Tim Diem Cong Suat Max

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B GIO DC V O TO

TRNG I HC K THUT CNG NGH TP. HCM

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NGUYN NGC TRUNG

TM IM CNG SUT CC I CA PIN MT TRI .

LUN VN THC S Chuyn ngnh : Thit b, mng v nh my in

M s ngnh: 60 52 50

TP. H CH MINH, thng 07 nm 2012

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B GIO DC V O TO TRNG I HC K THUT CNG NGH TP. HCM

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NGUYN NGC TRUNG

TM IM CNG SUT CC I

CA PIN MT TRI.

LUN VN THC S Chuyn ngnh : THIT B , MNG V NH MY IN

M s ngnh: 60 52 50

HNG DN KHOA HC: TS. TRNG VIT ANH

TP. H CH MINH, thng 07 nm 2012

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CNG TRNH C HON THNH TI TRNG I HC K THUT CNG NGH TP. HCM

Cn b hng dn khoa hc : TS. TRNG VIT ANH Lun vn Thc s c bo v ti Trng i hc K thut Cng ngh TP.

HCM ngy 14 thng 07 nm 2012 Thnh phn Hi ng nh gi Lun vn Thc s gm:

(Ghi r h, tn, hc hm, hc v ca Hi ng chm bo v Lun vn Thc s)

1. TS. Hunh Chu Duy - Ch tch 2. PGS. TS. inh Thnh Vit - Phn bin 1 3. TS. Ng Cao Cng - Phn bin 2 4. . TS. Trn Vnh Tnh - U vin 5. PGS. TS. Quyn Huy nh - U vin, Th k

Xc nhn ca Ch tch Hi ng nh gi Lun sau khi Lun vn c

sa cha (nu c).

Ch tch Hi ng nh gi LV

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TRNG H K THUT CNG NGH TP. HCM PHNG QLKH - TSH

CNG HA X HI CH NGHA VIT NAM c lp - T do - Hnh phc

TP. HCM, ngy . thng.. nm 2011

NHIM V LUN VN THC S

H tn hc vin: NGUYN NGC TRUNG Gii tnh: Nam

Ngy, thng, nm sinh: 09 - 06 - 1965 Ni sinh: TP HCM

Chuyn ngnh: Thit b , mng v Nh my in . MSHV: 1081031028

I- TN TI:

TM IM CNG SUT CC I CA PIN MT TRI.

II- NHIM V V NI DUNG:

- Ni dung : Tm im cng sut cc i ca pin mt tri - Phng php nghin cu : M phng - Kt qu t c : Thc hin c m phng gii thut tm im cng sut cc i ca pin mt tri

III- NGY GIAO NHIM V: 15 - 09 - 2011

IV- NGY HON THNH NHIM V: 15 - 06 -2012

V- CN B HNG DN: TS . TRNG VIT ANH

CN B HNG DN KHOA QUN L CHUYN NGNH

TS. TRNG VIT ANH

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LI CAM OAN

Ti xin cam oan y l cng trnh nghin cu ca ring ti. Cc s liu, kt

qu nu trong Lun vn l trung thc v cha tng c ai cng b trong bt k

cng trnh no khc.

Ti xin cam oan rng mi s gip cho vic thc hin Lun vn ny

c cm n v cc thng tin trch dn trong Lun vn c ch r ngun gc.

Hc vin thc hin Lun vn

Nguyn Ngc Trung

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LI CM N

Ti xin chn thnh cm n TS.Trng Vit Anh Ph Trng khoa in in t Trng i Hc S Phm K thut Tp.HCM, ngi thy ht lng ch bo, hng dn, truyn t nhng kin thc chuyn mn cng nh nhng kinh nghim nghin cu trong sut thi gian hc tp v thc hin lun vn ny.

Xin chn thnh cm n Ban Gim Hiu, Ban ch nhim khoa C - in in t, Phng qun l sau i hc ca Trng i Hc K thut Cng ngh Tp.HCM to nhng iu kin tt nht v vt cht ln tinh thn chng ti hon thnh tt lun vn ny.

