mu-c CO cau true MMC Dieu khien dur bao hiru han cac trang thai dong cat cac van cho bo biin ddi da

Dieu khien dur bao hiru han cac trang thai dong cat cac van cho bo biin ddi da mu-c CO cau true MMC

A p p l y i n g Finite C o n t r o l Set - iVIodel Predictive Control for Multilevel M o d u l a r C o n v e r t e r ( M M C ) Tran Hung Cie&ng^'^*, Tran Trgng Minh\ Pham Viet Phwffng' 'Truang Dgi hoc Bdch khoa Ha Noi - So 1, Dai Co Viet, Hai Bd Trung, Hd Ngi

^ Dgi Hgc Hong Dire, So 565, Quang Trung, Dong Ve, Thanh Hoa, Viet Nam Din Toa sogn-29-01-2018; chdp nhgn ddng; 18-01--2019

T6m tit

Qua trinh tinh toan phirc tap cua phaang pfiap diSu khien dg bao (MPC) cho bo bien ddi da mirc cSu true module (t\AI\AC) la mgt v§n d§ cliinh cSn khic phuc de giam ap Igc tinh toan, XCP ly tin hieu cOa bg diiu khien. Bai bao nay trinh bay phaang phap dieu khiin dg bao hO'u han cac trang thai dong cat FCS-MPC d§

giam thieu toi da s6 loot tinh toan trong bo bien ddi MMC. Khi ap dung FCS-MPC cho MMC thi a mdi chu ky trich mau, trang thai chuyen mach tdt nhSt se dagc Iga chon di tao ra dong dien phia xoay chieu co dang sin, dien ap tu dien cua cac pha dug'c can bing do do se han chi toi thiiu dong dien vong chay trong mach cua MMC Phaang phap nay se giam thiiu do trS tin hieu va tin so dong cit cua bg bien doi Day la phaang phap dg bao mo hinh gian ti4p nham khac phuc tdng do meo song hai cua dong dien, dien ap a mdc thap nhit. Phaang phap nay khac phuc dagc nhung han chi khi ap dung dieu khiin dg bao cho bg bien ddi MMC hoat dong a che do ba pha vai cong suat lan va dien ap cao. Cac nghien ciru mo phong cua phaang phap MPC tren bo biin ddi MMC ba pha dagc thgc hien tren phan mim Matlab-Slmulink da cho thay cac au diem cua bo bien doi khi ap dung thuat toan diiu khiin dg bao.

TCf khoa: Bo bi§n d6\ da mifc, MMC, Dieu khien dy bao hUu h^n trang thai dong cSt FCS-MPC Abstract

The complex process of computation of Model Predictive Control (MPC) method for the Modular Multilevel Control (MMC) is the main issue to overcome to reduce the computation, signal processing of the controller This paper proposes Finite Control Set - Model Predictive Control (FCS-MPC) to minimize the computations in the MMC converter When applying FCS-MPC for the MMC for each sampling cycle, the best switching state will be selected to generate sinusoidal alternating current, the capacitor voltages of all phases are balanced, thus limit the loop current in MMC circuit. This method will minimize the signal delay and switching frequency of the converter This is the indirect model forecasting method to overcome the total harmonic distortion of current and voltage at the lowest level. This method overcomes the restriction when apply MMC converter in three-phase mode with high power and voltage. Simulation for MPC method on three-phase MMC converter in Matlab-Simulink has proven the advantages of the converter when applying predictive control algorithms.

Keywords: Modular Multilevel Converter, MMC, Finite Control Set - Model Predictive Control FCS-MPC 1. Phan mof d a u phiic tap khi ma rong cap dien ap cao hon, sir mat

„ - • - ; . , ; • * . » , -i - can bang dien ap tu dien [4]. Gan day, bo bien doi da Bo bien doi da muc duac nhieu su quan tam , ,,ir./-^'j *i ' / ^ ^ .. , •£ ' *-;

, . . " , , , , - ',,; ^",^^- 1 u- • tauc MMC duoc phat trien voi nliieu uu aiem vuot nghien ciru do co nhung mt aiem vuat troi khi ap . -• i u' • J ' u u- n,- • A-- • •,

