Dieu Khien Dong Co 1 Chieu

7/29/2019 Dieu Khien Dong Co 1 Chieu

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BI TP LN

IU KHIN T NG IIGio vin hng dn : PGS.TS Phan Xun MinhSinh vin thc hin : Mai c Chnh

Nguyn Kh HoanPhm Trung ThnhLp : KT1 K50


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THIT K B IUKHIN TC CHO NG C

IN 1 CHIU


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I. TNG QUAN V NG C

IN 1 CHIU V CCPHNG PHP IU KHINNG C IN 1 CHIU


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Khi tin hnh thit k 1 b iu khin nichung, vic u tin ta phi hiu bit vc tnh ca i tng t xy dng mhnh ton hc cho i tng. Cng vicny cung cp cho ta nhng hiu bit vi tng , gip ta thnh cng trong vic

tng hp b iu khin.


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1. Cu to, phn loi v nguyn

l hot ng ca ng c in 1chiu.


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a. Cu to :

Kt cu ca ng c in 1 chiu gm 2phn chnh l phn tnh (stator) v phnng (rotor)


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b. Nguyn l hot ng :

Khi t ln dy qun kch t mt in pkch t Uk no th trong dy qun kcht s xut hin dng kch t ikt lm xuthin t thng . Tip t mt gi trin p U ln mch phn ng th trongdy qun phn ng s c 1 dng in i

chy qua. Tng tc gia dng in phnng v t thng kch thch to thnhmmen in t.


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c. Phn loi :

Cn c vo phng php kch t ngi ta chia ng c 1chiu thnh cc loi nh sau :- ng c in 1 chiu kch t bng nam chm vnh cung c in 1 chiu kch t c lp ngha l phn ng

v phn kch t c cp in bi 2 ngun ring r.- ng c in 1 chiu kch thch ni tip : cun dy kch

thch c mc ni tip vi phn ng.- ng c in 1 chiu kch thch song song : cun dy

kch thch c mc song vi phn ng.

- ng c in 1 chiu kch thch hn hp : gm c 2 cundy kch t , 1 cun mc ni tip vi phn ng, 1 cunmc song song vi phn ng.


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2. M t ton hc ng c in 1chiu

- Tn hiu vo ud

- Tn hiu ra n(t)

Ta c phng trnh ud = i. r + L. + kl. n(t)dt

di

(*)


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T = L/r Thi gian qun tnh in hayhng s thi gian in t

Thi gian qun tnh c hayhng s thi gian in c.

kd : hng s khuch i ca ng c.

Phng trnh (*) l phng trnh m t tonhc ca ng c in 1 chiu.

t a2 = T. Tc , a1 = Tc , ao = 1 , bo =kd, ta c :


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M hnh trng thi tuyn tnh:

t x1 = n(t), x2 = , y(t) = x1dt

dn


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M t ng c min tn s


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3. Cc phng php iu khintc ng c in 1 chiu

Da vo c tnh c ca ng c in 1 chiu ta c ccphng php iu khin tc sau :

iu khin tc bng cch thay i t thng .iu khin tc bng cch thay i in tr ph Rf trn

mch phn ng.iu khin tc bng cch thay i in p phn ng.

Di y chng em ch cp n phng php iukhin tc ng c in 1 chiu bng cch thay i

in p phn ng. Phng php ny c s dng chyu iu khin tc ng c in 1 chiu kch tc lp.


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a. iu khin tc ng c 1 chiu khng ochiu quay dng Tranzito

- S nguyn l :


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b. Phng n iu khin c o chiu quay dngTranzito

- S nguyn l dng Tranzitor :


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- S nguyn l dng Tranzitor v khuch i

thut ton :


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iu khin tc ng c 1 chiu dng Thyristor

Dng iu khin ng c c cng sut ln vin p phn ng cao.

- S nguyn l :


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II. THIT K B IU KHINNG (PID)

Trn thc t c rt nhiu phng php thit kb iu khin cho ng c 1 chiu nh thit kb iu khin theo lut kinh in ( t l, t l -tch phn, t l - vi phn, t l - vi tch phn),

theo lut iu khin hin i ( gn im cc,phn hi trng thi-quan st trng thi), theo lutiu khin phi tuyn(SMC, Gain scheduling) .Tuy nhin trong bi tp ln ny chng em sdng phng php thit k b iu khin theo

lut PID iu khin ng c 1 chiu v biu khin PID c c tnh mm do ph hpcho hu ht cc i tng cng nghip.


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1. S chc nng:

My pht tc FT o vn tc x ca ng c a tinhiu ra l in p uFT n khi cng. Khi cng cchc nng so snh tn hiu uFT vi tn hiu t r(t)

v a sai lch e(t) ti b iu khin. B iukhin da vo sai lch e(t) cp in p iukhin u(t) ti cc thit b chp hnh tng haygim in p ud t phn ng ca ng c.


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2. S khi

- My pht tc FT c nhim v o tc x ca ng c,n c cu to v hot ng ging nh 1 my pht inmini c kch t c nh, b chuyn i ny coi nh 1khu khuch i c h s khuch i Kf vi uFT = Kf.x.

- ng c in 1 chiu bin i tn hiu in thnh tn hiuc theo phng trnh :

1...)(

2 ++

=

sTsTT

ksG

ccu

d

C


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- Thit b chp hnh chuyn tn hiu iu khin u(t) tcng vo cc c cu chp hnh (Tranzitor, Thyisror) iu chnh in p cp vo phn ng ng c .

tuKtudt

tduT

CHd

d

CH(.)(

)(. =+

- => Thit b chp hnh l khu qun tnh bc nht c

hm truyn :

B iu khin thc hin theo lut PID cn c xc nhthng s v cu trc.

sT

KG

CH

CH

CH

.1+=

)..

