NLN* 118-7/2014*13
J LlTA CHON HE S6 0 THEO CHI S6 DAO DONG MEM CHO TRlTOfC TRONG HE T H O N G DIEU KHlEN T A N G
ThS VU THU DIEP*, PGS. TSKH NGUYEN VAN MANH, DH Bach Khoa HaNoi Bai bao trinh bay phwong phap xac dinh cac hg sd 0 cua cac bp dieu chinh ben vwng chat Iwgng cao trong he dieu khien tang theo chi so dao dpng mem. Xuat phat tw cau true tya ben vwng cua bp dieu chinh, bai bao dwa ra moi quan he giwa chi so dao dpng mem v&i tan so cdt va he so 6, cd chwng minh rd rang. Cuoi cung la vi du minh hoa.
I.DATVANOe
Y nghTa eua vide su dung hp dilu khiln tdng dd dupc r l t nhieu tdi lieu d l cap din [11[2][31.
Trong dd, y nghTa quan trpng nhdt Id hidu qua khu nhilu cua vdng trong. Trong bai toan tdng hap he thing dilu khiln thudng dua ra yeu c l u tinh khang nhidu phai can bdng vdi tinh dn djnh bin vj>ng cua he thing Hd didu khiln tdng ed kha nang tilm I n khu nhieu qud trinh rdt tdt nen d ddy ta uu tidn tinh bin vung cua nd han Id tinh khdng nhilu. Mat khac ta thdy toan bp he ting cd du tm I n djnh cho trudc thi ti>ng vdng cQng phai dam bao du tru* on djnh cua vdng dy. Vay dd todn he cd du tru on djnh chde chdn ed t h i dua ra ydu elu dy tru on djnh vdng trong Idn han hdn so vdi vdng ngodi.
Trong so cac chi so vd chit lupng eua hd thong (thdi gian qud dd, sai leeh cyc dai, dp qua dieu chinh, dd tdt d i n eua qua trinh qud dp) thi chi sd v l dd t i t d i n hay chi sd dao ddng cua qud trinh qua dO cd y nghTa vat \)/ r l t quan trpng. Chi sd dao ddng mpt mat phan dnh true tilp tinh chit dao dpng cua qud trinh qua dp Mat khdc, nd lien quan ddn su phdn bd nghiem cua phuang trinh dac tinh va do do nd phan dnh tinh chdt I n djnh eua hp thdng.
Do vdy, trong thyc t l thidt k l , ngudi ta thudng ddt ra yeu cau thda man chi so ndy. Ngodi ra, chf sd dao ddng cd mdt uu dilm vupt trpi so vdi cac khai niem du trO I n dinh khac. Dd la sy xac dinh nhdt qudn eua nd ddi vdi^mpi he thdng vdi dp phuc tap khdc nhau. Cd t h i ndi, chi sd dao ddng Id khdi nidm vua phan anh chit lupng qud trinh didu khiln vCra phan anh tinh chit on djnh va dy tru on djnh cua h$ thing.
Trong tai lipu [4] dd dua ra cau true bin viJng toi uu cua cdc bO dieu khiln trong hg ting. Tuy nhidn viec lya ehpn cae hp so 0 d l hg dam bao yeu c l u v l dy tru on djnh v l n chua dup'c d l cap.
Bdi bao phan tich vd trinh bay phuang phap lua ehpn cdc he sd 0 theo ch? sd dao ddng mdm m [5].
2. N^N T A N G L Y T H U Y D T
2.1. Cau true tang va cau true hg mpt vdng twong dwong wng von khau dieu chinh thw k
Mdt he thdng dieu khien tang ed c l u true nhu hinhi.
—9S-9H*-
^
Hinlt I So do cdu true h? ihSng dieu khien ci nidng
Trong do:
z. y, u - lln luat la: tin hieu ddt, dgi lupng ra cua he thing va, tin hidu tdc ddng dilu khidn (thudc vdng trong cung);
F„ 0„ R,' cdc khau ddng hpc thudc tdng thu i, Sa do he mdt vdng tuang duang, ung vdi khdu dilu chfnh thu k nhu hinh 2. Trong dd: VMR goi la ddi tupng tuang duang cua vdng thu k.