, , . , ~ , J. , r . . , ' ; , . , ; troi kni ap dune cho he thone co dien ap rat cao va aung cho cac he thong dien ap cao, cong suat ion de * ' ' ° , „" . , - • . '~ u • i u i. . , ' . ° , * , , , ; ; . , , . , ; auoc SU Quan tam nghien cmi bai nhieu nha khoa hoc img dung trong cong nghiep, ket noi cac he thong . . ' ,, : ^-.. ,. ., . , , .; . ; . , ., ; , . - i

, . . . ; _ , ,, „ ; , ., '. . tren the gioi, day la bo bien doi co the tao ra nhieu dien va nguon nang luang tai tao. Doi voi cac ung . j , , . ' • ; . • " * -- • i u - ' - „ , ' , , ° ? - , * - , . , , , > 1 w u-1 - 1 ; j J muc dien ap voi cau true don gian ma khong can may dung 0 muc trung ap 3,3 va 4,16 kV thi bo bien doi u - • ' . • • u~ , u ' i - I^- • i-u' .i • •' ^ • x t n ^ /XT ,^ I n • . r^ • _. X I • Di^n ap ttung gian trong he thong chuyen doi, co the da muc cau true NPC (Neutral Point Converter) la . ,£ ^ . f . , r^ ,i. • , u ' i u--^ ,,. , . i „ , . ; : ,. . , . , j . „ . can bang dien ap cac tu bang cac phuang phap khac motgiaiphap tot [1], doi v a i c a c u n g d u n g c o a i e n a p . m - r ' u - •• -A • u ™ T,-rf i ^ i , . i_- I -; j-= i ' /'^r.r. .?. j j ri uli^u [3], Tuy uhien, viec ap dung cac phuang phap cao han 6 kV, bo bien doi da muc CHB (Cascaded H . . ; , . .: / , . ,-x *j ^ - \-~ , . . , . - , u D , , . , , , ' • . J „n r-,1 rA r.- 1 dieu khien cho bo bien doi gap nhieu kho khan khi tsndge) thuang duac su dtmg 1 , 2 , 4 . Ben canh , \ , _ . - . ' . r^i r<n • a ^ 1 1 , -, , ^ •' ..; ^ ,* . •; ^ Z •' "• i.x -' , , , , , " i yeu cau muc dien ap cao [4],[51 va dieu khien cac nhung uu diem, con mot so nhuac diem phai khac ;• ; , , „ , ^ ,- . , , . - . ,u' ^A^ ^ ^ UP.- „V„5;

, ^ . ' , a , i . , • . . i ,, ,; , bien cho MMC la mot thach thu'c Ion, doi hoi phai pnuc trong cac bo oien doi a a m u c nhu': dieu khien se , . j . -^ / - *-- i u'^ i. A- A-- ...,

•^ * • dat duoc nhieu muc Ueu dieu khien nhu dong dien ra xoay chigu co dang sin, dong dicn vong phai dugc han ch6, dien ap tu tren cac SM phai dugc can bang.

' Dia chi lien he: Tel,: (+84) 989 100.084 Cac muc neu nay da dugc thuc hien bang cac phuong Email: tranhungcuong@hdu.edu.vn

