ = ua = UdiVR1 = -id = -iZ tng theo ng cong hm m

Ngt xung iu khin a vo S2. Do nh hng ca L trong ti, dngin trong cun th cp v qua dng trong cun s cp vn gichiu c. Dng trong cun s cp chy qua VR1 v qua na tri cacun s cp.

Nhp VR1 kt thc khi dng iVR1 tng ln gi tr 0

5.3.4 Nghch lu p cu ba pha


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S1, S5, S6

1 3

2

ZuZ1 uZ3

uZ2

Ud

uZ1 = uZ3 = Ud/3

uZ2 = -2Ud/3


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S1, S2, S6

1

32

uZ1

uZ3uZ2

Ud

uZ1 = 2Ud/3

uZ2 = uZ3 = -Ud/3


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S1, S2, S3

1 2

3

ZuZ1 uZ2

uZ3

Ud

uZ1 = uZ2 = Ud/3

uZ3 = -2Ud/3


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S2, S3, S4

2

31

uZ2

uZ3uZ1

Ud

uZ2 = 2Ud/3

uZ1 = uZ3 = -Ud/3


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S3, S4, S5

2 3

1

ZuZ2 uZ3

uZ1

Ud

uZ2 = uZ3 = Ud/3

uZ1 = -2Ud/3


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S4, S5, S6

3

21

uZ3

uZ2uZ1

Ud

uZ3 = 2Ud/3

uZ1 = uZ2 = -Ud/3

= S

+ R

= = < S + R >


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T

I


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5.3.5 iu khin nghch lu p cu 3 pha

Nguyn tc thay i tn s xung ln: Ud Tn s: tn s pht xung vo cc b kha

uc Phn phi Khuych i


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Nguyn tc iu bin rng xung - PWM

IN P RNG CAiN P IU KHIN

Pht xung

p

xung

y xung

S1, S3, S5

S2, S4, S6

uZ1 = uZ2 = uZ3 = 0


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5.4 Nghch lu dng

5.4.1 Hai chc nng ca b chuyn mch

trong nghch lu dng

t in p ngcln thyristor, ng thyristor.


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Tham gia vo qu trnhchuyn mch

5.4.2 Nghch lu dng mt pha

Gi s V1, V2 m, dng in qua tiiZ = Id

in p trn cc t uC1 < 0, uC2 < 0.

Mun ng V1, V2: m V11, V12.


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Mun ng V1, V2: m V11, V12.

Dng iZ = Id chy qua V11, C1, C2, V12in p trn cc to chiu.

Trong thi gian in p trn cc t cn


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B chuyn mch thc hin chc nngth hai

Qu trnh chuyn mch kt thc khiiV3 = iV4 = -iZ = Id

5.4.3 Nghch lu dng 3 pha

Thyristor chnh: V1, V2, , V6 T chuyn mch: C13, C35, , C 26, C24 Diode phn cch: V11, V12, , V16.

0120 = V1

V2


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V3V4V5V6

iZ1

iZ2

Id-Id

iZ3

Nhp V1, V2, V11, V12

iZ1 = Id; iZ2 = 0; iZ3 = -Id

uC13 > 0

uV3 = uC13 > 0: V3 ang trng thi kha

Nhp V3, V11, V2, V12


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a xung iu khin m V3.uC13ng V1.Dng Id chy qua V3, C13, song song viC13 l C35 v C15, V11, vo pha 1.

uV13

= uZ12

uC13

< 0 ... V13 vn ng.Id so chiu in p trn C13.

B chuyn mch thc hin chc nng th 1

Nhp V3, V11, V13, V2, V12

Khi uV13 = uZ12 uC13 = 0 ... V13 m ...Dng chy qua V3 v V13 vo pha 2.

Qu trnh chuyn mch: dng chyvo pha 1 gim dn, dng chy vopha 2 tng dn.


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B chuyn mch thc hin chc nng th2: tham gia vo qu trnh chuyn mch

Qu trnh chuyn mch kt thc khi dng

chy vo pha 1 gim v 0 v dng chyvo pha th 2 bng Id.

Chuyn sang nhp V3, V13, V2, V12

5.4.4 iu khin nghch lu dng


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Chng 6: Thit b bin tn


Dng bin i nng lng in xoay chiu bng cch thay i tn s Phn loi theo s lng pha

- Mt pha- Ba pha

- m-pha


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Phn loi theo s- Trc tip- Gin tip

+ Ngun p+ Ngun dng

6.2 Bin tn trc tip


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Bin i trc tip in p xoay chiuthnh in p xoay chiuc tn s khc


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12 1 2( 1)

TT T n

p= + n: s na chu kin p u vo

to nn na chu kin p u ra

2 1

1 2 2( 1) f T p f T p n

= =+

[ ] 1 12 2( 1) T TT p n qp p

= + =


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Tn sin p u ra f2 < 25Hz v khng thiu khin v cp

Bin tn trc tip t c s dng

[ ] 1 12 2( 1)T T

T p n qp p

= + =i vi bin tn 3 pha:

6.3 Bin tn gin tip

6.3.1 Bin tn ngun p

CHNH LU NGHCH LU P

UdII > 0

Cf, Lf: mch lc

Mch lc cng vi chnh lu to thnh t hi


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Mch lc cng vi chnh lu to thnhngun p mt chiu u vo canghch lu p

Cf: nhn dng phn khng.

