dieu khien toc do cua dong co dien mot chieu diendandaihoc.vn 03051921112011
TRANSCRIPT
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NG CIN MT CHIU V VN
IU KHIN TC CA NG CINMT CHIU
CHNG 1
NG CIN MT CHIU V CC PHNGPHP IU KHIN TC
1.1 NG CIN MT CHIU:
1.1.1 Khi nim chung:
ng cmt chiu c s dng vi mt s lng ln trong kthut thit
k bi v nhng c trng tc quay (tc xon) kh thi vi nhng cu hnh
in khc nhau. Tc ng cmt chiu c th kim sot mt cch m i v
trong a s cc trng hp (th) c tho ngc chiu quay. T khi ng cmt
chiu c mt hiu sut cao ca qun tnh t lc xon ti r to, chng c th tr
li (p ng) nhanh chng. ng thi, phanh ng lc ni mt pht sinh
nng lng n c cp ti mt in trcm bin, hoc phanh phc hi (phnhi), ni m tpht sinh nng lng c cp (nui) trli ngun cung cp in
mt chiu, c th thc hin trong cc ng dng ni mong mun dng nhanh v
hiu qu cao.
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Da vo cch cc t trng phn tnh ( stator) c to ra, bn trong
ng cmt chiu c chia lm 4 loi khc nhau: nam chm vnh cu, vt kha
mch r nhnh (mch song song), vt kha mch ni tip, vt kha mch hn hp.
Sin, ng cong m men xon- tc , v ng cong dng in- mmen xon cho mi cu hnh c minh ho trong cc hnh t I-2 n I-5. Hnh I-
1 minh ha mt th mmen xon-tc ca ng c m n cho thy cc
mmen xon m ng cc th cung cp cc tc khc nhau in p
nh. Vi mt m men xon cho c cung cp bi ng c , th dng
in-m men xn c thc s dng o hm nh lng dng in nh
khi in p quy nh c s dng. Nh mt kinh nghim (quy lut) chung,
nhng ng c chuyn giao (truyn) nhng m men xon ln (ti) nhng tc
thp, v nhng m men xon cng c ngha l nhng dng in ng cln.
M men khi ng hc m men cn Ts l m men ln nht m ng csn ra
tc bng khng tng ng vi s khi ng hoc qu ti ng c. tc
khng ti max l tc duy tr ln nht m ng cc tht c; tc ny
ch c thc thc hin khi khng c ti trng hoc m men xon c ng
dng ti ng c( ch khi n chy khng).
Trong hnh t I-2 n I-5, V l in p mt chiu ngun cung cp, IA l
dng in cc cun r to, IF l dng in trong cc cun stato, v IL l ton b
dng ti pht ra bi ngun cung cp in mt chiu.
Cc trng in t trong cc ng cnam chm vnh cu (PM) (hnh I-2)
c cung cp bi cc nam chm vnh cu, m khng yu cu ngun ln bn
ngoi v khng c sn sinh pha trc cng sut lm nng ln I2R. S la chn
mt ng cPM l sng sut hn v nh gn hn so vi cc ng cmt chiu
tng ng khc bi v t trng ko di ca cc nam chm vnh cu l mnh
m. B rng bn knh ca nam chm vnh cu l xp x 1/4 ca b rng bn knh
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mt cun t tng ng. Cc ng cPM c o chiu quay mt cch n
gin bi chuyn mch.
Hnh I-1 th quan h m men xon-tc ca ng c
S iu khin in p ng dng t dng in v s thay i chiu ttrng chtrong rotor. ng cPM l l tng trong cc ng dng iu khin
my tnh bi mi quan h tuyn tnh ca c trng mmen xon-tc ca n.
Thit k ca mt biu khin lun lun n gin khi ng c l tuyn tnh t
cc phn tch h thng c n gin ho i rt nhiu.Khi mt ng cc s
dng trong mt v tr hoc trnh ng dng iu khin vi cm bin phn hi ti
mt biu khin, n c xem (quy vo) nh mt ng cservo. Cc ng c
PM chc s dng trong cc ng dng cng sut thp m nh lng cng
sut thng c gii hn n 5 m lc (3728 W) hoc nh hn, vi nhng s
phn loi theo sc nga nh l ph bin hn. ng cmt chiu PM c thc
qut bng chi than, khng chi than, hoc cc ng cbc.
Cc ng cmch nhnh (mch r, hay mch song song ) ( hnh I-3 ) c
li v cc cun kch t kt ni song song, chng c khi ng bi cng ngun
cung cp. Ton b dng in ti l tng ca cc dng trong li (ct) v cc dng
kch t. Cc ng cmch r ( cc ng ckch t song song ) cho thy tc
gn nh l hng s trn mt di ln ti trng, v c cc m men xon khi ng
tc khng ti(max)
tc
mmen
xo
n
mmen khing (Ts)
mmen xon
dngin
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( m men xon ln nht khi tc bng khng ) khong 1,5 ln ln m men
xon hot ng, c m men xon khi ng nh nht trong cc ng cmt
chiu khc, v c th tit kim c chuyn i cho php c thiu chnh
c tc bi vic t mt vn k ni tip vi cc cun kch t.
Hnh I-2 Sng cin mt chiu nam chm vnh cu v th quan h
m men xon-tc
nam chm V
IL
mmen xon
tc mmen xon
dng in (IL)
dng in (IL)
V
tc
mmen xonIL
mmen xon
IA
IF
bin tr
dng ttrung nh(1-5% )
xp xhng s
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Hnh I-3 Sng cmt chiu mch r(ng cin mt chiu kch tsong
song) v th m men xon-tc .
Cc ng ckch t ni tip (Hnh I-4) c li v cc cun kch t mc ni
tip ng thi cc dng kch t v dng trong li l bng nhau. Cc ng ckcht ni tip cho nhng m men xon khi ng rt ln, tc quay bin i rt
cao v ph thuc ti trng, v tc rt cao khi ti trng nh. Trong thc t cc
ng ckch t ni tip loi ln c th gy trt khc lit khi chng t nhin
mt ti trng (v d nh trong vic s dng mt dy ai, khi ai trt) do cc lc
ng lc cc tc cao. iu ny gi l chy ph hng . Tuy nhin khi ng
cnp li ti, iu ny khng khng cn t ra mt vn g na. ng th
m men xon-tc cho mt ng c kch t ni tip l ng c dng
hyperbolic, cho thy mt mi lin h ngc gia m men xon v tc v cng
sut gn nh l hng s trn mt di rng.
Cc ng chn hp (hnh I-5) bao gm c cc cun kch t ni tip v
song song, kt qu ca t hp cc c trng ca c cc ng ckch t ni tip
v cc ng ckch t song song. Mt phn ca ton b dng ti truyn qua c
li v cc cun ni tip, v s gi nguyn dng ti ch truyn qua cc cun mch
r. Tc ln nht ca mt ng chn hp b gii hn, khng ging nh mt
ng ckch t ni tip, siu khin tc ca n khng tt bng so vi mt
ng cmch r ( ng ckch t song song ). M men xon sinh ra bi cc
ng c hn hp c phn nh hn cc ng c kch t ni tip c cng kch
thc.
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Hnh I-4 Sng ckch tni tip v ngc trng m men xon- tc .
Hnh I-5 Sng chn hp mt chiu v ngc trng m men xon-tc
Lu rng khng ging nhng cnam chm vnh cu, khi cc tnhin p cho ng cmch r nhnh (ng ckch t song song ), ng ckch
t ni tip, hoc ng cmt chiu hn hp b thay i, chiu quay s khng
i. L do cho iu ny l cc tnh ca c stator v rotor thay i theo t trng
v cc cun li b kch hot bi cng mt ngun.
1.1.2 Phng trnh ng lc hc ca ng cin mt chiu PM.
Khi li ca mt ng cc kim tra vi mt ng ho trkhng vi
li c nh v vo mt v tr, Trkhng ng cxut hin tng ng vi
mt in trR trong mch ni tip vi s t hp song song ca mt cm khng
L v mt in trth hai RL. Trong khi li bt u quay mt in p c t
dng in (IL)ILIA
mmen xon
mmen xon
tc
V
cun kch
tc chyph hng
V
IA IL
tc
mmen xon dng in (IL)
mmen xon
IF
mch ni tip
mch songsong
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cm trong cc cun li gi l sut in ng phn hi chng li in p s
dng. Trc , mch in tng ng cho li c th hin trong hnh I-6.
RL, tn tht in trtrong mch t, n gn nh cng mt loi vi in tr
c ln ln hn R, in trca cc cun, v thng n gin. Nu chng tacho rng in p s dng cho li l Vin v dng in chy qua li l Iin,
phng trnh in cho ng cl:
Hnh I-6 Mch tngng cho li ng c
wkRIdt
IdLV ein
inin .