Xin chn thnh cm n n tt c Qu Thy, C ca Trng i Hc K thut Cng ngh Tp.HCM ging dy, trang b cho ti nhng kin thc rt b ch v qu bu trong sut qu trnh hc tp cng nh nghin cu sau ny.

Xin cm n bn b, ng nghip v c bit l nhm thc nghim chung Trng i Hc S Phm K thut Tp.HCM v Trng i Hc K thut Cng ngh Tp.HCM di s hng dn ca Thy Trng Vit Anh nhng ngi lun ginh nhng tnh cm su sc nht, gip v khuyn khch ti cng nhau vt qua mi kh khn trong sut qu trnh thc hin lun vn ny.

Xin cm n Gia nh to mi iu kin ti yn tm hc tp tt trong sut thi gian va qua.

Xin cm n Ban Gim Hiu Trng Cao ng Giao thng Vn ti TPHCM v tt c bn b thn thuc ng vin, to iu kin thun li v h tr cho ti rt nhiu trong qu trnh hc tp, cng tc cng nh trong sut thi gian thc hin lun vn.

TP.H Ch Minh, thng 06 nm 2012 Ngi thc hin

Nguyn Ngc Trung

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TM TT

Nghin cu ny trnh by phng php tm im lm vic c cng sut cc i ca

pin mt tri (MPPT) bng gii thut INC. Tc gi s dng Matlab/Simulink xy

dng m hnh pin mt tri v m phng gii thut v s dng thc nghim kim

tra gii thut.

Kt qu m phng v thc nghim cho thy s cn thit phi s dng MPPT trong

h thng pin mt tri v bng vic s dng gii thut INC, h thng nhanh

chng a pin mt tri vo lm vic ti im c cng sut ti u.

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ABSTRACT

This study presents the Maximum Power Point Tracking (MPPT) technique of

Photovoltaic by INC Algorithm. The author uses Matlab / Simulink for modeling

and simulation of solar cells and the Algorithm.

The simulation results and experiment shows the need to use MPPT solar system

and by using the INC algorithm, the system was quickly put photovoltaic to work at

optimum power point .

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MC LC

TRANG Li cam oan i Li cm n ii Tm tt iii Mc lc v Danh sch cc ch vit tt vii Danh sch cc bng vii Danh mc cc biu , th, s , hnh nh viii Ni dung lun vn Chng 1.....................................................................................................................1 TNG QUAN .............................................................................................................1

1.1 Tng quan chung v lnh vc nghin cu, cc kt qu nghin cu trong v ngoi nc cng b ..............................................................................................1 1.2. Mc ch ca ti ............................................................................................1 1.3. Nhim v ca ti v gii hn ti................................................................4 1.4. Phng php nghin cu ....................................................................................4 1.5. Nidung lun vn ...............................................................................................5

Chng 2.....................................................................................................................6 C S L THUYT .................................................................................................6

2.1 M hnh pin mt tri ..........................................................................................6 2.2. B chuyn i DC/DC boost converter ............................................................13 2.3. im lm vic cc i ca Pin mt tri ............................................................16 2.4. Cc phng php tm im cc i ca pin mt tri ph bin ..........................21

2.4.1. Phng php in p hng s .......................................................... 21 2.4.2. Phng php P&O (Perturb and Observe)....................................... 22

Chng 3...................................................................................................................25 CHN GII THUT B D IM CNG SUT CC I CA PIN MT TRI .........................................................................................................................25

3.1. Phng php INC (Incremental Conductance) .................................................25

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3.2. M hnh m phng gii thut ...........................................................................27 3.2.1. M hnh Pin mt tri ....................................................................... 28 3.2.2. Gii thut INC................................................................................. 31

Chng 4...................................................................................................................33 KT QU M PHNG ..........................................................................................33

4.1. M hnh pin mt tri ........................................................................................33 4.2. Gii thut MPPT ..............................................................................................35

Chng 5...................................................................................................................42 KT QU THC NGHIM ...................................................................................42

5.1. M hnh thc nghim .......................................................................................42 5.2. Kt qu thc nghim ........................................................................................50