phap dieu khien tuyen tmh c6 di6n nhu PI, PWM dk dieu che do rgng xung, SVM dk di^u khien dien ap can bang muc dich de didu khien cho MMC [6], cac ket qua thu dugc con nhieu han che nhu t&i so dong cat van lan, tong dp meo song hai THD cao.., Bai bao nay dk xuit phuang phap dilu khign FCS-MPC nham muc dich giam qua trinh tinh toan phiic tap cho bg bien doi MMC de dat nhieu muc tieu dieu khien Cling mgt liic, dong thoi dap iing tot cac muc tieu dieu khien ciia MMC ciing mpt liic nhu: dieu khien dong dien day ra bam theo gia tn dat ciia chiing, giu cho dien ap tu dien o mot vi tri can bang xung quanh VjxJN va han che toi da cac dong dien vong. Trong MMC CO mgt so hiJU han cac trang thai chuyen mach, phucmg phap FCS-MPC se loi uu cac trang thai chuyen raach de du doan ciia cac hanh vi he thong va chgn nhiing trang thai chuyen mach phii hgp nhat, Phuong phap nay da lam so lugng tinh toan se giam dang ke. Mac dii qua trinh tinh toan bo dieu khien MPC phiic tap hon cac bp dieu Iduen truyen thong [6], tuy nhien no cho chat lugng dieu khien vai do chinh xac cao va on dinh [7], Cach tiep can MPC cho MMC trong bai bao nay la thuc hien vai FCS-MMC de giam so lugt tinh toan ciia ham muc tieu khac phuc phuang phap MPC dugc thuc hien trong [7]. De thuc hien FCS-MPC, mot mo hinh MMC ba pha vai tai RL dugc trinh bay trong phan 2. Phan 3 phan tich mo hinh toan hpc ciia mgt MMC va dua ra mo hinh toan hgc rai rac ciia bp bien doi MMC de thuc hien phuang phap MPC. Phan 4 thiet ke he thong dieu khien MPC cho MMC. Phan 5 thuc hien mo phong mo hinh bang phan mem Matlab/Sunuhnk, Ket luan trinh bay trong phan 6.

2. Cau triic va mo hinh toan hoc bo bign doi IMMC

2.1 CSu true bp bien ddi MMC

0101 lirgng N Hinh 1 la ciu tnic MMC gom co pha dugc tao thanh rir hai nhanh van chiia so w ^_^

cac SM m§c n6i tigp nhau. Dien ap s''3>',';_ , ^.-^

n6i pha dugc liy 6 diem giua 2 cugn khang Lo cua i nhanh van. dien ap mot chi^u d k vac dirge cap bai mot ngu6n chung duy nhit Vj.-. Tong ^^^^^^^

ciia m6i nhanh van b^ng t6ng dien ap DL- J SM ciia nhanh van do, khi do la m6i SM se cbiu rauc dien ap la V^^/N. Miic dien ap cua MMC phy tnuoc vao s6 lugng cua cac SM tren moi nhanh van Isj-

c i u niic ciia MMC thuc hien mk noi tiep mpt loat cac van ban din vdi nhau, do do se dan gian trong qua trinh digu khiln deng bp cac van va co the giam ton thit cua bg bi6n d6i [7]. Dieu nay co duyc la do cac van phai dong cit d tin so va dien ap thap.

S6 Iugng cac SM ciia bg bign dfli MMC phu thugc vao yeu ciu ve c i p dien ap d phia xoay chieu va cong suit trao ddi tir phia mgt chilu sang phia xoay chieu.

vk mat ly thuyet, s6 lugng cac SM co the tang len vdi so lugng khong han che nham dap iing vdi mpi yeu cau ve miic dien ap dau ra d phia xoay chieu.

2.2 Nguyen Iy hogt dgng ctia MMC

Cac SM ciia MMC dugc ciu tao bdi hai van ban dan IGBT mac song song vdi mgt tu dien C nhu hinh 1, moi SM co hai trang thai chuyen mach la {0;1}, trong do 1 iing voi fi-ang thai tu dien dugc noi vdi mach, tuong iing vdi SM dugc ON va ngugc lai.

Hinh 2 mo ta cac n-ang thai ON va OFF cua SM trong trudng hgp chieu dong dien co chieu duang nhu d hinh 2a va trudng hgp dong dien cd chieu am nhu d hinh 2b,

Hinh I. Cau tnic bg bi6n d6i MMC

Trong dd, trang thai ON hay trang thai "chen vao" la trang that ma dien ap diu ra d phia AC ciia mdi SM bing dien ap Uc d phia DC, trang thai OFF hay trang thai "bypass" la trang thai ma dien ap dugc dua ra o phia A C cua SM bing khong.

Hinh 2. Trang thai ON va OFF cua cac SM khi: a) ddng dien cd chieu dudng, b) ddng dien cd chieu am,

Mach dien tuang duang mot pha ciia MMC nhu hinh 3. Nguyen ly hoat dgng cua moi SM dugc trinh bay trong [9].

