alahap

1. LEVAN DOANH
NGUYEN THE CONG
NGUYEN TRUNG SON
CAO VAN THANH
.. ,,~ ,
NHA XUAT BAN
KHOA HQC VAKY THUA.T

2. LE VAN DOANH, NGUY~N THE CONG
NGUY~N TRUNG SON, CAO VAN THANH
'A A? K
DIED KHIEN SO
MAY DrEN•
(Dung cho sinh vien cac truong ky thu¢t)
NHA XUAT BAN KHOA HOC VA KY THU~T
HA NOI " 1999

3. Chla Irdch nhiiJm xw:ll /Jdn
Bien ItJp
eM IxiII :
Ve bia :
Ma ,,6:
I·I!.!>. I·Lo;. TO nANG HAl
N~uy~ f)i'inl!:
Trap Viill Cam
Ihnm" IAII
KHKT-9fl
41-91-99
In 1000 euon kh6 16 x 24 em ~ COng ty in HAng khOng. Gi!'iy phep xu!'it bBn
8641-91- 16/6/99. In xong va n(lp h1u ebi~u thang 7/1999

4. UJI NOI DAU
Trong nhii:ng nltm gdn ddy di~u khiln may di/fn co bUGe phat triln
nhdy v9t. Do liz klt qua eua vi~c tang ctJng suat va cae linh ndng eua linh
ki~n di~n tit cong sUIlt uiI viifc pha! trilfn va Iwan thi~n cae co cau di~u
khitn so co l¢p trinh, eua cae b" vi xu ij, vi dieu khiCn. Truyen d¢ng di¢n
thong minh dlja tr~n kJ thu¢,t dieu khien s6 cho phep tq.o nen h~ thong
truyen d¢ng di¢n c6ng nghi~p chae chtin, tin ca.y, hiiju ,mtit caD, dcii dieu
khi{n rr'jng, dam brio cae chile nl1ng bdo U~... vi du, IPM rIntelligent Power
Module) eua Mitsubishi Electric dcii cong sur'it til 10 Aj600 V den 1200
A/3300 V, ASC 600 ella ABB, ALTNAR eua Telemecanique... ia eae bf) di"i!u
khiCn d{)ng co xoay chieu vai cae finh ndng eMit luong nhu M trnyen d¢ng
mQt chieu.
Nhung hq-n ehe eua hJ thurU luang tlf nhu sl/ troi tMng so, slj lam
ui¢e on dinh dai han, nhCtng kh6 khrm eua ui¢e tlwe hi~n die chile nang
dfeu khien phl1c tqp dti thue day vi€,!e chuyen nhanh sang c6ng ngh¢ s6
trong nhung nam 70. S,-! xuut hi~n ua hoan thi~n eua cae bl') vi xU if mqnh
nhung nam 80 cho phep thlfe hien dieu khien vecto, tc!o n~n h¢ truy"~n d¢ng
xoay ehieu co chat luqng caD. Kj thuq.t 86 eung eho phlip tgo nen cae thu{J.t
toan dieu khien phuc tqp ma kJ thu¢-t tuang tl! khong cho phep.
Ngoai ra di~u khten 86 can eo Uu tht" quyet .dinh ve mq,t c6ng nghi!.
CiLng mot ca eau dieu khien 80 co the d6ng var tro giao dii?n uai nguiJi
UQ,n hanh, thlfe hien crie ehue nang ehq,y, dUng, doi ehieu, dlf bao, tu uan...
Moi ehue nling phue tqp eua truy~n d¢ng dir;n deu co the giili quyet dU(Jc
being cae co eau di"i!u khien s6. Di"i!u khien so con cho p/zep tiet ki€'!m linh
ki¢n philn cl1ng, cho pltf!p lieu chunn !toa: vai cung mot b¢ vi xu If, mr)t
edu true philn cung co the dung cho nwi ung dung, chi' can thay doi nl')i
dung b(J nha. Cuoi eung nho tien b6 trang et'lng ngM maeh to hap eho phep
thlj:c hir;n cci"-e ehue nang phl1e tQ.P voi k[ch thude nho, d(J tin ct;ty caD, liIm
vii!c chric chrin.
Tuy nhien di"i!u khien so may di~ cung ddt ra n/tCtng doi hOi kM,t
khe. Vi¢c thanh ltip cae lhu¢.t toan di,eu kllien ciln biet ro cae d4c t[nh eua
d6i tuqng dieu khien, ma hinh cua chung d cluJ" d(J lien tuc dlng nhu a
eM" dO rai rgc. Dieu khien 096 to. dieu khien thai gian thue eua qua trinh
phtle tQ.P, dien bien nhanh chOng, dai hoi hJ thu{).t li,!p trinh hi! thong £1
mUe caD.

5. Dieu ldllen s6 nuiy di~n ta noi hQi t~ dia nhieu nganh hhoa hqc PO
cong ngM thuQc linh vljc kJ thuf!,t di¢lt, di~n tli cong suat, dleu khien tlj
dong, kJ thu.(jt vi XII 1:'1... ddy La linh vue nit moi, chua dUQc gioi thi~u
£lay dli uai dQc gid Vi¢t Nam. Cac tac gid mong mu6n tTtnh bay nhung co
so t6i thu?i, thuQc linh vI./e di~u hhien s6 may di~n nhi'tm giup eho dQc girl
bllae dau tll'fp cq,n vai linh ul,Lc nay.
Quyen sach "Dieu khien 86 may di~n" gom 9 chuang.
Chuang 1. DQi rllang uc dieu khien 80 may dien, ITlnl! bay kllal quat
nhilng udn di! co brin cua dicu khiln nuiy dien, so sanh kJ thuq.t dieu khUn
tllang tu va dieu khitn s6. So do kh6i tOng quat cua dieu khien s6 nuiy
di¢n.
Chuang 2. Co sd .ui I:y tin I!i¢u so la chuong co tinh cMit chudn bt,
frrnh bay kh6,i quat co so bUn d6'i Laplace rai rQ.e va oien d6i Fourier rai
rqc.
ChuOl.g 3. Mo hinlt may di~n va of! bien d6i, trinh bay If thuye't may
dicn t6ng quat, m6 kink lien tue !.iQ. ma hinh Toi Tq,C clla nuiy difn va OQ
biell doi theo quan die"m dieu kllien.
Chuang 4. He thong dieu kllien 86, tTlnh b4)' phuong phrip phan tich
hi! dieu khien s6, dij.c tfnil elk b¢ dieu khifn s6', phuong phap tinh cae yeu
t6 chiit luang cua Il{ di"l!u khUn 80.
Chuang 5. Tong hqp he dicu khien so, trinh bay phuang phap Mng hqp
M dii!u khlen sfi trong mien z, t6ng hap h~ dieu khie"n so tTOng kh6ng gian
fI'qnl? thrll.
Cln/ong 6. Cau truc phlm Cling ut"l yeu cii-Ii phan miJm voi dillu, klli/In
so. trlnh bay yeu cau d6i uoi b¢ pi .ui If va c6c giao di(!n, d~ diem lq,p
trtnh phan mem eho dii.lu kllifn sri.
Chuang 7. Dleu kllien so may di~n m¢t chieu, trinh bay cae van de
phrin dell ua Mng hqp he dieu kkien so nw.y dtfn m¢t cllieu.
Chuang 8. Dieu khie'n st'; may di~n xoay chleu 0 che' dQ x6.c lq.p, trinh
bU.y phuong phap phan tich Va t6ng hap dieu kllien s6 may kh6ng dong
bQ va dong bQ, dUf trr;mg phuong pllap dieu khien t/fa til thong rota la
phuong pllap dang th6ng dung.
Chuang 9. Dieu khic'n 86 !J1a)' (h¢1t ..lOay ciueu 0 clte'dq qua d6, tTinh
bay phuong pllap phdn ticll hi! dieu khien s6' may di¢n 0 chi d¢ chuyen
mqeh va qua dr).
QUYr"n .wich nay do cae can b(J nllom Dieu khien may di~n, B6 mon

6. Thie't bt di~n, Trl1iJng Dqi h9C Bach khaa viet. PGS. PTS. Le Van Doanh
chit bien.
C6 the coi quyt!"n Elach "Dieu khiPn ,;6 may dien" ta ph"lLn 66 sung eho
giao trinh "Dieu khlen tlf d¢ng trui~n d¢ng dien". Quyen stich nay dung
eho sinh vien cae ngiLnh Thie't bt di¢n, TIj dOng haa Xl nghiep, Dieu khien
tlf d6ng, Ky thu¢,t do va tin hoe e6ng nghiep. Quyen such nay cung dl1qc
dung lam tai lieu tham kluio cho cac k.Y sl1 di~n dang cong lac trong cac
co qu.an nghien c/lu, san Iunt va eae lop sau dqi hQc.
Vi trtnh dq va thoi gian eo hqn, sach hhOng tninh khoi sai s6t. Chu.ng
t6i mong nhq.n duqc cdc gop y, nhq.n xet cua d6ng dao bq.n d()C. Mvi thl1
til, gop y xin gUi r>~ B6 m6n Thiet bt di~n, Khoa Nang htqng, Truong Dqi
h9c Bach Khoa Hil. NOi, DT 8692511. Chung lOt xm cluin thanh cam an.
Cac tac gia

7. ChlEllng I
'A 'A A' K , , ,
DAI CLJONG VE DIEU KHIEN SO MAY DII;:N
Ch11dng nay co dnh chat nh(lp 1ll,6n, trlnh bay cau true cua h~ th6ng diflu
khien truyen d(mg di~n t11dng tl,i va truyen dqng di~n dieu khie'n bang ky
thu*,t s6, so sAnh uu khuyet diem cua tung M th6ng, phan tich s11 can thi~t
phaj ph6i hQ'p ca hai M th6ng diflu khi@,'n bJdng tl,i va dieu khien s6 trong
truylm d¢ng di~n, phan dch cac van de din s6 trong dreu khien truy1n d¢ng
di~. PhAn dch cac yim cau d6i vai cac kh6i trang dieu khien s6 may di~n.
1.1 CAU TRUC HJl; TH6NG TRUYEN DONG DIJl;N
1.1.1 So' db kh6i t6ng quat ella h~ th6ng truyen dl)ng dit1in
Tren hinh 1.1 lit sCI do kh6i t6ng quat cua M ,~h6ng truyen dqng di$n gom
nhreu kh6i chis. thanh hai m~ch chfnh:
- Mqeh d(ing life gom bi) bien deli vii d¢ng Cd truyfm dqng. B9 bien doi
dong vai tro bitrn dOi di~n ap nguem cung cap ve di~n ap, dong di~n, tan so
phu hQ'p voi yeu cau cua cac d(mg cd truYfm de)ng,
B¢ bien doi co the la be) bien doi may di~n: may phat di$n m(;it chieu,
xoay chieui b9 bifn d5i di~n tit: khuech d~ t~, di~n khang baa bOa; bi? bien
d6i di~n tit cong sui'lt, BI) bien deli di~n tit cong suat th1c eMit lit cac b¢ chuyen
~p-
Oieu !chlin Oi€u kbien
vi tri: ~V- dong rJi~n
foe t!.a
Oi§u I.-hie'n
f=~
bg bii'n rJoi
t=
80 diin'} rli{n
y If!n
aa.'"dt;~; .fj~crimbiin ~:~,
dOng ,Ji~n h:e
cam
n lacJ9
vi fr/~
00 loc dp va vi lri'
Hlnh 1.1 Sd d6 kh& t6ng quM eua M thOng truy@n dQng diil:n.
7

8. ml;lch di~n ttl: lam vi(lc i'1 che d~ chuy~n nw-ch tl,l nhi~n do sl,l thay doi cuc
~l.nh cua di~n ap nguon ho~c chuyen rn,!ch cuang buc. Do sl,l horm thien cua
kg thu~t di$n tu: conp; suat vai sl.! ra dai clla tiristo (1960), tiristo khoa bang
cl,lc dieu khie'n GTO (Gate Turn - Ofr Thyristor 1970;, tranzito c6ng suat kg
thu:,H MOS (Metal - Oxide - Semiconductor 1980), tranzito luang c1c c6ng
cach di~n IGBT (Insulated Gate Bipolar Transitor 1990) voi cac uu diem
chuy€fn m~ch nhanh, tlnh nang dong lip cao, chac chan, hi~u BUat cao, d¢ tin
c{l.y cao nen ngay nay cac b¢ bien doi dien tu: cong suat hoan toan chiem uu
the
DOng cd truyen dong co cac loai dong cd IllOt chfeu, uong cd kh6ng dong
b¢, d¢ng cd d6ng bo va cac 10<:li dQng Cd d~c bi~t khac. Cac d9ng cd nay dlf;;C
cung dip M.ng dien tip u, dong di~n i va ~o nen momen cunp; cnp eho too Cd
khOng dfl c;ttp a day.
Mqch dieu khien bao gam eac carn bien do Itfl'lnp; dimg dg danh gia cac
thong s6 tn;mg thai cua lu~h dong h.1c va cac b~l di"~u khie'n tac dQng len cac
th6ng sO cua bO bien d6i nham duy tri cac dnh nang cua h~ thong truyfln
d9ng vI! toc do, dong di~n, mamen cung nhu cac ml,lc dich Illd may, ham, d6i
chieu quay va cac chuc nang bao ve khac
Cae cam bie'n do luang tronp; hi'> thong truy'fm dong di~n thuong bao gam:
- Cam bien dong diE)!n, thl1dng Ie. may bien dong danh gia tlnh trflng ul.ang
tai eua dOng Cd.
- Cam bien toc do thlJdng dung may phat t6e, bo chuyen m<;lch quang
dUng b/il thong tranzito quang va dia rna hoa.
- Cam bien vj trl. dung dIa rna hoa va bl> chuye'n lll.<:lch quang.
Cae bo dieu khien co th~ phftn thanh hai loai:
- BQ dH~u khien gan xac dinh thu tl,l va thdi die'm phat xung rnoi va khoa
cac Hnh ki~n di~n tu cong Buat theo eac chien lude dfeu khien bl? bien doi
nham cung dip cho dong cd nguon di~n ap va tan so theo dbi hoi eua truy'fm
dQng.
- BO diEm khien thui[Lt toilll nhatn giai quyel nhiing van de rieng cua
truYEm d¢ng nhu dieu khien toc df,l vA. vi trio han ch€ dong dipn, elic yeu cau
rna lllay ham va d6i chien. Th6ng thuang tin hieu ra rua kh6i dieu khien nay
130 m6men.

9. 1.1.2 Dieu khh!n tllang tl,l' va di~u khi6n 56
So d6 khrii hinh 1.1 If!. so db M th6ng di~u khi~n truy~n dQng di~n t1.1dng
tt1 quen bi€t. Trang ;;;d do nay cac thong so tr~ng thai cua cac khoi la cac d~i
luqng lien t!c. Tin hi(!u tit cac b(.l cam bign va cac b(J di"eu chinh 18. cae dai
IUQng li~n tuc nhAm duy trl di.ic tinr. cO cua dOng co thea dbi hoi eua ph! tai.
Tren hinh 1.2 Ia Sd do di~u khie'n hOn hqp tuong tu va so dung dieu khi~n
truyl'm dqng di~n m(>t chiEm Sd do gam 2 philn:
- Phan tUdng W haa gom cae eam bien da Iuilng dong di(!n va t.oe d(l, bo
dieu ehinh dong dien, b(.l bi~n d6i a dAy la b(J bam dieu bien d(.l r(.lng xung
1 - - - - - - - - - - 1
IB9v,xir1y 1
,
N
£. Bo hl6u chinn U
00 Icc d~
Ph.i"lll<lnllto,r
DBDRX dieu bien dO rOng )(ung. u di~ ap dieu khien bO bien deli
v~ tfn hi~u d~t dong di~n " sai I~ch dong di~n, 'v sai lech lac do
Hinh 1.2. So dO chllc na.ng dl~u khi@:n hOn hop Wong III va s6
Phan diEm khie:n so han g-om b9 vi xi't ly Jam nhi~m V1,l dieu ehinh toe d(l
va eae ehur nnn!! an tm'i.n. dong b¢ hoa. Sl,t khae nhau cd han eua phan dieu
khie'n s6 ;;;n ',"::1 dieu khie'n tuong tl,t la a ch6 vi(!e danh gia thong s6 trl.lng
thai eua he thOng va dua tin hi~u dieu khi~n tien hanh thea tong bUde thai
f;ian g9i lfl tin hieu rili r~c, tin hi~u luqng ti't hOa hO!.ie tin hi(!u so, Lue do a
moi thai die'm rai rl.le co mot to hqp bit lUang t.in tue vi'> h? t.hling. ell: thong
t.in s6 hoc chi eo hai llllk 0 vi"t 1 va thong s6 trl.lng thai ella h(! th6ng truyen
d(lng dUQe danh gia bang m(lt day bit.
B(l vi xlr If rling haat d(.lng t.hea nguyen If Iuong tu ho:'l thai gian. Thl1
tl! cae lenh dUQc thl,te hi~n thea tOng buac thai gian. Vi cae h(J vi xu If co
kha nAng thl,te hi~n dong t.hai cae thao tae voi so IUQng ral Ion nen thai gian
xtt If nl(.lt l~nh .may rat ngiin. VI d1 bO vi xtt Iy 8 bit co kha nang bieu diEln
2k = 256 trl.lng thai, voi b(l vi xU: ly Hi bit la :l[(! = 65535 trang' thai.
De' ph6i hQp giua ph':in so va philn tuong hr phii eei ho d6i t.udng tl! - s6
9