Nguyn tc iu khin: Nguyn tc iu khin tn s xung:

f2: tn s xung pht vo nghch luU2: s dng chnh lu c iu khin, hoc s dng chnh lu khng iu khin

v b bin i xung p Nguyn tc PWM chnh lu chcn l khng iu khin.

UdI > 0

IdI > 0

PI > 0 Cng sut khng tho chiu

6.3.2 Bin tn ngun dng

Lf: Mch lc

Chnh lu v mch lc phi ctnh cht ngun dng mt chiu


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CHNH LU NGHCH LU DNG

Nguyn tc iu khin:

f2: tn s xung pht vo nghch lu

I2: s dng chnh lu c iu khin.

Id > 0

UdI > 0 hoc < 0 Cng sut c tho chiu

Chng 7B kh hi


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B kha xoay chiuv thit b bin i in p xoay chiu


B kha xoay chiu: ng, ct dng xoay chiuThit b bin i in p xoay chiu: thay i gi trin p xoay chiu

Phn loi theo s lng pha- Mt pha- Ba pha

- m-pha


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m pha

Phn loi theo s- C bn- Tit kim

Phn loi theo phng php iu khin-iu khin hon ton- Bn iu khin

7.2 B kha xoay chiu

7.2.1 B kha xoay chiu mt phaNG

NGT

sinm

ZZ Uu

d

diLRi ==+

Z: gc bt u


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Z g iz(z) = 0

( )

sin( ) sin( )Z

R

m m LZ z

U Ui e

Z Z

=

2 2 2; arctan

L Z R L

R

= + =

f1()f2()

NG

NGT


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7.2.2 B kha xoay chiu ba pha

Gm 3 b kha 1 pha


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7.3 Thit b bin i in p xoay chiu

Ti thun tr R

7.3.1 Thit b bin i in p xoay chiu mt pha


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Ti R, L:

Khi < <

sin( )m

Z

Ui

Z =

Z =


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( )

sin( )

R

m L

Z

Ue

Z

Khi 0 < <

Khng iu khin c in p.Thit b lm vic nh b kha xoay chiu

Ti L

Khi /2 < <

(cos cos )mZU

i L =

= /2


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( )L =

Khi 0 < < /2

Khng iu khin c in p.Thit b lm vic nh b kha xoay chiu

7.3.2 Thit b bin i in p xoay chiu ba pha

Gm c ba b bin i in p xoay mt pha mc vi nhau


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CHNG 8: BO V V IU KHINCC THIT B BIN I


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8.1 Bo v cc phn tin t cng sut

8.1.1 Cng sut tn tht v lm mt

1 2 1P p p p = +

P Cng sut tn tht


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1p Cng sut tn tht chnh

2p Cng sut tn tht ph

20 ( )T AV F P U I R I = +

j a th

th jv vr ra

T T R P

R R R R

= +

= + +

Nhit mt ghp

Tj Nhit mt ghpTa Nhit khng kh mi trng


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a g gRjv in tr nhit gia mt ghp v v linh kin bn dnRvrin tr nhit gia v v cnh tn nhitRra in tr nhit gia cnh tn nhit v khng kh mi trng

Lm mt:

Cnh tn nhit Cnh tn nhit + qut gi

Cnh tn nhit + nc Ngm trong du bin th

8.1.2 Bo v dng in

Cu ch:

CC phi chu c dng lm vic nh mc ca thit b Nhit dung chu ng ca CC phi nh hn nhit dung ca thit b cn

bo v nhit lng (I2t)CC < (I2t)TB

in p h quang ca CC phi tng i ln Gim nhanh dng inv tiu tn nng lng trong mch.


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Khi CC t, in p phc hi phi ln Khng lm cho h quang chyli gia hai cc ca cu ch

Lp t: c nhiu cch

Tng pha ca cun dy s cp hoc th cp MBA Ni tip vi tng van Ni tip vi tng nhm van mc song songu ra ca thit b bin i

8.1.3 Bo v qu p

Qu p trong

S tch tin tch trong cc lp bn dn(qu trnh ng ca diode v thyristor) Bo v bng mch R C u song song vi diode hoc thyristor

Qu p ngoi


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Q p g

Ct khng ti MBA trn ng dy, CC bo v nhy, sm st, Bo v bng mch R C mc gia cc pha th cp ca MBA ng lc

R .. 10 1000 C 0.01 1 F

8. 2 iu khin cc thit b bin i8.2.1 Khuych i thut ton

2

1

r vRu uR

=

Khuych i o


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1R

Mch so snh

...

...

ccr

cc

U u uu

U u u

+

+

>=

+ >

Mch tch phn

1r vu u dt

RC=


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-

+

R

C

ur vr

duu RC

dt=

Mch vi phn

8.2.2 Mch to xung chun s dng IC 555


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1 1 2 2 2

1 2 1 2

0.693 ( ); 0.693

0.693 ( 2 )

t C R R t CR

T t t t C R R

= + =

= = + = +


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Mch lt n s dng IC 555

1.1T RC=

13

ccV

Dien Tu Cong Suat - Doan Quang Vinh

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