2.2. Cau true cac bp dieu khien trong hg tang Cdc bp dilu chfnh trong hp tdng dup'c xdc d\nh trdn ea sd quan dilm tdng hpp hd bin vung ehit lupng cao. C l u true he hd cua he mdt vdng tuang duang thd k [6] nhu sau:
^*(-^)^ —
(1)Cau true cac bo dieu khien trong he tang [4]
nhu" sau:
«,(») =
iR,(')-
K(:!)-
w-
(«..
(".
e,
0^)s
"l)(9.-,-«.) -*..i)(9.-|S + l)
^^0-\s)
o;' (s)
(2) Trong do cac h? so 9^ la cac h$ so khSc 0.
* Email: [email protected]
1 4 ' N L N - l i s ' 7 / 2 0 1 4
•rBfT"
khdu dieu cliinh tliu t 3. PHLFONG PHAP XAC BjNH 8,
Ti> SO" a6 hinh 2 ta co ham truyin he ha cua h§
mpt vong tu'ang duang thu- k.
Tac6: //,(s) = «,(j(),F,_(j) Thay v^o c6ng thu'c 1 ta co:
H,(s) = R,(s).VJs) = I
3 fl,M = -!-F-'(,>) ffjS
(3) Nhu vay cau true bp dilu chinh vong thir k cua he tang gl6ng vo'i bo di§u chinh b§n vOng ch^t iupng cao cua he mpt vong. Ly iuan tuang tu nhu trong tSi li§u [5] co duac bp dilu chJnh tua bin vung (co cau true bin vu'ng khong hoan toan so vdi truc^ng hap iy tuong), nhu sau:
K,U) = -, , W (4)
Trong do VhjifPT la ph^n phan thuc cua d6i tuang tuang duang V,ak-
Khi do ham truyin ha vong thu k la:
W, (j) = R, (.sW^^ (s) = — F - (sW (s) I
e,s
Theo (1) ta thay Hils) la mpt ham phSn thiJc.
Theo (2) ta c6 H^(s) co dO t r i van tai b^ng 0 vi theo (2) ta thly tich (Rt-Ot) luon la mpt phan thuc (Hp,(s)) hay:
;!,(j) = / / , „ ( i ) 0 ; ' W (7) Thay Ri,(s) a (7) vao (6) ta o6:
W.(J) H,U) RiM W,„(i)0;'(s)
(8) Nhu vay tu (8) ta th§y dp t r i van tai cua d6i tuang tuang duang vpng thu k (1,^,) b^ng dO tre van tai cua d6i tuang vong thu k(T„): T,(R = T^.
Thay vao (5) ta dupc:
H,(..•,) =
e„s
(5) Trong dp iia, la thai gian t r i cua d6i tupng tuong duang vong thu k (WCT.)-
Xac dint} T.M,
Tlf sa d6 hinh 2 ta d l dang thiiy:
H,(s) = R,(s)y U)
O l dan gian hoa ta k^^ hi0u lai nhu sau:
//(s) = «(i-)F(s) = ^
[//.W = //(!•)
Trong do: j R , ( i ) = « ( j ) [F_,,(S) = F(.!) Thay s = -mctj+joj vao (10) ta c6 [5]:
H{-mta + Jto) =
(9)
(10)
(11)
NLN* 118-7/2014*15
Vdi m la ehi sd dao ddng mdm vd m(o)) = /Wg -
. Id md dun eua H(-moj+ju}).
•0)- - TO) +~+arcig m Id pha cua H(-moj+joj).
Ta thIy hiln nhidn rdng, pha ^(w) cua ddc tinh mIm giam dan dieu theo tan sd, tu (p(0) = -(7i/2+arctgmo) d i n (p(oo} = -ao.
Td eac kit qua trong [5]
m(uj} < mo
limm(ftj) = l i m m „ -
lim m{a)) = Hm m^ - Tacd:
\imA{6}) = lim
lim A(a}) = lim
Dilu nay chdng td rdng, khi t i n so tdng din (oj = 0 ^ co) thi bien dp bdt dIu tu gid trj vd cung Idn, sau do giam ddn din 0. Han nua, d vung t i n sd Idn: A((o)=—.