10. va b(l d6i so - Wdng tI,r. Trong cac ml,lc tiep thea se trinh bay chi tiet hOl.lt
d<)ng cua b¢ vi xu ly va cac bQ d8i ti.fdng t~ - s6 va h(l doi s6 - tUdng tlJ.
1.2 SO SANH DlEU KHIE:N s6 vA DlEU KHIE:N WONG TV
Vi¢c so sanh giua hai kg thul,l.t difuI khien tuong t« va diim khilln so rat
ur nh~ nhung cung riH thu vi. MOi lol,li dieu khie'n deu the hi¢n nhung uu va
nhu9c die'm, viec so sanh cho ta thay rO 51.! dm t.hiet phai chuyen sang ky
t.hu~t diea khien s6.
1.2.1 Cae h(l" chi cua dieu khU~n tllang tl,l' '10'8 lIU diem cua dieu
khU~n s6
- Nhu9C diem quan trQng nhal cua kg thu~t. tl1dng tt! lien qUlin den s,!
troi th6ng so do cac nguyen nhan co nguon goc khac nhau (do nhi¢t, h6a-ly,
Cd hoc. )
Cac hi~n tl1Qng nay lam thay d6i thOng so cua cae Hnh kien di~n tu, thay
doi di~n dung cua cac tl,l hoa, thay doi di~n tra cua cac chillt ap. Nhung hi~n
b.1Qng nay dan den su thay dbi Ch~111 thOng s6 cua cae phan til, Hun xuilt hi~n
di~n ap l(ich hay di~n lip t.roi 0 dau ra cac b¢ khuech dl.li thu~t t.oan Vi(!c khli
sl.! troi thong so doi hOi cac nha thiet ke 11ll.lch phai tim cae giai phap nhu sU:
dv.ng cac 1111ilch bu lam phuc tl.lP nll.lch va bing gia thanh. Trang khi do cac
linh ki(i.n so chi co hai muc cao va thilp (0 va 1) kh6ng ch~u anh huong cua
s1 troi.
M¢t nhl1t;jc diem kh:ic cua kg thu(tt tUdng tu la nhl.lY VOl nhi~u. Nhi~u co
th~ phit. sinh do ban than linh ki~n (nhii2!u ve nhi~t) ho~c nhieu kg sinh blm
ngoiH do anh hUdng cua moi truong. LOlili nhieu nay d~c bi¢t quan tr9ng vI.
t.rong vi{c dil';.u khi{n truyen d(>ng di~n cac bO bien d6i la ngubn nhitu ga.y
:'mh huang dang ke dE'n tudi di~n.
Cae cao truc so co t.he dl1Qc baa v~ chong nhiliu bang cae ky thu<)t lip
dl,lng cho kg thu~t tuong t.1,l nhu man chan, b9C kim., ngoai ra ng"Ubi t.a thubng
dung ky thu~t 19C so cho phep 10l.1i bo d.c diem bat thubng ma kMng hliln ch~
dili thong cua llll.lch
Vi~l' truy'en dan t.in hi~u wong t1,1 cling !¢p khci khan do sl) suy giam tin
hi~u, trong khi do truyen dan ti.n hi¢u so a ph~tn vi hqp ly khbng ch!u anh
huong cua 51) suy giam..
Cac linh ki~n kg thu~t tudng t1,1 Cling co tinh chat khac nhliu ve th6ng
)0

11. ;;6 khi dl1Qc Sfill xuat hang lo~t. Nguai ta cd the lo~i tru dUQc 81,1" sai khac ve
thong s6 bang phl1dng phap xac suat cling nhl1 chu y trong khi thie't ke che
t~o, tuy nhien hiEm tUQng nay lam cho cac linh ki~n kg thu$.t tuong t1,1 kelU
on d~nh va la nguon goc clla nhi~u.
Vi~c th1,1c hi~n Dl.9t so chuc nang nhll nho hoac tr~ Mng ky thu,flt wong
tlj gi.p nhieu trd ng~i, tuy v~y h).i cd th~ thl)c hi~n nH dOn gian bang ky thu(i.t
so.
Cuoi cling can luu y rang do dnh phllc tl:p cua vi.~c thl1c hi~n cac bl) di~u
khie'n kinh die'n rat it chuc nang tl10ng tl) cd the' dl1Qc th~c hi~n bang m~ch
t6 hQp va can den nhieu Hnh ki~n roi, vi~c thl,ic hi~n mach va hi~u chinh
chung ton nhieu thai gian va cong su-c, d.n co nhieu tiep di~tn lalll giam d¢
tin c~y cua cac nwch wong tl1. Vai lllU-C dO phu-c t~p ma m~ch tl10ng t1,1 trd
nen bat hdp Iy thi. doi voi nwch so van de trd nen kha ddn gian.
1.2.2 Uu dU~m cua thiet bi tllang til va nhllQ'c diem cua thil1t bi so
N goai cae nhuQe diem da phan deh d ml,lc trlm, ky thu!t dilm khien tlldng
t1,1 cung co nhung uu diptn ntH h~t ma khi chuy~'n sang kg thu(i.t 96 ta phai
hiu y giai quyet. Hai uu die'm quan trQng clm ky thU:;tt Wong tlj do IS. tac
dQng nhanh va lien tlC, trong khi do ky thu(i.t s6 we dOng ch~tn hon va xl1
Iy cac d~i luQng Iii roi r~c. Cac mc diem nay d~t ra nhreu van de doi voi vi~c
thiet ke h~ thong truyen d¢ng dit?n.
The dQn.g nhanh: Cac hi~n tuQng di~n to trong may di~n va bi? bien d6i
thuang di~n bien rat nhanh va cO th~ pha huy toan hI? he th6ng n~u x{ty ra
s1,1 co. Cac sd db wong h! tac dong gan nhu Wc thai trong khi do cac cd Call
so mc dl?ng Co thai gian.
V1l m:?t dfeu khH~'n"'96 van de thai gian tic d{lng d:Jt ra theo cac gdc do
khac nhau ti:Jy theo bai toan Cl the' clla M thong truyen dOng btl bien d6i
-d¢ng cO dit"m.
- BQ bien dOi cham, vi du b¢ chinh luu tiristo lam vit?c VOl hroi 50 Hz,
trong trllang hQp nay dieu khie'n so co the coi nhl1 TIlt ly tl1ong, co the' thve
hi~n cac chuc na.ng M.o v~ va. vi~c dil!u chinh dl1Qc thl,ie hi~n biing bQ vi xu
ly co tinh nang thong thl1dng.
- B(j bie'n deli tae d¢ng nhanh, vi dl,l b¢ bam lam vi¢c a tan ::;6 hang chlc
kHz, trong trl1ang hQP nay ngay cit. bi) vi x-l1 1y tac u¢ng rat nhanh ding din
phii Il1u y d~c bi~t va phai d1,1 dnh cae chien 1uQc dieu kh;en d(a tren cac
11

12. glai phan '(e phan cung ho~c chuang trinh ph!n mem
V~ ml)t phAn cU"ng ta co the' dl! kipn ('ftc ('au true khae nhau:
" C;'iu true IHi (rong do cae chuc nang doi h6i tae dim~ nhllnh vi dl;l nweh
yong dong di~n dude' thlie hi".'n hhng cae Hnh kien tuong tit, con cae khai khac
dung kg thm):t so,
(':.( true hl),'lh t.Dnn dlfa trfon ky thu~t gO co th€ d1,1a lren cae glai phap
r.,lU tr(if' kh:it' nO'll! ~r11 dung n1¢t hoae nhih: b¢ vi xU lj !fun "j~c song song
hu;w 3rt d~tng cae phan tlt ben ngoai nhu b6 nho ngoai, bb d~m., m~ch logic
hlp trinh . Ngoai ra ('0 the su dl.,lng bi? vi xl! If th6ng dl;lng hoac chuy{m dung
nhtl b(:l xU: ly tin hi$u, b6 vi dieu khie'n th1,1e hi~n c~c chue nang dic bi¢L
V{. m~t p11i.'W 111(.m dl,fa tren cfic quan ni{'lll tin hqc ho~c quan niqm Vp
dieu khi6n tl,l d"ng,
Ve m:.).t tin hQc chuClng tdnh phan mell.l can co linh ch::lt ciiu trlie, su
d~ng ng6n ngiJ g~n vai ngon ngfJ' may (assembly) hol}.c ngtm n~{ cap CaD
nhung cflOg co nhung dQ.c dnh ctta hQP ngil" nhu ngi>n ngir C. Trong m9i
trdang hqp nhling kh6 khan rifmg ("ua vi¢c l(tp tdnh thdi gian thl'C 1a t$p
hung vaa van de an toan va tac dQng nhanh.
Ve m~t di~u khie'n dut Tn cae gitti phap rifmg, vi~ mo Mnh hoa M lh6ng
reti r~c dl,fa tren bi~n doi 1., bien tl'~ng tMi nhU'ng cac phudng phap nay chi
don gUm trong t:ruong hqp h$ th6ng tuyen Hnh W)t bien !OlQt bi€n VEto, ln9t
bie'n rll}, tat ca cae bien co the do duqc. Trang trubng hqp may di(n Cl;I the
III nlliy di~n dong bo, kh6ng dbng b¢ hi phi tuye'n va nhieu bien, mQt s6 bien
quan tl'qng nhU: mornen, ttl thOng rolo C1ia may dien khang dong bi), dong
di~n trong dAy quan eln cfw. m:iy dit;>n dong bb khong do duqc Cuoi cirng rnt)t
86 thong s6 chl yeu cua may nhtt di~n lrd rota elm dong eC1 khong dong ho
khbng pMi Iii. hang so. Vi nhilng dl).c dif.'m tri>n mf) hinh ViI c~lu true ella mlilch
oieu khien chn rl'lt nhieu van de ca.n phai giai quyet luy da co nhiim ..:6ng
trinh oe. e~p Leti "an de nay.
Tue drlng liln lUi:
D~c die'01 tac dqng lien tl,lc eho phep cae Hnh ki~n hwng tv su d~ng hu:u
ich cho vi~c kh6ng ehe' eae bien (dong di~n, dien lip) CO:'ill bien thi8n rat nhanh
va co the gay nguy hiem ve rhU'dng di~n nay cac linh kien sO 111m vi(le Val
cac dai 111~mg r(ji r~c va the' hi(ln nhlJ'c!c diem trong linh vUe thn s6 bien thi~n
nhanh
12

13. - M9t so phep toan lien t~c thuang du(}e S11 dung trong ky thu~t dfeu
khien, thong d~ng nhat la phep deh phim. BQ hi~u ehinh PI (deh philn ty l~)
dieu ehinh dong di~n bien thien nhanh t~o nen ache dQ xtie I~p gia trj dong
di~n trung binh bang gia trj dong di~n dl)t, trong khi do b(:t tieh phan s6 chi
eho gia t.rj gan dung ~llu gia trj trung blnh nay.
- lJa so d~i lu(}ng gl.lP trong thvc te ia cac d~i lu(}ng HEm tue. Dieu khi€n
t.huan .,0 doi hoi sv d~ng cae bi) doi tttdng t1,t - s6 sau bo cam bien. Vi$c nay
d':t ra van de d(:t chinh xae va s6 hit do dUQ"e d6i voi dnh toan trung gian va
doi voi cae bien ra tac d(:tng len cac eo cau eong Buat.
- Ve m~t rai r':.e hoa, vi d~ eac dUll bien toe dq neu ta chQn hq dim bien
tac dqng theo tan so, vi~c do se t.ien hanh trl,tc tiep duol d.;mg s6 nhung d':t
dt/<;lC dQ ehinh xac cao se doi hai nhieu thai gian va ehu k5' lay m:1u phAi Ion,
dieu nay la bat l<;li cho vi~c on djnh eua illach vong dieu chinh, d~e bi~t. Q fan
so thap. vi the nguai ta tro I~i sit d~ng may phat toe va hi) bien d6i tuong
tv so co dai thong tot ho~c thay doi d¢ ehinh xac (s6 bit) tuy theo truang hQP
sil dung va dili toc do (t6c dq eao, toc dq thap, dieu chinh toe d¢, dieu chinh
vj t.ri ..J. Dieu nay d(1t ra van de ve lay mliu b:h buqc phlti co thai gian thvc
hien cac phep tinh dm thiet.
- Van de IUQ"ng tv hoa cling rat nh1.lY cam khi Jilill vi~c voi momen nha
tl'ong vi~c oieu chinh m{lch vong dong di~n. Dj{~u chinh sO dnh toan mrle d~t
dong di~n, a mue thap ehuan dong di~n ling voi so bit nha, do do kho xac
djnh. Nhi?u gay 1'a do viec Iu(;mg til hoa se Ion vA. d~ tao nen cae sl,l co, VI d~
t':.o nen dao dong.
DIm gitin I'(i thiel k€ eua Ji"eu khien lurTnK W
Trong m~c t.ren t.a thay rang dieu khh~n tuong tv t.ro nen n~ng ne doi
voi cac d;~u khien phrlc tap, tuy nhi~n amlic dlj ca c!'lu hQP Iy thi diEm khien
tl1dng t.1,1 I~i nIt dan gian ve phudng dien cau true.
Thl,1c v$.y vi ::;v hQ"p Iy ella thiet hj ho;,e do cae t.hu nghi$m tieu chuan hoa
(dap ling dieu hoa, dap ling xung ddn vD nguai ta thl1ang co thai quen tim
kiem cac fila hinh toan lien t~c hang cae phuong trinh vi phan, ham truyen
d~t. va xac djnh kha d~ dang M so khu€eh d~i va hang so thai gian eua hi)
die.u ehtnh. Cac mo hinh nay Iii. gan dung nhung cae ky su biet TO chung dUQc
slr d~ng cho t.fnh toan sa h(:l cae b6 hieu ehtnh con cae thong so cua no co the
duqc tiep t~c hieu ehinh b1l.ng thVc nghi~m t~i eho lAp dat
13

14. SIj tim kiem cau truc dlja tr€m viec Stl d1,lng cac m~ch yang long ghep van
~-~~~-~-~-~~~-~-­di! giai quyet hem. Trong cac diU truc nay dau ra clla bl? di"€m chlnh ung voi
m¢t Yang, vi d1,l m~ch yang t6c d6 tTd thanh dai 111c;mg d~t cho b(:l diflu chlnh
cua m~ch yang b€m trong, vi d1,l m~ch yang dang dien, Cac bien nay lit cac
d~i h.1dng vat Iy, lien t1,lC nhtt dong di~n, t6c dQ dttQ'c do bang cac cam bien
ttwng tl,l cung clp cac d~i 111Q'ng lien tI,lC Ia cac di$n lip s1.1 d1,lng m(lt each
trl,lc tiep Tom l~i vi~c thi/~l ke m~ch dieu khie'n t.llcrng t.l,l va lien t.1,lc Cl'm M
thong dan den cau truc diim khi~n ddn gian
Trong khi do dieu khie'n so thl10ng d1.1Q'c coi Iil. di~u khien phuc tap. Cac
bien dieu khie'n khd truy nMp, trit trllong hgp chllcrng trinh phAn ml:'!m da.
dV kien. Neu ta Stl dung- b6 vi x1.1 If de thvc hi¢n nhieu chue nang can phai
thVc hi~n tam nhin tong the'. Dieu khien so cd the Hnh h9i Hnh thAn clla
dieu khien h1dng tv doi voi cac mach vong ben trong: lam gan dung lien tiep,
chia cat bai toan Ian thanh cac bai tOlin nho nhllng vi~c thvc hi~n bltng 96
khang Hnh ho~t nhu dieu khiP'n tttcrng- t.11.
- Chllcrng trlnh phan m"em phai x1.1 Iy tren mot khoi toan bO cac van de
ma dieu khien tlldng tu giiii quyet bang cac l11Mun rieng re,
- Viec thay d6i cae h~ so cua cac bc) dfeu chinh so t€ nhi hcrn nhieu so
voi vi~c hieu chinh be) dieu chinh tucrng b,1. Khi thu nghi~m m~ch tucrng tl,1
ta co the' dieu chinh tit tit cac thOng so Ine)t cach an toan, trong khi do voi
ky thu~t 96 l11"t IOi ve so cd the' gay nen M.u qua nghiem tr(;mg.
- Cuoi cung vi$c L1y mau rat d~ gay mat 6n djnh va kh6ng phiii baa gid
cung co th{i" gW dU<;jc thOng s6 cua chu ky lay mau do anh huang cUa thai
gian tinh toano
Do v~y eac 1116 hinh Sil d1,lng thl10ng 13. 1116 hinh lien tl,lc, dan den cac
thuit toan dieu khien lien tl,le sau do lam gan dung bang eac thul}t toan rai
n:te.
Chien luQ'c nay co nhung h~n che' (xual hiiiin dao dong ho~c mat 5n djnh
ma cac mo hlnh lien t1,lC khang the dl,1 tinh het), vi the vi{Jc m6 hinh hoa h~
thong thea quan diem dieu khie'n so dUQc phit trie'n rat m~nh. Ta se thAy 1'6
trong cac ehucrng tiep thea cae phudng phap bieu dien toan hQc 1a cOng Cl,l
quy gia doi vai vi$c tong hQ'p quy 1u~t dieu khien khi ta bien ddi cae m6 hlnh
t.oim hQc thanh cac ,,(1 do chtk mmg,

15. 1.2.3 Cae LlU diem c6 tlnh chat quy't d!nh cu. dieu khi'n s6
Ta thay rang trong cac lInh vl,lc quan tr9ng di'eu khi~n tuong tl,l co Liu
diem n6i bAt so vd'i di~lU khien so: do Ia dnh tac dong nhanh, Mc dOng li{!n
tl,lC, st dOn gian cua diu truc dieu khie'n. Nhung neu dieu khien may di~n
dAn dAn chuy~n sang dieu khien hoAn toan s6 IA do cac d$.c dnh quyet dinh
cua cac Hnh ki¢n 96. Cac Hnh ki¢n so cho phep thtc hi~n cac thao tac phlic
ll;tp duoi d:;mg rAt chIle chan. Do dnh cMt nay noi chung 80% linh ki~n co
m(l.t tren thi truong hii?n nay la cac Hnh ki(ln s6. Do v~y mOt trao lLiu chung
trong ky thu~t la chuye'n ttl ky thu~t hldng tl,l sang ky thu~t s6 rnA dillu khilln
may di(!n khbng phai Is. truang hQ"p ngofJ.i I¢. ThlfC vi[l.y, ky thu~t s6 cho phep
tAng ty s6 gilla dnh nA.ng va gia thAnh. Cac uu di~m cua ky thut),t s6 th{i' hi(!n
cJ hai mat:
Dieu khi€'n thijng minh
Cac chuang trinh phAn m"{illl cho phep t6i uu hOR di"eu khien va thay d5i
cac dnh nang mong muon, VI dl di~u khien rna men hoac t.u thong kh6ng
doL .. Co the' thl,lc hi(ln dieu khien logic phuc t~p nhLing trong truang hQ"p nay
gia thanh thiet bi r:'it dilt va ton nhieu thai gian thl1c hi¢n. Nha di"llu khie'n
so ta co the tru tinh cac d.i tien, Cll the la:
- Trong do luang va xu Iy tin hi¢u.
- Trong vi¢c danh gia cae d~i 1t1Q"ng ben trong h¢ thong (tu thong, cac
bien theo d9C trlc d va ngang tr1,lc q) ho~c cac bien ngoai khi ta muon lo~i
bO ml)t so cam bien VI dl dun ·bien toc do.
- Trong vi¢c xay dl,lng cac thui[tt toan rn~nh han cac b(l dieu khie'n PID
kinh dien vi d1,.l nhu dieu khie'n phi tuyen, ho hi(lu chinh tl,l thich nghi, M
th6ng co rno Mnh chua":n, che do tntQ"t va hi¢n nay Ie. dj"llu khien rna, dif!u
khien nOron.
~ Trong vi¢c tu vi'ln bao tri va phat hien sl,f co.
- Trong vi~c tn;l giup tl,l dong hoa qua trinh (Ina- l1uiy, ham, tinh toan
quy d~o chuan).
Viec tang cae tinh Dang nay eo the lam giam gia thanh do vi¢c don gian
hoa ve philn cung.
Dan Kian hOa lhifl hi, t;eu chufin h6a va tich hflP h6a
Vi cae chuc nang dieu khie'n dl1Qc thVc hi¢n chu yeu bang philn mem, cho
15

16. nlm voi cung mQt thi~t bi phan cung onl)t bt) vi xu ly va cac giao di~n) dut;lc
sit dl,lDg cho mQi 11ng dlDg. Dreu nay dan den giaill cac chi tiet d1,l' phbng, do
do lilln giaill gia thanh.
MIJi.t khac dfeu khien may di~n IuOn nllm trong khung canh t1j d"ng hoa
toan btl hi? th6ng, ngay nay dut;!c thlJc hi~n bimg may t:inh. Vcri cung m"t cong
ngM (sCi va cilng cac b¢ vi xu ly) co the th1jc hi(!n muc phan cAp t! dQng hoa
khac nhau, Hun de dang cac dch hQ'p va dong b¢ hoa llWi phan tu. Cae dnh
chat nay khOng de dang nh~n dllQ'C vdi tl'l hQ'p bao ghm mQt may dnh trong
tam, cae otolmit l~p trlnh va cac b¢ di~u chinh tt10ng t1,1-
1.3 XU HUONG PHOI HOP mEU KillEN so vA D1EU KHutN TUONG
TV
Do cac d~c diem da neu a tren trong linh v1jc dieu khit?n truyen dQng
dii;m xu huang hQ'p ly Iii. dieu khien s6 dUQ'c th1jC hi¢n trucJc het a dfeu khie'n
toc dl) va vi tri ciing nht1 dieu khien so bl) bien dl'li. Cae chllc nang dbi hOi
diE!U khie'n tac d¢ng nhanh duQ'C th1jC hi(!n bang dieu khien tuong t!. Cac
chuc nang a muc d(l cao, di~u khien th6ng minh nhung th1,l'c hil;m ch~m han
se duQ'c th!c hi~n hllng kg thUt).t s6.
~n hlfu'-=C"-=ro='~"-t______-1
L __~O::..c .llI'ft"'=---_~.,_'--1 A ()o hit/no til' " ,
..!....- N " ;J. eo cOm hien vQxll'ly
Hlnh 1.3. Cau true dieu khien sO dOng cO di~n mot chillu.
Ta tra I:;ti vi du sd do hlnh 1.2 Cau truc dieu khie'n so cua sel do hinh
1.2 duQ'c cho tren hlnh 1.3.
Trong sd do nay ta nh~n thay co sl) ket ht;!p giua dieu khien tuong t1,1 va
di"eu khien so.
16
Co s! phan chia cac diE!U khien dong di¢n, toc d(l Vll vi trl.
Dua vao cae: tin hi$u lien quan den an tOl'ill.