Hinh 3. Mach dien tuang duang mgt pha ciia MMC Cugn cam Lg co tac dung ban che cac ddng dien qua dp trong mach [9], Vdc va idc la dien ap tdng va dong dien phia mot chieu, ip va /„ la dong dien nhanh tren va nhanh dudi mgt pha ciia MMC, Vp va V„ la tong dien ap tren cac tu cua nhanh tren va nhanh dudi ciia MMC, Vj va /} la dien ap va ddng dien xoay chieu ciia MMC (J = a,b,c). lit so dd hinh 3, moi quan he giua ddng dien nhanh tren, dong dien nhanh dudi va ddng diSn phia xoay chieu dugc the hien bdi phuang trinh (1).

Theo tai lieu [10] nguyen tac cdng don dien ap ciia mdt pha trong MMC:

( 2 )

' 2 2

Tir (1) ddng dien phia xoay chieu ciia MMC:

K-'p-i (3) MMC hoat dgng tdt khi dien ap cac tu dien phai

dugc dieu khien bam so vdi gia tri dat. Do dd, muc tieu dieu khien la giG dien ap tmng binh cua cac tu bam gia tri dat va gia tri ciia chiing phai dugc can bang. Trong md hinh tat ca cac dien ap tu dien dugc coi nhu mgt ngudn dien tuang duang nhu hinh 3, khi hoat ddng bmh thudng tat ca cac tu dien dugc tich dien den gia tri dinh mirc Vdc/N. De dat dugc gia fi-i nay MMC bat mdt SM ciia mgt nhanh va tit 2N-1 cac SM cdn lai trong nhanh dd.Cac tu dien dugc tich dien phuc vu cho mot mirc dien ap cd gia tri bang Vt^i/N. Khi tat ca cac tu dien da dugc tich dien, bg dieu khien se gin tin hieu de bat va tat cac SM de tao ra mgt dien ap AC ttir mdt ngudn DC hoac ngugc lai.

Tai mdi thdi diem ISy mau, chi mdt niia trong tdng sd SM trong trong moi pha dugc bat, vi vay tdng so cac tu dien lam viec ndi tu nhanh tren va nhanh dudi cung la bang N tai bat ky thdi diem. VD' Neu co N cac SM d nhanh tren dugc bat thi tat ca SM d nhanh dudi se dugc tat, vi vay dien ap AC se la tdi thieu:

-N NJ

⁽⁴⁾

Khi CO N cac SM a nhanh tren dugc tat thi tat ca SM a ithanh duai dugc bat, dien ap AC se la t6i

Ik

~ N , (5)

Tir qua trinh bat tat cua cac SM nen dien ap tren phia xoay chieu AC ludn dao dpng trong cac miic -VdJ2 den ^VdJ2 vdi mdi budc dien ap la VjJN.

Dien ap AC tang bang each tat cac SM d nhanh tren ddng thdi bat ciing luc sd SM d nhanh dudi, 2.2 Phuo'ng trinh todn hoc cua MMC

Tir hinhl ta dugc md hinh toan hgc ba pha md ta dong dien ciia bp bien ddi MMC nhu cong thiic (6).

- 2 '-Z^'

(j-a,h,c) (6)

Trong dd: idc la ddng dien phia mdt chieu DC, ijz la

ddng dien vong chay trong mach, /, la ddng dien dau

ra phia xoay chiSu. Cac phuang trinh dien ap cua

nhanh tren va nhanh dudi ciia cac pha:

d',. dl,

= v,^-^L-^^+Ri +L -^ + ri.+v

"^ dt "^ dt '

^',. di ' dt J" '• ^i "J '

xfk+l) se dugc so s 1 VCI gia a tri dai Xr^»

(7)

.H^E^c.

^{(y^p:n) (9)}

Trong do S^- la miic dien ap ciia mdi nhanh. Tir (6) phuang trinh cua ddng dien dau ra xoay chieu tren cac pha dugc cho bdi (10).