Chng 6...................................................................................................................54 KT LUN V HNG PHT TRIN CA TI ........................................54

6.1. Kt lun ..........................................................................................................54 6.2. Hng pht trin ca ti ..............................................................................54 TI LIU THAM KHO ....................................................................................56 PH LC

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DANH MC CC T VIT TT

PV : PhotoVotaic : Pin quang in ( pin mt tri )

MPPT : Maximum Power Point Tracking : D tm im cc i

P&O : Perturb and Observe : Phng php nhiu lon v quan st

INC : Incremental Conductance : Phng php INC

NOCT : Normal Control Ttemperature : Nit vn hnh bnh thng

DANH MC CC BNG TRANG

Bng 3.1. Thng s ca pin mt tri thng mi MSX 60 ti 1 kW/m2 , 25 oC .......29 Bng 3.2 Thng s ca pin mt tri thng mi WN-15 ti 1 kW/m2 , 25 oC ..........43

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DANH MC CC BIU , TH, S , HNH NH TRANG

Hnh 1.1. Phn b tng s gi nng 3 thng 1,2,3 nm 2011 .....................................2

Hnh 1.2. Bc x mt tri ti ba thnh ph tiu biu nm 2010 ................................2

Hnh 2.1. Mch in tng ng ca pin mt tri ..................................................8

Hnh 2.2. M hnh pin mt tri l tng....................................................................9

Hnh 2.3. M un pin mt tri.................................................................................10

Hnh 2.4. c tuyn I-V vi cc bc x khc nhau..................................................12

Hnh 2.5. c tuyn P-V vi cc bc x khc nhau.................................................12

Hnh 2.6. S nguyn l mch boost ....................................................................13

Hnh 2.7. Mch in khi S ng..............................................................................14

Hnh 2.8. Dng sng in p v dng in trn cun dy L khi S ng ...................14

Hnh 2.9. Mch in khi S m ................................................................................15

Hnh 2.10. Dng sng in p v dng in trn L khi S m ...................................15

Hnh 2.11. c tuyn I-V, P-V ca pin mt tri vi im cng sut cc i............17

Hnh 2.12. Cc im MPP di cc iu kin mi trng thay i .........................17

Hnh 2.13 S khi ca h thng MPPT tiu biu. ...............................................18

Hnh 2.14. B DC/DC gip ht cng sut cc i t pin mt tri............................19

Hnh 2.15. Gii thut MPPT da trn cc in p hng s.......................................22

Hnh 2.16. c tnh ca pin mt tri .......................................................................23

Hnh 2.17. th PV khi bc x thay i v s lm vic tm im cc i ca

phng php P&O ..................................................................................................23

Hnh 2.18 Gii thut P&O.......................................................................................24

Hnh 3.1. dc (dP/dV) ca PV ...........................................................................26

Hnh 3.2. Gii thut InC..........................................................................................27

Hnh 3.3. M hnh pin mt tri c xy dng trong Matlab/Simulink ...................28

Hnh 3.4. M hnh pin mt tri thu gn ...................................................................28

Hnh 3.5. Bng thng s u vo ca pin mt tri ...................................................29

Hnh 3.6. c tuyn I-V, P-V vi cc bc x khc nhau (Nhit pin 25oC)..........30

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Hnh 3.7. c tuyn I-V, P-V vi nhit vn hnh khc nhau (bc x 1kW/m2)...30

Hnh 3.8. B phn o in p v dng in .............................................................31

Hnh 3.9. Gii thut INC c xy dng trong Matlab & Simulink.........................31

Hnh 3.10. M hnh m phng c tuyn pin mt tri .............................................32

Hnh 3.11. M hnh m phng gii thut .................................................................32

Hnh 4.1. Bc x mt tri........................................................................................33

Hnh 4.2. c tuyn PV ca pin mt tri.................................................................34

Hnh 4.3. c tuyn IV ca pin mt tri..................................................................35

Hnh 4.4. in p lm vic ca pin mt tri ............................................................36

Hnh 4.5. Dng in lm vic ca pin mt tri ........................................................36

Hnh 4.6. Cng sut lm vic ca pin mt tri.........................................................37