17. - BQ dieu khien s6 dlla tin hi(>u dong Il(I hall.
Ml}.ch vbng lUang til in m(lch dieu chlnh dong di~n va b(l bi~n d6i phAi
rot nhanh va 6n dinh d~ dong di~n phdn il:ng dQng ca tac d(mg giln nhtl lil:c
thai . Chufln mil:c dong di~n dllQ"c tlnh toan bang bO dieu chinh 56 toc dQ. Lien
h~ giua cac phhn di~u khien 86 vA. dieu khi~n tllong tv nha cac bQ d6i wang
ttJ- s6 A- D va b¢ d6i s6 - luong l~t O-A. BQ di?!u chlnh thuang 11 PID ,,6. Mo
hlnh loan hQe ella M th6ng va phllang phap phftn deh h~ tMng dieu khi~n
truyen dOng di(!n mQt chieu s~ dllQC dl! c~p trong "huang 5.
1.4. PH61 flOP D1EU KHiEN TUONG TV vA DIEU KHIEN s6 TRONG
D1EU KHlE~ DONG CO KH(JNG D()NG BO
&0-,. ba
Ph. '"-";!--!--1
MayblM
ap Kung
Cuv chI pha C
Bp vi xV Ii
580,
8# sasanll
Hlnh 1.• 0i8u kh~n dOng cd hh6ng dl.ng bO r6to dAy quAn ph6i hdp
d~ khiin hJdng IIJ vi dlkJ khiiin sO.
11

18. De' lam sang to tinh than ph6i h<;lp dil!u khien s6 va dieu khien tt1dng t1,l
ta xet so do dfeu khien d~ng co khong di"ing b~ rOta day qmin co hai nguon
cap tren hlnh 1.4.
Stato dut;lc cung cap tit lubi 50 Hz, dieu khi~n dU:9c thllc hi$n Mng vi~c
di~u chinh nguon cung clip cho rota qua b~ bien tan ba pha. Moi pha rota
dU<;lc n6i voi hloi qua hai cau Graetz n6i song song ng119c.
Tr{m Old do hint"! 1.4 ta nh~n thay:
- Phan di(m khien tuong t1,i baa gom mliy phlit xung va logic chuy{{n m~ch
cua chung.
Philn dil~m khien s6 tht!c hi$n m(:it s6 chuc nang dieu khien b(l bien tan:
• Phat tin hi$u di"eu khien ba pha
Xac dinh thai diem chuyen llwch cua m(:it cau so voi cau kia bAt da.u
t1 s"l,i deli dau cua dong di~n. Dieu nay dUQc xac dinh nha b<) lQc co tan
s6 cat dUQc kMng che.
Tinh toan dieu ki$n dau cUa goc moi cau ngu<;lc (If'2. = Jr - '1'1) de dAm
bAa s1,l lien b,lc cua di$n lip trong phs co lien quan.
1.5 VAN DE TAN s6 TRONG DIEU KHiEN s6 MAY DI~N
De thay ro cac van de d~t ra voi dieu khien so d~c bi$t neu so slinh voi
dieu khie'n tuang t1,l ta xet vi dl,l dau ti~n ve dieu khi~'n trl,lC trong robot. Ta
co the dLla ra co thai gian th1,lc hi¢n cac dieu khien khac nhau tren bieu do
thai gian d hlnh 1.5 gom 6 muc dieu khh~·n. Trang l$p trinh thai gian thvc
de thvc hi$n nhiem Vl,l nay ta co the gia. thh~t rang mlii chuc nang dUQC th1,iC
hi$n bang mot chuong trlnh con rieng re nam t'rong DlUC Ull tien ngat rieng.
Vi ly do an toan so cang Ian muc Ull tien cang cao. Ta co the dua ra gia tri
dien hinh cua chu ky lay mllu gan voi tUng nhi~m Vl,l. Nhu v~y co thEi phAn
ra cac nluc sau:
Muc 1, chuan vi tri dUQc hien thj vm chu ky co 10ms;
Muc 2, bt) dfeu chinh v1 tri, may tinh quy d~o voi ehu ky My mau 10ms;
Mue 3, ma.y phAi dap ung voi toc d(:i trong khoAng vai mili giay. DAi
tMng Me d9 vao khoang vai trAm Hz, do do chu ky lAy ma.u co mili glAy.
- Mue 4, momen phili dap ung trong khoang vai tr6m micn') gilly, cae m~eh
vbng dong di~n phAi co dAi tMng vai. kHz, chu ky bly mau khOl:lng 100 J.1s;
- Muc 5, bl) nghich luu cung ctlp eho d¢ng Cd cha:p hanh dung sO do tranzito,
18

19. tan s6 chuye'n m~ch thuang
Ion tu 5 den 20 kHz, chu ky
bam la 50 fiS.
- Milc 6, m6i be;. bien doi
phAi kh6ng ch€ d1l9C cac hi(m
tt/9ng di~n xAy ra rat nhanh
(an to~m, giarn sat 51! chuyen
nWch cua linh ki~n, do do
khoAng thai gian co micro
giay ho~c nha hdn).
Mot vi dl khac ve bieu do
thai gian la bO bien d6j toc dO
de;.ng cd dUQC cung cap bing
bO bien doi chuyen m~ch tl!
nhit"m bang cau tiristo a tan
so 50 Hz. Ta c6 cac rnlilch
vong dong dit"m va doi voj be;.
ngh~ch 11lu co tan so rat thilp,
Trim bieu do thai gian hinh
1.6 tan s6 chuyen rn~ch eua
,
chu ky may f(nh qui ,juo - Jams-
(hu kif b{j ,ji€u chihh vi fr;' ~ /0 ms
(nil ky bo (lie" eli/nk IDe tla., tms
Chu,;: bOJjig~~lnhdon (lifn Jo S
ChI! ky hdm rhu kif ,,, hi !J;en rfai gidm $fjf 3,, '"50]''i , ~lpS ,
~,"" Jri1~ 6lf6lr6l"
- --
--
Hinh 1.5. Si~u d5 thdi gian di~u khi~n true
raMt b~ng bO nghieh Illu Iranzito.
, y
'" m -m
chu ky bp (Mu chin/!
d009 Jien'3,]ms
, clw ky enuye}" ,, milch bp Nlnda; 4 s,
~3,lmS
,
~
bi? bien doi 113. viii tram Hz,
thai gian dap ung so voi bieu
dO hinh 1 5 chi ling voj 3 milc Hinh 1.11. Siau do thdi gian bQ bign dOi ehuyiin
m~ch tV nhi~n bA.ng bO chinh Illu tiristo
mac 3: dieu chinh toe do;
mac 4: di"E!u chinh dong di¢n;
muc 5: philt xung di"eu khi~n hi? bi{fn doL
1.6 BAI TOAN DAT RA DOl VOl DIEU KHIEN SO MAY DIeN
Dieu khien so nUly di¢n la dieu khien thai gian thljC clla d6i tL/9ng co rna
hinh toan phuc t;:tp. N6i chung nhi$rn Vl dieu khien so nHiy di~n dUdC chia
thanh cac blloe sau
1.6.1 Xiy dvng mb hinh dieu khi~n
Xuat phat til nhiem Vl dieu khie'n truyen d¢ng diE;!n ch(;m sd do bo bien
doi va d(mg Cd tnlyen d¢ng thich h9P, xay dl!ng sd do rn<),ch di?ng ll,lc va dieu
19

20. khie'n. TO: mo hinh tong quat phan tich va chia thanh cac vbng diEm khien.
Phan cap die vang dieu khien xac dinh vang dieu khien tu'dng t1,1 va vang
dieu khie'n ::;0, ch9n chien IUge dieu khiE'n.
l.S.2 Xciy dl,l'ng mO hinh toan cho he trUYEm dQng di~n
Xay dl,lng mo hinh toan eho bl? bien d6i dQng cd truyen d(mg va mo hinh
toan cua cae cam bien do luong, cac co cau so sanh, chap hanh.
1,S.3 Xac dinh thong so cua cac m~ch yang tuang tl,l'
Can ell vao cae dap ung Hnh va d(>ng va ket cau m~eh vang dieu khien
tu'ong tv, phan tieh va tong hop thOng 56 m~eh vang tuong t1,1 du'a trEm co so
ham truyi;m va bien deli Laplace.
1.S,4 Xac dinh thong 56 cua m~ch Yang di~u khien 56
Nhi$lll Vl,l nay baa gom hai van d'A quan trt;mg:
- Phiin cling: ch9n bo vi xli ly cd bit may, toc do, dung hieing bo nha, s6
giao dien VaG ra t.hich hl.1p eho nhi~m VI,l dieu khien.
- Phan mem: MC dinh ehu ky lilY nul.u va lap trinh eho m~eh di"eu khie'n
so. D1,1 t.inh d.c ch(ie nang bao v~, an toan, lien dQng v, cac ehllc nang ma
lluiy, ham dong cel. De thVc hi$n cae ehue nang nay t.a se si1 dung eac m6
hinh so d-lJa tn?n bien doi Laplacp roi rac (hien d6i z), ph,n tieh m~ch dieu
khien tudng tl,l va so dua t.ren co sa grafeet, m~ng Petri. Chung ta se phan
tich chi tiet cac van de nay trong cae chuong sau
De lam vi du ta xet cau trlle t6ng quat ella h$ thong diCu khie'n hoan
toan s6 dong dieu khif,'n dong cel mot. chieu gom cae mach vong dieu chinh
dang di~n va dieu ehinh t6c dQ. TrE'n hinh 1-7a 1ft sa do chue nang, hinh 1-7h
h sa uo bf.i t.ri phi"m eung va hinh 107c 1< bi~u do thai gian. May tlnh thu'c
hien nhi~m vu bo dieu ehinh cling vdi cae C<'l.Ill bien tac dQng len bQ bien doi
]fl b6 ham dong di~n 1119t chieu cung cap di~n eha d9ng co 'Trong so do 16 trl
phan cling hinh 1-7h ta nhan thay co su phan ehia nhi~m Vl giila 2 may vi
tinh:
20
May vi tinh chinh d,m nhipm·
Dietl chinh vi t.ri
Dieu chinh toe dQ
Dieu chinh dong dien

21. ----- I Cdm-bieiJ~____--J
--- -- ------ ·1 Cam hien d:EZJ-------------
May I/nh chinh
_Dieu chinn vi ki'
_Di€1/ eh/nh lo~ do
_OI€U chinn dong dl~n
_An foon
· T/nh cae (tiling ddl vi fri'
· Giao hip
· Ghi
~ D{~IJ khien fruyen dJ Ilfli
0) Sd di5 kh5; cllI/'C nang
h) Sd clJ ba' fr/ plufn cII'ng
, _____________ Do vi Iri'
____________ Da 10' dp
r- ______.._ Df} dang dien .,
,- __ fin h;§u Jieu /chien &5 bIen £J, r--- -
, B" d'" I ' : I "~' ~2 O,eu chrnh vi Irr 'pp H--t----L+-T- pp ~ I I I:1-
3 [),1!u chlnh toe do L_l1U~_ ~__~_4 5_~---':__ 7i_~~_ 3 ,4 ~ 67
4 Oi'eu chlnh dong dien i: ________ ~-----+-i ~
5 Chu.in bl d,1!u chlnh dong olen' : Tcv " I
, fo------ ________-----j----".f
6 Chuiin bl dj'eu chi'nh tOe do: Tcp
-7 Ghl :
T
- ------------j
,
PP Tni ve chudng tr'inh chtllh J.o- __
To, Chu ky lay miiu cua bQ dl1!u chi'nh dong
----i'!-- ----
T, v Chu ky lay miiu be dleu chi'nh toe d6
c) Bie.~ da Ihiii gion
T,." Chu ky lay mau bo dieu ehlnh VI Irl
Hlnh 1_7. Cau true he th6ng dleu khie'n hoan toan 0.6.
21

22. An toan, baa v~
Danh gia momen can nhall1 nl1,le dich btl dl).e dnh
Tinh tOfin cae gia tri d!).t vj trl
Giao tiep voi ngttbi dieu khien
Ghi cae sl,f ki~n
Dieu khie'n vi~e truyen du Ii~u
May tinh thu: hai dAm nhiem viee xu If du Ii~u vi trl.
Ta nhan t.hay cae thai diem lay UlaU ling vai cae m~eh yang khac nhau
kh6ng dttqc dong b¢ hoa. Ta co t.he dnh d@"n dieu nay bA.ng each dua va~ thOi
gian t~ trong cae m6 hlnh eua ham tTuyen. De xilc dinh b¢ dieu ehinh ta
phai nghien cuu tirng yang dieu chinh bat dau tu yang trong nhat rai Ian luqt
xet. tirng yang ngoai.
Theo quan die'm If thuye't diflU khie'n tl,f d(lng bieu do thai gian toan M
thOng dUQ"e cho tren SCI do hlnh 1-8.
00 dqc
tc ' T~ui giO!l linn (oan
can !/Jlet cho a;ell kniln t~, Thill rian tlhh loan clllltin hi
clio r:hll ky lIip th~o
I I I
: I_Df Ire~9ay ~11 !uTi bp bi~~(O;= 1f
I I I
I DOfrifu'dngdtlo'ngfO'ng .. r; I t NT-r; I••------~~~~~~~~~~~--~,----------.il·.----~--~-----.
I I I
I Cnll KY ' T I T I
I~·__________-C~~~~__________·,i··----------~------------·
I I
I NT(U-d';yN=2) I
I-·----------------~~~~----------~·,
Hlnh 1-8. Bieu do thai gian eua hI;! di.. khign hoan toan s6.
D6i vai h~ th6ng dieu khi€!n ngttoi ta t.hltong phan thanh 2 tTl,lC:
- Truc d¢ng Il,fC gom nguan dien, b(J bien d6i, phu t..1i di$n CCI gdln d(Jng

23. -'-
NgU'On ifn
' ,
ral jBp hien 1I0i finn
'. j~
True dOllg Jut:
, BP t:!i~U khie~ ,;0,.,,~
1
.
,
'~ ~!:'
~.~
Macy lin/!
~, ',i:
%
~
~
~ '~
' Bp (!feu Hie-n L:
eire-dO hot? t!$1Jj
!
,
IGia(l flip,,, Gia frj cf';l
Hlnll ,.8 C.!u tr(,!c chung h~ thOng ky thu$.t dUQc dibJ khien bang may tfnh.
Ir·············· ---------,
IiB9 hien rJ6i linh
IN9uan ifn t
~
Moy
Pdifn
r ~
Co' eau lac orinJ
8# aim bien (foe rip, ..!
Ir( tlifn ip,tlring 1I1f1l)
11111
( )
89 tfi€u khiin
,
m
I J J
c )
May hi7h lillie hltf'fJ eric fl1IJ¢1/rXm
t
I G'-om ,01 chung !
Hlntl 1_1D M6i rll~n M gilia tr!,le dong Il,lc va do Itldng di'eu khien.
23

24. l:d di~,n va e~lc h~ thong truyen d¢ng.
1'r!,ic do luong dieu khip·n bao gam:
B() dipu khie·n mai, xU: If c:-ic ehue nang logic dieu khie'n ehuyen m~eh
eua cae bo bien doi. Do IA eae ehde nang lap I~i, ed tan so eao, dnh
den an toan eho dc Iinh ki08n di~n ttt cong suat. Van de nay co the xu
If bang cite llH.lCh doc 11~p hm)c dua vao trong clie chllc nang eua bo vi
xV If toe d9 ca~ .
• May tinh lam nhiem vu dieu ehinh (ll1~eh vong dong di~n, toe do, vi
trl. Hnh tonn quy dQ.o, urinh gia cae dai IUdng khOng do dUdC, bil anh
huang nhipu, bil phi toy~nJ. Vi'! llltt phan et1ng c(; thp· su dlng mot
hoac nhfeu uQ vi xV l.v hmle c,ie linh kipn chuyen dung khae.
• B) dieu khie'n ehe do hO:.lt d¢ng. Do la cae Go gi}im sat xfie dinh eae
ehe do h01.1t dong: ehay, dirng, 1110 nItiy, rhM hi~n Sl( co.
Trong khoi do lui1ng dieu khi~;n tif,u chuan hie d¢ng nhanh dong vai tro
quan tn:mg. MOt so chac llang nam d tanh gidi cae khoL Neu ta muon thvc
hien lll(lCh vang dong dipn t:ic dong nH nhanh ta eoi nhifl1l VI nuy do b6 dieu
khii'in gan IhVe hipn Hlnh 1-0 h'l. diu t.rue chung eua hp thong ky thu3.t duqe
elif-,lI khipn hilllg m;:iy dnh, can hinh 1-10 h'l. moi IiEm hf gitta trl,le d¢ng lLie
va t.rlc do itrong dii'u khipn.
Ta nh~n thay h~ thong dipu khi~n ;;0 nuiy djpn Ia kH c11n phue t.1!-P trong
do may tinh thalll gia vfw qua trinh do Iltang, dfeu khi6n, xV Ii tin hi~u nhil.lll
t.ae d¢ng len he thong dong il,il: gaUl ll11iy di~n v;'t b9 bien doL 0 dfly ta phai
giai quyPt. van de phOi gher m1iy tinh Vl h~ t.hong truypn d¢ng di$n va l.ip
trinh dicu khif'n ht;- t.hong nhnm thim mH.n e~ic yell ci1u cong ngh~.
24

25. C/ul'flng 2
xv LY TiN
Chuang nay trlnh bay khai qUIlt nhung viln oe cd ban ctm cong el,l toan
hoc ;ot! dl,lng trong dieu khie'n so, do J: Xl! lY tm hii?u ,.;6 ),'0 gom vi~e bie'u
di{;n t:~ic M thong roi rl:J.c, hillll t.ruyen o:~t eua hI') thong l'iJi n~e, phan deh h~
t.hong rai r~c trong lllien z, bien d6i Fouripr rai r~c va h6 iQc s6.
2.1 TiN HI/!:U VA HIt TH6NG ROI ~c
2.1.1 Tin hieu tU'ong tl!
Tn dri quen vbi d.c tin hifu co d9 dn v,l bien thihl lien tlc VI du di(;n
~lP do dHQC tren qp nhi~t ngau cho t.a thong tin vll nhiet do moi tntong hi
ham cli~n lip lien tl,lc theo t.hai gian u(tJ, dien ,ip tren r:tfc nuiy phit toe cho
ta th6ng tin VP tOc dQ true quay rfmg ill h(llH lien tlc thf'o thai gian nit) Mot
cach tong quat. ta dinh nghia tin hi$u tuong tt ill ham co 00 ldn bien thien
lien t.l,lc. Tren hlnh 2 la i.?l. dl:J.ng bieu dien cua tin hipu htdng t.V XltJ
2,1.2 Tin hi~u iU'qng tu h6a
o t
0)
60
40
30
20
oL-------------~t
b)
Hlnh 2.1 Tin hieu luang lu ia):. Tfn hie!) luang IW haa (b).