.++= (I-2-1)
w l tc quay vng ca m t(rad/s) v ke l hng sin ca m tnhngha nh sau:
w
Vk
emf
e =(I-2-2)
ng cnam chm vnh cu (PM) diu khin v phn tch, ta s thy
nhng phng trnh iu khin ca n chi tit hn nhiu .V s tng tc gia
trng stator v dng in phn ng,momen xon pht sinh bi ng cin
mt chiu PM s t l thun vi dng in phn ng:
Vemf
Vin
Iin
L
RL
R
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T=kt.Iin (I-3-1)
ktc nh ngha nh hng s momen xon ca ng c. Hng sin ke
v hng s momen xon kt ca ng c in PM l nhng tham s rt quan
trng, chng thng c thng bo trong cc c im k thut ca nh snxut.
Khi ng lc hc ca h thng c xem xt, momen xon T ca ng c
c cho bi
LinLa TTdt
dwJJT +++= )(
(I-3-2)
Ja v JL l nhng momen c cc qun tnh ca phn ng v gn lin ti
trng, Tin l momen cn chng li s quay ca phn ng, v TL chng li momen
xon ca ti.
Khi ng cc ni vi ngun in, phn mg s tng tc cho n khi t
ti mt trng thi n nh. Ti trng thi n nh, phng trnh I-2-1 trthnh
Vin = R.Iin + ke.w (I-3-3)
Ch rng ti trng thi n nh, t phng trnh I-3-2, momen xon ca
ng ccn bng vi momen ti trng ginh.
Tm Iin trong phng trnh I-3-1 v thay vo trong phng trnh I-3-3 ta c
wkTk
RV e
t
in .. +
=
(I-3-4)
Momen xon ca ng cc tnh theo phng trnh
wR
kkV
R
kT tein
t ..
=
(I-3-5)
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Phng trnh trn ni ln mi lin h tuyn tnh gia momen xon - vn tc
ca ng cmt chiu PM vi in p khng i.
Hnh I-7 biu din ng momen - vn tc v ng cong cng sut - vn
tc cho mt ng cin mt chiu nam chm vnh cu. V momen - vn tc
quan h tuyn tnh, n c thc biu din trong gii hn ca momen khi
ng TS v vn tc khng ti wmax nh:
=
max
1)(w
wTwT
s
( I-3-6)
Cng sut pht ra ca ng cmi tc khc nhau c thc biu din
nh sau
==
max
1..)(w
wTwTwwP s
(I-3-7)
Cng sut u ra ln nht ca ng cxut hin
0.2
1
max
=
=
w
wT
dw
dPs
(I-3-8)
Gii vn tc cho
w * = 1 / 2. wmax (I-3-9)
V vy vn tc tt nht khi chy mt ng c nam chm vnh cu t
c cng sut u ra cc i l bng mt na vn tc khng ti.
Ngoi nhng hng s momen v hng sin, nh sn xut thng cng ch
r in trR. Gi tr ny hu ch trong vic xc nh dng in trIS ca ng
c
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Hnh I-7 c im ca ng cin mt chiu nam chm vnh cu
R
VkI intS .=
(I-3-10)
Phng trnh ny cho dng in c gi tr ch khi r to ca ng ckhng
quay; mt khc, dng in rto c ginh v sut in ng trong nhng
cun r to. Dng in trl dng in ln nht chy qua ng ccn c vo s
cung cp in p. Phng trnh I-3-1 v I-3-10 c th s dng lin h momen
cn TS vi hng s momen, cung cp in p, v in trphn ng:
RVkT intS .=
(I-3-11)
1.2 IU KHIN TC NG CIN MT CHIU
Cngsut
Mmen
ungmmen - vn tc
ungcng sut - vn tc
wmaxw*
Vn tc
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1.2.1 Khi nim chung:
V phng din iu khin tc ng cin mt chiu c nhiu u vit
hn so vi loi ng ckhc, khng nhng n c kh nng iu chnh tc d
dng m cu trc mch lc, mch iu khin n gin hn ng thi li t chtlng iu chnh cao trong di iu chnh tc rng.
Thc t c hai phng php cbn iu chnh tc ng cin mt
chiu:
iu chnh in p cp cho phn ngng c.
iu chnh in p cp cho mch kch tng c.
Cu trc phn lc ca h truyn ng iu chnh tc ng cin mt
chiu bao gicng cn c b bin i. Cc b bin i ny cp cho mch phn
ng ng choc mch kch tng c. Trong cng nghip thng s dng bn
loi b bin i chnh:
B bin i my in gm: ng cscp ko my pht mt chiu hocmy in khuch i (KM)
B bin i in t: Khuch i t (KT) B bin i chnh lu bn dn: Chnh lu tiristo (CLT) B bin i xung p mt chiu: tiristo hoc tranzito (BBXA)Tng ng vi vic s dng cc b bin i m ta c cc h truyn ng
nh:
H truyn ng my pht-ng c(F-) H truyn ng my in khuch i - ng c(MK-) H truyn ng khuch i t - ng c(KT-)
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H truyn ng chnh lu tiristor-ng c(T-) H truyn ng xung p-ng c(XA-)Theo cu trc mch iu khin cc h truyn ng, iu chnh tc ng
cmt chiu c loi iu khin theo mch kn
(ta c h truyn ng iu chnh tng) v loi iu khin theo mch h
(h truyn ng iu khin h). Hiu chnh tng truyn ng in c cu
trc phc tp, nhng c cht lng iu chnh cao v di iu chnh rng hn so
vi h truyn ng h. Ngoi ra cc h truyn ng iu chnh tc ng c
in mt chiu cn c phn loi theo truyn ng c o chiu quay v khngo chiu quay. ng thi tu thuc vo cc phng php hm, o chiu m ta
c truyn ng lm vic mt gc phn t, hai gc phn t v bn gc phn t.
1.2.2 Nguyn l iu chnh in p phn ng:
iu chnh in p phn ng ng cmt chiu cn c thit b ngun nh
my pht in mt chiu kch tc lp, cc b chnh lu iu khin vv... Cc
thit b ngun ny c chc nng bin nng lng in xoay chiu thnh mtchiu c sc in ng Ebiu chnh c nhtn hiu iu khin Uk.
Hnh II-1. S khi v s thay thch xc lp.
V l ngun c cng sut hu hn so vi ng cnn cc b bin i ny c
in trtrong Rb v in cm Lb khc khng.
BB
L k
Uk
Rb RuI
EuEb(Udk) U
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ch xc lp c th vit c phng trnh c tnh ca h thng nh
sau:
Eb - E = I Rb + RI
u
dm
udb
dm
b IK
RR
K
E
+
= (II-2-1)
MUdk = )(0
V t thng ca ng cc gi khng i nn cng c tnh ccng
khng i, cn tc khng ti l tng th tu thuc vo gi trin p iukhin Ukca h thng, do c th ni phng php iu chnh ny l trit .
xc nh gii iu chnh tc ta rng tc ln nht ca h thng
b chn bi c tnh cbn, l c tnh ng vi in p phn ng nh mc v t
thng cng c gigi trnh mc. Tc nh nht ca di iu chnh b
gii hn bi yu cu v sai s tc v v m men khi ng. Khi m men ti l
nh mc th cc gi tr ln nht v nh nht ca tc l:
dm
M= max0max (II-2-2)
dm
M= min0min
tho mn kh kh nng qu ti th c tnh thp nht ca di iu chnhphi c m men ngn mch l:
Mnmmin = Mcmax = KM.Mdm
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Trong KM l h s qu ti v m men. V hc tnh c l cc ng
thng song song nhau, nn theo nh ngha v cng c tnh cta c th vit:
)1(1
)( minmin == Mdm
dmnm KM
MM
1
1.
)1(
max0max0
=
=M
dm
dmM
dm
K
M
MK
M
D
(II-2-3)
Hnh II-2. Xc nh phm vi iu chnh
Vi mt ccu my c th th cc gi tr0max, Mm, KM l xc nh, v vy
phm vi iu chnhD ph thuc tuyn tnh vo gi tr ca cng . Khi iuchnh in p phn ng ng cbng cac thit b ngun iu chnh th in tr
tng mch phn ng gp khong hai ln in trphn ng ng c. Do c th
tnh sbc:
Wo max
Wma x
Wmin
Wo min
Wk1
Wk1
Mnm minMm0
M,I
W
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10/max dmo M
V th vi ti c c tnh m men khng i th c gi tr phm vi diu chnh
tc cng khng vt qu 10. i vi cc my c yu cu cao v di iu
chnh v chnh xc duy tr tc lm vic th vic s dng cc h thng h
nh trn l khng tho mn c.