•i='„-',- (""

Md hinh toan hpc cua ddng dien trong mien thdi gian hen tue thu duge bang each giai phuong trinh (7) va(lO) v a d u g c the hien bdi (11).

1 di^

~dt L + 2L,

6 day;

•[v^^-^^^-l^+^O'j] (^1)

(> .ti} '

3. D i e u k h i e n dtr b d o cho b o bien doi M M C S.l Gidi thieu ve phuffng phdp dieu khien du bao

\^ / l a i j

B$ dieu khiln FCS-MPC

Hinh 4. Ciu tnic d i k k h i ^ n MPC cho MMC[7]

Cau tnic dieu khien du bao cho MMC dugc th6 hien trgn hinh 4. Nguyen tac boat dpng ciia MPC dua tren viec du doan hoat dpng ciia md hinh d cac chu ky Iam viec tiep theo va tinh toan trang thai lam viec tdi uu thong qua ham muc tigu phu thudc vao dac diem cua timg he thdng [9] Xet he thong vdi bien can dieu khien la x(k). Dua trgn md hinh rdi rac ciia he thdng, cac gia tri hien tai ciia cac bien dieu khien x(k) dugc sit dung de du doan cac gia tri ciia bien trong tuang lai d chu ky tiep theo la x(k-^l) cho tit ca cac trang thai chuyen doi. Tat ca cac gia tri du doan

ham muc tieu, ham muc tieu iing vtn J^^% . chuyen mach (S) tdi uu se dugc chgn de ddng ca van ciia bp bien ddi, ddng thdi Iam uang Iha' toan tiep cho chu ky sau.

Vcm la dien ap pha so voi digm tmng tinh. Dien ap ra ciia mdi SM duoc xac dinh bdi (8).

v, = 5.v, ( : . ^ I ^ . Y ) (8) 6 day S nhan trang thai 0 hoac K tir (8) dien nap

mdi nhanh ciia MMC dugc cho bdi (9),

Ti T,

! ,trfi-/J^___^

•••-I ;r,(k*l)

.

! lit

'"""•••] Xlf

i(k*2)

Hinh 5. Nguyen ly du bao tin hieu ciia MPC[7]

Phuong thiic du bao tin hieu ciia MPC dirge thS hien nhu hinh 5. Trong dd tk la chu ky trich mau dau tien, tk.] va tk^2 la cac chu liy du doan cac trang thai Iam viec tiep theo cua tin hieu dieu Idiien. Gia sii MPC dugc ap dung cho he th6ng vol ba trang thai chuyen doi la xi, X2 va Xi vol gia tri dat la khong doi.

Trong moi chu ky du bao ham muc tieu se xac dinh gia tri sal lech gma cac trang thai ciia bien dieu iihien so vol gia tri dat, va gia tri sai lech be nhat se dugc chgn lara tin hieu dieu khiSn cho he thong, 6 hinh 5 tai thai drem k+i tin hieu xi(k+l) dugc chpn lam tin hieu dieu khien, o thai diSra tk.2 tm hieu X2(k+2) dugc chpn lam tin hieu dieu khien, cac tin hieu nay dugc clipii do ham muc tteu xac dinh CO khoang each nlio nhat SO voi gia tri dat. Cac chu ky tilp theo qua trinh dugc lap di lap lai nhigu lin dua tren thuat toan lap ttinh dugc dinh sin.

3.2. Chiin tmc FCS-MPC cho bf biin Mi MMC Phan nay trinh bay viec ap dung FCS-MPC cho MPC. So vol cac phuong phap digu khiin MPC khac nhu: GPC-MPC (Continuous Control Set MPC);