26. Neu bien d¢ cua tin hi~u liflfl t~c la rdi r~c til gQi tin hi~u do la tin hi~u
luang tit hoa Tren hlnh 2.1b la d~ng bieu dien cua tin hi~u luqng tu hoa cua
tin hi~u lien tlc.
2.1.3 Tin hi,u rai r(lC
Ne'u t~i tUng buoc thdi gian gQi la chu ky rai r~c T ~ ta X8.C d~nh dO Ian
cua tin hi$u ta duqc tin hi$u rai r;:te, neu bien d9 cua tin hi$u rai r;:te Iii lien
tlC (kh6ng dudC IU9'ng tit hoa) thi tin hi~u do gQi li'l tin hi~u Jay mAu. Hlnh
2,2a la bigu dien tin hi~u lay mau.
2.1.4 Tin hi~u so
Tin hi~u so lit tin hi~u dl1Qc rai rt;lc hoa ea bien so va bien dQ, khae voi
tin hi~u tuang tv la tin hi~u lien tlC v~ bien s6 va bien dO. Hlnh 2-2b bieu
dien t.in hi$u so x(nT).
'5D -.------- - -----
:: ::-:l~i::
I
0) b)
Hih 2.2. Tin hi~u lay m§.u (a); Tin hi~u s5 (b).
2.2. CAC H¢ THONG XU LV TiN HI¢U
Ta thudng phan lo~i M thong xu Ii dn hi~u thea dn hi~u can xu If;
- H~ thOng tuang tI! co cac d~i 111Qng vaa va ra I~ tin hi¢u tl1dng W. Hinh
~L_ _~b
a) b) oj
Hih 2.3. H~ thOng ttl(Jng tl.,l (a): He thein9 s6 (b); He theing xU Iy sO tOng quat (e).
26

27. 2.3a lit Sd do M th6ng hidng tlj.
- H~ th6ng s6 co cac d:;ti hiqng vao va ra lit tin hi~u s6. Hinh 2.3h la sd
do h~ thong s6, trong so db nay ta nhi;ln thay neu h~ thong so duqc n6i vai
h~ thong tuang tv thi t:;ti dau vao cua no phAi co b¢ d6i tuang tlj s6 ADC va
dau ra phai co b¢ d6i s6 - ttfdng tv DAG H~ thong xit ly tin hi~u so t6ng
quat cho tren hinh 2.3c.
2.3 B1EV DlEN TiN H1J1:V.ROI R4C
M¢t tin hi~u rai Tac dtfc;:lc bieu dWn bang day gia trt thljC ho!}c phuc. N~u
tin hieu do dtfc hlnh thanh hOi gia tri thtfc thl do 18. tin hi~u thtfc, con neu
dtfqc hinh ths.nh bai gia tr! phttc thi gOi IS. tin hi~u phuc.
Tin hi~u rai r~c duac ky hieu li'I. x(nT), trong do nTs }i'I. bi€n d{)c l~p, n
li'1. so nguyen, T~ Iii chu ky lay m:lu De thu*n ti~n bien dien ta chml'n hoa
_ nTs
bien dqc I~p nTs vai chu ky liiy mau Ts Wc Ii'!. '1'= n.
,
Ve m.'lt toan hoc tin hi~u rai r~c x(n) duJc bieu dien nhu sau:
~
bOieU thuc toan hoc N I .:5 n .:5 N2
x(n) = (2-1)
n con l:;ti
vi dl!- 1 Day xung dan vi
Trong mien n day xung dan vi duc
bii~u dien nhu sau:
(2· 2)
n ' 0
Do thj cua o(n) cho tren hlnh 2-4.
v{ du 2 Day buac nhay don v~
Day buac nhay dan vi trong tni~n
n dU;lc dinh nghia nhl1 sau:
)
In,.o
u(n) = '
~ 0 n 0
(2·3)
Do thj cua u(n) cho tren hinh 2.5.
o(n)
3-2-10 2 3
Hlnh 2.4. Xung ddn vi.
Urn)
-I 0 n
Hlnh 2.5. Day bu6c nhay dCln vi.
27

28. 2.4 H~: THONG TUYEN TiNH
2.4.1 H~ thong xu Iy 56
He thong xli ly s6 ULlQC di).C t.nrng bdi ll1(Jt toan tll T hlill nhiem VI bie'
doi day vao x(n) thanh day ra Y(UJ, ky hii}u nhu sau:
T
T[xlnj] = y ho;W xln} -~ yIn)
N{;u h¢ thong Iii tuyi;n t.inh. t.min tll T thoa man nguyen Iy xep chong
nghia 1:i:
T[ax,tn) + bx~(n)] = RT[x,lnl] + hT[x~(n) = aYn) + by~(n) (2-4)
a, b Iii h:li hi'mg so hat ky:
YI Is dap ting cua kich t.hich x I(n J:
y~ La qlip ttng Ct'm kfch thfch x2(n).
2.4.2 Oap ung xung eLla h~ thong tuyen tinh
M6t day xln) bllt k~' CD t.h{: dUde bi{iu diEm bang bi{iu tht'ic tong sau day:
x
xln) = Vx(kL(~(n - kl
. h~--x
Neu hi' thong b tuy~;n dnh
x
ylnl = T(xlnlJ == 'l'[.2;xlkh-(n - kl]
,~~
vi x(kl u(Jc lap vO'i n nl'n tn co
x
y(n) == T[x(n 11 = 2:x(kIT[(~(n - kJ]
k ---:0
x
YIn) = ~xlklhl..(nl ,
j,,=-x
h!-(nl gQi la dap tlng xung ('['In he th6ng tuy(n tlnh.
(2-51
(2-61
(2- 7)
(2- 81
(2-91
Hp thong tuy{:n t.inh h:lt hir;n co hl(nl kh6ng rhl thlU)C viw k, con np'u
viii t,lc d6ng g:i6ng nhau d (,,1[ thni lli(lll' kh:ll: nhau h~ th6ng sf' cho d,ip dng
kh,ic nhau hi h(' thong pht,l thui'll' v:tO theri gian DCli voi hr· th6ng btit hjp'n dap
28

29. ung xung kh6ng ph! thu¢e vao thai die'm xuat hien eua xung, hie do deh ehi1tp
rai rQ.e CUR tic d¢ng v6i d:,ip ling xung 5e eho tin hieu dati ra eua he thong
h(n) = T[o(nl] thl
h(n - k) = T[(~(n - k'l] = h).,:(n)
Phuong trlnh (2-9) dan den tong deh eh~p
,
ytnl = l:x(k)h(n - k)
~ =--«
T6ng cae deh eh~p thuang duqe viet ngan gon nhu san:
yin) = x(n)*h(n), hoae
yin) = h(n)*x(n)
(2-1m
(2- III
(2- 12)
(2- 18)
Ve phai cua (2.13) co dnh chiH giao hoan nghla la eel the viet (2.12) nhu
sau:
,
yin) = l:htklx(n - k) (2- 14)
k =--«
Ve m~t v~t Iy sIJ giao hoan nay co nghia Iii. neu dau vao eua h~ thong iii.
x(n), dap ling xung ia h(n) va dau vao cua M thong ia htn), dap ung xung iii
x(n) thl h~ th6ng se eho ra eung 1ll¢t dap ling dliCJe deh chi1tp bili hai ham.
2.5 DAp liNG XUNG vA HAM TRUYEN DAT
Dap ung xung hit) ia dap ung eua he thOng khi xung kieh thieh la Dirae
haEm toan d!)c tru'ng cho M thong rdi r~c Dap ung eua h~ thong d6i v6i mQi
be d¢ng bat ky duqc X;:le djnh hb.ng cae bie'u thlie tieh chap (2- 12), (2-14).
Viee xac djnh dap ung xung trong nhicu truang hQp rat kho khan, do do ngu'di
ta thuong dung ham truyen dat de' d~c trl!ng eho M thong. Vi~e xae dinh
ham truyen d~t elm h~ thong xung s~ duqe giai quye't. tron ven khi ta hie'u
di~n he thong va tin hi~u rai rae trong mien z.
2.6 BlEU DIEN H~ TH6NG vA TIN III~U R(lI R4C TRONG
MIEN Z
2.6.1 Bieu di~n z thu~n
Trang cae mue trt10e ta kh1'tO sat tin hi~u va h~ thong rai rae trang miEm
bien 86 d¢e ii1tp tIJ nhien Trang nhieu truong hqp each khao sat trIJc tiep nay
g(lp nhfeu kh6 khan VI ht? thOng phlir: tiP va hieu qua kh6ng eao. Ta :311 d!ng
phudng pha.p khao sat gian tier thong qua phep bien d6i lam nhiem vu ehuyen
29

30. mi~n bi~n so dQe l~p sang milln mai.
Bit'!n doi z dong vai tro ·nhli bien d6i
Laplace trong vi~e phan tfeh tin hi~u
va M thong lien We vi the ta can
gQi bien doi z Iii bien doi Laplace rai
rf,lc. Quan h~ giua mien n va mien
z dU9C minh hQa tren hinh 2.6,
2.6.2 Bi~n d6i z
Mlfln n
bi@n doi z th14n
billn d6i z ngl1!;1c
Hlnh 2.8. Bien doi z.
Bien d6i z eua tin hieu rai r~c x(n) trong lUren bien s6 dQc ioip tV nhien
n 1a phep bien d6i tin hit?u X(z) trong mUm phue z theo hie'u thue sau
x
X(z) = Lx(n)z (2-15)
n=--Xl
Theo quan die'tn toan ttl: ky hi~u ZT lit toan tu: bien d6i phue ta se co:
ZT[x(n)] = X(z) hoac
ZT
x(n) --..... X(z) (2-16)
Bien doi z lit chuoi lay thua vo hl.ln. Chung se h9i t~ neu ehm5i (2-15) hi)i
t~. z Iii bien so phuc co the· viet dlioi d;:tng phan tht!c va phan ao:
z = Re[z] + jlm[z].
Vi n lay gia tri tit - 00 den +00 nen bien d6i z theo (2.15) gQi la bien doi
z hai ph18. Neu n co gia tIi tit 0 den 00 ta co bien doi z mQt phia:
X 1(z) = Lx(n)z
n=O
Trong m~t phang z co l1l~t vong tron
llng voi Iz I = r = 1 gQi la vong tron ddn
vj. Tron vong tron nay z = eI'lJ. Hinh 2.7
bieu difin vong tron ddn vi. Vong tron ddn
0. d~e bi~t quan trong khi danh gia cae
d~c tinh eua M thong so dt!a vao vj tri
di~m eve, diem zero (kh6ng) khi chung
nam a trong hay ngoai vong tron don 0..
Vi dlj.
Cho tin hi~u roi r;:tc sau dAy:
30
(2-17)
Re[Z]
Hlnh 2.7. VOng trOn ddn vi.

31. {
20
x(n) = 0
vai-oosn:s2
voi n con I~i
Ha.y xac dinh bi@n d6i z hai phia, m9t
phfa va mien hQi tl}. eua chung,
TrIL loi:
Tin hi~u x(n) co chieu dai [- , 2] =
00 du:qc hie'u dien tren do thi hinh 2.8,
Theo dinh nghia bien doi z hai phla
t.a co;
D6i hien n = - III ta co:
X(z) = 2:2-mzm + 2z-1 + 4z-2 + 1
m=J
,
GQi Xj(z) = 2:Z1Tlzm yaj
2 - z
ta dU:Qc:
m=i
,
X(z) =-- + 1 + 2z-1
+ 4z-2 vaj Iz I 2 va z 0
2 - ,
Mien hOi tl cua X(z) ni'nn Mn trong Yang tron co ban kinh 2, trlt g6c toa
d¢. Bay gio ta tinh bien d6i Z Dl9t phla cua x(n):
2
XJ(z) = Lx(n)z-rl = 2:2nz'1l = 1 + 2z-1 + 4z-2
n=1I nO
Mien hQi ty cua Xl(z) Ia toan b(l mat pha.ng Z tI'U gOc t9a d¢ z = O.
2.6.3 eVe va zero (Poles and Zeros)
Trong tht,lc te ta thu:ong gi:lP bi~n deli z cho du:6i d!;lng ty s6 cua hai da
thuc va nhU: yay X(z) lit ham huu ty eua z.
X(z)
N(z)
D(z)
(2-18)
31

32. - Ta g[.Ji cac die'm z =:; zr sao cho X(z,orJ = 0 ia cac zero cua X(z), do
chlnh Iii. nghi(lll cua h'( s6 N(z) Neu N(z) h da thtic b~c M ct'm z thi X(z) co
M zero.
- Ta g[.Ji clic diem z =: zl'~ sao cho X(zl'~) = 00 IS. clic ci'c cua X(z), do lit
nghi~m cua mAu so D(z) Nell D(zJ la da thti'c b~c N thi X(z) co N ci'c.
Ta co the bieu di€-n X(z) dttai d~ng cl/c va zero:
Neu N(z) la da thti:c h~~c Mella z:
N(z) =: b + biZ +
thi t.a co the: viet:
M
N(z) =: bM(z - zlIl)(z - zIl2l.··IZ - zOM) = bMfllz- ZUI.)
vai zr Iii cae nghi~m cua N(z).
Nell D(z) Ii da thli'c bi1tc N Clla z:
D(zl = a + alz +
thi ta co the viet:
vili zp/.. Iii cae nghi~m cua D(z)
Tu do suy ra:
X(z) =:;
N(z)
D(z)
~ ------
/=1
v6i
Trong 12-19) ta nMn thay co the' xet tinh cMit cua X(Z) qua cac zero Z,,/,
va cac clic Zpk. Trang lll(lt phang phli'c cac ci'c dli(je bie'u difin bang dau g:lch
cheo (X) con cae zero dU{jc hie'u di€!n bang cac khuy~n nM (0),
32
vi du
Cho x(nJ = OIn) + 30(n - 1) + 20(n - 2)
Tim X(Zl. mien h9i tl va cae ci'e, zero ella X(Z).
Trri liJi:
X(Zl = L x(n)Zll =:; 1 + 3Z-1 + 2Z-2
n=--'

33. Mien hQi tl}. is taan b(l m~t phiing Z, trii Z = o.
Tim qlc va zero:
(Z + l)(Z + 2)
X(Z) ~ Z-2(Z2 + 3Z + 2) ~ Z-'(Z + l)(Z + 2) ~
Z2
X(Z) co hai zero t~i ZUI = -1
va ZU2 = - 2 va tn(lt c~c kep t~i Zpl
= Zp2 = O. Vj tri cac ct!c va zero
cha tren hinh 2.9.
-2
z
-,
Im{ZI
Re(Z)
Thea d~nh nghla cua mien hQi
tl thi mien ht;li tlJ cua X(Z) khong
chua cac Ctc vi t{li dci X(Z) khong
xac djnh. Trang trl1ang h!;lp nay
x(n) iii ehu6i huu h{ln X(Z) hOi tl}.
trim taan llu)t pMng Z trii g6c t9a
d(l IiI vj tri cac et!c Zpl va Zp2.
Hlnh 2.9. Vi irf ella cl)c va zerO.
2.6.4 Bien doi Z nguQ'c
Tim goe x(n) thea anh phlic X(Z) thea cong thuc:
1
x ~-- J X(z)zn - I dz
, 2'lrJ C
(2- 20)
c Is cluang cang khep kin baa quanh gOc t9a d(l ella mi;lt phiing z thea
chieu dl1!1ng va nam trang miElD h(li tl}. clla x(z).
Trang tht!c te ta co ba phuong phap tinh bien doi z ngu!;lc:
Tinh trt!c tiep deh phan (2-20) dung Ii thuyet th~ng du,
Khai trien thitnh chuoi Illy thua thea z ho~e z-I,
Khai trien thanh tong cae phdn thuc toi gUm.
2.6.5 Cae tinh chat co ban cua bien doi Z
- Tinh chiit tuyln tinh:
Gia stt x(n) lit to hop tuyen tinh cua hai d!ly xl(n) va x~(nl
x(n) = a1xl(n) + bxin) ; a, b lA cac hang s6 thi
,
ZT[x(n)] = L [axj(n) + bX2(n)]Z-n = aX1(Z) +bX2(ZI
n =-0
(2.21 I
33

34. - Tinh chat tre
Neu yen) = x(n - n) thi
ZT[x(n - n,)] = Z-11nX(Z)
_ Nhan day voi ham mu an
Neu yen) == allx(n) thi bien deli Z la:
' oc Z Z
ZT[y(n)] = L anx(n)Z-n = L xn( - )-11 = x(- )
n=-« n'-« a a
D::to ham cua bien dbi Z
•dX(Z)
dZ
= L (-n)x(n)zn - I
n=-«
NhAn ca. 2 ve voi -Z ta co:
dX(Z). •
-z -- = -Z L (_n)x(n)Z-n - I = Lx(n)Z-n
dZ n=-« n=-oc
Tit day suy ra
ZT[nx(n)]
Tieh ehtjp eua hai day
dXCZ)
-Z
dZ
Ne·u day K,(n) Ill. deh ch(ip cua hai day x1(n) va x.2(n) nht1 sall:
x.,(n) = xj(n) * xin)
thl trong mien Z ta e6:
X,(Z) = X,(Z).X,(Z)
- Tich eua hai day
Neu X:-(n) Iil deh eua hai da.y x1(n) va x 2(n) nht1 sau:
x}(n) = x j
(n).x2(n)
thi trong mien Z ta co quan M
1 Z,
X 3(Z) = 2-. fXj(v) Xi-)v- dV
nJ v
T!long quan eua Iwi tin hi¢u.
(2- 22)
(2- 23)
(2- 24)
(2-25)
(2- 26)
Hilln tt1dng quan cua hai tin hi~u x(n) va yen) dt1QC djnh nghiB nht1 sau:
•
rxy(n) = L x(m)ytm - n)
Ill=
34