6(0
V$y xdt theo chidu tang tin so, dac tinh mim cua hp thong ludn ludn bdt dau tw v6 cyc trong gdc phan tw thCr ill va tiin dan ve phia nwa am true thyc, sau dd di theo hinh xodn 6c, thuin chiSu kim ddng ho, va hpi tn dan vdo goc toa dp (xem hinh 3).
Khi tan s6 tang din: w = 0 -> w, dudng ddc tinh mem lien tuc cat nua dm true thye moi khi pha cua nd dat gid trj: -n, -Zn, -5%, ... tuang ung vdi cac tan s i : u}\<u}2<co3<.-.
Mdi diem cdt giua ddc tinh mIm vdi nua am true thuc cd t h i djch chuyen d i n dilm - 1 bdng each thay doi chi so dao dpng mIm. Khi ehf sd dao dpng mIm tang (mo tang), thi dac tinh mIm md rdng ra vd dilm cdt dich sang bdn trai. Ngupe Igi, ktii chf sd dao dpng mIm giam, ddc tinh mIm co
lai vd diem cat djch sang ben phai. Vdy, se tdn tai mdt gia tri mo sao eho dilm cIt trung vao dilm - 1 .
II
/ I I I
I
IV
Hinh 3. Duang cong dac linli mem fie ha ciia IJ? bin vQng
Khi dac tinh mIm di qua dilm - 1 , phuang trinh sau se cd nghipm:
H{~mQ} + JQ}) = A{co)e"'^'"^=-\ (12) Theo hinh 4 dd thdy ring, dilm cIt thu i xay ra khi pha ^fwj = n - liix. Nlu dilm elt do trung vdi -1 thi phuang trinh (12) thoa mdn vdi nghiem:
p^ =:-m^o), + Jo)^. Kd ca tan so dm, ta cd c§p nghidm lien hp'p:
p, = -m,co, ± JQ), = -m^, (1 - e""') ± j(0,.
Ta ed pha:
(p(Q}, ) = -] (y, + — + arctg{m,
o]=^
-iTti> 0), = arctg{m_) + 2{i~l)7r (13) D l thay ring, khi chuyin tu cdp nghidm thu / sang /+1 thi phdn ao tdng them mdt lup'ng Idn han Znl2, cdn phdn thuc Id sd dm va ludn giam theo qui luat - /WQ/ (1 - e*^').
Nhu vdy, cdp nghipm ung vdi dilm elt dau tien se ndm gdn gdc tog dp vd gan true ao nhlt, cdn cac cdp nghiem tilp sau cdng ndm xa din v l ben trai. Cap nghidm dau tien quylt djnh dp dy tru I n djnh cua hd thong vd cd anh hudng manh nhlt d i n ddng di0u cua ddc tinh qud dd- Cgp nghidm dIu tien la cdp nghipm trOi cua hd thong, Nlu cap nghiem trpi ndm trdn dudng bien mem cho trude, thi hiln nhien cdc nghidm cdn lai se ndm ben trdi dudng bien mdm dd.
Vdy> hdng sd qudn tinh 6 eua he thing phai dup'c xac dinh, sao cho dilm cdt dau tien cua ddc tinti mIm vdi nua am true thuc la dilm (-1,jO). Khi
16* NLN-118* 7/2014
dd, gdc pha bdng -TI va bien dp bang 1. Nhu vdy ta cd dilu kien:
( ^ ] - TOJ H h arctgm = —n.
M(<o) =
> 6J = — arctgm 2-12
(!•
(14)
(15)
(16) arctgm
- arctgmi
'*j\S^
Trong do mck id chi sd dao ddng vong thu k.
Nhan xet:
d cdng thuc (17) ta thIy Ok cd quan he vdi chf s6 dao ddng d vdng thd k (m*) vd thdi gian t r i cua ddi tup'ng vdng thu k. Nlu nhu xdc djnh dupe thdi gian tre ndy vd cho trudc chf sd dao ddng d vdng thu k thi ta se de dang xdc djnh dupe 6k.
4. CHINH DINH CAC Bp D l t U CHINH THEO CHi S6 DAO DONG M^M VA Vt Dg
Chf so dao ddng Id khai nidm vua phan anh chit luang qua trinh dilu khiln vda phan anh tinh chit I n c^nh va dy trd I n dmh cua he thing.
