ISSN: 2354-0575
^^—-^^ DE XUAT P H U O N G P H A P DIEU K H I E N MOf PI (•^ •• ^ BAM D I E M C 6 N G S U A T C ^ C DAI DAN P I N DIEN M A T TRCH
' ° - " " ' Le Thi Minh T a m ' , Nguyin Viet Ngir', Nguyen Van DirongS Nguyen T h a n h Tien^
I Trudng Dgi hgc Su pham ky thugt Hung Yen 2 Bp Gido due vd Dao tgo 3 Hgc vien Ky thugt Quan su Tom t i t :
Bdi bdo ndy de xuat mgt phuang phdp thiet ki bp diiu khiin bdm diem cong sudt cifc dgi (MPPT) cho he thdng Pin dien mat trai (PV) sir dung phuong phdp dieu khiin mo PI vai su thich img cda cdc nhan to eho cdc tin hieu ddu vdo. Phuong phdp dieu khien md PI dugc dua tren mgt kien trite hi thong diiu khien hai cap, trong do kit hap cdc uu diem cua logic md vd dieu khien PI thdng thuang. Qud trinh Idm viee on dinh, ede h0 sd cua PI duac diiu chinh bdi lugt md di gidm thdi gian xu ly vd dam bdo su on dinh, chinh xdc cua hi thong. Ngodi ra, cdc tin hiiu dua vdo bd dieu khiin md PI dugc dieu chinh tu ddng ede he sd dua trin he thdng logic md (FLS). Cdc FLS dugc dgc trung bai mpt quy tdc tap md dd la cdu diiu kien ma the hien mdi quan he giua cdc yeu to ddu vdo (sai lich vd vi phan cda sai lech) vai ddu ra. Cach tiip can ndy tgo rampt bp diiu khien MPPT thich ungvd tdng dugc hieu sudt eua hi thdng. Cdc kit qud md phdng cho thdy hi^u qud ciia phucmg phdp de xudt cd the dgt dugc diim cdng sudt cifc dgi trong bat ky diiu kien ciing nhu cdc cdp do khdc nhau cua hire xa mat trai vd nhiet dp tren Pin diin mdt trdi (PV) Tie khoa: Pin diin mat trdi. (PV), Bdm diem cong sudt cue dgi (MPPT), Diiu khiin ma PI (FLS - PI).
1. D^t vin di
Thuat toan MPPT duoc coi la mgt phin khdng the thieu trong he thong Pin PV, dugc ap dyng vdi mong muon nang cao hieu qua sir dung ciia dan Pin mat trdi. No dugc dat trong bp dieu khiin bg biin d i i DC/DC. Cac thuat toan MPPT digu khign ciia bp bign ddi DC/DC sir dyng nhieu tham so, thuong la cac tham so nhu dong Pin PV, dien ap Pin PV, ddng ra, dien ap ra eua bo DC/DC.