35. thi trong mien Z ta co quan h¢
1
R,.(Z) ~ X(Z)Y(-)
. Z
Dinh Ij giri trt dew
(2- 27)
Cho ta gia trj tl.li g6c t9a d¢ cua m¢t day khi biet bien d6i Z cua no
~ x(l)
X(Z) = L x(n)Z = x(O) +--
n_() Z
h'ly lim eua X(Z) khi Z -+ Xl ta co:
x(O) = lim X(Z).
x(2)
+-
Z2
+
x(n)
+--
Z
(2- 28)
Ung d~ng cac tinh chat Cd han cua bien d5i Z ta eci co bang bien d6i Z
thong dmg, giup chung ta tfnh nhanh han cae bien doi Z. Bang 2.1 lit bien
doi Z cua cac hiull thong dmg.
Urin/.: 2.1. IIlell dol Z th6nj,t dl.lllj,t
M!n n Mi~n Z MiG hl;oi II,J
J(n} 1 Toan bi;o m4t ph.ing Z
Toan bi;o mal phoing Z
~(n - no) Z-no troJ I~i 0 n6u no 0
trW I;;l.i ~ neu no 0
u(n} 1
I ' 1
- -
l_Z- 1
u(-n - I) 1 'Z 1 I
--l-Z-!
nu(n) Z·, 1 z 1 ' I
(I-Z 'I'
anu(n) 1 1 z 1
---
l-aZ-1
-au(-u - 1) 1 1 z 1 0
I
---
[
1-aZ-1
I
35

36. nau(n) IZ I :: a
IZ I :: I
1-2aZ-1coSOJo +a2Z- 2
1-az-lsin,~__ I IZI lal I
L -, 'Z·,·________ ~1-2aZ cOSlllo+_'__l __._______
2.7 B1£U DIEN CAC H~ TH6NG RDI RAC TRONG MIEN Z
Til da bi~t trong mien n h$ thOng tuyen dnh bat bif:;n dl1t;Je d~e trl1ng
bang dap ung x-ung h(n) nhung viee phan deh h$ thong nhieu khi g~p khci
khan nhu dnh dch eh~p, xet on djnh..
De giai quyet khci khan trong mien n ta ehuyen each bieu di~n he th6ng
sang mien Z va dua ra khai ni~m ve ham truyen d~t eua M thong raj r~e.
2.7.1 Ham truyen diilt ella h~ th6ng rai r~e
Ham truy?m dl:lt ella he thong roi rle 11 bien d6i Z eUa dap ling xung va
dl1;1e ky hi$U la H(Z)
HIZ) ~ ZT[h(nl] ~
y(z)
X(Z)
12- 29)
Ta xet ham truyen dt:;lt ella mot M thong rai rl.le ctU1}e Ina ta bang phuong
trinh sai phan: quan h$ VaG - ra eua mOt M thong rai rl:lc tuyen t:inh bat bien
d119C eho hdi phuong trinh sai phan sau day:
N M
L a),y(n - k) = 2: b,x(n - r)
k'O r=1l
(2- 30)
Lay bi{{n d6i Z eua (2-30) ta dtt1}e
36

37. M
k)] ~ ZT[2: bdn - ,)]
1'=0
• N • M
2: [ :2:ay(n - k)]Z-tl
n=--oo k=tl
~ 2: [ 2: b,x(n - ,)]Z~
n--;.o r'U
SU: dlng Hnh chat tr(!; va tlnh chAt tuy~n dnh eua bien d6i Z ta co:
M
L brZT[x(n - r)]
1'=0
M
2: b,ZX(Z)
r=()
M
X(Z) 2: b,2°
r=1I
Tir dci ta suy ra ham truy~n d~t H(Z) voi cae M s6 a],. va hr eua phlldng
trinh sai phfm nhll sau:
Y(Z)
H(Z) ~
X(Z) N -L a~Z -
],,=11
2.7.2 Bieu diEm ham truyen dl;lt thea cac clIC va z~rO
(2-31)
Cling gi6ng nhll tin hi~u rdi r~, ham truy~n d~t H(Z) eua mi)t M thong
roi r~c cd the duqc bieu dilin bAng cae diem eVe va cae zero eua n6 nhu sau:
M
ZIZ-I)n (1 -
1'=1
H(Z) ~ C
N
Z Z-I-n (1 - pk )
k= I
M
n (Z - Zrl
CZN - M
r= I
~
N
n (Z - Zflk)
k=l
2.7.3 PMn tich h~ th6ng trong mien Z
Cae phan ttl: thl!C hi$n:
- Phan tli tre
(2- 32)
37

38. GQi x(n) la dau va~, yen) Iii dau ra, quan M giua dati van va dati ra cua
phan tii: tre trong mi~n Z se iil:
38
yen) = x(n - 1)
ZT[y(n)) = ZT[x(n - 1)] suy ra Y(Z) = Z-IX(Z) (2- 331
Nhu vi).y phep tre trong miEm n dugc thay bang Z-l trong miEm Z.
Tr{!n htnh 2.10a Iil so do kh6i phan tii: tre.
- PM.n til. c¢ng
G9i xl(n) iil cac dim vaa, yen) iil dau ra ta co quan M:
M
y(n) = L Xj(n)
;:1
Lay bien d6i Z ta co:
M
ZT[y(nl] = ZT[2: xi(nl],
;=1
M
suy ra Y(Z) = L X1(Z)
i=1
Tren hl.nh 2.1Ob Ia sa do khoi cUa phan tu c¢ng
- PM.n til nM.n vdi Mng s(i
(2- 34)
GQi x(n) hi dau vaa, a Iii hang so, yen) Iii dau ra ta co quan he sau:
yen) = ax(n)
Lay bien d6i Z ta co
ZT[Y(n)J = ZT[ax(n)1, suy ra Y(Z) = aX(Z)
Hl.nh 2.10c la so do kh6i cua phan tu nhan voi hang s6
XI (Z)
l r'
X(z)
aJ
x(z) ~
IY(2) Z ix(z)
Y(Z} ' olX(Z)
c)
+ •Y(Z)=I:X. (z)
/.1 I
-xc(zC:)-i!--:Cy'rz-:J-_-,-xrz:C)
(2- 35)
Hlnh %.10 Phn tJ tra (a): Ph!n til eOng (b): Phn til nhan vdi hAng s6 (e).

39. 2.7.4 Phin tich h. th6ng rai r,c
Vi~c phan dch h~ th6ng rai rl.lC dl,ia trim nguyen tac chung sau day:
- Tach M thong t6ng quat thanh cac M thOng nM han
- Tim quan M ghep n6i
gilla cac kh6i nha han nay
- Tim ham truy~n dl.lt
H/ZJ cua cac khoi thanh phan
- Tim ham truy~n dl.lt cua
torm M thong theo cac Hj(Z)
va quy Iu~t ghep noL
vi dl!.
Xc!)
HInti 2.11. H~ th6ng rilj rae c6 phan h~.
Cho hi;! th6ng roi rl.lC co so db khoi tren hlnh 2.11. Tim ham truyl'!n dl.lt
chung cua M thOng thea H1(Z) vA H 2(Z).
Trd liJi;
Quan h~ H1(Z) va H 2(Z) 1a quan h~ phAn hM. D!)t bien ph! Y1(Z)
Y,(Z) ~ X(Z) + H2(Z)Y(Z)
Y(Z) H,(X)Y,(Z) ~ H,(Z)[X(Z) + H,(Z)Y(Zll
= H1(Z)X(Z) + H 1(Z)H2(Z)Y(Z), tit do suy ra;
Y(Z) [1 - H 1(Z)H2(Z») = H1(Z)X(Z), ta dUQc hi'im truy~n dl.lt:
Y(Z) H,(Z)
H(Z) =-- ~
X(Z) 1 - H,(Z)H,(Z)
2.8 BltU mJi:N HI); TH6NG vA TIN HII);U RbI RAe TRONG MIiJ:N
TAN 86
Ta d.ii biet bang bien ddi Z co the nghien cuu M thong va tin hi~u riJi rl.lc
va xac d,nh ham truyen dl.lt cua chung. Ta con co the' su dlng mc)t c5ng CJ. toan
h9C khac IS. bien ddi Fourier giup cho vi~ bieu di~n M thOng va tin hi~u rai rl.lc
tit mien bien so dt)c I~p n sang mien tan so liim tlC w. SI$ Him h~ gilla cae mn~n
bieu di~n va cac phep bien dai dUQc minh hqa tron hinh 2.12.
2.8.1 Bi4!n d6i Fourier rai r,c (DFT- Discrete Fourier Transform)
Bien doi Fourier riJi rl.lC cua day ham tuan hoan x(n) co chu ky N dUQc
dlnh nghIa nhu sau:
39

40. 1. thllin
Mi€nZ
, allan hf gida bien
' ' .J-,1.
I dol z va bien aQi
1 Fallrie.r
1
,
Hlnh 2.12. Quan h(l gilia mfln n, Z va w.
'X(k) = ~l x(n)ei N kn
n=O
L,
Neu ta d~t W N = e-JN, ta co:
2;1 2
w~n = e1 Nl.;n, WN.......n == e1N I.;n
(2- 36)
Ta co thf viet l!;li bieu thrlc bien doi Fourier raj r~c (2- 36) nhu sau:
N-I
X(k) = L x(n)~n (2-37)
n=O
Ta co the bieu diEm DFT Mng ky hi~u toan tii nhu sau:
DFT
x(n) - - - X(k)
Bien doi Fourier raj r~c nguqc IDFT (Inverse Discrete Fourier Transform)
duqc dinh nghta nhu sau:
~(n) (2- 38)
ho(lc
~
x(n) (2- 39)
~
Bien deli Fourier rai r~c 18. phep bien d6i th1Jc hi~n tuang ung mQt vecto
X(k) trong mren am s6 rai r~c k voi mQt vectd xac d~nh trong mien bien s6
n. Ban chilt cua DFT Iil bi~'n d6i phl1c vi:
10
L,
wNl.;n = ei N ==
2n :,!;n
cos- kn - jsm- kn.
N N
(2- 40)

41. Doi voi cac day kMng tuan hoan cd chi~u dai huu h~n, DFT duQ'c d~nh
nghia nhu sau:
X(k) ~
N-l
L x(n)w~n
n=O
OsksN-l
(2-41)
va kj hi~u
o k con l~i
IDFT
X(k) - - -..... x(n)
Bien dd'i Fourier nguQ'c (lOFT) duQ'c djnh nghia
1 N-J
- L x(n)W-kn
= N n=(I nX(k)
Osk.:sN-l
(2- 42)
va kj hiiJ!u
o k eon l::ti
IDFT
X(k) - - -..... x(n) ,
o dAy ta gqi X(k) la phd rai r~c eua dn hi~u x(n), hieu dien duf:li d,;mg modun
va argument ta co:
X(k) ~ IX(k) Ie1~(')
~(k) ~ arg(X(k)]
IX(k) I g9i la phd bien de) rai rac.
p(k) Iii phd pha rai r~c.
2.8.2 Bil1n dOi Fourier nhanh (FFT- Fast Fourier Transform)
(2- 43)
DFT trd thanh phan tu- quan trc;mg trong xU- Ii tin hi~u 36 hoi vi co the'
xay dl,l'ng nhtrng thu*t toan thl!C hien OFT rat hi~u qua, can it phep dnh,
thl,l'C hilim rat nhanh. Khi tinh OFT cho N diem me)t cach tntc tiep theo (2-41)
din N phep nMm phuc va (N - 1) phep c9ng phuc. V~y de Hnh N h$ so OFT
ta dn thl!C hi~n N1 phep nhlin phuc va (N - 1)N phep cc)ng phuc.
Nell chuy@'n (2-41) sang d~ng lUQ'ng giac
X(k)
N-1 2.n:nk 2-mk
= Lx(n)[cos(-- ) - jsin(-- )]
n=O N N
N-] 2.n:nk 2.n:nk
= L {(Re[x(n)]cos-- + Im[x(n)sin(-- )])
n=O N N
2nnk
-j(Re[x(n)]sin(
N
) - Im[x(n)]cos
2.n:nk
(N I)} (2- 44)
41

42. thi DFT co N diem dl1Q'c Hnh vai 4Nl phep nhlin va 4(4N - 2) phep c(.lng.
Ngoai ra con phai edt giu va dich ehuy~n day eac h~ s6 sin va cos tl10ng ung
vai cac M s6 WNrU;. cling nhl1 2N mau th1C eua day vao x(n) phllc.
Du cho co m¢t 56 ph€p dnh dl1Qc dOn giAn 'bOt nhO cac M 56 +1, °-1
nhung dO phllc tf.lP khi dnh DFT tr1c tiep tang ty l(l vai NZ.
Thu~t toan bien desi Fourier nhanh FFT cho phep giall1 bOt s6 IUQng phep
Hnh m6t cach dang ke'. Co nhieu thu~t toan th1,1C hi~n FFT nhung dEm d1,la
trim tu tuc:lng thl,{c hi~n DFT N di~m bang cac DFT cd so di~m tt hon vi khi
Hnh DFT trl,{c tiep do tinh chat cua cac ham lUQng giac ta dnh thira nhieu
quan h~ theo chi s6 n va k.
Ta nghien cuu tnot df.lng FFT dan giAn nhat gQi 1a thu~t toan cO s6 2
phan chia thea thOi gian (Radix 2 Decimation in Time, R2DIT) de chi qua
trinh tach DFT. Ten gQi cO so 2 de chi so diem DFT co th~ viet duai df.lng
N = 21., vai L lit so nguyen thl1bng lay giua 3 va. lB. Cae phep Hen ket can
thi€t trong qua trlnh tEi.ch dUQc thvc hi4;!n trong llliElO thai gian. Co th@,' nh~n
dUQc ket quA DFT N diem chan Mt ky bang to hQp ket qua. thl,{c hi(ln hai
DFT N/2 diem, do v~y chi din thl,{C hi~n 2(N/2) = N l /2 phep dnh.
Neu ta tien hitnh l~p If.li lien tii'ip va nhieu phep tach doi, trong trubng
hQp thu~t toan R2 bao gia ta cung co dUQc 21• thi cu6i cung ta chi din th1,1c
hi~n DFT nhci hai diem.
Theo thUl).t toan R2DIT ta tach day vao x(n) phuc N diem thanh hai dAy
x!(n) va. xz(n) co N/2 die'nt.
x!(n) = x(2n), n = 0, 1, ..., (N/2) - 1
x1(n) = x(2n + 1), n = 0, 1, ', (N/2) - 1 (2-45)
Theo djnh nghia DFT N diem, X(k) Ii Anh DFT et'la x(n) dUQC viet duai dl;lng:
X(k)
N/l- !
= L x(2n)WNlnk
n=()
k = 0, 1, ., N - 1
t'lfl- 1
+.1 x(2n
n=O
vi WNl = (e12'!IN)1 = e12JrI(NI1) = W
N12
do do (2-46) co. the dUQc viet theo da.y x1(n) va x2(n) nhu sau:
42
(2-46)
(2- 47)
(2- 48)

43. trong do X](k) + X2(k) la cac DFT dUQc chia dOi (N/2 dielu).
Trang truong hQp dung thui).t toan FFT de dnh DFT N diem ta chi can
NlogzN phep dnh phuc. Vi dl,l N = 1024 ta thl,lc hU;lD nhanh hem 100 Ian.
Trong th!c te ml}t IC duy nhAt co tM th!c hi~n FFT 64 di~m con FFT 512
di~m dUQc dl}t tr~n mc)t card duy nhat. Trong cac may dnh nha cd th~ chl.lY
chudng trlnh FFT 1024 - 4096 diiim, con doi Val lll.ay tinh Ian 13. tren 16.000
di£fm.
2.9 BO LQC s6
2.9,1 Nguyen Iy qua trinh IQc tin hi~u
Xet Sd dEl chuc nang 19c tin hi~u Him t1c tren hinh 2 13.
Tin hi~u x(t) dUQC lay mfi:u thea thai gian boi khcia dien tu: K, nhiP lay
mau T thanh tin hi4;!u lay mau x· (t).
y(t~
y(/~
H1nll 2.13. Qua tr'inh Joe tin hi~u.
Tin hi~u x-r(t) dua van mf.'ch dch phan dung bang thoi gian xU: Iy cua bi)
doi tudng h,t so ADC. Thai gian duy trl mau phai nha hdn thOi gian lay ma.u
T. KM qua dau ra cua mJilch RC Ie. tin hi~u dUQC lay mAu va duy tri xT*(t).
Trong bi;! ADC moi mA.u dUQc IUQng til: hoa va chuye'n thanh mao 56 nhi
phan cua r bit cua m6i 1111U se dUQC bie'u di~n Mng 0 hol.lc 1 (kh6ng ho:;i.C cd
xung).
51,1 IUQng to hoa Iii vi~c gaD cho m6i mau mot gili tri duy nhat trong so
cAc muc gi.A tri cd the co dUQc .vB. M.ng 2f. Vi dl,l r = 10 cd 210 = 1024 muc
gia tri.. M6i bit dUQc chuy~n qua mi;!t duang rieng sao cho mau duc;Jc ma hoa
xwit hi~n a dau ra cua ADC duoi dl.lng tel hQp nhi phan dong thai d r duong
ra. Mdc cao nhat co the gbm r xung, muc thap nhat gam r gili trj. O. To rna
cang dai trl:c la sO bit trong tu ct'mg Ian thi dl? chinh xic cua mau cang Ian.
43