Hinh 4.7. in p lm vic ca pin mt tri tng ng vi cng sut thu c.......37

Hnh 4.8. Bc x mt tri thay i nhanh................................................................39

Hnh 4.9. in p lm vic ca pin mt tri ............................................................39

Hnh 4.10. Dng in lm vic ca pin mt tri ......................................................40

Hnh 4.11. Cng sut lm vic ca pin mt tri.......................................................40

Hinh 4.12. in p lm vic ca pin mt tri tng ng vi cng sut thu c .....41

Hnh 5.1. M hnh thc nghim ..............................................................................42

Hnh 5.2. Pin mt tri v thng s ca nh sn xut ................................................43

Hnh 5.3. S mch cng sut v b phn o lng dng in.............................44

Hnh 5.4.S nguyn l mch iu khin .............................................................45

Hnh 5.5. S mch in mch iu khin ..............................................................46

Hnh 5.7. Mch iu khin v mch cng sut thi cng...........................................47

Hnh 5.8. Lu chng trnh chnh ......................................................................48

Hnh 5.9 Lu chng trnh MPPT......................................................................49

Hnh 5.10. in p v cng sut v dng in pin mt tri .....................................52

Hnh 5.11. rng xung kch Mosfet .....................................................................52

Hnh 5.12. Cng sng ca ti l bng n 20W ................................................52

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Hnh 5.13. in p trn ti v dng in chy qua ti .............................................52

Hnh 5.14. in p pin mt tri...............................................................................53

Hnh 5.15. in p pin mt tri...............................................................................53

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Chng 1

TNG QUAN

1.1. Tng quan chung v lnh vc nghin cu, cc kt qu nghin cu trong v ngoi nc cng b

Ngy nay, nhu cu s dng cc ngun nng lng ti to ang tng ln mnh

m do bi cc ngun nng lng ha thch ang dn cn kit v chng gy ra

nhng hu qu v mi trng nh hiu ng nh knh, l lt Trong cc ngun

nng lng ti to nh nng lng sinh khi, nng lng a nhit, gi, thy in

nh, nng lng mt tri ang dn tr nn rt ph bin bi v chng c nhiu u

im trong phng php pht in, chi ph bo dng thp, an ton cho ngi s

dng, khng gy nhim mi trng v c bit ngun ti nguyn ny cc k ln.

Tng tiu th nng lng ca con ngi trn th gii hin ti (tnh tng cng

tt c cc loi nng lng nh du ha, than , thy in, v.v.) khong 15 nghn t

watt, tc l ch bng khong 1/5000 cng sut d tr ca nng lng mt tri cho

tri t. Trong s 15 nghn t watt cng sut nng lng m con ngi ang dng,

th c n 37% l t du ha, 25% l than , v 23% l kh t (tng cng ba th

ny n 85%), l nhng ngun nng lng cn kit nhanh chng v khng phc

hi li c .

Vi tc khai thc hin ti, th cc ngun nng lng ha thch s gn nh

ht i trong th k 21. Tng lai nng lng ca th gii khng th nm nhng

ngun ny, m phi nm nhng ngun nng lng ti to (renewable energy), v

d nh nng lng gi v thy nng. Nhng tng cng d tr ca tt c cc ngun

khc ny (trong ch yu l gi) ch bng khong 1 phn trm ngun d tr nng

lng mt tri. Bi vy c th ni tng lai nng lng ca th gii chnh l nng

lng mt tri.

Vit Nam, v tr a l u i cho chng ta mt ngun nng lng ti to

v cng ln, c bit l nng lng mt tri. Nm gn ng xch o, Vit Nam

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nm trong khu vc c cng bc x mt tri tng i cao, nng lng bc x

mt tri trung bnh t 4 n 5kWh/m2 mi ngy[1].