Cac thuat toan nay dtiac so sanh dtza theo cac tieu ^^^ ' ' ' " S dncfc cac moi quan he dong dien, chi nhtl hi«u qua dinh diSm lam viec CO cong suit * ? " ^P ™ ™"8 ""^^^ ^^f" P ' "
Idn nhat, so lugng cam bien sir dung, dp phiic tap p y . ( ^ - ^ ^ ^ I n - 7 ^ + 1 (1.1) eua hp thong, tdc dp bien doi. Mgt bat Igi Idn ciia ' " '
cae he thdng Pm PV la ddi hdi chi phi tuong doi 1=1 { ^ \ \ r (T— T \ (\ ')\
cao hon miic cin thiet cho he nang lugng so vdi '''' •^'^UOOO/ ^^ "^' cac nguin nang lupng tai tao khac nhu nang lugng r 1 aV \ 1 gio. Vi vay toi da hda hieu qua cita cong suat dau P= f7— VI^,^- ^^n^''^'P\i^)~ ' ^^-^^
ra bing each bam sat digm cong suat eye dai la rat
quan trpng cho hoat dgng toi uu cua he thong Pin Trong do:
PV. He t h i n g Pin PV dugc ndi vdi ludi dien thong I : ddng dien quang (A);
qua bp chuyin dii DC-DC Dd dat dugc MPPT I^; dong dien chay qua DIODE (A);
trong he t h i n g Pin PV thi gia tn dien ap ra (hoae 1^^,: ddng dien chay qua ngi tro song song ddng) cd t h i dugc quy dinh bing each ap dung mgt \^ (A);
tin hieu diiu khien eho bg chuyen d6i[l-2]. Dg dat I: ddng dien chay qua tai va npi trd noi tiep duoc MPPT, thuat toan diiu khiin md PI da dugc R3 (A);
d i xuat va thyc hien ddi vdi Pin PV Mono-cell do I^; dong dien bao hda cua diode D (thuong hang Bosch (Diic) san xuit eo nhiing thong so ca liy 15=8.10-^) (A);
ban do d diiu kien tieu chuin (lOOOW/m^ d 25''C): I^idong dien bao hda dan Pin PV (A), p _ 50 w , Vj,,pp= 18 V, I„pp = 2 , 7 7 A , y ^ = 22,12 R^,^, R^: la npi trd song song va ngi trd ndi y"Y = 3 , 0 4 A. tiip ciia dan Pin PV(£1);
V: dien ap tren tai (V);
2 C i c yeu to anh hirong den hieu suat Pin PV V^: la dien ap ngin mach (V);
Tir so d i tuong duong cua Pin PV Hinh 1. q. dien tich (C);
Khoa hpc & Cong nghe - So 4/2014 Journal of Science and Technology 73
Hinh 1. Mgch diin tuang duang Pin P V
ISSN: 2354-0575
n. he sd mat ghep p-n trong dan Pin P V G i n diing cd the liy n = 1, ^
I ' nhiet dp tuyet d i i cua b i mat dan Pin PV gia tri eiia T = 300k;
k' he s i Boltzman(J/K).
Tir dd md phong va nhan dugc cac dac tinh V-A, dac tinh cong suit cua dan Pin PV nhu Hinh 2. Hinh 3.
S=1000W/ttf - ' ' ' * '
s=aoow/nv' " " " ^
S=600W/in= -"-''^
S=400W/m- • — " ^
— - . T=40-C -
-1
S=200W/in^ - " " ^ ^ ~ \ \ 111
100 150 200 250
0
P(7*«
T = 4 0 t :
S=BOOW/m- -~-^^_
S-600W/m- \ ^ ^ S=400W/m^ . • S=200W/in- X / v
_--—"""
50 100 ISO VnKageCuives
<r^' -^
200 260
^^-^
\
•\\
"A •
300 350 40 V l « ^ E ( V )
b)
Hinh 2. Duong cong dgc tinh V-I vd P-Vcua Pin PVkhi cuong do hire xg dnh sang mat trdi thay ddi
- ^=— -^=- —^-.—
S^lOOOW/m^
T=100'C T = B o r T=60°C T=40'C
Voltage C m w s
-___
^^>' , \
1 i
\
\ \ -
^. \
\'\W
0 50 100 150 200 250 300 35D M
^aih'i.Duangcong dgc tinh V-I vd P-V cua Pin PV khi nhiet dP eua Pin PV thay dSi Dudng cong dac tmh V-I va P-V cua Pin PV duge thi hien tren Hinh 2 va Hinh 3. Hinh 2 biiu thi quan he V-I va P-V khi biic x^ anh sang mat trdi thay d i i . Hinh 3 biiu thj quan he V-I va P-V khi nhiet dp ciia Pin PV thay doi.
Tir trgn dudng cong dac tinh V-I cho thay, Pm PV la mgt ngudn dien ap hay nguon dong dipn mpt chiiu c6 tinh phi tuyen tinh cao.