44. Day miu mil hoa dllc;1c dua vao b(J loc 56 DF (Digital Filter), a do mil
dudc dnh toan theo cac phep toan c(mg, tru, nhlin, tr€! clla mot thu~t toan
loc nao do. 0 dhu ra cua DF xuflt hi$n mil moi la tin hi$u s6 dil dllc;1C loc.
Trong bO deli s6 - h1dng h! DAC mtii ma tac d(lng len mot nhorn cac khoa
di~n tu dif!u khien vi~c c(lng cac muc di~n ap chuan cua mtii bit. Ket qua dAu
ra Clla DAC ta duc;1C tin hit$u tttdng tv y.r(t) co d!;lng btiOc. Cu6i cung tin hi~u
qua nwch bon cl!c co the' coi la loc khoi ph~c, a do day tin hi$u tt1dng tv co
dl:lng bt10c h(t) duc;1c chuye'n thanh tin hi~u ra lien tlC y(t).
Luu y la Hit ca cae ho~t dong xli Iy cua mtii mau ph.ii nha hdn thai gian
lay llli'lU va can dam bao sU dong bO cho cae ho~t dQng ella cac khoa di~n ttl.
1
Van de nay duoc giai quyel hang day xung don dieu bOa tan s6 T t~o nen
bang b¢ dao dong chuan.
Vi T lit thong 56 chinh cua hO IQc s6 do do can chu y d~c bi~t den st! on
djnh tan 56 ella b¢ dao dOng nay.
Uu diem ca bim cua bi? loc so la co d(J tin c~y cao, st! on djnh cua thong
56 ma cac b¢ Joc tuong ttl kh6ng the eo dUc;1c.
2.9.2 BO xU- Iy tin hi9U 56 D$P
B¢ xtr Iy tin hi~u s6 DSP (Digital Signal Processor) Iii b¢ xli Iy chuyen
dlng duqe thi€t ke rieng cho vi~e tht!e hi$n eae I$nh s6 hoc, do do thvc hi~n
nhanh hdn bo xii Iy thong dlng. Chuang trlnh cua chung sii dlng cac I$nh
s6 hQc nhieu hdn l$nh truyfm dli li~u va vao-ra. Noi chung DSP lay mdu tin
hi~lU vao sau do ehuyen qua b¢ IOc thl'Jng thAp rai tinh twin cae dau ra moL
Cac tin hi~u ra nAy den h1Qt chung duqc chuyen sang b6 doi s6-tttc1ng tv DAC.
Cac thao tac chinh lit phep nhan va tich liiy.
Theo djnh ly lAy ma.u Nyquist llloi th6ng tin tUdng tt! co the' duqc kh6i
phle DI?U thn s6 liiy mAu ba.ng ho~c Ion hdn hai Ian tan s6 cao nhM cua tin
hi$u ban dau.
Cae tin hi$u thl!C co thanh phlln thn s6 cao nhat tuang d6i nha. DO ri?ng
dAi BW (Band Width) dUQc djnh nghfa bang tan s6 thitnh phan tin hi~u bang
m(:lt nu-a cong suat, 0,707 bi~n d(:l cua thRnh phlln m~t chi~u. DO r¢ng dai
duqc Hnh gan dung theo phudng trinh:
0,35
fl-W = (2-49)
t,
44

45. tr In thai gian suan tang eua tin hh?u, dUQc xac djnh tll: 0,1 den 0,9 trj s6 tin
hi~u cuoi, cho phep h~ thong nMn dUQc it nhat 5 mliu trong khi 11111c tin hi~u
tang hOl;1c giam nhanh.
B¢ IQc so dap ung xung toi h~n FIR (Finite Impulse Response Filter) co
bieu thlie dau ra:
yen) = bx(n) + bjx(n - 1) +b2
x(n - 2) +
Cr day
M la s6 Ian IS:y mliu qlc d(~i
yen) la dati ra clla milu d t.hi:li gian n
x(k) la dau vao clla milu t.hai gian k
b(k) Iii. h$ s6 clla bl? lQc ella !lUlU thai gian k
M
yen) = L bkx(n - k)
k=1I
+bMx(n - M) (2- 50)
(2-51)
Trang chuong 6 ta se nghi?n cuu ky cach thtje hi~n philn cung va chudng
trinh phan melll eho FFT V~ DSP
2.10 LAY MAU vA LI1U GIU TiN HIEU s6
Trang he thOng dieu khien so ctlc milu dtiQC hlY tti cac d~i hiQng lien t.le
nhu di$n ap, dong di$n, toc do.. Vai tro clia ho lay mfiu lit bien doi tin hi~lI
lien tlC thanh tin hi$u rai r~c. Trang bi? lay mall tiep diem dong l.;ti de tin
hieu di qua trong khoimg tMi ginn lay mau. Trang thlc t.EO' khoang tMi gian
lay mau nlt ngan so voi hang s6 thai gian Clla cae t.hi:li die'm 0, T, 2T .., t.rong
do T la chu ky fiy mau. Giii'a hai Ian lay mau lien tiep L¢ lay mau khong
nh*n tni?t t.hOng t.in nao Phan tl1 Iuu gifi se. chuyen deii tin hi~u da dugc lay
miu thanh tIn hi~u gan lien tl,lc, ti$m c;ln voi tin hi{lu tnioc khi no dUde lay
mau. Phan t1 hiu giil don gi~m nh.1t. Iii. phan tl1 chuyen dOl tin hi$u lay milu
thanh tin hi$u b~c thang va khong doi giila hai thai diem Jay mau. Do 1;
phan tu.: do~n thang, ve toan hQC duoe bietl djen bang da thu:c bt:i-c khong nen
gQi Iii. luu giii' b*e kh6ng ZOH (Zero - Order - Hold), co ham truyen dJ;l.t
ZOH(s). Tren hinh 2.15 la sf1 do Jay mau va luu gilt tfn hi$ll
Phan t.11 luu git co Lll~e dnh ella bi? IQc thong thap, hlm trdn tin hi~u lay
lllaU x'(t) In llli?t day xung thanh tin hif.u xh(tl co bUm do khong doi Hnh tll:
thai diem hlY mau den t.hai diem lay mli.u m0i
o ~ t. T. (2- 52)
45

46. Phlln tu luu giu cd chuc na.ng dch pha.n tin hi~u xung x*(t) giua hai thai
diem lay miu k@' tiep nhau vi dch phiin mQt xung cho ta tnQt hang so. N~u
coi dau ra cua b) lay I1l:lU Ja m~t chuoi xung tn;mg luqng, ta cd th~ I~p duqc
quan M giua tin hieu lien tl,lC va dau ra cua bQ Hiy mAu Iii:
x' (t) = 0T(tl.x(t)
0T (t) la m¢t chudi xung ddn vj.
(2- 53)
Co the' coi b6 lay llU1U iA b¢ dieu bien voi dau vao III tin hieu dieu bien
x(t) va chuoi xung ddn vi h1 song tnang nhu tren hlnh 2.16.
Bieu thuc cua chuoi xung ddn vi
•
Or ~ 2: OCt - kT) (2- 54)
~=-x
trong do o{t - kT) Iii lll¢t xung ddn vi xuat hiifn t~i thdi die'm t = kT, nhu
vay tin hi~u da lay llU1U co the dllqc viet Iii:
16
x'(t) ~
2: x(t).O(t - kT), ho~c (2-55)
~=
~
x' (t) ~
2: x(kt.J.o(t - kTJ (2- 56)
k=--oo
, 4r--~-'-~~
, 'fll! !!, , ,
I0 0
-2 t
-, _4 L ___-L_ _ ,
0 w 10 30 0 10 20 30
oJ 'J
'I --r-~
i 1
2f ,
of
Vj -=-----;~ ZOH
~,
,~
1.L dJ
, ..' - - - - - -
, ,
0 W 10 30
OJ
Hlnh 2.Hi. U'y mau va h.1u gili lin hi~u
a) Tin hi~u VilO x(I): b) Tin hi~u lay mau x·(ll, c) Tin hi~u ra xll(I):
d) Sd d6 lily mau va loJu gioJ.

47. 89 lay ma~
• • •
r-----------------,
lOT(t)
,
, ,
, ,, ,
, ix,,(t.I(f} I
D/'eu bi€n xllng ,, ,, ,, ,
-3T -2T -T 0 T 2T 3T t
L _________________ J
aJ
Hlnh 2-18. Quan niem ve b~ lay mau
eo) Chu6i )(ung dOri vi', b) B¢ lay m~u.
b)
Vi bi~n de? cua xung Dirac 18. vo cung Ian nen de thu~)n ti¢n ta dung chieu
cao mui t~n de chi cU:bng d~ hay di~n deh cae hiull xung nay Tren hinh 2.16a
chiEm caa mui t~n tr~n d6 thi x~(t) hldng ling v6i uti Ion cua moi gia tri dl1Q'c
Iiiy lllall tit x(t). Trang thlCc tii da s6 cae ham thCfi gian lay gia tr~ khOng nhi
han goc 0, do do bieu thtic elm t.in hi~u lay mAu Ill:
•
x'(t) :: L x(t).Mt - kT) (2-57)
k'l1
Dap ting xung iii xung co chieu caa 1 va chieu n)ng T sec. Bieu thuc eua
dap ling xung hi
h(t) = !(t) - I(t - T) (2-58)
Ham truyen iil anh Laplace cua p(t')
ZOH(p) = {h(tl) = J[1(t) - l(t - T)]e1'I _dt = (1 - e11'I)ip (2-59)
Bang 2.2 cho ta dap ung xung cua tin hi~u hlY mdu va bien d6i Z cua no.
47

48. I
~
I
',
~
I
o~.
I
0
- rU
•
I ~ i-
-
~
.1-~I- I CI, IC-
I
-0
O
I
I ~
~
~
~ ~
~ ~
N,I C
' -
0
, -. ~
~
!:~
.'=~
I~
=
I ,f--
I =
/
I~
~
I
-I
,~
j~
~
~
,~
.
~
'- !-- :1 ,i t
~
~
~ l- e
I: I
t:- F- F
-
t
I
~,~
II.:1 - ~
-
~
0
~.
~
I e
N.1 IT
•
2 0
3
~
I
~
~
f
~,
I ~ •
•
.
=
rn
I iii;.,~
I ~.
I •
•
I ·0
1.1 cr
.,
I
,'N -I
~I N 0
I
•
•
•
•
48

49. ~
g
o
•h,
,
•
'!.
+
:2 !./'
•
I'---------
+
~
+
•,,o
•
........ '---'-J
•
=-.
=.=
=~
I
49

50. Chuung 3
MO HINH MAY DIEN VA
THIET Bl BIEN 061
Vi$c nghil!n cuu cac dnh ch.it cua may di~n quay va thiet bi bien d6i ban
dAn cOng sua:t b che dt;! qua dQ nh~m m1,lc dich danh gia kha nang chju d~ng
cua thiet bi voi nhung ung sua:t Ian 'Ie di(ln, nhi(lt va cO trong di~u ki~n lam
vi(lc kM.c nghi¢t coa che di? qua dO, m$t khac ding nham nh*n biet cac quy
lu~t cua thiet bi dieu khii!n nham duy tri ch€ d¢ lam vi~c djnh nl1.1c cua may
di~n va thiet bi bien d6i.
Th~dq~_M_~~~6~~_*~~~m
vi¢c ache d¢ dinh muc. Tuy nhilin thiet b! di~n can phAi san sang lam vi(lc
trong cac di~u kien ba:t thudng nhu xuat hi(ln ngan m~ch, Old may, .... Cae ch€
dO nay chu yeu dAn den ung suat ca nhu I~c di~n dong tron dAy quan, cl,l the'
trong dau dAy quan, momen tren tt1,lC dt;!ng co, ung suat nhi~t.
Vi¢c nh~n bi~t ham truYflD coa d6i tu(;mg di~u khien Ia can thiet khi thiet
ke cae thiet bi diEm khien. De nghien cUu may di(ln va thiet bj bU!n d6i trong
qua trinh liun vi¢c binh thuong ciing nha b ch€ dO qua de) can xay d~ng mO
hlnh toaD hqc cho may di~n va thiet bi bien d6i. Tn..atc tien ta nghien cUu 016
hinh CI che de) lien tl,lc sau do 18. 016 blnb Q cbe di? rai r:;tc.
3.1 cAc GIA TIUih DON GIAN
D~ nghien cUu may dif!D d ch€ dQ qua dQ ta dU:a ra mi?t s6 gia thiet dan
gian hoa sau day:
3.1.1 May di~n khong bao hoa, quan h~ giiia dong di~n V8
tu thong '8 tuyen tfnh
3.1.2 Phin bd hinh sin
Cac day qua:n b6 tri tren m(l.ch tit cua may di~n quay t~o nen suc tit d9ng
phAn b6 chu ky hinh sin, nghia iii chi chu y tai st! pM.n b6 khOng gian cua
dieu hoa b*c nha:t.
50

51. 3.1.3 MIliCb thOng 86 t(llp trung
Gia thil§'t ti€t di~n eua dAy qUlln diI nM de' m~t d¢ dong di¢n phan b6
deu, k€t cau d6i xllng.
3.2 ruM TAT NHUNG VAN DE co BAN vE sue DI~N DoNG vA
M()MEN DI~N Til eVA H~ TH6NG DAy QUAN co DONG DI~N
eay QUA
Khi n m;;teh (eo hi;! so t1! eam Lj
) dong di¢n ij ch~y qua co liAn h¢ ho cam
the hi¢n qua h~ s6 h6 cam Mjk tit thOng eua day quan duqc xae djnh Mi bieu
thue
V'i = Ljij + L Mjkik (3- 1)
k = I
k ,.. i
Suc di¢n dt')ng cam ling (s.d.d.) el
trong day qmtn du;lC xitc dinh theo bieu
thlic:
(3- 2)
Dl.1o ham (3- 2) theo t va the van (3-0 ta thay co 2 I01;li sue di~n d¢ng
cam ung trong dAy quan:
- N€u L I
, Mjk' ij va ik kh6ng doi, trong truang h;1p eho phep ehuyen d¢ng
quay theo goc e s~ xuat hi~n suc di/?n d¢ng quay:
(JVl de
ilf} dt
- Neu Lj, Mik' i, va i~ kh6ng d5i, gOc quay {} khbng doi, tu thong moe
vang chi bien thiE!D theo thai gian ta co sue di~n d9ng biPn tip:
Suc di~n d9ng cam ung trong day quan i se Iii:
iJV'1 d(J
e· =-~
II i!f} at
(3- 3)
M6men dien tit:
1 1 ,IL i
=~Ii~ +
2 j ,'j(j
(3.4)
51

52. 'fa nMn th.iy sl1 bien dai nang il1Qng di~n tu thanh cd nang va ngl1Qc IJ;l.i
chi xay ra khi trong bieu thuc cua cbng suat di~n ttl co m~t thanh phan suc
di~n d(lng quay.
Trang cac ap dv.ng sau nay ta coj mamen di~n tu co chiEm dUdng, gQi Mll
Iii mbmen dang cd va Me la mamen can Phudng trinh chuyen c1¢ng cUa d(mg
cd co the viet la:
(3- 5)
.J la mamen qmin tinh eua phan quay.
3.., MO HINH eVA MAy DIJ1:N MQT eHIE:U
3.3.1 Sa db va phU'ong trinh t6ng quat eua may di~n mQt ehieu
Sd do tong quat cua may di~n mOt chUm cha tren hinh 3.la
- 'frlc Od (trlc dqc) ung voi tTlC tu clla day qmln kich tU, thuong ky
hj~u bang chu f
- Trlc Oq (tll,lC ngang) ung vai trlc ttl clla m¢t so day qutln phl co d~nh
(vi dl day quan bu) ta hinh dung nhu m(lt day quan ky hi~u 13 g.
TrElll trlc ngang Oq thl10ng d~t chbi di~n A, B cia phan ung. Luu y nlng
giua chai dien A va B ph3.n {jng tlic d¢ng nhu lll¢t cu¢n day co trlc tU luon
huang thea trlc ngang Oq, tren hinh 3.lb bieu diE'in chieu dong di~n phAn
ung co chiEm ngl1Qc nhau so vaj duong qua chai dien khi cac thanh dAn philn
ung cnuyen d¢ng. Lay chfeu quay theo chieu kim d6ng ho vaj quy udc dau:
Dong di$n dUdng t~o nlm trong day quan cua no ttt th6ng dUdng,
Suc tis d¢ng d1./dng tJ;l.O nen dong di~n dtldng trong day quan.
Quy uac dau nay dung cho cac may di~n quay, doi val di~n ap cae day
quan dung yen du~c coi nhu tai, day quan phan ung nhl1 lmiy phat.
Cac thOng s6 d(c tnmg cha lUay di~n m(lt chi~u:
ai Di¢n trd uiL dien cam eli,a day quan
day quan klah ttl trlc dqc d: Rf
va L[
day qUlin co dinh (day quan bU.) ngang trle q: Rg va Lg
day quan phan ung giua hai eha! di~n A va B: Rq va L'l
b) Ho aim giiJa hai day qudn theo tr,!c ngang q: Mgcl

53. c) H6 cam gi(la cu¢n k{ch til f va phan ling n~u choi dien dgt theo trllC
dQc ad: Mfd, neu chi cd dong di$n klch tu if thl chi cd tU thong 1f'u = Mfdif
Quan h(! giua tit thong va dong dif!n lit:
~'d ' !M
i,=
~'r
,
L,
i Iflql : L'l ;Mgq iq ,
, ,
,1/'g Mgq' Lg i g :
Cae phuong trinh di~n cua 3 dAy quan 18.:
B
0
i,
A
,,1
1
'J
d~'r
+--
dt
d~'~
+--
dt
'1
d,
_'t~1
cit
~wc
i,
I, d
'I
(3- 6)
(3- 7)
(3- 8)
8
0
0 @ ~wc
09 @
09 @
09 @
09 0
@
A
'1
® Dong Olin ti)' ngobi
® 00119 Ji~(I fif frong ro
b)
Hlnh 3.1. So do mAy di~!n mQI ehiEtu
a) Sd do t6ng quat va (]uy llilc ch(eu cae dt'lng dien; b) Chl'eu dong dien ph'an LIng.
53

54. VI cac day qwln r va g co dinh so vc'Ji M tQa dq (Od, Oq) nen hai phuong
trinh dA.u tien cua (3-8) chi xuat hi~n s.d.d. bi~n ap. Day quan phan ung giii'a
hai ch6i di(m A '1a B tac d(lng nhu: cul)n day tr1,lc ttt Oq t~a nen sdd bien ap
khi tit thOng bi~n thien thea trlc nay, ngoai ra vi day qUAn chuyen d¢ng se
xuilt hi~n sdd quay.
eqr ::= wr~'.1 = Mrdw,lr·
Vi bO qua bfio bOa ta coi sdd quay ti l~ thu~n vc'Ji t6c dO quay va dong
di~n kich tii.
C6ng suat Wc thai do may di(ln m¢t chieu 1:.:;1.0 nen:
dJ/! .. R' 0 • 4
Pe = Uqlll ::= - qlq~ - Iq dt + (3- 9)
C6ng suat tuc thai gbm 3 thanh philn:
Thanh phan dau tiEm R'liq2 ling vc'Ji t6n hao Joule,
Thanh phAn thu hai ung voi bien thlen cua nAng hlc;Jng ttt truClng dch
hly,
Thanh phan thli ba
1a cong suat ca.
3.3.2 May di(!n mQt
chieu tong quat
Xet cau truc may di~n
nu)t chieu t6ng quat tren
hinh 3.2, trong do co 2 d6i
chtH di~n:
Ad va Bd thea trlc clQc
Od
Aq va Oq thea tr1,lc
ngang Oq
Di$n tra phan ung
kh6ng d6i thea tr1,lc Od va
Oq:
{
B,
+-B,
/'
'
;(we 'd
f
II
Ad/ I i I
v,1/ ill-.
/' 'I
A,
4-r: - i,
~1 f:::p
9
H In h 3.2. So do may dien mOt chieu tOng qulU.
Ttl m1C 3.3.1 ta !my ra ('.3.C phuong trinh di~n tii
54
d