D l ddnh gia tinh chit dao dpng cua qua trinh qud dp, ngudi ta thudng dung khai nidm he sd tdt dan (v^. Hd so t i t d i n Id chf s i dp suy giam bidn dp dao dpng sau moi ehu ky. Chf sd dao dpng m vd hp so t i t dan t{/ cd quan h^ theo cdng thuc sau: v/ = I - e " ' " "
o l i vdi hp tdng chf cd tin hi^u ra d vdng ngoai cung Id bilt 6\sgc yeu edu chit lupng cho trude.
Tuc id hd so tit d i n ij/ hay chf sd dao ddng m d vong ngodi eung Id dup'c cho trudc. Vi vdng trong cdn ed dp on djnh tot han vdng ngoai do dd ta ehpn chi sd dao dpng cua vdng trong Idn han vdng ngodi.
Vi du : Xdt mpt h0 thing cd cdu true nhu sau:
n ' n
>H Ri 0. h —1 0; |-Hdm truyen eua Oi(s) vd 02(s) nhu sau:
100e^">
0,(5)
(1 + O,9.s)(l + O,38i0(l+0,225) 1 + 0,65
Khi dd hdm truyin cua cdc bp dilu chfnh theo cdng thuc (2) se la:
Ta thIy theo (15) (16) nlu eho trudc chf sd dao dpng m ta tinh duac tan sd dao ddng w vd hdng sd qudn tinh 9.
Td edng thdc (16) thay lai chf so nguydn ban eua hd tdng ta cd:
(17)
fi, =0.01-
-e,\
/?. =0,1
-(l+0,9s)(l + 0,38)(l + 0,225)
Nhu vdy thdi gian tre cua cdc doi tupng vdng ngodi vd vdng trong nhu sau:
r, = 0,32 (phut) r2= 0,095 (phut)
Vdi chf tidu he sd tdt d i n y/ = 0,9 tuang dng vdi chf so dao ddng mi = 0,367.
Thay so vao (17) ta duac: 0, = 0,385 Khao sdt cdc trudng hp'p cua m2 theo dai gia tri td m2 = mj = 0,367 d i n gid trj m2 = 20mi = 7,34 ta thu dugc k i t qua md phong vdi cdc trudng hpp nhu hinh 4 vd 5.
Trong dd:
5% la dd qua dilu chfnh Tq la thdi gian dilu chfnh li Id tieh phdn sai so tuylt d i i
lt = jlsiO^l, £{l)=iit)-y(l).
h Id tich phdn sai sd binh phuang:
/2 = ^iOdi
Hinh 4. Dac tinh qud dQ da Ap thong khi thay doi chi s6 dao dong mem nti cua vong trong
NLN'118-7/2014'17
Hinh 5 Cac chi tieu chdt lupng va h? so 62 theo citiso dao dgng mem m;
Nhan xet:
Khi tang gid tri chf so dao dpng cua vdng trong m2 dgc tinh qua dp cua hd thong thay ddi theo chilu giam dp qud dilu chfnh (6%) vd tang dd quan tinh Tq. Cung vdi dd Id cae chf tieu chat luang id tich phdn sai sd tuyet ddi (h) vd tich phan sai so binh phuang (/2) cung tdng. Tuy nhien khi tang ms din mdt gia trj ndo dd (m2 £ 5m,) tuang dng vdi gia tri d ddy id m2 = 2 thi ddc tinh qud dp cua he thdng vd cac chi tidu chit luang trdn hdu nhu khdng thay ddi. Nhu vdy sa bd cd t h i ehpn m2 = 2m,.
5. K^T LUAN
Bdi bdo trinh bay phuang phdp xae djnh cac he s i 9 cua cac bd dilu chfnh bin vung chit luang cao trong hd dieu khiln tdng theo chf sd dao dpng mem. Phuang phap ly lugn khoa hpc, kit qua cd t h i dp dung de tinh toan hieu chfnh cac he thong dilu khiln cdng nghiep.
ABSTRACT
This paper presents a method of determining coefficients 0 of controllers in cascade system based on the soft oscillation index and quasi- robust structure of controllers. The paper shows and proves the relationship between soft oscillation index, cutting frequency and coefficient 6. Finally, an example is illustratived.