Cdng suat phat ra cua Pin PV dau ra chiu sy anh budng ciia cac yeu td nhu. cudng dp anh sang, nhiet dp moi trudng va phu tai va hieu suat cua dan Pm PV phy thupc vao goc tdi ciia tia sang ehieu Ign be mat dan Pin PV. Dudi dieu kien eudng dp anh sang va nhiet dp moi trudng da dinh san, dan Pin dien mat trdi eo thg lam viec d dien ap dau ra khac nhau, nhung chi cd mot gia tri dien ap dau ra tuong ling vdi diem eong suat dat eye dai.
3. Diiu khiSn b$ biin ddi DC/DC trong he thong P i n P V
Bp DC/DC duge diing dg xac dinh digm lam viec cd cdng suat Idn nhat ciia pin va lam on dinh ngudn di^n mpt ehigu lay tit Pm PV de eung cap eho tai va ae quy. Bd bien ddi DC/DC edn cd tac dung digu khign chg dp nap va phong de bao ve va nang cao tuoi thp eho ae quy. Cd nhieu loai bp bien doi DC/DC dugc sii dung nhung phd bien nhat van la 3 loai la: Bp tang ap Boost, bd giam ap Buck va bp hon hgp tang giam Boost - Buck. Ca 3 loai DC/DC tren dgu sit dyng nguyen tac ddng md khda dien tir theo mgt chu ky dugc tinh toan san dg dat dugc myc dieh sir dung. Tiiy theo myc dich va nhu cau ma bp DC/DC dugc lya chpn eho thich hgp Diiu khiin tin sd ddng md ciia khoa K de he dat duge diem lam viee tdi uu nhit phai diingden thuat toan xae dinh diim lam viec cd cdng suat Idn nhit (MPPT) dua tren mach vong phan hdi ba thong so ca ban; dong dien, dien ap va cong suat ciia dan pin.
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- Phuang phdp mach vong difn dp phdn hdi
Bp dieu khiin Rv la bd PI Dien ap ra d dau cue cua Pm PV dugc sit dung nhu mpt biin diiu khign cho he. No duy tri diim lam viec cua ca he sat vdi diem lam viec cd cdng suit Idn nhit bing each digu chinh dign ap ciia pm phii hgp vdi dien ap theo yeu cau[3].
Phuang phap nay ciing cd nhiing nhuge diem; bd qua hieu suat ciia biie xa va nhiet dp eua day pin mat trdi. Khdng dugc ap dung rpng rai cho he thdng lim giii dien nang.
Vi v^y phuong phap diiu khiin nay chi thich hgp dudi digu kien do hire xa dn dinh, vi no khdng thg tu dpng xac dinh diem lam viee toi uu khi diiu kien anh sang va nhiet dp thay ddi[4].
MPPT
Hinh 4. Mgeh vong diiu khiin dien dp
- Phuang phdp dieu khien phdn hdi cong suat
Co thg dieu khien cong suat tdi uu bang each eho dao ham dP/dV = 0 trong dieu khien phan hdi cdng suat. Nguyen tic hoat ddng cua phuang phap nay la do va khueeh dai cdng suat cua tai. Uu diem eiia phuang phap nay la khong can quan tam den d§c tinh lam viec ciia Pin PV. Tuy nhien, phuong phap nay khugch dai cong suat ciia tai chii khdng phai la eong suit ra khdi nguin Pin PV. Mae dii mgt bd biin ddi cd kit hgp phuang phap MPPT cd thi se eho hieu qua cao tren dai rgng cac diim lam viec, nhung d i i vdi mgt bg bign ddi khdng tot, toan bp cong suit CO the se khdng din duge tai do su t i n thit nang lugng- Vi vay phuong phap nay ddi hdi mpt bd biin ddi that hoan hao[4-6].