55. (3-10)
(3-11)
Rrif
dV'r
Uf
~
+-
dt
Rgig
dl/'g
u, ~
+--
dt (3-12)
-Rid
dV'd
uJ
~
- Wrf'q
dt
uq
~ -Riq -
dV'y
+ w,rllf'd
dt
Hai phuong trlnh euoi eua (3-12) khae dau Ie. do gOe quay eho pbep ehuyen
tit tit thOng trl:le l/'q theo chi~u duong cua sdd quay v(:!i edr
.
C6ng suat di~n tuc thbi clla may di~n m9t ehieu
Mamen di$n tu gAn voi
cac suc di~n dQng quay ehia
rna toc d¢
Mdt ='I'diq l/'qid (3-13)
Lo~i may di~n mQt chieu
nay ia may di~n co tu thOng
vuong goc thuong dUng trong
1119t s6 may di~n m()t chi~u
d~e bi~t nhu may di~n khueeh
dl,ii. Ngay nay do s~ pbat trien
eua di~n tit dmg suat ngu'oi ta
khtmg dung cac may di$n
khue'ch d~i n[ta, nhung M
phuong trl.nh (3-12) thl,tc te
kh6ng thay deli doi vai cac lo~i
(j d'l'u +
dt
o
. d¥'lI )
,--lJ dt
d
Hinh 3.3. May di~n mOt chi~u khOng bu.
55

56. may di(!r. quay khac, Cl the ii dCii vai may di~n xoay chipu
Tren cac trlc dqc va ngang ta con cd the' thay cac day quan kich ttl noi
tiEfp hoac song song, do ia cac day quan biI va day quan d6i chieu.
3.3.3 Anh huang eua day qu'n bu
Ta sf! nghipn cuu Sd hwc anh hliong ella day quan biI phan ting phan ting
d6i voi tinh nang cua may di~n tn9t chieu 0- che d¢ qua d9.
u) May dUn khiinK hfl
Khi khbng co day qmn g sCI do t.ong qmit hinh 8.2 dan toi hinh 3.3. HI?
phl1C1ng trinh tu (3-6) den (:3-9) tro thanh:
dil
L--
I tlt
b) Muy difn mljl chif?1I C(; bii
IJhcin lin/.! philn linK
De biI phan ung phi'l.n ung,
day quan g phii duqc mac nbi
W3p voi day quan q sao cho dong
dip,n ig va ill bang nhau va trai
dau. Theo hinh 3,4 ta thay xuat
hi¢n di~n ap 1110i tren cac qtc
u' ::= U + u
q q ;:
ig = -ill
The vao cae phuClng trinh tU
(3- 6) de'n (3- 9) ta dUQc;
dil
L--I dt
u'lj = -(R'I + Rg)~1 - (L'I
~1
i = i, ,
(3- 14)
d
Hlnh 3.4. May di€m mOl chieu c6 bu.
(3- 15)

57. Ta nhi;t.n thay h~ phuong trinh (3-15) ding cimg nguon g6e phuong tdnh
(3-14), Vi$e bu kh6ng liun thay doi de quy lu~t bi~n thiE!D ve djnh tinh, nhu:ng
VEo ujnh IU9ng bu hQp Iy se tao n€m
L'I + L~ - 2M;:1 L'I
do v~)y bil se !fun gi8.ll1 d;i.ng kP' ui~n cam philn dng, do do lam gdll1 hang ,,()
thili gian d che dQ qua do. Tii do suy fa ket lu(O: Du Cel hil pMn ling philn
ling hay khong thlmay dien m(Jt ehicu ciing tmln theo h~ phuong trinh (3.14J
nhung khi hu phan ung phan ring ph/ii them R)! vilO ~I VII thay the L'I bang
m6t uit?n cam co gia tri nha han nhieu.
3.3.4 Dieu ehinh t6e dO dong ea mot chieu bing tile dong len di~n
ap phsn ling
Tiep thea ta xet 11lQt VI d1 ve vi~c diell chinh t{)e 16 d(mg co mot chieu
Dat. R
L
R)! + R'I
L+L-2M'I )! ~'1
Cae phuong trinh (3-14) lip d1,lng cho eh0 d¢ d{mg cd, ('oi 1'1 va am. Nell
ta kh6ng thay d6i di~n lip kich tu, phLidng trinh dau tien chung to dong di$n
i l kh6ng thay dtii va bang ghi trj dong kich tU han uihl II. H~ thong ph:'!.i
tuan thea phtiong t.rlnh 13-111
Vi i l
= II kh6ng deli, h~ tMng (3-111 h tuyen tlnh va eo the' up d1,lng
hien doi Laplace cho cae E;ai phan. do d6 dan dfin phuong trlnh sai phan
L.Uq(pl = MtdII(/~w/PJ - (R + LplL.i'llp)
t..Crn(p) = ,fpL.(u,(p) + Mtilt,,~i'i(pi
Gi1'li h~ phuong trinh sai philn my tim duqc L.UJ,.(pl Vl1 t..i (p) thea hjPn
'I
MfdIIL.U'lip)
(MldII,)~ + JpfR + Lp)
-JpL.Uq(p) + MluIIc-..Mc(pJ
= (MldItt
)2 + Jp(R + Lp)
} (3-16)
Phuong trinh 13-16 cho ta anh htidng eua t..l:'I(p) V~l L.ML(p) den toe u)
va dong elien phEW ling. Thea quan dipm drilu ehinh ta co t.he' nghien eriu ham
57

58. truyfm gifta t6c dO v~' di~n ap phhn ung. Vi dl n~u gift thi~t m6men kMng
deli va phtm ung phan ung dUQc biI het (L = 0) ham truy~n trd nen bi€u thtlc
ddn giAn:
vai
~/p) ki~
6.Ull(p) 1 + TmP
1
ki =~~
M ld l f(1
T m HI. hAng so thai gian Cd eua dCJng cd
* Vi d1,l bang so cho df,ie tinh d(mg cd va cua tai
di~n tra va di~n cam philn dng (gia thi€t co biI):
R = 0,05Q, L = 1 mH
mcnnen qUlin tfnh cua phan quay J = 100 kg.m2
Dieu ki$n dau:
Ull = 200V, IqCl = -200A, Wro = 47,5 rad/s
tao nlm hang so Mtu1f( = 4 Wb
NghUm cUu bien thien toe d): bat dau ttl eht de? nay ta giam dOt ngqt
di~n lip Uq
20V
20
p
con momen ed v§.n kh6ng d6i 6.Mc(p) = 0
Thea phudng trinh (3-16) ta co the tlm dl1(JC gOe t9a d) va dong dii;ln
thea thai gian
w/t) = 42,5 + 5,4exp(-3,4t) - 0,4exp(-46,6t)
i (t) = -200 + 464[exp(-3,4t) - exp(-46,6t)].q
Cae quy l~t bUln thi~n n~y dU(Jc ve trfm hinh 3- 5, ta nh~n thay mng
bien thien di~n ap 20V lam xu:H hi~n dong di$n ngu'Qc, do do sinh ra snh
huang giSlll t6e Ian nhung kh6ng vu(Jt qua gia tr! dlnh mde eua no. Sau khi
xmlt hi~n bien thien dong di~n vaj hang s6 thai gian L/R, dong di~n va toe
d) trd ve gia trj on d!nh vai hAng so thCli gian cd bang:
RJ
58

59. Mo hinh toan h9C clla
may di~n mQt chiim nghi€m
cuu d tren cho phep giAi
quy~t van de dnh tOlin h~
th6ng di~u khien, ngay Cft
truong hgp dQng Cd d1igc
n6i voi bl? chinh hiu co dieu
khign
D;;ic dnh Clla may dit?n
m9t chi~u Cl the la muc bil
phAn ung phan ung co anh
huang rat Ion den d~c dnh
clla b¢ chinh hlu va co the'
danh gia anh huang nay
~
;-
•
-
-3
'41,5
45.0
'2.5
40.0
:
-..
- -- - -- -- -- - --
L-i==
mng 1110 hinh toan h9C clla Hlnh 3-11, T1Sc dQ vii dOng di~n phttn Llng dQng cd kfch
may di(m mqt chieu tLJ dOc lap khi dOt nhien bign thien dii!!n ap phn ling.
3.4 MO HiNH ToAN H«;Ie eVA MAy mj):N XOAY eHlEU
3.4.1 Sa db may di, xoay chi'eu
Xet may di~n quay ba pha (dong bQ ho;:ic kh6ng dong bQ) o;tato la nlt;1ch
2n
ti1 t;:to ttl truong quay co b6 tri 3 day quan a, b, c co trlc tit l~ch nhau :3
doi voi may hai ct,(c (p 1) nhu hinh 3.6a
May di~n co the thu9C lo~i bat ky, 0 day kh6ng the hi~n day quan roto.
Quan he' gii1a tit th6ng va dong di~n la ham so' clla goc quay dl).c trung cho
v1 tri tuc thoi Clla roto d6i vai stato. Ta co the don giAn hoa vi~c nghi€lfi cuu
may di~n xoay chieu ba pha tht,(c Mng phep thay doi bien 0;6 gOi la bien doi
Park bieu dilin may dien tht,(c theo hal trlc toa dq vuong goc (Od va Oq)
Trlc Od (trl,lc doc) lam voi pha ft goc f) va tIl:lC ngang Oq ch(lm sau Od nlN
goc n!2 (hinh 3.6b).
3.4.2 Bien d6i Park
Duo; dt;1ng ma tr~n st,( thay doi bien theo h~ toa d(l d, q va t9ft d¢ tt,( nhien
a, b, c d1iQc bieu di~n bang phuong trlnh:
59

60. b d
d
8
o)«[--'-=---t---
v';; i 9
aJ
bJ
Hlnh 3.8 Sd do may dien tv trudng quay
a) Day qua:n IhllC a, b va c: b) Day quoin giA wdng d va q.
2,. 4
cos H cos (0-
3) cos ((J -)
3
2 2. 4
:1
sinO sinO? - ---I sioW -) il
:l :1
(3- 17)
1 1 1
2 2 2
ie
d day ilr dong di(m dQc trlc
iq- dong di$n ngang true
i,,- thanh phan dong diE1'n tliang dliOng voj thanh philn thti tu' kh6ng, de'
hi thong- (3.17) co tinh chfit nghjch d~lO, nhung chi khi i co l1l:Lt, tcing i +
ii' + ie khac kh6ng. Ta co the' viet phuong tdnh (3-] 7) duoi Jl).ng rut g9n:
i = Aid'I 'Ill('
(3-18)
A Iii lila trt~n Park.
Ngh~ch daD etta (3-17) cho t.a t;m d¢ thW: thea t9a do vuong gac:
1'1
COS H sinf.i 1 id
,
. 'ii' cos (H- y,') sm(A'T) 1 i (3- 19)
'I
4, 4JT
ie eos (H - sin(A
3
- - ) 1 i
3
60

61. hoac du6'i dl;l-ng rut g9n:
i = KJi (8-20)ahe dq
Neu chu y den cac h~ so clla hai dong dau tien Clla (:~-17) va hai c9t daH
elta (3-19) ta nhi).n thily cac day quan a, b, c xep chOng tao nfm suc til d¢ng
phiin b6 hinh sin thea fJ co cVc dl;l-i lan h1;1t trimg v(ji truc pha Oa, Ob, Oc co
the dll~lC thay the bAng hai cu¢n day gia tu'i'mg d va q co tr1,lc ttl ludn c6 djnh
so v6'i cac tr1,lc Od va Oq nhll hinh 3.6b.
S1 thay doi bien so cling dU;1C ap d1,lng cho hEI' thOng difn fip ua
' ub
' U
c
va til thong ~'a' ~'h' ~, cua stat.o. Cae phl1dng trinh tong quat cd d:tng:
ud '!
~
Aual,,, (3- 21)
U]l
~
A-I u
d'I
(3- 22)
~)tlt] ~
A~'''!K (3-23)
~';II'c K' ~' dq
(3-241
3.4.3 Phuong trinh Park
Kh6ng ph1,l thu¢c v~lo (illY quan rota, ba day quan tren hinh 3.6a t.uan
thea cac phl1dng trinh tong quat:
dll'
dt
(3-25)
cit
. d~'c
ltl, = - Rll' - dt
R la di~n tro 1119t pha Clla stata. Ta viet dl10i dl;l-ng ma tr;.'i.n tong quat
ci
uhc = - RiI'.' - -dt~rabc'
Ap dl:mg bien doi Park cho he phlldng trinh (3-20), (3-21'l va (3-24) ta
dllQC
Ta nh~n thay
d
A-(A-I)IjI'iI
dt
61

62. 0 -1 0
d ,
A ~ (A-I) 1 0 o i
dt
0:0 0
ttl do, b~ng each khai tri~n ta co:
dV'd da
ill - VJq~
de
de
dt
dV''1
dt
+ '1'oJ--
dt
(3.26)
U o = -R) -
dl/'
dt
3 phuong trinh (3-26) t:;10 nell cae phuong trinh Park.
Ta nMn thay co sl,t triIng hQ'p hoan toan cua hai phlwng trinh dau tien
vcri hai phuong trinh cuni cua lluiy di$n 1119t chieu t6ng quat (3-12), chi co
dB
dieu khac Iii d day dt kh6ng phai Ia toe dq quay 'r' Vi day qmlD gia tllong d
va q cua hinh 3.6b tlldng tv day quan phAn ung cua may di$n mcit chi'flu: cae
tr1,1c tit co dinh so voi toa do t~o nell boi tr1,1c Od va Oq nhllng thanh dtln
chuyen d(mg so voi tr1,1c t9a d9. 'fa co the di den k€t !u:)n: Bien d6i Park d6i
voi day quan ba pha a, b, c ding gi6ng nhU: bien doi cua c6lectd len phlln ung
nuiy di~n m9t chieu.
62
3.4.4 COng su4t va mOmen
C6ng suat tue thbi cua day quan a, b, q a mQi thai dUl11l bang
Pc = u)a + uj,iL, + ucic
bang bifin d6i Park theo (3-20) va (3-22) ta tim dUQc ve thu hai
3
Pc =T(U,}d + uqiq + 2u,~(,).
Khi lilt d1,lng phuong trinh (3-26) ta co:
3
+-(w.i
2 or U II
d
1/) id
) - .
'I dt
3 . d~'d
(1- +
2 'dt
. dV'q
, -+
4 dt
Ta nh~n thay trong bieu thuc Pl co 3 thanh phhn:
d,
2· -'-)
' dt
(327)

63. 3 ,
thanh philn - -R (i l + i + i}l bieu dien ton haa Joule trong philn
2 U I
lJ:ng
3 dV'J dV' dV'
thanh phlln - OJ + i'l -+ 2 (l
bie'u dien bien
2 dt dt lCIt
thi€m thea thbi gian cua nang hlqng tit tru:dng tlch liiy.
3 de
- thanh phan - (f,AI - V'lidl - ~'n vi'li c6ng suat CO' bien doi thanh
2 dt
cong sua:t di~n trong may. Trang truong hqp tQa d¢ gall voi roto, khi do I.a
toe d¢ We thbi, momen di$n tit bang:
3
Melt = 2 (!fllliq - !/'qiul (3-28)
.Ket qua Day lll(Jt IBn nlia trung vai bieu th(ic (3-13) doi vai may dit';ln
lll¢t chieu tcing quat.
3.4.5 Khcii ni~m ve may dh~n t6ng quat
Bien d6i Park co the ap dng cho cae lo~i lllay di~n xoay chiflU bat kyo
Vi~c ch9D t~la d(J (Od, Oq) ph1,l thu9C vao cau true cua m;-iy va lo~i bai toaD
thuong g~p.
Vi dl vbi may di~n dong h¢ Dfm ch9D t9a d¢ gaD voi roto va dnh den doh
doi xung eua nilly_ D6i vai may di$n khOng dong bi) bien doi Park co the ap
dlng cho stato va roto. Sl,l' d6j xling llH.lch ttl cho phep tuy y chr.m b~ t9a d¢.
Bien doi Park cung dlh;1C ling dlng cho cac lo~i may di$n khac nhu may
di~n phan khang, may di~n xoay chieu co vanh gop...
Nha bien deli Park quan h$ giG:a tit thOng va dong di$n dlt9c dan gian
bOa va thl,l'c te gi6ng nhu truang hap may di$n mi)t chieu tong quat.
Bien d6i Park cho ta thay 16 sl,1 tuong tv cua qua trinh bien d6i nang lU9ng
di(ln cd cua cac lo~i lllay di$n quay khHc nhllu vi the ta gQi cac phuong trlnh
Park IA phuong trinh may di~n tong quit. Cac phuong phip nghiAn cuu qua
trinh qua di) cua cac lOJ;li may dien khac nhau co nhieu d~c diem chung. Tuy
nhien d6i voi tUng lo~i may dien khac nhau cling co nhftng npt rieng can luu y.
3.5 MAy m¢N DONG BO
3.5.1 L$lp phLJong trinh may di,n dlmg bet au dl,mg bien d6i Park
Cho may di$n dong b¢ ba pha, hai cl,1c, sd do bi,§u di~n tren htnh 3.7 ta
63

64. nh~n thay:
- '1'ren stato ha day quan pha a, h,
c co cac t.rlc I~ch pha 2-'1/3.
- '1'rEm rOto day quan kich tu ky
hi$u bflng ehi s6 f:
'fr~lc Od eua M t9u d(J (Od, Oq)
ch9n trung vai trl,lc tu euan kieh ttl.
Khi quay vt t.ri Od dl1Qc dlo.lc trung
bang gdc
o = (Oa, Od)
of!
ot
'fren rota cd bo tri cae day qUlln
can dju ngan nwch. Ta cd the bieu di€in
bang hai day quan ngan mach D
thea trl,lc d9C Od va Q theo tr~lc
ngang Oq.
Neu cac day qWln stato ut1:JC
xem nhu may phat va day quan
kich ti1 xem nhl1 tAi cac phl1dng
t.ri.nh di~n clla 6 day quail. Ii'!:
cllf'
u,,=-R),,-
ot
-Ri[
dlJ.
c ~ - -~
dt
dV'1
(3- 30)
, ~
R[il +
dt
0 R)i[)
dl.{'i)
~ +-~
dt
0 R()iO
d'rf'()
~ +--
dt
64
b
d
I
~ ~
C
Hlnh 3.7. S(I db day quin th,Je
eua may di~n d'oog be.
~
d
Hlnh 3.B. SO db may di~n dOng b6
theo true d va q.
G