Hnh 1.1. Phn b tng s gi nng 3 thng 1,2,3 nm 2011[1]

Hnh 1.2. Bc x mt tri ti ba thnh ph tiu biu nm 2010[3]

Tuy nhin, vi tim nng ln song nng lng mt tri li ang gp nhng

ro cn ln v k thut v cc ro cn khc. Ro cn k thut l mt trong nhng

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thch thc ln cho vic s dng pin mt tri hin nay do bi gi thnh cao v hiu

sut chuyn i nng lng cn thp. Gi ca mt m un pin mt tri khong

3.5$/Wp v nu tnh c chi ph lp t h thng th khong 7$/Wp dn n gi

thnh in nng pht ra cn rt cao khong 0.25 0.65 $/kWh gp gn 5 ln in

nng pht ra dng ngun nng lng ha thch [2]. Ngoi ra cn cc ro cn khc

nh thiu s h tr v chnh sch ca chnh ph, nhn thc ca mi ngi v nng

lng, s tham gia ca cc t chc c nhn vo cc d n pht trin ngun nng

lng ti to.

khc phc nhng ro cn , c bit l lin quan n gi thnh v hiu

sut ca pin mt tri rt nhiu gii php c thc hin. V d nh lin quan n

gi thnh ca pin mt tri, cc nh nghin cu v sn xut pht trin cng ngh

sn xut pin theo hng hin i, lin quan n vic ci thin hiu sut chuyn i

nng lng c hai phng php ch yu l ci thin hiu sut ca pin da trn

cng ngh sn xut pin v ci thin phng php s dng pin mt tri.

Phng php th nht, cc nh nghin cu v ang tm ra rt nhiu cc

phng php nhm nng cao hiu sut ca pin mt tri nh dng vt liu mi, thm

ch l phng php pht in mi. Phng php th hai c th c thc hin bng

cch s dng b thu nng lng tp trung ht c bc x cc i hoc s dng

b d im cng sut cc i m bo pin mt tri lun vn hnh iu kin ti

u v cng sut pin s t c cc i.

Trn th gii v trong nc c nhiu nghin cu v h thng pin mt tri.

Ch yu v cc lnh vc nh:

n nh v nng cao in p pht ra ca h thng pin mt tri [5,6]

Cc phng php iu khin nhm a h thng pin mt tri lm vic ti

im cng sut cc i [16-26].

Cc phng php nghch lu nhm ci thin cht lng in trong h thng

nng lng mt tri [4-15].

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Cc phng php ngn nga hin tng Islanding cho h thng pin nng

lng mt tri [12,13].

Cc phng php iu khin cng sut tc dng, cng sut phn khng v

dng in bm vo li ca h thng pin mt tri ni li [12,13].

1.2. Mc ch ca ti

ti tp trung nghin cu cc phng php tm im lm vic cc i ca

pin mt tri. Trn cc c tuyn ca pin mt tri, tn ti mt im vn hnh ti u

ni m cng sut nhn c t pin mt tri l cc i. Tuy nhin, im vn hnh

ti u ny khng c nh m n thay i theo cc iu kin mi trng c bit l

bc x mt tri v nhit pin. V vy tm im lm vic cc i (MPPT) ca pin

mt tri l mt phn khng th thiu ca h thng pin mt tri m bo rng cc

m un pin mt tri lun vn hnh trong iu kin ti u.

C rt nhiu phng php MPPT c nghin cu v cng b. Cc

phng php khc nhau nhiu kha cnh nh mc phc tp, thng s o

lng, s lng cm bin yu cu, tc chuyn i v gi thnh. ti s nghin

cu cc phng php MPPT. Mc ch ca nghin cu ca ti l xut

phng php MPPT ti u vi kh nng p ng di cc iu kin mi trng

bc x thay i v c th thc hin m hnh vt l vi chi ph thp.

1.3. Nhim v ca ti v gii hn ti - Nghin cu phn tch m hnh pin mt tri, phn tch cc c tuyn I-V, P-

V ca pin mt tri, s ph thuc cc c tnh ca pin mt tri di cc iu kin

mi trng.

- Phn tch tnh cn thit ca im lm vic cc i ca pin mt tri.

- Nghin cu cc gii thut MPPT ca pin mt tri, xut phng php MPPT kh dng.

- Dng phn mm Matlab/Simulink nghin cu m hnh m d tm im lm vic cc i ca phng pin mt tri.