Trong phm vi ph ti cho php c th coi cc c tnh c tnh ca truyn
ng mt chiu kch tc lp l tuyn tnh. Khi iu chnh in p phn ng
th cng cc c tnh c trong ton di iu chnh l nh nhau, do st
tc tng i t gi tr ln nht ti c tnh thp nht ca di iu chnh. Hay
ni cch khc , nu ti c tnh cthp nht ca di iu chnh m sai s tc
khng vt qu gi tr sai s cho php, th h truyn ng s lm vic vi sai s
lun nh hn sai s cho php trong ton b di iu chnh. Sai s tng i ca
tc c tnh cthp nht l:
minmin
minmin
oo
os
=
=
cp
o
dm sM
s =min
(II-2-4)
V cc gi tr Mdm, omin, Scp la xc nh nn c th tnh c gi tr ti thiuca cng c tnh csao cho sai s khng vt qu gi tr cho php. lm
vic ny, trong a s cc trng hp cn xy dng cc h thng truyn ng in
kiu vng kn.
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Trong sut qu trnh iu chnh in p phn ng th t thng kch tc
gi nguyn, do m men ti cho php ca h s l khng i:
Mc.cp=Km.Im=Mm.
Phm vi iu chnh tc v m men nm trong hnh ch nht bao bi cc
ng thng = m , M = Mm v cc trc to. Tn hao nng lng chnh l
tn hao trong mch phn ng nu b qua cc tn hao khng i trong h.
E = E + I(Rb + R)
IEb = IE + I2(Rb + R)
Nu t Rb + R = R th hiu sut bin i nng lng ca h s l:
( )22
dm
uuu
uuu
K
MRRIEI
EI
+
=+
=
**
*
RMu +=
Khi lm vic ch xc lp ta c m men do ng csinh ra ng bng
m men ti trn trc: M* = Mc* v gn ng coi c tnh c ca ph ti l
Mc* = (* )x th
( ) 1****
+
=xu
R
(II-2-5)
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Hnh II-3 Quan h gia hiu sut truyn ng v tc vi cc loi ti khc nhau
Hnh II-3 m t quan h gia hiu sut v tc lm vic trong cc trng
hp c tnh ti khc nhau. iu chnh tc bng cch thay i in p phn
ng l rt thch hp trong trng hp m men ti l hng s trong ton di iu
chnh. Cng thy rng khng nn ni thm in trph vo mch phn ng v
nh vy s lm gim ng k hiu sut ca h.
1.2.3 Nguyn l iu chnh tthng ng c:
iu chnh t thng kch ca ng cin mt chiu l iu chnh m
men in t ca ng cM = KI v sc in ng quay ca ng cE =
K. Mch kch t ca ng c l mch phi tuyn, v vy h iu chnh t
thngcng l h phi tuyn:
dtd
rrei k
kb
kk ++= (II-3-1)
trong rk- in trdy qun kch thch,
rb - in trca ngun in p kch thch,
m
u
1
1
x=0
x=-1
m
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k s vng dy ca dy qun kch thch,
Trong ch xc lp ta c quan h:
;kb
kk
rr
ei
+= =f[ik]
Thng khi iu chnh t thng th in p phn ng c gi nguyn
bng gi trnh mc, do c tnh cthp nht trong vng iu chnh t
thng chnh l c tnh c in p phn ng nh mc,t thng nh mc v
c gi l c tnh cbn (i khi chnh l c tnh t nhin ca ng c). Tc ln nht ca di iu chnh t thng b hn ch bi kh nng chuyn mch
ca c gp in. Khi gim t thng tng tc quay ca ng cth ng
thi iu kin chuyn mch ca c gp cng b xu i, v vy m bo iu
kin chuyn mch bnh thng th cn phi gim dng in phn ng cho php,
kt qa l m men cho php trn trc ng cgim rt nhanh. Ngay c khi gi
nguyn dng in phn ng th cng c tnh ccng gim rt nhanh khi
gim t thng kch thch:
( )
uR
K2
= hay ( )
2**
=
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Hnh II-4 S thay th(a)c tnh iu chnh khi iu chnh tthngng c(b)
Quan h(ikt),(c)
Do iu chnh tc bng cch gim t thng nn i vi cc ng cm t
thng nh mc nm ch tip gip gia vng tuyn tnh v vng bo ho ca
c tnh t ho th c th coi vic iu chnh l tuyn tnh v hng s C ph
thuc vo thng s kt cu ca my in:
.. kkb
k err
CiC
+==
Uk rbkLk
ikrkk
I
E
max
m
c tnh c bn
0
b,
a,
Lk(Uk)
ikk
0
c,
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1.2.4 iu khin ng cin mt chiu PM bng in t:
Dng n gin nht ca iu khin ng cl iu khin mch h, m n
gin l iu khin gi trin p v nhng c trng ca ng cv xc nh ti
iu khin vn tc v momen. Nhng hu ht vn quan tm ph thuc loiiu khin tng no ni in p tng c thay i sinh ra chuyn
ng mong mun. y c gi l mch kn hoc mch iu khin phn hi v
n ph thuc vo vn tc u ra / hoc momen cm bin ti nhng gi tru ra
phn hi lin tc so snh u ra thc t ti mt gi tr mong mun gi l im
tp hp. Khi biu chnh thay i u ra ca ng cdch chuyn st ti
im tp hp. Biu chnh vn tc in t c hai kiu: b khuych i tuyntnh v b bin i chiu rng xung. Mc du c hai h thng c thc thit
k cho mt chc nng tt hn, cc biu chnh bin i b rng xung c ci
tin m chng iu khin cc tranzito cng sut lng cc nhanh chng gia cc
gii hn v s cn bng ni thao tc rt hiu qu (tn tht cng sut l ti thiu)
hoc bt v tt FET. B khuch i ph khuch i cng sut tuyn tnh lm tha
mn nhng ph thuc tn tht nhit t n hot ng trong vng tuyn tnh
ca thao tc tranzito. Ta s tm nhng biu khin ph kinh t, s dng nhng
b khuch i tuyn tnh, nhng bi v yu cu cng sut thp, d ch to, kch
thc nh, v gi thnh thp, chng ta s tp trung thit k b khuch i, gi
l b khuych i bin i chiu rng xung (PWM).
Nguyn l hot ng ca my khuch i PWM c biu din hnh II-5 .
Mt in p mt chiu cung cp cng sut nhanh chng c chuyn thnh mt
tn s f cnh gia hai gi tr ( v d Bt v Tt ). Tn s ny thng ln
hn 1 KHz. Gi tr cao c gi trong thi gian mt xung t trong thi gian chu
k T cnh
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fT
1=
(II-4-1)
Sng c to ra c mt chu k cng sut, c nh ngha nh t s gia
thi gian ON v chu k sng, thng thng c tnh theo phn trm:
Chu k cng sut = (t/T).100% (9.16)
Trong khi chu k cng sut c thay i (bi b iu chnh), dng in
trung bnh chy qua ng cs thay i, gy ra nhng s thay i v vn tc v
momen u ra. N ch yu thay i v chu k cng sut ch khng phi l gi
tr ca in p cung cp cng sut m xc nh nhng c trng u ra ca ngc.
Hnh II-5
B bin i brng xung ca ng cin mt chiu
PWMelectronics
dc powersupply (Vs)
+
t
T
T
pulses:
faster(large t)
slower(small t)
example drive circit
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S khi ca mt mch iu khin phn hi tc PWM cho ng cmt
chiu c th hin hnh II-6. Mt p k pht sinh mt tn hiu ra tuyn tnh
lin hn tc ca ng c. N c so snh vi tc mong mun t
trc (mt in p khc c thiu khin bng tay hoc iu khin bng mytnh). S c v dng in ca ng cc cm nhn bi mt my iu chnh
n chiu rng xung m pht sinh rng mt xung vung iu chnh nh mt
tn hiu ra. Tn hiu ny c khuych i ti mt mc thch hp cho in p
iu khin cho ng c.
Hnh II-6
motor
tachometer
poweramp
PWMregulator
electronics
measured speed
+
-
set point(desired)
speed
in pPWM
Dng inmotor
Chu trnh cng sut thpChu trnh cng sut cao
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Hnh II-7 in p PWM v dngin motor
Trong iu khin ng cPWM in thi chiu nhanh qua phn ng, v
dng in qua ng cb tc ng bi tnh t cm v khng trca ng c.
Do tc i chiu cao, dng in qua ng cc s dao ng nh quanh
gi tr trung bnh ging trong minh ha hnh II-7. Khi cng sut vng quay cng
ln th gi tr trung bnh v tc ng cchy cng tng
V d minh ha: Mch cu hnh H cho ng cmt chiu:
Mc d c th thit k v to ra mt a quay cho mt ng cphiu
khin ring v cc thnh phn nng lng, nhng c mt vi thit k mch tch
hp c kh nng tit kim c nhiu thi gian v tin bc trong thit k my.