TAI LIEU THAM KHAO
[1] Altmann, W „ Practical Process Conbd tor En^neers and Techneians, Newnes, 2005.
[2] Astrom, K. J. and Hagglund, T , PID ConMer Theoty, Design and Turang. The Instwrnentation, Systems, and AutomaBan Society. 1995,
[31 Jonathan Love, Process Automaton Handtxxik A Guide to JheayandPraclioe. Springer, 2007
[4] NguySn VHn Manh, Vu Thu Di#p, Phuong phap tong hop h^
aiu Aft«n tang tfieo quan diem bin vung cao //Tap chi KHCN Nhiet, 03/2014 S6l16,tr.23-27
[5] N g i ^ w van MgnK Phutmg i^wp l6i ini hoa cdc lie ihdng diSu kiiiindditugngbdl^inll LugntoTSKH Tr NSngluyiigMaLxcova. 1999
[6] MaHb HB. Oninwuawibiii CIIHUHJI pooaciimoii KacKodHoU MaiaiKAibiynpawxiiim TerL[i03HcpiinnKa. 2000, J>r!; 9 C 22-2
Phan bipn: TS Vu Nhw Lan
XAC DINH THin GIAN SAY MUOI
(Tiep theo trang 12)
In the article, author presents methods for definition the thermal Blot cnterion (Biq), the thermal Founer criterion (FOq). the moisture transfer coefficient (a J . Besides the author of article admits some physical thermal factors of refined salt of the other authors which are published in the Journals consist of the moisture diffuse coefficient (fim), the thermal conduction coefficient (X), the heat capacity (C) and the kinematic viscosity (jj) of drying hot air
The result of research defines the drying time for refined salt in the fluidized bed drying is 18 minutes
Key word: Salt refined drying in fluidized bed dryer,Drying time;Fluidized bed dryer for refined salt drying, refined salt,salt dryer.
TAI L I E U T H A M KHAO [1] Bang Quoc Phu, TrSn Th§ So'n, Tran V3n PhO - Truyen nhiet (2004) NXB GiSo due, HS Npi
(2] TrSn Van Pliii - Dich chuyen nhieu ciu tie trong cdc qua trinh cdng nghe va phuong ph^p xdc dinh d0c trung nhi$t - chat cOa mOt so san pham tftyc pham va vat li$u am - Luan An ti4n sT khoa hoc Riga 1938 (tieng Nga)
[3] Tran Van Phu (1997), Nhung vin de chgn IQC cOa 19 thuyet truyen nhi$l truyin chat - Bi\ giang cao hpc, DH BSch K h o a H d NQt(ig88)
[4] TrJn Van Phii. N g u y i n Hay. Biii Trung ThSnh (2006) Dan nhiet vd khuech tdn am lien hqp cua v$t li^u dang ciu trong cac thiit bl siy /6p soi. Tgp chi Khoa hpc & Cflng ngh# nhi#t, S6 72 t h a n g l l 2006,
[5] T r l n VSn Phu (2002) Tinh toan va thiet k l h§ thong say, Nha x u ^ t b a n Giao di,>c.
[6] Biii Trung Thanh (2011) "Nghien cuv ky thuit siy muoi tinh bang phuung phdp siy tang sol", lu^n ^n tien s7 kJ thu^t, Dai hgc Nong Lam Tp Hfl Chi Mmh
[7] Holman J., Hea( Transfer, M c G r a w - H i l l , Inc. N. Y. 1992.
18] Ronal D K Stoessell (1975), "A non steady state method for determining diffusion cofficiency in porous media", Department of GeologyJ ousiana state University, Baton, Lousiana 70803, Journal of geophysical research, vol 80 No 36
[9] Mujumdar AS and Lixin Huang (2005), Single droplet evaporation and drying. Mechanical engineering department, Me6203 Mass Transport, Singapore
[10] Almaz Optics, \nc"Main properties of table salt". 12 Chadsford Cl Marlton. NJ 08053, USA Time definition of refined salt drying in the continuous fluidized bed dryer from similitude process of heat conduction and moisture diffusion
Phan bien: GS. TSKH Tran Van Phu