EMPC (Explicrt MPC) thi FCS-MPC khong cSn kSt hop voi cac phuong phap digu chg hay digu khign khac raa van cho chat lugng dign khign tSt. Viec nay se giup cho cau tnic he thgng digu khign dgn gian hon [10], Uu digm cila FCS-MPC la co thg kgt hgp cac yeu cau dieu khien ciia MMC nhu: digu khign cac dong dien xoay chieu, digu chinl, .,an bang dign ap hi dijn SM va giam thigu dong dicn vong trong bo bign dot. Cac buoc thuc hign FCS-MPC cho M M C ' i ) Do dong dien nhanh ttgn, nhanh duoi cua MMC tren ca ba pha, do dien ap ttgn mgi tu dien vc(k)- ii) Tao ra cac gia tt, dat cua bign digu khien nhu: dong dign dat i„.I<K) VOI cuong do va tan so nhu bign digu khign mong muon; iii) Ttr mo hinh toan hoc lien rac toe luen ngoai suy cac b,in dieu khicn d,.,,. a,a„ ... \ t h d o n g dien vo„= > o phuo:,. , b • t , ! ° i ' ' ' ^ • ! * E u l e r [ 7 ] d g d u o c - , . . . a , n , . : ,- J k ^ S ° " -u Allien Irons

chu ky liy m i u tidp dieo la tk^i; iv) Thuc hien tdi uu hda cac bidn didu khidn b i n g ham muc ti6u.

a. Xdc dinh so trgng thdi chuyin mgch ctia MMC:

Trong bg bidn ddi M M C mgt pha vdi (N + 1), tdng sd trang thai chuydn ddi thg hien bdi (12) [8]:

M = C i \ 2N\

N\{2N-N)\

⁽¹²⁾ Trong MMC ba pha, sd trang thai chuyen ddi la M^ trang thai. Vi du: bd bien ddi ba pha MMC vdi 1!(N=10) muc dien, so trang thai chuyen maeh tren ba pha cua MMC la 184756^. Vi ham muc tieu se dnh tat ca cac trang thai chuyen ddi trong cimg mgt chu ky dieu khien ngn sd trang thai chuyen doi se quyet dinh tde do xir ly tin hieu ciia bd digu khien.

Khi sd mirc cua bp bien ddi tang len, so trang thai chuyen ddi se tang Ien theo cap sd nhan, do do ap luc dnh loan cua bg digu khien trong cimg mot thdi gian trich mau la rat ldn. Vi vay phuong phap FCS-MPC se tdi uu cac trang thai tinh toan va chi chpn nhiing trang thai phii hgp trudc khi dua vao xii ly tin hieu.

b Dieu khien tin hieu dong dien xoay chieu:

\i-(ki G,alr,dongg:0

(JIICI

,

i(lt-l) t(k) ,fk+l) i(k+2l ifk+3)

Hinh 6. Thuat toan dieu khien du bao ddng dien Muc dich ciia du bao tin hieu ddng dien la digu khign sao cho ddng dien ra bam sat dong dien dat, Theo Euler md hinh gian doan cua ddng dien xoay chieu phia dau ra la:

i,{k-i'l)=Ai^{k)-hB[v^„{k + l)-v^^{k+\)

™{^ + l ) C ]

(13)

Trong dd:

"clt+i)--^ E ("..C+il-vl^+i))

- ; c = |l 1 1]' Tir phuong trinh (13) t a x a c dinh dugc ham muc tieu toi uu hda gia tri dong dien nhir (14):

• / , i - | w C ^ + i ) - ' / ' ^ + ' ) |

Trong dd ijie/k + 1), ij(k + I) la ddng dien dat va ddng dien dg bao cac pha dugc tinh tir cong thiic (13). Trong mpt khoang thdi gian trich mau dii nhd thi /,^^(k+i) ^ i^,,^(k), khi do (14) vilt lai nhu (15).

•^A=\'jrefi^)-'A+^i

⁽¹⁵⁾ Ham muc tieu (15) se tinh gia tri sai lech nhd nhat ciia ddng dien xoay chieu so vdi gia tri dat. Gia tri tdi im ling trang thai chuyen doi se de lam tin hieu ddng cat van de tao ra ddng dien tren tai xoay chieu va lam gia tri de du bao cho chu ky lay mau tiep theo, c. Dieu khien can bdng dien the ty dien-

Viec dam bao can bang dien ap trgn tu dien cua cac SM la van dg quan trong trong dieu khien MMC deMMC hoat dpng an toan va dam bao chat lugng den dang sdng dau ra [7]. Tir (9) ta suy ra dugc mo hinii gian doan cua tin hieu du bao dien ap mdi nhanh nhu phirang trinh (16).