Xt v vn c bn ca vic iu khin ng cmt chiu. Mc ch cui
cng ca bn c th l iu khin tc chiu quay, gc, v (hoc) momen
quay.
Vi yu cu iu khin tc ca ng cmt chiu, chng ta c th phi
thay i dng cung cp cho ng c. iu khin hng quay th chiu ca
dng in cung cp cho ng cphi i chiu. iu i hi mt b khuch
i dng in v mt vi thit b chuyn hng dng in. gii quyt yu
cu ny, ngi ta a ra khi nim mch cu H (H-bridge). Ngi ta s dng 4
transistors xp theo hnh H xung quanh ng cmt chiu ( nh hnh v di)
v ln lt kch hot tng cp ti mi thi im cho hng mong mun ca ng
c.
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Nu transistor Q1 v Q3 kch hot, Q2 v Q4 tt th dng in s truyn qua
ng ctheo hng nh hnh v v ng cs quay theo 1 hng. Tip n, khi
Q2, Q4 kch hot cn Q1, Q3 tt th ng c s quay theo hng ngc li.
Ngi ta c th to ra mt H-bidge vi ngun BJTs hoc MOSFET, nhng c
th rt kh chn ng hng quay mong mun bi trasistor. Do ta s thc
hin mt gii php s dng ng truyn ca khp cht bn dn cho cc IC iu
khin chuyn ng, gii php ny c thc tng thch cho vic iu khin
ng cmt chiu. Xt LMD18200, mt mch cu H 3A, 5V thit kc bit
iu khin ng cmt chiu v ng cbc. Ngoi ra n gin cch iu
khin ngi dng c th s dng c tnh an ton v qu dng v qu nhit, c
th s dng rng xung thay i h thng, v c th tng hm ng c. S
chc nng c minh ho di y.
Q1Q1
Q4 Q3
Q2
Q4
Q3
Q2
+V
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S chc nng:
S chc nng v thng tin iu khin:
input
logic
drection 3
brake 4
pill 5
current
sensing
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Thit k ny s dng MOSFET power vi cc diot c nhim v bo v tia
qut ngc i qua transistor. Cc cc ng cc ni gia u ra 1 v u ra
2. in p cung cp c th ln ti 55V. Cc tn hiu s bn ngoi iu khin
hng, vic hm v cc u ra khi nhit ln hn 1700 C. Khi nhit vt
qu 1450 C sc xc nh bi b bo nhit.
S khi hon thin ca thit k biu khin tc c minh ho nh
hnh v. im thit lp tc c xc nh bi mt vn k hoc mt gi tr
in p vo. Mt ng ho tc c ni thm vo ng cnh l b cm
ng cung cp mt cch o tc ng c. IC LM3525 bin i rng xunglu chuyn khp cht bn dn c s dng iu khin u vo biu khin
ng cH-bridge.
11
10
9
8
7
6
5
4
3
2
1
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CHNG 2
LM3525PWM
LMD18200H-bridge
motor
ng h o tc
iu khin hung
im t vn k
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THIT K PHN CNG IU KHIN NG C
MT CHIU
2.1 THIT K NGUN CUNG CP CHO MCH CHUN HO V VI XLVi x l cn ngun 5V, do ta thit k mch t ngun 220V thnh 5V
nh hnh v di:
2.2 GHP NI CARD THU THP S LIU 12 KNH VI MY TNH
2.2.1 Cng ni tip RS-232
a s cc h vi x l u c ghp ni vi my tnh thng qua cng ni
tip RS-232. y l mt chun truyn thng kh ph bin vi cc my PC hin
nay.
Thng thng cc my tnh u c hai cm DB9 hoc DB25 pha sau
dnh cho cng ni tip RS-232.
c im ca RS-232:
Thng tin c truyn theo kiu im - im. Ph hp vi truyn thng tin s, nh phn. Truyn theo kiu ni tip khng ng b. Truyn khng cn bng nn d bnh hng bi nhiu.
220
BA1
12V
12V
0
C1
2200m/25V
C1
2200m/25V
C1
100n
C1
1000m/16
C1
100n
C1
100n
C1
1000m/16v
C1
100n
7805
In Out0
In Out0
+5V
-5V
0
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Phn ln tn hiu c truyn dng m ASCII. Truyn song cng cn 3 dy. Mc in p ca tn hiu: Mc 1 l -3 : -12V
Mc 0 l +3 : +12V Khong cch truyn ngn ckhong 15m. Tc truyn ti a: 19600bps.Bng b tr cc chn trn cm DB9 v DB 25:
Tn hiu DB9 DB25
TxD 3 2
RxD 2 3
RTS 7 4
CTS 8 5
DSR 6 6
GND 5 7
DCD 1 17DTR 4 20
RI 9 22
Hnh dng cc cm nh sau:
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ghp ni h thng vi x l vi my tnh PC cn c cc mch chuyn
i mc t mc TTL sang mc chun RS-232 v ngc li. Cc mch thng
dng hin nay l cc mch dng Transistor lm b chuyn i, dng b cch ly
quang v dng vi mch chuyn dng. Trong n ny ta dng vi mch chuyn
dng MAX 232 ca hng MAXIM.
2.2.2 Vi mch MAX 232:
Vi mch MAX 232 lm nhim v chuyn i mc TTL li vo (pha h
C8051) thnh mc 10V pha truyn ra (My tnh) v cc mc t3 : 12V pha my tnh thnh mc TTL a vo vi x l.
S chn ca vi mch MAX 232:
5
4
3
2
1
9
8
7
6
DB9
5555555
5555555555555
55555
DB25
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hng INTEL l thng dng nht, nhn nhn mt cch tng qut v h
MCS_51 ta c bng tng kt.
Tn gi Cng ngh Rom trong Rom ngoi Ram trong Ram ngoi Timmer/Count
8031 NMOS Khng 64Kbyte 128Kbyte 64Kbyte 2
8051 NMOS 4Kbyte 64Kbyte 128Kbyte 64Kbyte 2
8751 NMOS 4Kbyte
EPROM
64Kbyte 128Kbyte 64Kbyte 2
8032 NMOS Khng 64Kbyte 256Kbyte 64Kbyte 3
8052 NMOS 4Kbyte 64Kbyte 256Kbyte 64Kbyte 3
Phn ln cc b vi x l 8051 c ng v theo kiu hai hng DIL vi
tng cng 40 chn. Mt s khc c ng v theo kiu hnh vung PLCC vi
44 chn. Hnh sau l s chn ca IC8051 theo kiu DIL 40 chn.
Gii thch s chn v chc nng ca 8051.
P2.0P2.1P2.2P2.3P2.4P2.5P2.6P2.7P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7PO.0PO.1PO.2
PO.3PO.4PO.5PO.6PO.7
212223
2425262728123456783938373635343332
AD5
AD1AD0
AD3
AD2
AD4
AD6AD7
A11
A9A10
A15
A13A12
A14
A8
13
1110
12
1514
1617RD\
WR\T1T2INT1INT2TXDRXD
33p
33p
11,0592 MHz
29
30
31
9
PSEN
ALEEA
RST
40
20
19
18
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Schn
K hiu Chc nng
18 P1.0P1.7 Cng vo/ra Port
9 Reset Li vo Reset tch cc mc cao
1017 P3.0p3.7 Cng vo/ra Port v tt c cc ng dn vichc nng c bit
18 XLAT 2 Li vo ca b dao ng thch anh bn trong
19 XLAT 1 Li vo ca b dao ng thch anh bn trong
20 VSS Chn ngun ni 0V
2128 P2.0P2.7 Cng vo/ra Port 2 ni cc ng a ch cao tA8A15
29 PSEN Dng cho b nhchng trnh ngoi
30 ALE Cho php cht a ch
31 EA lm vic vi Rom ngoi hay Rom trong
3239 P0.7P0.0 Cng vo/ra Port 0, cc ng a ch thp tA7A0
40 VDD Ngun cung cp 5V
2.3.1 S khi ca b vi xl 8051:
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-Interrupt control : iu khin ngt
-Other registere : Cc thanh ghi khc
-128 Byte RAM :
-Timer 1, 0 : Bnh thi
-CPU : n viu khin trung tm
-Osillator : Mch dao ng
-Bus control : iu khin Bus
-I/O port : Cc Port xut/nhp
-Serial Port : Port ni tip
-Address/data : a ch d liu
-Cng truyn ni tip RS - 232
2.3.2 Cch t chc v truy cp b nhca 8051
B nhca 8051 ni ring v h MCS_51 ni chung chia lm 2 vng b
nhring bit: B nhchng trnh v B nhd liu.