- Phuang phdp mgch vong dong di^nphdn hoi
Phuong phap nay chi ap dyng vdi nhirng thuai loan MPPT cho dai lugng diiu khiin la ddng d^:
Hinh 5. Mgch vdng ddng dien phdn hdi (Ri trong mgch dieu khiin Id bg PI) Dua vao phuong phap diiu chinh ba thdng sd dong dign, dien ap va cdng suit ciia dan Pin. Da cd rit nhiiu cac thuat toan diiu khign bam diim cong suit eye dai nhu: phuang phap nhiiu loan va quan sat (P&O, phuong phap gia tang dien din dugc nghien ciiu nhieu, Tuy nhien giai thuat P&O la khdng phan biet dugc "sy thay ddi eong suit do thay doi dien ap vdi sy thay d i i cong suit do thay ddi cudng do sang". Nhuge diim chinh cua phuang phap nay la khong tim dugc chinh xac diim lam viee CO cdng suat Idn nhit khi diiu kien thdi tiit thay doi. Dac digm cila phuong phap nay la phuang phap cd can tcixc don gian nhat nhit va de thyc hien nhat, trong trang thai on dinh digm iam viec se dao ddng xung quanh digm MPP, gay hao hut mpt phin nang lupng. Phuang phap nay khdng phii hgp vdi dieu kien thdi tiet thay ddi thudng xuygn va dot ngpt. Hay phuong phap gia tang dign dan cd uu digm dp Idn eua dien dan gia tang se quyit djnh dp nhanh cham trong viec tim ra diem MPP, nhung khi dien dan gia tang Idn qua se lam eho he thing boat ddng khdng chinh xac tai diem MPP va se bi dao dpng. Do do, eac thuat toan uu viel khac dugc de xuat, trong do dieu khign md duoc xem la phuang phap ly tudng. Phuang phap ket hgp dieu khien md vdi bg dieu khign kinh dien PI duge trinh bay chi tiet d phan sau
4. Thigt k£ diSu khiin m d PI bam diem cong suat cnc dai dan Pin PV
Do cau true don gian va ben vimg ngn cae bp dieu khien PID dugc diing phd bien trong eac he digu khien cdng nghiep va dap img duoc yeu cau dat ra.
Chat lupng cua he thdng phy thupc vao cac he so Kp K^, Kp ciia bp dieu khign PID. Nhung vi cac he sd nay chi dugc tinh toan cho chg dp lam viec cu thg ciia mdt he thdng vdi cac tham sd ciia ddi tugng da duoc xae dinh. Vi vay trong qua trinh iam viec ngu cac tham sd ciia he thdng thay ddi thi dai
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ISSN: 2354-0575
lugng ra cung thay ddi nghia la bd PID khdng edn dam bao chat lucmg nhu mong muon.
Cac hg can dieu khign trong thyc te chii yeu la cac he phi tuyen chiia eae than sd khdng bigt trude va cac tham so bien ddi theo thdi gian tham chi nhigu phan tir phi myen khong the mo hinh hoa duoe, dong thdi trong qua trinh lam viec cung chiu nhigu anh hudng tir nhieu mdi trudng. De thyc hien chinh djnh tham so ciia bd digu khign PID ngudi ta cd nhigu phuang phap. Mot trong nhiing phuong phap dd la su dung bd md PID.
Cau triic cua he dieu khiin: (Hinh 6).
Nhigm vy cua bd digu khign md trong so do trgn la chinh dinh lai tham sd Kp, K eiia bg digu khign PI cho phii hgp vdi yeu cau dat ra, Ddi tugng digu khien d day la dac tuyen ciia Pin PV. Bp dieu khien ben trong diing bd diiu khiin PI kinh diin bp dieu khign bgn ngoai dung bd dieu khien PI md dg
Hinh 6. He thdng dieu khien kinh diin ket h bp diiu khien md
- Sa dd eau tnic bp digu khien m d PI (Hinh
Hinh 7. Sa do diiu khiin PWM
Integutor Hinh 8. Cdu true khoi md-PI
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Hinh 9. Md hinh bd MPPT
- Kgt qua md phdng dac tinh eong suat d i u ra ciia Pin PV vdi cudng dd biic xa 1 OOOW/m^ nhiet dp 25»C
Hinh 10. A i i '''•'' ^"".^ '<udi ddu ra cua Pin PV vai cuang dp bice xg lOOOW/m^ nhiit dp 25"C
- Kit qua mo phdng dac Uiyen cdng suit ciia Pm PV vol cudng dp biic xa 800W/m^ nhiet dp 25-1 (Hinh II).