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- Thit k thi cng b MPPT kim tra gii thut.

1.4. Phng php nghin cu - Thu thp ti liu lin quan n ti nghin cu.

- Nghin cu cc m hnh ton hc ca pin mt tri. ngh m hnh tnh

ton c th.

- Nghin cu b tng p DC- DC

- Thc hin m hnh m phng pin mt tri v cc gii thut MPPT.

- Thit k thi cng b MPPT kim tra gii thut xut.

- Phn tch cc kt qu nhn c v cc kin ngh.

- nh gi tng qut ton b bn lun vn.

- ngh hng pht trin ca ti.

1.5. Ni dung lun vn: Chng 1: Tng quan

Chng 2: C s l thuyt

Chng 3: Chn gii thut b d tm im cng sut cc i

Chng 4 : Kt qu m phng

Chng 5: Kt qu thc nghim

Chng 6: Kt lun v hng pht trin ca ti

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Chng 2

C S L THUYT

2.1. M hnh pin mt tri T khi hiu ng quang in c pht hin bi nh vt l Edmund Becquere

nm 1838 v pin mt tri u tin c pht minh bi Charles Fritts vo nm

1883, k thut pin mt tri (PV) pht trin ng k. S pht trin l: ci

thin hiu sut chuyn i nng lng, thc y qu trnh sn xut, gim chi

ph sn xut v thm ch cng gii thiu ca mt s th h mi ca PV. Qu

trnh pht trin k thut PV c m t trong hnh 1.4. Hin nay, hiu sut cao

nht ca PV (khong 40%) t c trong phng th nghim. Tuy nhin,

hiu sut module PV thng mi cn thp, khong 15%. Vic gim chi ph sn

xut ln cng t c.

Hiu sut pin l t s ca nng lng in t nh sng mt tri. Vo bui

tra mt ngy tri trong, nh mt tri ta nhit khong 1000 W/m. Trong ,

10% hiu sut ca 1 module 1 m cung cp nng lng khong 100 W. Hiu

sut ca pin mt tri thay i t 6% t pin mt tri lm t silic khng th hnh,

v c th ln n 30% hay cao hn na, s dng pin c nhiu mi ni nghin

cu trong phng th nghim.

C mt s loi pin mt tri nh: n tinh th, a tinh th, v nh hnh,

nhiu mi ni, t bo nng lng mt tri hu c v pin mt tri mng mng,

v mt s loi khc.

Tuy nhin, nhn chung pin thng mi c phn thnh 3 th h:

a) Th h u tin: lt silic (n v a tinh th).

b) Th h th hai: mng mng (cadmium telluride [CdTe], copper indium

gallium diselenide [CIGS], v amorphous silicon [a-Si]).

c) Th h th ba: polyme/hu c, quang in ha.

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Pin mt tri sn xut trc tip in mt chiu (DC) khi hp th photon t

nh sng mt tri. C nhiu ng dng s dng in DC t cc m-un ny. Tuy

nhin, hin nay vic in DC chuyn thnh in AC v ha ng b vo li

in ang rt pht trin v li ch v nhu cu nng lng. Nhn chung, cc ng

dng ca pin mt tri c th c phn loi thnh hai nhm: nhm c lp v

h thng kt ni li in.

H thng c lp thng c s dng trong khu vc vng su, vng xa, hi

o. H thng ny thng bao gm mt s thnh phn: nng lng mt tri, c

quy d tr v b iu khin. Bin tn cng c th c s dng chuyn i

in DC thnh AC. B iu khin l thnh phn quan trng, c bit l iu

khin qu trnh np, x c quy d tr v ngn chn vic sc qu mc hay x qu

mc. Ban ngy, pin mt tri cung cp in cho ti v sc cho c quy d tr v

ban m ch c c quy cung cp in cho ti.

V cu to pin mt tri bao gm mt lp tip xc bn dn p-n c kh nng

bin i trc tip nng lng bc x mt tri thnh in nh hiu ng quang

in c gi l pin mt tri. Khi nh sng chiu ti pin mt tri, nng lng t

nh sng (cc photon) to ra cc ht mang in t do, c tch ra bi in

trng. in p c to ra v o c ti cc im tip xc bn ngoi, v vy

ta o c gi tr dng quang in khi c ti kt ni vo. Dng quang in c

to ra trong pin mt tri v t l thun vi cng bc x.