EA
RST
ALE
PSEN
Oscillation
CPU
Buscontrol
TIMER 0
Interruptcontrol
Otherregisters
Serial port
INT1*
INT0*
TIMER 1
P1P0 P2 P3
I/O Port
RXD*TXD*
Serialport
128 ByteRAM
ROM4K
TIMER 0
TIMER 1
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2.3.2.1 B nhchng trnh (Program Memory)
B nhchng trnh (ROM, EPROM) c thc nhng khng ghi c,
b nhchng trnh c th ti 64 Kbyte. i vi 8051 c ROM trong vi dung
lng 4 Kbyte, vi nhng loi khng c ROM trong ta phi dng ROM ngoi lu gi chng trnh, khi c ROM ngoi phi thng qua tn hiu PSEN
(Program Store Enable). Do vy tn hiu PSEN ch c tc dng vi ROM ngoi
cn i vi ROM trong tn hiu PSEN s khng c tc dng.
Sau khi RESET CPU bt u thc hin t vng 0000H, tip theo l n
vng t cc ngt ca XPU ta ch 0003H n 0023H. Vic s dng ROM
trong (i vi nhng loi c ROM trong) v ROM ngoi c biu hin bng
cch s dng chn EA (External Acess).*Khi chn EA ni vi Vcc:
- i vi nhng loi c ROM trong 4 Kbyte nh 8051 th chng trnhthc hin ta ch 0000H n 0FFFH ca ROM trong sau tip tc
ta ch 1000H n FFFFH ca ROM ngoi.
- i vi nhng loi c ROM trong l 8 Kbyte s chn ta ch 0000Hn 1FFFH ca ROM trong v ta ch 2000F n FFFFH ca ROM
ngoi.
- i vi nhng loi c ROM trong l 16 Kbyte s chn t a ch0000H n 3FFFH ca ROM trong v ta ch 4000G n FFFFH
ca ROM ngoi.
*Khi chn EA ni vi Vss:
- Lc CPU s lm vic ton b vi ROM ngoi. Do vy i vi nhng
loi khng c ROM trong th chn EA phi c ni vi Vss.Trong khi truy cp b nhngoi CPU s vit 0FFH ti b cht ca Port 0
nh vy n s xo bt c thng tin ti Port 0 m SFR c th cn ang gi, nn
vic vit ra Port 0 trong khi ang truy cp b nhngai s b sai. V vy nn
nh: khng ghi ra Port 0 khi b nhchng trnh ngoi ang c s dng.
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2.3.2.2 B nhdliu
B nhd liu (RAM) nu c a ch l 8 bit th cho php CPU 8 bit thao
tc nhanh hn, nu a ch l 16 bit c th truy cp c phi thng qua thanh
ghi DPTR (Data Pointer). Vi 8051 c 128 Byte RAM trong c th ghp vi 64Kbyte RAM ngoi. Trong sut qu trnh CPU truy cp ti b nhd liu s pht
tn hiu c RD v tn hiu ghi WR.
i vi 128 Byte ca RAM trong bao gm: 32 byte thp nht l nhm 4
bank thanh ghi, mi bank thanh ghi gm 8 thanh ghi R0 R7. Khi s dng cc
thanh ghi trong chng trnh phi np 2 bit vo thanh ghi Program Status Word
(PSW). Tip theo l 16 byte trn vng cc bank thanh ghi ta ch 20H 2FH
l vng cc bit a ch, vng ny c 128 bit. Bit 0 ca byte 20H c a ch l 0 vbit 7 ca byte 2FH c a ch l 7FH.
2.3.3 Cc thanh ghi chc nng c bit (Special Function Registers SFRs)
SFRs- cc thanh ghi vi chc nng c bit gm c thanh ghi s liu v
thanh ghi iu khin nh Timer, cng ni tip, h thng ngt... SFRs c a ch
t 80H n FFH. Bng cc thanh ghi trong SFRs ca 8051:
Registers Mnemonic Internal Address
Port 0 Latch P0 80H
Stack Pointer SP 81H
Data Pointer DPTR 82H 83H
Data Pointer Low Byte DPL 82H
Data Pointer High Byte DPH 83H
Power Control PCON 87H
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Timer/Counter Control TCON 88H
Timer/Counter Mode Control TMOD 89H
Timer/Counter 0 Low Byte TL0 8AH
Timer/Counter 1 Low Byte TL1 8BH
Timer/Counter 0 High Byte TH0 8CH
Timer/Counter 1 High Byte TH1 8DH
Port 1 Latch P1 90H
Serial Poft Control SCON 98H
Serial Data Port SBUF 99H
Port 2 Latch P2 A0H
Interrrupt Enable 1E A8H
Port 3 Katch P3 B0HInterrupt Priority Control 1P B8H
Program Status Word PSW D0H
Accumulator Acc or A E0H
B Rgister B F0H
Thanh ghi t trng thi chng trnh (Program Status Word - PSW) bao
gm cc bit trng thi phn nh trng thi ca CPU. Thanh ghi PSW c t
trong cc thanh ghi chc nng c bit SFRs
CY AC FO RS0 OV P
*PSW 0 (Parity P): Bit kim tra chn l, c t bi phn cng
P=1: Nu s cc bit =1 trong thanh ghi ACC l l
P=0: Nu s cc bit = 1 trong thanh ghi ACC l chn
*PSW 1: ngi dng nh ngha c.*PSW 2 (Over flow OV): Cbo trn, c t khi c trn xy ra ca
php tnh s hc.
*PSW 3 (RS0): Dng chn bank thanh ghi.
*PSW 4 (RSI): Dng chn bank thanh ghi.
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*PSW 5 (F0): Ctrng thi.
*PSW 6 (auxiliary Carry Flag AC): Cnhph, c thnh lp khi c
nhsang t bit 3 ca ton hng trong php cng.
*PSW 7 (Carry Flag CY): Cnh, c thnh lp khi c s nht bit 7
ca ton hng ca b ALU.
2.3.4 Cc cha ch trong 8051
2.3.4.1 Cha chtrc tip (Direct Addressing)
Trong ch ny mt ton hng cha a ch ca mt nh, a ch ca
nhc cho r xc nh bi 8 bit a ch cn ton hng kia l thanh ghi. V d:
ADD A,7FH
Cu lnh ny s thc hin cng ni dung nh7FH vi ni dung trong
thanh ghi A, kt qu chuyn vo thanh ghi A.
Cha ch dng khi lm vic vi RAM trong v cc thanh ghi trong
SFRx.
2.3.4.2 Cha chgin tip (Indirect Addressing)
Cha ch ny dng vi c RAM trong v RAM ngoi. Trong ch
ny mt ton hng l 1 thanh ghi c s dng cha a ch ca nhcnton hng kia l thanh ghi. Nu a ch ca nh 8 bit ta c th dng cc thanh
ghi R0 R7 ca cc bank thanh ghi hoc l Stack Pointer. Nu a ch l 16 bit
ta ch c th dng thanh ghi. V d:
ADD A,@R0
Cu lnh ny s thc hin cng ni dung ca nhc a cht trong
thanh ghi R0 vi ni dung trong thanh ghi A, kt qu chuyn vo thanh ghi A.
2.3.4.3 Cha chthanh ghi (Regiter Addressing)
Trong ch ny ton hng ngun hoc ton hng ch c th l 1 trong 8
thanh ghi ca bank thanh ghi chn. V d:
MOV R0, B
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MOV A, R7
2.3.4.4 Cha chtc th (Immediate Addressing)
Trong ch ny ton hng ngun l hng s c km theo m. V d:
MOD A, #100; Np vo A s 100 h cs 10
MOD A, #10H; Np vo A s 10 h cs 16
2.3.4.5 Ch thanh ghic trng (Register Specific Addressing)
Trong mt s trng hp ta dng ch ny gi thanh ghi. V d:
MOV 0E0H, #1; Chuyn hng s 1 vo trong SFR 0H
2.3.4.6 Cha chthanh ghi chs(Register Specific Addressing)
Ch ny chc dng tra bng (Look Up Table). Trong ch
ny a ch ngun hoc a chch c t trong hoc l DPTR (Data Pointer)
hoc l PC (Program Counter). V d:
MOV DPTR, #8100H
MOV A, #0
MOV A, @A+ DPTR
2.3.5 Cng vo ra song song
8051 c 4 cng vo ra song song: Port 0 (P0), Port 1 (P1), Port 2 (P2, Port
3 (P3)
Khi cng c s dng l cng ra: S liu c a vo thanh ghi SFR tngng, ng thi c a ra cht v tip tc pht ra tn hiu sau khi vic
ghi c hon thnh, gi tra ra cng ra c thay i khi gi tr mi c
cht.
Khi cng c s dng lm cng vo: u tin l vit gi tr FFH ra cng,sau chn no ca cng c mc in p thp sc nhn bit l 0 v cng
c thc vo SFRs tng ng.