Hinh 11. Dgc tinh cdng sudt cua Pin PV vdi cuang dp bircxg 800W/m' nhiet dp 25^C 5. Ket luan
Tir kgt qua md phdng tren phan m i m matlab ta thay khi sir dung bp dieu khiin chinh dmh tham s i md - PI iam chat lugng dpng eiia he thing tang Ign ro ret. Khdng cd dp qua digu chinh va dao ddng trong qua trinh qua dp it, thdi gian qua dd ngin, triet
KJioa h(?c & Cfing nghS - So 4/2014 Journal of Science and Technology 77
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tieu hoan toan sai le tinh. Day la hudng diiu khiin md cd nhiiu triin vpng khdng ehi eho ddi tugng la Pm PV ma edn cho nhiiu ddi tugng digu khien khac trong cdng nghiep.
Tai lieu tham khao
[ 1 ]. Roberto Faranda, S.L, Energy Comparison of MPPT Techniques for PV Systems, WSEAS Trans, on POWER SYSTEMS, vol. 3, No.6.
[2]. Y.Kohata, K. Yamauchi, M. Kurihara, "High-Speed Maximum Power Point Tracker for Photovoltaic Systems Using Online Learning Neural Networks", Journal ofAdvancedComputational Intelligence and Intelligent Informatics, vol. 14, no. 6, pp. 677-682, 2010.
[3]. M.S AitCheikh, C.Larbes,G.F.Tchoketch Kebir and A.Zerguerras, Maximum power point tracking using a fuzzy logic control scheme, Revue des Energies Renouvelables Vol. 10 N03 (2007) 3 8 7 - 3 9 5 .
[4]. Hohm, D.P&M.E.Ropp, "Comparative Study of Maximum PowerPoint Tracking Algorithms"
Progressing in Photovoltaics: Researehand Applications November 2002.
[5]. Hohm, D.P and M.E. Ropp, Comparative Study of Maximum power point tracking algorithms.
Progress in Photovoltaics. Research and Applications, 2003, Vol.11, N o . l , pp.47 - 62.
[6]. Walker, Geoff R., "Evaluating MPPT converter topologies using a MATLAB PV model"
Australasian Universities Power Engineering Conference, AUPEC "00, Brisbane, 2000.
A PROPOSED MAXIMUM POWER POINT TRACKING ALGORITHM BASED ON FUZZY PI Abstract:
This paper proposes a methodology of designing a Maximum Power Point Tracking (MPPT) controller for photovoltaic systems (PV) using a Fuzzy of Proportional-Integral (PI) type controller with adaptation of sealing factors for the input signals ofFGS. The proposed method is based on a two level control system architecture, which combines the advantages of fuzzy logic and conventional PID control.
During transient and steady states, the PlD's gains are adapted by the fuzzy logic-PI to damp out the g-ansient oscillations, to reduce settling time and to guarantee system stability and accuracy. Also, the conditioned input signals of the FLS-Pl are tuned dynamically by gain factors which are based on fuzzy logic system (FLS). The FLS is characterized by a set of fuzzy rules which are fuzzy conditional statements expressing the relationship between inputs (error and change of error) and outputs. This approach creates an adaptive MPPT controller and achieves better overall system performance. The simulation results demonstrate the effectiveness of the proposed adaptive FLS-Pl and show that this approach can achieve a good maximum power operation under any conditions such as different levels of solar radiation and PV cell temperature for varying PV sources.
Keywords: Photovoltaic (PV), Maximum power point track (MPPT), fuzzy control.
Ngu-M phan biin: TS. Biii Trung Thanh