Pin quang in (pin mt tri) tiu biu cho thit b chuyn i c bn nng

lng mt tri thnh nng lng in. Cng nng, nhit ca t bo

quang in v in p vn hnh nh hng ln n c tnh cng sut v dng

in ng ra ca pin mt tri.

Ngy nay, quang in vn l ngun nng lng tng i t tin. V vy,

iu quan trng l phi s dng pin mt tri ng cch t c cng sut

ti a. t c iu ny, cc tm pin mt tri thng c b tr mt v

tr c nh v nghing v pha Nam ti u ha vic sn xut nng lng hng

ngy v bui tra. S nh hng tm pin c nh cn c chn cn thn

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nhn c nng lng cc i theo ma trong nm. Khi cn, c th iu chnh

hng t pin theo nh k. C bn, cc tm pin c mt im hot ng ti u

gi l im cng sut cc i (MPP) . l mt im m cc tm pin c th

pht cng sut ti a t nh sng mt tri.

Mch in tng ng ca pin mt tri c cho nh hnh 2.1.

Hnh 2.1. Mch in tng ng ca pin mt tri

Mch in gm c dng quang in IPH, it, in tr dng r RSH v in tr

ni tip RS, c tuyn I-V ca pin c m t bng biu thc 2.1 [3, 27]:

Sph sC SH

V IRqI I I exp( V IR) 1kT A R

(2.1)

Trong :

IPH: dng quang in (A)

IS: dng bo ha (A)

q: in tch ca electron, q = 1,6x10-19 C

k: hng s Boltzmanns, k =1,38x10-23 J/K

TC: nhit vn hnh ca pin (K)

A: h s l tng ph thuc vo cng ngh ch to pin, v d cng ngh Si-

mono A=1.2, Si-Poly A = 1.3

Dng quang in IPH ph thuc trc tip vo bc x mt tri v nhit ca

pin [3, 27]:

HUTE

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PH SC I C RefI I K T T (2.2) Trong :

ISC: dng ngn mch ti nhit tiu chun 25OC (A) v bc x 1kW/m2

KI: h s dng in ph thuc vo nhit (A/OC)

TC: Nhit vn hnh ca pin mt tri (0K)

TREF : Nhit tiu chun ca pin mt tri (0K)

: Bc x mt tri (kW/m2)

Mt khc, dng bo ha IS l dng cc ht ti in khng c bn c to ra

do kch thch nhit. Khi nhit ca pin mt tri tng dng bo ha cng tng theo

hm m [3, 27]:

3

C GS RS

Ref Ref C

T qE 1 1I I expT kA T T

(2.3)

Trong :

IRS: Dng in ngc bo ha ti nhit tiu chun (A)

EG: Nng lng l trng ca cht bn dn

i vi pin mt tri l tng, in tr dng r RSH = , RS = 0. Khi mch

in tng ng ca pin mt tri c cho bi hnh 2.2:

Hnh 2.2. M hnh pin mt tri l tng

Khi , biu thc (2.1) c th c m t nh biu thc 2.4.

HUTE

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PH SC

qVI I I exp 1KT A

(2.4)

V dng bo ha ngc tiu chun c th c biu din nh biu thc 2.5.

SCRS

OC

Ref

II 1qvexp

kAT

(2.5)

Thng thng, cng sut ca pin mt tri khong 2W v in p khong

0.5V. V vy, cc pin mt tri c ghp ni vi nhau theo dng ni tip - song

song sinh ra lng cng sut v in p ln. Mch in tng ng ca m

un pin mt tri gm c NP nhnh song song v NS pin ni tip c m t nh

hnh 2.3.