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Port 0, Port 2, Port 3 ngoi cc chc nng ca cc cng vo/ra cn c cc
chc nng khc. thc hin cc chc nng khc nhau th cc bit tng ng
ca cc thanh ghi trong SFRs tng ng phi c t (thng l bng 1).
Port 0, Port 2 c dng ghp ni vi b nhngoi, Port 2 a ra byte caoca 16 bit a ch cn Port 0 u tin a ra byte thp ca 16 bit a ch v
sau c th gi hoc nhn byte d liu. Byte a ch thp phi c cht
bn ngoi, lm vic ny th b vi iu khin pht ra tn hiu ti chn ALE
cht byte a ch thp.
Port 3 bao gm cc ngt, cc u vo Timer/Counter, u vo/ra ca cng ni
tip, cc tn hiu iu khin cho php ghp ni vi b nhngoi.
Pin Alternate Funtion Mnemonic/DesignationP3.0 Serial Input Port RXD
P3.1 Serial Output Port TXD
P3.2 External Interrupt 0 INT0#
P3.3 External Interrupt 1 INT1#
P3.4 Timer/Counter 0 External Input T0
P3.5 Timer/Counter 1 External Input T1
P3.6 External Memory Write Strobe WR#P3.7 External Memory Write Strobe RD#
2.3.6 Timer/ Counter
8051 c 2 Timer/Counter 16 bit, c 2 c th hot ng nh Timer cng c
nh Counter. Khi hot ng nh Timer thanh ghi c tng ln 1 ti mi chu k
my, ta c th coi l m chu k my, mi chu k my gm 12 chu k dao ng
ca thch anh. Khi hot ng nh Counter thanh ghi tng tng ng vi s thay
i 1 v 0 ti u vo chn T0, T1. Chc nng l Timer hay Counter phi cla chn ng thi cng phi chn 1 trong 4 ch hot ng. Vic khi to
hot ng v iu khin cc Timer/Counter da trn 2 thanh ghi TMOD v
TCON trong vng cc thanh ghi c chc nng c bit SFRs.
2.3.6.1 Thanh ghi TMOD (Timer/ Counter Mode Control Register)
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GATE C/T M1 M0 GATE C/T M1 M0
*Gate:
-
Khi GATE = 1: Timer/Counter x c php hot ng ch khi chnINTx mc cao v chn iu khin TRx c t.
- Khi GATE = 0: Timer x c php hot ng bt c lc no bit iukhin c t
*C/T: La chn Counter hay Timer
- C/T = 1: Counter, ni dung bm c tng ln bi xung ngoi kchvo T0 (P3.4).
- C/T = 0: Timer*M0, M1 : Chp nhn m theo cc gi tr tng ng nh sau:
M1 M0 Mode
0 0 0 ; m 13 bit0 1 1 ; m 16 bit1 0 2 ; m 8 bit tng np li1 1 3 ; Timer 1 khng hot ng
Timer 0 hot ng nh 2b Timer ring bit 8 bit
2.3.6.2 Thanh ghi TCON (Timer/ Counter Control Register)
TF1 TR1 TE0 TR0 IE1 IT1 IE0 IT0
*TF1 (TCON 7): Cbo trn ca Timer 1. t bi phn cng khi
Timer/Counter trn. Xo bi phn cng khi x l vectphc v ngt
*TR1 (TCON 6): Bit iu khin Timer 1 c t v xo bng phn mm
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*TF0 (TCON5): Cbo trn ca Timer 0. t bi phn cng khi
Timer/Counter trn. Xo bi phn cng khi x l vectphc v ngt
*TR0 (TCON 4): Bit iu khin Timerc t v xo bng phn mm
*IEI (TCON 3): C ngt 1 theo sn. c t bi phn cng khi sn ca
xung ngt ngoi a vo chn INT# c pht hin v xo khi x l ngt.
*IT1 (TCON 2): Bit iu khin ngt 1. t v xo bng phn mm, vic t IT1
ti sn xung ca tn hiu v ti INT#, vic xo IT1 khi tn hiu ngoi ti chn
INT1# c pht hin v xo khi x l.
*IE0 (TCON 1): Cngt 0 theo sn. c t bi phn cng ca xung ngt
ngoi a vo chn INT0# c pht hin v xo khi x l ngt.*IT0 (TCON 0): Bit iu khin kiu ngt 0. t v xo bng phn mm vic t
IT0 ti sn xung ca tn hiu v ti INT0#, vic xo IT0 khi tn hiu ngoi ti
chn INT0# l mc thp.
2.3.6.3 Cc ch hotng ca Timer/Counter
*Mode 0: L bm 8 bit, tn hiu ngt xut hin khi m trn, v vy n m
c 213 hay 8192 xung s cho 1 tn hiu bo ngt.
*Mode 1: Hot ng ging nh Mode 0 nhng ch ny l 16 bit tc l m
c 216 hay 65536 xung s cho tn hiu bo ngt.
*Mode 2: Ch 8 bit tng np li. TLi s lm vic nh b
Timer/Counter 8 bit, khi m trn sm c t trong THi (Phn byte cao
ca thanh ghi 16 bit) s tng np vo trong TLi v bm li tip tc lm
vic, tn hiu ngt c pht ra khi Timerm trn v tng np li.
*Mode 3: Timer 1 khng hot ng vo gia sm ca n,, vic ny ngngha vi t TR1 = 0. Timer 0 ch ny thit lp TL0 v TH0 nh 2 b
m ring bit, TL0 s dng cc bit iu khin ca Timer 0, TH0 vi chc nng
v Timer (m chu k my) v tip nhn s dng TR1 v TF1 t Timer 1. V
vy TH0 coi l Timer 1.
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2.3.7 Giao din ni tip
Cng ni tip c th truyn nhn ng thi. N cng l bm nhn ngha
l c th bt u nhn byte th 2 trc khi byte trc c c t thanh ghi
nhn. Tuy nhin nu byte u tin vn cha c c trong thi gian nhn bytetip theo th byte u tin s mt. C 2 thanh ghi nhn v truyn ca cng ni
tip l Specia Funtion Register SBUF. Vic ghi ti SBUF l np vo thanh ghi
truyn, vic c SBUF l truy cp vo thanh ghi nhn. Cng ni tip c 4 ch
hot ng:
*Mode 0: Hot ng nh thanh ghi dch. D liu vo/ra ni tip qua
RxD/TxD, u ra dc theo xung ng h. 8 bit c truyn hoc nhn bt u t
LSB. Tc baud l 1/12 tn s xung thch anh.*Mode 1: D liu vo/ra ni tip qua RxD/TxD. 10 bit d liu c
truyn hoc nhn bao gm 1 bit Start (thng mc 0), 8 bit d liu bt u t
LSB v bit Stop (thng mc 1). ch ny khi nhn d liu th bit Stop s
c chuyn vo bit RB8 trong thanh ghi Special Function Register SCON. Tc
baud thay i c.
*Mode 2: D liu vo/ra ni tip qua RxD/TxD. 11 bit d liu c
truyn hoc nhn bao gm 1 bit Start (thng mc 0), 8 bit d liu bt u tLSB, 1 cho php lp trnh, 1 bit Stop (thng mc 1). Khi truyn d liu bit
th 9 c chuyn vo bit TB8 trong SCON c thc t gi tr 0 hoc 1,
cng c th l bit kim tra chn l (P trong PSW). Khi nhn d liu bit 9 sc
chuyn vo bit RB8 trong SCON trong khi bit Stop b b qua. Tc baud c
th l 1/32 hoc 1/64 tn s xung thch anh.
*Mode 3: D liu vo/ra ni tip qua RxD/TxD. 11 bit d liu c
truyn hoc nhn bao gm 1 bit Start (thng mc 0), 8 bit d liu bt u tLSB, 1 bit cho php lp trnh, 1 bit Stop (thng mc 1). Khi truyn d liu bit
th 9 hoc cng c th l bit kim tra chn l (P trong PSW). Khi nhn d liu
bit th 9 sc chuyn vo bit RB8 trong SCON trong khi bit Stop b b
qua. Tc baud thay i c.
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Trong c 4 ch hot ng:
- Khi d liu nhn c khi to v s dng SBUF nh l thanh ghich.
- Khi nhn d liu: Mode 0 phi c iu kin RI = 0 v REN = 1Cc Mode khc nu bit REN =1 th bit Start bt u c nhn.
*Ch truyn a knh (Multiprocesor Communication)
Trong ch 2 v 3 cn c dng cho vic truyn a knh, trong cc ch
ny bit d liu c nhn v bit th 9 c chuyn vo RB8 sau l bit
Stop. Cng c thc lp trnh sao cho khi bit Stop c nhn th ngt ni tip
sc tch cc ch khi bit RB8 = 1. Nt c trng l cho php t bit SM2trong SCON, bng cch ny cho php s dng ch truyn a knh.