W

⁽¹⁶⁾

Dg dieu khien can bang dien ap tu dign, phuang phap FCS-MPC thuc hien bd sung bien dieu khien vao ham muc tieu. Do dd, liic nay ham mue tieu eiia bd didu khidn nhu cdng thdc (17):

^..=-'.M[Z|'',(*+I)-^|] ("'

d Dien khien dong dien vong.

Theo [7] dien ap tu dien se tao ra ddng dien luu thdng trong mach, vi vay ngoai viec dieu khien can bang dien ap tu dien, viec han che ddng dien vdng cung la mdt yeu td can thiet Md hinh toan hge rdi rac cua ddng dien vdng dugc thuc hien theo cdng thiic (18),

, ( ^ + l ) = ^ ( f O . . - v , , ( * + l ) - v , ( i + l)) (18) Ham muc tieu cua FCS-MPC cho MMC dugc hinh thanh tir viec kdt hpp didu khien cac bien ddng dien, dien ap tu dien, ddng dien vdng md ta bdi (19).

J,j=J.,^Ji,+^k{k + ^)\

⁽¹⁹⁾ Trong dd X\, A.2 la trgnp sd, cac trgng sd cd vai trd tao ra sir lien he cac bien va thdng nhat chiing trong cimg mdt dan vi tinh toan, trgng sd chua^ cd phuang phap tinh cu thd ma dugc xac dinh bang phuong phap thuc nghiem [9]. Tir (19) ta co so dd thuat toan dk diSu khidn MMC theo FCS-MPC.

Hinh 9 md ta dien ap ra tren c a a,b.c pWa Tfiin: hien do

Tir,h,/k^!j V„(k+I).va,.,(k+]) tj^l^)- Vf

Hinh 7. Luu dd thuat toan ap dung MPC cho MMC 4. Mo phdng p h u g n g phap khien FCS-MPC cho M M C

Trong phan nay, tac gia trinh bay kdt qua md phdng bing phin mdm MATLAB/SIMMULINK cho bo bien ddi MMC d hinh 1 ap dung phuang phap dieu khien du bao FCS-MPC, cac thdng sd md phdng dugc trinh bay d bang 1.

Bang 1. Thdng sd md phdng Thong so

VJ, Dien cam loc L„

Dien trg loc rg Chu ki trich miiu T", Dien ap ttgn tai Tan so luoi

Gia tri 6000 10 6 200 5000 50

Don vi V mH

n

|JS V Hz Kgt qua md phdng ddng dien ba pha phia xoay chidu trgn hinh 8 cho thay ddng dien bam sat gia tri dat sau 0.001s va cd dang sm chuan.

Hinh 8. Dong dien ba pha phia xoay chieu tren tai Khi thay ddi gia tri ddng dien dat tir 60A Ign 120A d thdi diem 0,I5s thi phuang phap digu khiln MPC da cho dap ung vdi khoang thdi gian nhd la 0.00Is. Ket qua cho thay bd dieu khign cho dap iing nhanh dat chat lugng tdt.

xoay c h i i u . ' T l t h l y ring dien fP " °f„''5^'°„ga°y * 11 miic, tin hieu dien ap boat ^ S ™ °„„j ^a Hii chu ky dau tign, khong xay "'r'^THkn, 0.15s.

thay d6i dot ngpt che dp lam viec o ^ . , ^ j . Digu nay chiing to rang phuong pnap ^^g^, xuat cho tin higu dien ap cr phia dau J / cua bo bign dgi vol chat lupng tot o che dp lam . binh thuong va khi tbay doi che dp lam vice.

Hinh 9. Dien ap ra phia xoay chieu cua bp bien ddi tren cac pha a,b,c

' tl. Kgt qua phan tich Fc i^ gj^.