11.( sT

sTKG

D

I

PK++=


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=> S cu trc :


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3. Thit k b iu khin PID

- M hnh tng qut :


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- Da vo m hnh i tng ta thit k b iukhin theo phng php ti u m un theo lut

PID - ADD-t KT = KCH.kd.Kf, T1 = TCH, -1/T2 ,-1/T3

l nghim ca phng trnh

=> Bi ton thit k : La chn cc tham s ca

b iu khin iu khin i tng c mhnh hm truyn GT(s) nh trn to ra 1 hthng n nh v t tiu chun cht lng.


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- p dng c phng php ti u mun taa bi ton v m hnh dng chun iu khin:

Vi l hng s thigian tng.

Ta nhn c cc tham s ti u ca lut iukhin PID ADD :


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4. S nguyn l ca h thng iu khin


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- tng tin cy ca b iu khin, trn thc tngi ta thng chia b PID ra tng thnh phnchc nng :


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5. nh gi tnh n nh v cht lng ca hthng iu khin

- Chn ng c 1 chiu c T = 1 , Tc = 4 , kd = 15.- My pht tc c Kf =0.012.- Thit b chp hnh c TCH = 2, KCH = 20

- Chn ng c 1 chiu c T = 1 , Tc = 4 , kd = 15.

- My pht tc c Kf =0.012.- Thit b chp hnh c TCH = 2, KCH = 20


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/* c tnh tn s nyquist

-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 dB

-20 dB

-10 dB

-6 dB

-4 dB-2 dB

20 dB

10 dB

6 dB

4 dB2 dB

Nyquist Diagram

Real Axis

ImaginaryAxis


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/* c tnh tn s lga

-80

-60

-40

-20

0

Mag

nitude(dB)

10-3

10-2

10-1

100

101

-180

-135

-90

-45

0

Phase(de

g)

Bode Diagram

Frequency (rad/sec)


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Kh t ht l h th


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c.Kho st cht lng ca h thng sdng Matlab-Simulink

- Vi tn hiu vo l xung bc thang :


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- Vi tn hiu vo l xung nhn :


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- Tn hiu vo l sng hnh sin :


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- Nhn xt : Mc d cc tn hiu vo khcnhau nhng cht lng ca h lun lunc m bo. Nh vy cu trc ca h

iu khin l hon ton m bo yu cuv tnh n nh cht lng


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6. Hiu chnh cc thng s ca b iu khin.

- Cc thng s ca b iu khin PID c chn theophng php ti u mun nh trn m bo hthng cho lm vic n nh. T th c tnh qu ca h thng ta thy thi gian qu l qu di (35 sec)do cn gim thi gian qu ca h thng hthng c th tc ng nhanh hn.

- Ta s hiu chnh thng s ca b iu khin PID davo c tnh sau ca cc khu iu khin :- Khu t l c tnh tc ng nhanh, khi u vo c sai

lch th tc ng ngay tn hiu u ra. Tuy nhin khuny lun tn ti sai lch d.

- Khu tch phn loi b sai lch d ca h thng nhngl khu tc ng chm.- Khu vi phn l khu tc ng nhanh


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- u tin ta gim thi gian qu bng cch tng h sKP : chn KP1 = 0.93, KP2 = 5, KP3 = 10 ng vi ccm hnh hm truyn h kn gk1, gk2, gk3 ta uc th

c tnh qu xung :Step Response

Time (sec)

Amplitude

0 5 10 15 20 25 30 35 40 450

0.5

1

1.5

System: gk1

Time (sec): 33.3

Amplitude: 0.994

System: gk2

Time (sec): 6.24

Amplitude: 0.995

System: gk3

Time (sec): 4Amplitude: 0.995

System: gk3

Time (sec): 6.87

Amplitude: 1.42 System: gk2

Time (sec): 10.4

Amplitude: 1.28

T th khi KP t th T i h i


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- Ta thy khi KP tng th Tq gim nhng qu iuchnh tng (sai lch tnh tng). ci thin c tnh ny,ta tng cc tham s TI , TD ng vi gi tr ca KP lnnht (KP3)

- Chn TI1 =4,TI2 = 6, TI3 =10 tng ng vi gk1, gk2,gk3 :

Step Response

Time (sec)

Amplitude

0 5 10 15 20 25 30 35 40 450

0.5

1

1.5

System: gk1

Time (sec): 6.85

Amplitude: 1.42 System: gk2

Time (sec): 6.66

Amplitude: 1.27

System: gk3

Time (sec): 6.61

Amplitude: 1.15

Ta th khi TI tng th q i chnh gim T nhin


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- Ta thy khi TI tng th qu iu chnh gim. Tuy nhin th c tnh vn cn tn ti dao ng. trit tiu ccdao ng ny ta iu chnh h s TD ng vi h s KPv TI ln nht :

- Chn TD1 =1 , TD2 =1.5 , TD3 =2 tng ng vi gk1,gk2, gk3 :Step Response

Time (sec)

Amplitude

0 5 10 15 20 25 30 35 400

0.2

0.4

0.6

0.8

1

1.2

1.4System: gk1

Time (sec): 6.49

Amplitude: 1.15System: gk2

Time (sec): 5.92

Amplitude: 1.07

System: gk3

Time (sec): 5.17

Amplitude: 1.01


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Xin chn thnh cm n

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Dieu Khien Dong Co 1 Chieu