Khi trm ch (Maste) mun gi mt gi d liu ti mt trong vi trm t
(Slave), u tin trm ch gi ra 1 byte a ch xc nh trm tno chun b
nhn d liu. Byte a ch ny khc vi byte d liu l trong byte a ch ch th
ton bu b ngt, v vy trm tno cng cn kim tra xem byte nhn c v
xem n c phi l a ch ca mnh khng. Nu l a ch ca mnh th n s xo
bit SM2 v chun b nhn cc byte d liu sp c gi. Nu khng phi ach ca mnh n vn t bit SM2 ng thi bo bn v b qua cc byte d liu
n. Bit SM2 khng c tc dng trong Mode 0, trong Mode 1 c th dng
kim tra gi tr ca bit Stop, khi nhn nu SM2 = 1 th ngt nhn s khng c tc
dng tr khi bit Stop c nhn.
Tc Baud trong truyn ni tip:
i vi Mode 0: Baud rate =12
1 oscillator frequency
i vi Mode 2: Baud rate =64
2SMD oscillator frequency
SMOD = 0 : Baud rate =64
1 oscillator frequency
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SMOD =1 : Baud rate =32
1 oscillator frequency
i vi Mode 1 v Mode 3
Trong hai ch ny s dng Timer 1 dnh tc BaudKhi Timer 1 bo trn:
Baudrate =32
2SMD (Timer 1 Over Flow Rate)
Khi Timer s dng ch hot ng tng np li sm khi trn:
Baudrate =32
2SMD x)1256(12
1
THx oscillator frequency
Vic khi to v iu khin ch truyn nhn ni tip thng qua 2 thanh
ghi SCON v PCON
2.3.7.1 Thanh ghi SCON (Serial Part Control Register)
SM0 SM1 SM2 REN TB8 RB8 TI TI
SMO, SM1: dng nh ch truyn nhn nid tip
SM0 SM1 MODE
0 0 0
0 1 1
1 0 2
1 1 3
SM2 :Cho php truyn a knh trong Mode 2, MOde 3
Mode 1 SM2 dng lim tra gi tr ca bit Stop
Mode 0 SM2 khng coa tc dng (thng SM2 = 0)
REN : Cho php nhn ni tip, c t v xo bng phn mm
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TB8 : i vi Mode 2, Mode 3 bit th 9 sc chuyn vo, c t
v xo bng phn mm
RB8 : Mode 2, Mode 3 bit th 9 c nhn v chuyn vo
Mode 1 khi SM2 = 0, RB lab bit Stop c nhn
Mode 0 khng s dng bit ny
TI : Cngt khi truyn, c t bi phn cng ti cui cng ca bit
th 8 trong Mode hoc l khi bt u bit Stop trong cc Mode khc, phi c
xo bng phn mm
RI : Cngt khi nhn, c t bi phn cng cui cng ca bit th 8
trong Mode 0 hoc l gi bit Stop trong Mode khc, phi xo c bng phnmm.
2.3.7.2 Thanh ghi PCON (Power Control Register)
SMOD GF1 GF0 PD IDL
SMOD : Bit dng nhn i tc Baud
GF1, GF0 : General Purpose Flag Bit
PD : Power Down Bit
IDL : Idle Mode Bit
2.3.8 Cc ngun ngt v cch sdng ngt
Cc ngun ngt c t ti a ch t 0003H 0023H trong b nh
chng trnh. Khi c ngt th CPU s nhy ti vng m n phc v ngt, nu
chng trnh phc v ngt nm trong khong 8 byte th s phc v ngt ngay
trong vng , cn khi chng trnh phc v ngt m ln hn 8 byte v ccngun ngt khc ang phc v th s nhy vt qua vng ngt sau thc hin
chng trnh phc v ngt.
Bng cc vectngt
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Ngun ngt a ch
E0 0003H
TF0 000BH
IE1 0013H
TF1 001BH
RI & TI 0023H
Cch s dng ngt:
-t bit EA (Enable A11) trong thanh ghi IE = 1.
-t bit tng ng vi ngt trong thanh ghi IE = 1.
-Bt u phc v ngt ti a ch tng ng vi ngt.
2.3.8.1 Thanh ghi IE (Interrupt Enable Register)
EA ES ET1 EX1 ET0 EX0
EA (IE 7): Cho php hay khng cho php cc ngt hot ng.
EA = 0 khng c ngt no hot ng.
EA = 1: Ton b cc ngun ngt c php hot ng.
IE 6: Khng s dng
IE 5: Khng s dng.
ES (IE 4): Cho php hay khng cho php ngt khi truyn nhn ni tip.
ET1 (IE 3): Cho php hay khng cho php ngt khi Timer 1 bo trn.
EX1 (IE 2): Cho php hay khng cho php ngt khi ngt ngoi 1.
ET0 (IE 1): Cho php khng ngt khi Timer 0 bo trn.
EX0 (IE 0): Cho php hay khng cho php ngt khi ngt ngoi 0.
Th tu tin cc ngt:
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theo mc nh th c cc mc u tin cao xung thp nh sau:
IE0 : mc cao nht
TF0
IE1
TF1
RI & TI : mc thp nht
khi c su tin ta t cc bit tng ng trong thanh ghi IP = 1.
2.3.8.2 Thanh ghi IP (Interrupt Register)
PS PT1 PX1 PT0 PX0
IP7, IP6, IP 5: khng s dng v t bng 0
PS (IP 4) : nh ngha mc u tin ngt cho cng ni tip.
PT1(IP 3) : nh ngha mc u tin ngt cho Timer 1.
PX1 (IP 2) : nh ngha mc u tin ngt cho ngt ngoi 1.
PT0 (IP 1) : nh ngha mc u tin ngt cho Timer 0.
PX0 (IP 0) : nh ngha mc u tin ngt cho ngt ngoi 0.
2.4 CC LNH TRONG 8051
2.4.1 Lnh MOV
*C php : MOV ch, Ngun
* ngha : Chuyn gia Ngun vo ch
Trong ch, Ngun bao gm cc thanh ghi, cc nh, hng s.
2.4.2 nh ngha cc hng, bin
*C php : Tn bin UQU Gi tr
* ngha : Gn bin bng gi tr
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*V d : PI UQE 12H; c mt bin tn l PI c nh
ngha bng 1 byte c a ch 12H
2.4.3 Cc lnh s hc
*Lnh MOV
C php: MOV ch, Ngun
ngha: chuyn gia Ngun v ch
ch, Ngun bao gm cc thanh ghi, cc nh, c hng s
V du: MOV R0, #27H ; R0 = 27H
MOV A, R0 ; Ni dung ca thanh ghi A a vo R0
*Lnh ADD
C php: ADD ch, Ngun
ngha: Ni dung ca ch cng vi ni dung ca Ngun kt quc tr v
ch.
VD: MOV R0, #32H ; R0 = 32H
MOV R5, #23H ; R5 = 23H
ADD R5, R0 ; R5 = 23H + 32H = 55H
*Lnh ADDC
C php: ADDC ch, Ngun
ngha: Ni dung ca ch cng vi ni dung ca Ngun cng vi ni dung
ca CF, kt quc a vo ch
V d: MOV R0, #89H ; R0 = 89H
ADD R0, 0F8H ; R0 = 89H + F8H = 81H v CF = 1
MOV A, #37H ; A = 37H
ADDC A, R0 ; A = 37H + 81H + 1 = B9H
*Lnh SUBB
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C php: SUBB ch, Ngun
ngha: Ly ch tr ngun tr CF kt quc a vch
V d: MOV A, #0F8H ; A = F8H
MOV R0, #3AH ; R0 = 3AH
CLR C ; CF = 0
SUBB A, R0 ; A = F8H 3AH 0H = BEH
*Lnh INC
C php: INC Ton hng
ngha: Ton hng sc tng ln mt
V d: MOV A, #50H ; A = 50H
INC A ; A = 51H
*Lnh DEC
C php: DEC Ton hng
ngha: Ton hng s b gim xung mt
V d: MOV A, #50H ; A = 50HDEC A ; A = 4FH
*Lnh MUL
C php: MUL AB
ngha: lm php tnh A nhn B, phn cao ca kt qu gm 8 bit c a vo
B, phn thp ca kt qu gm 8 bit c a vo A
V d: MOV A, #50H ; A = 50H
MOVB B, 0A0H ; B = A0H
MUL AB ; A = 00H v B = 32H
*Lnh DIV
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C php: DIV AB
ngha: lm php chia A cho B, kt qua vo A, s da vo B
V d: MOV A, #0FFH ; A = FFH
MOV B, #0AH ; B = 0AH
DIV AB ; A = 19H v B = 5H
2.4.4 Cc lnh Logic
*Lnh ANL
C php: ANL ch, Ngun
ngha: Thc hin php AND, kt qu thu c a vo ch
V d: MOV A, #32H ; A = 32H
ANL A, #0FH ; A = 02H
Ch : ch v Ngun l cc thanh ghi , cc hng s.