65. trong do Ra la di/i!n tro pha cua day quan phlin ung.
RJ) va RQ di(!n tro day qua:n can
Rf
la di~n tro dAy qu.fn kich tit.
Sau khi ap d1,lng bien d6i Park cac phuong trinh (3-30) tu'cmg tL! nhu
(3-25) duc;lC th~ vaa (3-26) va duc;lc bieu diil!n thea cac d:;ti IUc;lng d va q tren
hlnh 3.B.
Tren hlnh 3.8 cac quan M gifta tit tMng va dong di~n th~ hiliin tuong UlC
tit gif:r:a cac cU9n day co tr1,lc tit 00 dinh vai nhau, m~t khac hai h9 vullng gOc
nhau. Cac quan h¢ nay la tuyen dnh do gill thie't may khOng Mo hoa, cac h$
so khllng ph1,l thu(lc fJ va duQ'C phan chia thanh hai M thOng d6i xung. Mqt
M thong cAp 3 ang voi cac dAy quan d,- f va D cua tr1,lc doc, m¢t M thong
dip 2 ung voi cac day qua:n q va Q cua tryc ngang va thanh philn cu6i cung
bi{i'u thl quan h~ gifta V' va io'
D~ thu~n ti~n cho vi~c bieu dien cae d~i IUQng khac nhau ta thuong dung
don vj tuong doL Cac gia trj tuong doi du9'c ky hi$u bang chu nha bang ty
so cua d:;ti IU9'ng thvc va d:;ti luong djnh muc cua no.
Thea d~i lu{;mg tuong d6i ta co tM' bie'u di~n cae phuong trlnh cua may
di(n dong bo:
Cac phuong trlnh di$n
ur ~
rfif
0 ~
rr)D
dJ/'d
_ dJ/'q
dt
dl/'
dt
d~r
+--
dt
d~'D
+--
dt
Cac phuong trlnh tit:
(3-31)
(3- 32)
(3- 33)
(3- 34)
65

66. I 1/'u I I nlaf IllaD' ' i :
. ~r
~
mal In mIDI ,I il
I ' , , .
i 1/'0 I lllal) mil) Inn ll) ,
(3-35)
'11 Iq UlI). iq
! .,I
~
i , ' ',. I
! lUaO IUU lO!
(3- 36)
!f'
~ I i
(3- 37)
Cae phuong trinh nang IU!;lng:
M ~
w(I/'uiq - I/Iid) (3- 38)
2H dw,
M, - M ~---
w dt
(3-39)
trong do: lu' lq la di~n cam gan voi cae di~n khAng d~ trung cho ch€ d¢ xac
I~p dong b(l voi tan so w; H la hang 90 d¢ng nang.
(3- 40)
di~n khang tlong bi? ngang trlc xl] = lqw (3-41)
diEm cam Iff' IOD' lIN Iii cae di~n cam cila cac day qulln f, D, Q va lllrn
Iii hCi cam gii1a day quan f va D.
- hCi cam gii1a m¢t pha stato a, b, c va day quan r6to vi dl maf ia hei cam
giua pha a va cu¢n kich ttl trl,1e ti€p tham gia vao bieu thd'c cua suc di~n
d¢ng trong.
dl,~n dun 1 gan voi dil)!n khling thu tl,1 khong:
x = low.
3.5.2 VI dl,J (rng dl,mg
H~ phuong trlnh (3- 31) den (3- 39) eho phep nghien euu d~e dnh cua may
di~n dong b(l (1 ch€ d(l bat kyo Khi toc d¢ coi li'l khong doi M thOng Iii cac
phtwng trinh tuyen dnh, co the giai ba.ng giai dch. Tuy nhien noi chung vi
toe d(l thay dl1i can co cae b(:t dilu chlnh di~n ap va toc d(l cae phuong trinh
tren khli phuc tl,lP, can dUQc xu If bang may dnh.
66
C che d) xlic Ji;l.p dong b¢ ta co:
uq = -r}q + xuiu + e
,e = In~fwif.
(3 _42)
(3-13)
(3-44)

67. Ta nghi€m cuu cac thOng so d:;ic trt1ng cua may di~n dong b¢ 0 ch€ d( qua
de). 0 day ta gioi h~n toc d¢ la kMng d6i, bang toc d¢ dong bQ, nghta la chi
xet den qua d¢ di~n ttl, b6 qua qua d9 di~n co va khOng co tMnh phan tha
tv kMng. Ta co the ap dl:lDg bien doi Laplace cho cac bien thil!n cua cac d~i
1t1Q'ng di~n. Cac phuong trlnh (3-31) dt;n (3-34) tro thanh:
6.ull(p) = -ra6.iip) - P6.1f'd(P) - w6.1j'q(p)
6.U
q(p) = -ra6.iq
(p) - p6.1f'lj(p) + w6.1j,/p)
6.ur(p) = rrAir(p) + p6.1fr(p)
o = ro6.if)(p) + p6.1j'f)(p)
o = rQ 6.io(p) + p6.1j'o(p).
(3- 45)
(3- 46)
(3-47)
(3- 48)
Trong cac phuong trtnh (3- 35) va (3- 36) nen thay the 11' va i ba.ng cac
sai phan 6. thea p.
Khu 6.if' 6.V'p 6.i[) va 6.V'n hung 5 phuong trlnh (3- 35), (3- 46) va (3- 47)
Phuong trlnh eon IfP xulit hi¢n 6.1f'd nhu ham tuyen Hnh cua 6.id va 6.uf
.
Cae M s6 lit. phan thuc bl)c 2 cua p
(3-49)
Ttl: va mA.u s6 cua Id(p) va g(p) cO cac nghi~m thl,tc vit. am co the bHlu
di~n duai d~ng:
Xu (1 + T'dP)( 1 + TdP)
Id(P) =
w (1 +.. T'dp)(1 +. TduP)
ham truy'fm kich ttl toan tu:
m'lf 1 + -TDP
g(p) ~-' -;-:--=-----::-:'---;;;;;---:
rf (1 + T'drJl)(l +. TunP)
(3- 50)
(3'51)
Cac hllng s6 thai gian T'll va T'do Ia hang so thOi gian qua d¢ cEi Is, va
Ian han con ha.ng s6 thai gian Td' Td vit. Tn lit. Mng s6 thai gian sillu qua
de) eo 0, Is vA nho hon,
VI ch€ d¢ bien thien kha chc).m (tan s6 tuong dttong eo 1 Hz) do do di~n
kha.ng qua de) dQC tr1,lc
(3- 52)
voi x'd::::: O,lxu .
Cae eh€ di? bien thiE!D nhanh co m$,t di~n khang sh~u qua d¢ dQC tr1,lC
67

68. Xd ;0: X'd
Td
Tdt)
voi Xd :::: 0,7xd,
'l'a khtl 6.i{) va 111fJQ giua ba phudng trinh (3-34) VB (3- 36)
Phuong trlnh eon l~i co the dUQe vilit:
6.'Pq(p) = Iq(p)6.iq(p)
lq(p) la phan thuc bf).c 1 cua q, co th~ viet duai d~ng:
1 + T P
x ~_=c'-­Iq(p) ~-- ~
OJ 1 + T'loP
(3- 53)
(3-54)
(3-55)
Cac hang sci thdi gian sh~u qua dl) T 'l vi'!. Tqo cung cB Td va Td,,' ta
eo di~n khang si{!u qua d9 ngang tr1,1c
T
'I
x
~ x --
Ci T
I
vdi x
'I
~ x d
3.5.3 Nghiin cuu ngln m,ch ba phs khi khOng tai
Cae tinh toan lien quan den che dO qua d(l cua may di~n dbng bO thuCJng
rat dai ngay ca trong truong hQp don gian nhat. Tuy nhien ta xet m()t trong
cac truong hQP quan tr9ng trong th1Jc te vi cac Iy do sau dlly:
- phuong phap nghien cllu eo tM' stl dlng cho nhieu vi d1,1 khac,
- che d9 nay thuong dUQc su dung trong thtl nghi~m, bhng cach ghi 81,1
bien thien dong di~n theo thm gian Mi vi phan tlch bang bieu do dao d(lng
cho pMp dnh toan cae th6ng s6 ehu yeo, No eho phep t~o nen qua trtnh xae
d~nh bang th!Jc nghit:'!m cac thong s6 eAn thiet cho vi~c nghien cuo toon b9
qua trlnh qua d9,
Ngan m~ch khbng tai bao gom lo~i bO mOt each d9t ngQt cac di~n ap ua'
ull' U'-' do do cac di~n ip ud va Oct' con di/iln :ip kkh tu of van gill kh6ng d6'i.
Khi kh6ng tEti a eMf d9 x:ic I~p dong bt) ta co: ud = 0, u,' = e,
Ap d1,1ng vao cac phudng trinh (3-31) va (3-32) cac bien thien:
LlUd(p) ~ 0
e
6.uq(p) ~
p
llur(p) ~ O.
GEl

69. Thay th~ vao (3-49) va (3-54) vao (3-45) ta duQ'c:
°== -era + pl,/p)]Lli,/p) - wlq(p)Lliq(p)
e
= wlip)Llitl(p) - ern + plq(p)]Lliq(p)
P
Giid h$ thong nay ta dllQ'C Lliip) va fliq(p).
vi co cac d~i illQ'ng tham gia vao phuong trinh cho pMp dan giAn hoa
Hnh toan m(lt cach dang k~. Dau tien djnh thl1c cua M thong co the· dUQC
viet mOt cach gan dung:
D = id(p)lq(p) (p2 + w2 + 2ap)
vai
rn w w 1
a = - ( - + - ) = - .
2 x(j x q Tn
Tala hang so thai gian cua stato co 0,1 den 0,2 , a w
Ta bi€t rang djnh thuc xulit hi~n trong mau s6 cua cac nghi~m 6.itl(p) va
Lli,!(p) va nghj~m cua mAu thuc cho ta guy lul)t bien thien theo thai gian.
Theo bi~u thuc (3-SO) va (3-55) dinh thl1c D duqc viet duai d;:tng
D
__ XdXq (1 + T'dpHl + TdP)(l + T qp)
(p2 + w2 + 2ap)
w2 (1 + T'dllP)(1 + Td,,p)(l + TqnP)
Quan sat mau s6 ta thl'Iy c6 cac hang s6 thdi gian xuat hi(!n trbng bi~u
thuc tuc thai cua Llid(p) va Lliq(p):
- Thanh phAn tAt dan vaj hAng s6 thai gian T'tl, Td' Tq
- Thanh phan daD dqng vaj tan 86 w va M so suy giam a.
Ti~n hanh dnh toan bang cach phlin chia thanh thil'a s6 huu ty va dan
giAn hoa dnh toan theo dJ cae d~i lUQ'ng
1 1 1 1 1 1 1
( - va -- ) ( - -- -- va - ) « w
T T T 'T J T 'T Td do d do q go a
Vi ch€ dQ ban .dl'iu la k.h6ng t9i citc dong di~n ban dau va gia 136 fl oang
dong di~n can tim, ta 00:
1 1
id(t) = -e[- + ( -
X.l x'd
e
1
- )exp(-tiT'.l) +
Xd
+-- exp(-at)cos wt
x.l
1
(--;-,
X d
1
---; )exp(-t/Td)] +
xd
69

70. e
iq(t) =~,-, exp(~at)sinwt
x 'I
Trang truang help nay b6 qua thanh phan Ti
Tinh toan dong di~n 1ll9t pha bat ky, sa d~ng dl;li h19ng v~t If ta dt1Qc
_ 1 1 1
-EV2[~ + (-
Xu X'd
- - )exp(-t/T'd)
Xd
1
+ (
Xu
EV2
+--
2
EV2
+--
2
1
I-
X
1
( -
Xd
1
+--- Jexp(-at)
X
1
- lexp(-atl
X'I
cost/
cos (2wt + fl,,). (3-58)
Cae dong di~n ih(tJ, ic(tl nh(m dt1Qc hAng each thay t.he tuong ung [{;I -
(2;r/3)] va [w - (4JT/311
Ket qua bieu do dong di~n qua d(l clt1Qc ve tren hinh :3. 9 + 3.11.
D,§ nh~n thay r!ng t.rong ia
cong thtic (3-5Bl thanh phan
cuoi cung (thea coszwt) co bien
d¢ rat nha so voj cae thanh philn
khac do do co the b6 qua va cae
hang so thoi gian T'd va Tu nit
khac nhau.
Trang bieu thuc (3- 58) dong
di~n ngan mach co 3 thanh phan:
- Thanh philn dau tiEm trong
Jau ngo~c vuong lit thanh ph~i.n
tat dan chu ky 1.l'ng voi 51! ng-an
can tu thong ban dau trong nu).ch
rota. Hang so thbi gian T'd chu
yeu dll!;lC xac dlnh Mng cac thong
s6 cua lll':ch kich tit va Td thea
thong so cua cu¢n can d;c tr1,lc,
con tu thong tlldng ling vai
70
,
t
A.
----WWTvMt
Hlnh 3.10. Ooog ngAn mlch pha B.
....... . .NWffivmm t
Hlnh 3.11. DOng ngar. miilch pha C.

71. trllong quay vd'i toc d9 w d6i vd'i cac pha stato, cam ung a do 1ll9t dong di(ln
co tan s6 w tAt thea quy lu~t cung M.ng 96 th.oi gian.
~ Thanh phlin thu hai 13. thanh phan khOng chu ky ung vdi 91,1' ngc1I). can
tit thOng ban dau trong 1119t pha bat ky (0 day la pha a) cua stato, vdj hang
sO thoi gian T = 1/a dt:i.c trung cua stato, bi~n d(l cua no phl thuQc vao vj
tri cUa clay quan so voj lll~ch klch tit t~ thai dit?m xay ra ngao l11!..1ch.
- Thanh philn thu ba ia thanh philn tat dan voi tan s6.gap doi li~n quan
den s1/ kh6ng dong clEm cua m!..1ch roto so voi stato
3,5.4 Do di.n khang va hAng so thai gian theo thi nghi~m ng6n
mOoch ba pha
Thi nghi~m duCJc thl,l'C hi~n vdi di~n ap giam (noi chung e 0,3 va nha
hon d6i voi may Ion) de' tninh hien tll~1ng bao hoa va gitUll ung suat Cd di~n.
Vi~c khai thac ket qua duCJc thl,l'c hien thea c.'ic duong cong thu duCJc tren
dao d(lng ky nhu hlnh 3.11, tufm theo cae guy luat (3-58) trong do thanh
phan eo tan so 2w co the b6 qua. Bien do cua thimh philn diEm hoa tat dan
lit M so cua bieu thtJ:c cos (wt + fj.,J i
trong phudng trinh nay. Ve m~t do
di (t)
thj khi ve duong b!l0 phia tren va 0 p..~/-~~~~~~~~~~~­
phla dl10i c~a duong cong bat ky cua
hlnh 3.11 va bang each do cae
khoang thai gian ch9n trttdc s,t khac
nhau giUa cac tung dO cua hai
dubng baa.
t.i'(t)
'-_L.i(t)
Mot nua hi$u so nay ia bien dQ
thea guy lu~t (3-58) co d;:tng:
Hlnh 3.12. Xac dinh bAng db thi hang sO
thili gian ella may di~n dOng b¢.
1 1 1 1
Ht) = e[ - H- - - lexp(-t/T'lI) + (, xli xli xd X el
1
-lexp(-t/Td)1
Xci
Di~n khl'ing d6ng b~ Xc! cla biet ba.ng each keo dai db thj den ch~ d~ ngAn
m~ch xae lap ta co the tim duqe thanh phan tUdng ung, tit do suy rll
1 1 1
lli(t) = e[-·- - - )exp(-t/T'el) + (
x'd Xd Xci
cac t9a d¢ thea duang loga tren hlnh 3.12.
Vi Td noi chung r:lt nha so vai Tel sau Dl¢t khoang thai gian ngan 6.i(tl

72. trung vai thanh phan qua de
1 1
Ili'(t) = e(-; ~ -)exp(-t/T'd)
x d Xd
Thi;l.t vi;l.y ta thAy rang do thj 6.i(t) co xu huang ti~n nhanh ve phia b~n
phai, trong dci a di~'m A, nOi suy 0 t =0 cO tQa d¢
suy ra X'd la d¢ doc cua duong tha.ng cho T'u'
Ta l:ti lAy cac t9a d¢ loga thanh phll.n sieu qua d{i
Ili(t) = Ili(t) - Ili'(t)
cho thea guy Iu~t
1 1
e( )exp(- t/Td)
xd xd
1
e(-
x'd
1
- ) ,
xd
D~ thi cua no Ia dubng thang lAy t = 0 (diA'm B) co t9a dO
1 1
e( - , - )
Xd X'd
Tit do suy ra xd va dt) diSc cUa duong tMng cho Tu'
tU do
Sv ton t:ti cua thanh phAn khOng chu ky tat dan trong bieu thuc (3-58)
do hai dUong bao xac d~nh tn10c dAy noi chung khOng d6i xung so vai trl,lc
thai gian va sl,t kh6ng d6i xl1ng phl,l thu¢c vAn gia tri (J{f De danh gW.' thanh
phan voi d¢ chtnh xac cao ta vI'! 3 dllong tr~n hlnh 3,11 voj sl,t kh6ng d6i xung
cl,ic d:ti r6i ve duang cong co t9a d¢ la trung blnh dai s6 cua cac t9a d(l hai
dllong bao,
3.5.5 Sa db tllang dllang
Cac phuong trinh til (3- 32) dgn (3- 36) co the dUQc hieu dien bang sa da
wong dllong Wang tl,t may bien ap hai'ho~c ba day quan,
Vf! m~t tr1,lc d«;lC so db co cAu truc raJ dan gian ngu tn gia thi{!t tAng h6
cam Mng nhau, nghia 18. ta coi tU thdng cam ung chung voi hOO dAy quan bat
ky hoan toan qua cUQn day thll ba. Gia thigt nay vbi gia tri wang d6i dUQc
cho bA.ng dAng thuc
nlaf == nlaD = nlfD =: Imd (3,59)
lmd Ia di~n cam dQC trl,lc. Ct1ng v~y ta d~t
m == IaU mq
(3,60)
72

73. ]a di~n cam ngang trl,lc.
Do vh doi voi tung day quan sJ,t khac nhau giua di~n cam ban than va
di~n cam chung the hi~m di~n cam ro cua dAy quan. Ta d{i.t:
lu=lmd+la
Iff = Imd + Ir
100 = ImJ + II)
I - I + Iq - mtj ~
IQO = Illlq + 10
(3- 61)
Ta chl1p nh~n di$n cam tan cua stato thea hai t~c la gi.6ng nhau. Trang
cac phuong trinh (3- 32) den (3- 36) thay bAng p ta duqc h~ phuong trinh toan
tu-:
p, I, + 1m, Imd Imd i,
Ur
Imd
't
It +Imd Imd it~,
+ (3- 62)
p p
0 Imd imd ' + If) +Imu in
p
Va
V'q ~ la + Imq 1m'! iq
~
'Q
0 Imq -+ IQ + Imq 'Q
p
(3- 63)
Cac phuong trinh ung voi so do tuong dllong bi{fu dien trl!n hinh
3.13 va 3.14.
Cac so do tuong dllong nay tuy kh6ng chua cac thOng tin llloi so voi hi:!
phuong trinh xuiIt phat (3-31) den (3-36) nhung rat ti~n ding vi cac Ii do
sau da.y:
- Cho phep hi~u r6 hOn ml)t s6 hiijm ttiQng vi dl,l phan bi~t ro chI! dQ xac
l![lp, chI! d¢ qua d¢ va sil!u qua dQ, moi nha.nh cua sO do co vai tro rieng ung
voi cAc chI! d¢ nay. Bang 3.1 cho clie eong thuc tinh dil)!n khang va hAng s6
thbi gian eua may di~n dilng b¢.
73