Thuc hien phSn tich Founer dang dien ap ra tren tai xoay chidu trong khoang thdi gian tir 0.16 dgn 0,2 s vdi bac song hai ldn nhit tdi bac song hai 20 nhu hmh 10. Ket qua phan tich tdng do meo song hai THD = 3,38%, cac sdng hai bac cao vdi bien do ldn xuat hien it, cho thay ro nhung uu didm khi ap dung phuang phap FCS-MPC cho MMC vdi viec chgn lua ttang thai ddng cat tdi im, Kgt qua phan tich cho thay muc tteu dieu khien da dat dugc ket qua mong mudn Sa THD g miic thap, gia tri dong dien va dien ap dam bao sir hoat ddng dn dinh cua tai phia xoay chieu, Hinh 11 cho thay dien ap tu ciia bd bicn ddi dugc nap tdi lOOOV trong khoang thdi gian ngan la 0.01s, qua trinh dao dpng khdng dn dinh trong khoang 0.01s den O.Is, sau do hoat dpng dn dinh trong cac chu ky lam viec tiep theo. 0 thai diem 0.15s khi thay ddi che do lam viec thi dien ap tu bign ddi khdng dang ke va hoat dpng trd lai trong khoang thdi gian ngan. Dieu nay the hien rd vai tro ciia phuang phap FCS-MPC da tac dpng va dn dinh dugc dien ap tat ca cac tu hoat

g trong chg do can bang.

Hinh 11. Hinh dang dien ap tren cac tu dien ciia SM ttong mpt pha bd bien ddi MMC

Hinh 12. Dong dien vdng tten ba pha cua bd bign ddi MMC

Hinh 12 md ta boat ddng ciia dong dien vdng tren ba pha cua bd bien ddi, ket qua eho thay ban dau tu 0 den 0, Is dong dien vdng cd gia tri ldn boat ddng khong dn djnh. Tuy nhien sau 0.1s dong dien vdng da hoat dpng dn dinh d mirc thap va khi thay ddn che do lam viec d thdi diem 0.15s thi ddng dien vdng dao dpng vdi bien dp nhd la lOA va trd lai trang thai boat ddng dn dinh trong thai gian ngan.

5. K I t l u S n

Bai bao da ap dung phuang phap dieu kliien FCS-MPC eho bg bidn ddi MMC, d l dilu khiln gia tri ddng dien, dien ap phia tai xoay chieu cua bp bien doi, dieu khien giam thieu gia tri ddng dien vdng chay ttong mach, phuang phap da thuc hien dieu

khien ket hgp ba bien dieu khien cung mdt luc do dd qua trinh thiet ke dieu khien trd nen linh boat va hieu qua hon, Tu yeu cau dieu khien, phuang phap FCS- MPC dugc thuc hien cho MMC da giam thieu vide tinh toan cac ttang thai ddng cat cua cac van ban dan dua tren cac md hinh toan hgc, cudi ciing da chgn lira nhung trang thai ddng cat tdi uu tir qua trinh du bao dg phat xung dieu khien cho van ban din.. Cac kit qua thu nhan dugc thdng qua phan tieh ly thuyet va mo phdng eho thay phuang phap didu khien dap iing ygu cau ve chat lugng dien ap vdi THD thap duoi 5%. So vdi cac phuang phap dteu che khac cho MMC dugc thethien ttong tai lieu [7], [10] thi day la phuong phap cd chi sd THD nhd han, dieu nay chung minh phuang phap dieu khien MPC eho thay rd uu digm nhu: kha nang dap img nhanh va chinh xac. MPC cung cd mdt sd nhugc diem nhu: ddi hdi bd xir ly phai boat dgng hen tue d che dp online vai cudng dp tinh toan cao.

Tai lieu tham khao

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Cortes (2005) Predictive power control of an AC/DC/AC converter Conf. Rec. 40t!i IEEE IAS Annu. Meeting, vol. 2, pp 934 -939.

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Model Predictive Conttol for Power Converters and Drives. Advances and Trends, IEEE Transactions on industnal electronics. Vol. 64, No.

2, February 2017

[10]. Jun Mei, Bailu Xiao, Ke Shen, Modular Multilevel Inverter with New Modulation Method and Its Application to Photovoltaic Grid-Connected. IEEE ttansactions on power electronic, Vol.28, No.ll, November20I3.