0 AND 1 = 0
0 AND 0 = 0
1 AND 0 = 01 AND 1 = 1
*Lnh ORL
C php: ORL ch, Ngun
ngha: Thc hin php OR, kt qu tr vch
V d: MOV B, #0AFH ; B = AFH
ADD B, #08H ; B = AFH + 08H = B7H
ORL B, #1FH ; B = B7H OR 1FH = BFH
Ch : 0 OR 0 = 0
0 OR 1 = 1
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1 OR 0 = 1
1 OR 1 = 1
*Lnh XRL
C php: XRL ch, Ngun
ngha: thc hin php XOR gia ch v Ngun, kt qu thu c tr vch
V d: MOV A, #37H ; A = 37H
MOV R2, #0BDH ; R2 = BDH
XRL A, R2 ; A = 37H XOR BDH = 8AH
Ch : 0 XOR 0 = 0
0 XOR 1 = 1
1 XOR 0 = 1
1 XOR 1 = 0
2.4.5 Cc lnh thao tc trn Bit
*Lnh CLR
C php: CLR C(hoc Bit) ngha: xo CF hoc Bit
V d: CLR C ; CF = 0
*Lnh SETB
C php: SETB C(hoc Bit)
ngha: SET CF hoc Bit
V d: SETB C ; CF = 1
*Lnh CPL
C php: CPL C(hoc Bit)
ngha: o CF hoc Bit
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V d: CLR C ; CF = 0
CPL C ; CF = 1
*Lnh ANL
C php: ANL C, Bit
ngha: thc hin php AND Bit vi C
*Lnh ORL
C php: ORL C, Bit
ngha: thc hin php OR Bit vi C
*Lnh JC(JNC)
C php: JC (JNC) Nhn
ngha: nhy n Nhn nu C=1(0)
*Lnh JB(JNB)
C php: JB (JNB) Nhn
ngha: nhy n Nhn nu Bit=1(0)
*Lnh JBC
C php: JBC Nhn
ngha: nhy n Nhn nu Bit=1 sau xo Bit
2.4.6 Cc lnh nhy khng c iu kin
*Lnh LJMP
C php: LJMP Nhn
ngha: nhy n Nhn vi khong cch ti a 16Bit
*Lnh AJMP
C php: AJMP Nhn
ngha: nhy n Nhn vi khong cch ti a 11Bit
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*Lnh SJMP
C php: SJMP Nhn
ngha: nhy n Nhn vi khong cch ti a 8Bit
2.4.7 Cc lnh nhy c iu kin
*Lnh CJNE
C php: CJNE X1, X2, Nhn
ngha: so snh X1 vi X2, nu X1 khng bng vi X2 th nhy n Nhn
*Lnh DJNZ
C php: DJNZ X1, Nhn
ngha: so snh X1 vi 0, nu X1 khng bng 0 th gim X1 i 1 ri Nhy n
Nhn
2.5 CHNG TRNH ASM
Cu trc chng trnh ASM
ORG 00H
LJMP START;
ORG O3H
RETI
ORG 0BH
RETI
ORG 13H
RETIORG 1BH
RETI
ORG 23H
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RETI
ORG 2BH
RETI
;-----------------------------------------------------------------------------------------------
;Khai bo bin, hng s
;------------------------------------------------------------------------------------------------
ORG 100H
START :
;Chng trnh chnh
;-----------------------------------------------------------------------------------------------
;Chng trnh con
;-----------------------------------------------------------------------------------------------
;Chng trnh phc v ngt
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PHN II
TNH TON THIT K CKH
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CHNG 3
THIT K L XO V TNH P SUT KH CN
THIT CP CHO PISTON-CYLINDER
3.1 TNH TON L XO:
3.1.1 Dliu u vo:
Thit k l xo xon c tr chu nn lp trong li trc chnh, chuyn v lmvic x=10 mm.
- Ti trng ban u Fminc tnh da vo trng lng ca ccu trc tipnn vo l xo khi lp rp, bao gm cc chi tit: bc trt, np, 2 vt M3,
trc nh, ng ng bi, 4 vin bi, i dao.
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V ccu ny trong solidworks v s dng cng c tnh khi lng vi
trng lng ring ca vt liu lm ccu l = 7,852 KG/dm3 ta c:
M= mbc trt + mnp + mvt + mng ng bi + mbi + mi dao
Trong :
mi dao= 0,5 Kg.
mbi= 4.0,9.10-3 Kg.
mbc trt + mlp + mvt + mng ng bi=309,2441.10-3 Kg.
i dao
4 vin bi
ng ng bitrc nh
bc trt
2 vt M3Np
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M= 0,313 + 0,5 = 0,813 Kg
Vy lc ban u Fmin= M.g= 0,813.10=8,13 N.
Trong : g l gia tc trng trng, ly g 10 m/s2
- Chn ng knh dy l xo: d = 2 mm.3.1.2 Tnh ton:
- Chn vt liu l xo l thp nhiu cacbon (Theo bng 14.1-trang 212-[1]) ta c: b= 1500 Mpa, vi ti trng va p, []= 0,3.b =
0,3.1500 = 450 Mpa
- Chn ch s ca l xo: c= dD =9. d v c c s tng ng ph hp (Theo [1]- trang 212 )
Trong : D - L ng knh trung bnh ca l xo.
d - L ng knh dy l xo.
(Cng thc 14.8-Trang 215-[1]).
- Ta chn ng knh ca dy l xo l 2 mm: d =1,6.
][.. max
cFk =1,6.
450
9..15,1 maxF =2 mm.
(Trch cng thc 14.6-Trang 214- [1])
Trong : k =3.4
2.4
+
c
c =1,15.
k-H s kn tng ca ng sut bin trong ca l xo do
dy b un cong.
Ta c ti trng ln nht khi lm vic l:
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Fmax = 22.450/(1,62.9.1,15) = 67,93 N
- S vng lm vic ca l xo.(Theo cng thc 14.9- trang 215- [1])
n=).(.8
..
).( minmax3
minmax1 FFc
dGx
FF
x
=
Trong : G=)]1.(2[ +
E L m un n hi trt.
Vi E, l modun n hi v h s poisson ca thp
Thay vo biu thc trn ta c G= 8.104 Mpa.
n= 59,4)13,893,67.(9.8
2.10.8.103
4
=
vng.
Quy trn s vng n ta c:
n = 6 vng.
- ng knh trung bnh ca l xo:D =c.d = 9.2=18 mm.
- Cc thng s kch thc khc:+ S vng ton b:
n0=n+(1,5 2) = 6 + 2 = 8 vng.
+ Chiu cao ca l xo khi cc vng st nhau (Tnh theo cng
thc 14.11 Trang 215-[1])
HS=(n0-0,5).d (8-0,5).2 = 15 mm.
+ Bc ca vng l xo khi cha chi ti (Theo cng thc 14.12
Trang 215-[1])
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p = d+ (1,1 1,2).n
max
Trong : max tnh theo cng thc 14.2-Trang 214-[1]
max= 43
max
.
...8
dG
nDF=1.n.Fmax= max
3
...
.8Fn
dG
c =
= 86,1493,67.6.2.10.8
9.84
3
= mm.
p = 2 + 1,1. 72,46
86,14= mm.
+ Chiu cao ban u:H0= Hs+n.(p-d) = 15 + 6(4,72 2) = 31,32 mm.
+ T sD
H0 74,118
32,31= < 2,5 3
l xo m bo tnh n nh (Theo trang 216-[1]).
3.2 TNH TON P SUT KH CP CHO PISTON-CYLINDER:
Ti trng ln nht khi lm vic tnh c trn: Fmax = 212,639 N
Fmax = ..R2xi lanh .Pmax
Pmax = Fmax/(..R2xi lanh)
Trong :
: Hiu sut, ly = 1.
Rxi lanh: Bn knh trong ca xi lanh, y ta chn xi lanh c Rxi lanh = 10 mm
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Pmax = 212,639/(1.3,14.102) = 0,677 (N/mm2) = 0,677/ 0,0981 = 6,9 at.
TI LIU THAM KHO
1. Csthit k my v chi tit my.Tc gi: Trnh Cht
NXB KHKT-2001
K hiu dng trong n l [1]
2. Tnh ton thit k h dn ng ckh - tp 1.Tc gi: Trnh Cht L Vn Uyn
NXB Gio Dc 2002
K hiu dng trong n l [2]
3. Gottleib T.M / Electric Motors and Control Techniques; TAB Books,McGraw Hill (1994).
4. Kenjo, T., Stepping Motors and their Microprocessor Controls, OUP1984
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5. Kenjo, T., Electric Motors and their Control Oxford SciencePublication, Oxford, England 1984.