Hnh 2.3. M un pin mt tri

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11

Mch in hnh 2.3 c miu t bi biu thc:

P PH P SS C

QvI N I N I exp 1N kT A

(2.6)

Pin mt tri chuyn mt phn bc x mt tri trc tip thnh nng lng in,

nhng mt phn chuyn thnh nhit cng vi pin mt tri c mu d hp th

nhit nn nhit vn hnh ca pin c th cao hn nhit mi trng. Nhit

ca pin di cc iu kin khc nhau c th c nh gi qua nhit vn hnh

bnh thng (NOCT). Nhit vn hnh bnh thng c nh ngha l nhit

ca pin di iu kin mi trng 20oC, bc x mt tri 0.8 kW/m2, tc gi < 1

m/s.

Cng thc sau c s dng tnh ton s khc nhau gia nhit mi

trng (TAmb) v nhit vn hnh ca pin mt tri (TC):

NOCTC Amb

T 20T T0,8

(2.7)

c tuyn I-V tng ng vi tng bc x nht nh c m t nh hnh 2.4

v hnh 2.5.

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Hnh 2.4. c tuyn I-V vi cc bc x khc nhau

Hnh 2.5. c tuyn P-V vi cc bc x khc nhau

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2.2. B chuyn i DC/DC boost converter B bin i DC/DC c s dng rng ri trong ngun in mt chiu vi

mc ch chuyn i ngun mt chiu khng n nh thnh ngun in mt chiu

c th iu khin c. Trong h thng pin mt tri, b bin i DC/DC c kt

hp cht ch vi MPPT. MPPT s dng b bin i DC/DC iu chnh ngun

in p vo ly t ngun pin mt tri, chuyn i v cung cp in p ln nht ph

hp vi ti.

Chng ta cn iu khin c in p v dng in ng ra ca pin mt tri t

cng sut cc i bt k iu kin nhit v bc x mt tri. Mun lm c iu

, ta s dng b d tm im cng sut cc i, b d tm phi p ng mt s

iu kin sau:

Vn hnh h thng PV cng gn cng tt t c MPP bt k thay i

kh quyn.

Chi ph thp, hiu sut chuyn i cao.

Giao in ng ra tng thch vi yu cu ca ti

Mch boost converter hay cn c gi l mch tng p. B bin i ny

ph hp vi cc ng dng c in p yu cu ln hn in p u vo. Nguyn l

hot ng ca b bin i ny da vo c tnh lu tr v tch phng nng lng

ca cun dy.

Hnh 2.6. S nguyn l mch boost

HUTE

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14

Khi S ng cho dng qua (TON) , dng in t ngun chy qua cun dy,

nng lng t trng c tch ly trong cun dy. Khng c dng in chy qua

it D v dng ti c cung cp bi t in C

Hnh 2.7. Mch in khi S ng

Hnh 2.8. Dng sng in p v dng in trn cun dy L khi S ng

Khi :

LL d

div V Ldt

(2.8)

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Suy ra:

dL Vdidt L

(2.9)

Mt khc:

L L Ldi i idt t DT

(2.10)

dL closedV DTi

L (2.11)

Hnh 2.9. Mch in khi S m

Hnh 2.10. Dng sng in p v dng in trn L khi S m

HUTE

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Khi S ng (TOFF), dng in cm ng chy vo ti qua it cng nh np li

cho t in C.

LL d o

div V V Ldt

(2.12)

Suy ra:

d oL V Vdidt L

(2.13)

L L Ldi i idt t (1 D)T

(2.14)

d oL opened

V V (1 DT)( i )L

(2.15)

Nng lng lu tr trong cun dy bng 0 khi kt thc chu k.

L closed L opened( i ) ( i ) 0 (2.16)

d d oV DT V V (1 DT) 0L L

(2.17)

T 2.17, ta c:

do

VV1 D

(2.18)

2.3. im lm vic cc i ca Pin mt tri Hin ti, pin mt tri vn c xem l ngun nng lng t . V vy, cn

phi khai thc cng sut ln nht c th t pin mt tri. t c iu , pin

mt tri cn c lp t ti cc v tr thun li v d nh hng nam, thm ch

c iu khin xoay theo hng mt tri thu c ngun nng lng cc i.

V c bn, trn ng c tuyn PV ca pin mt tri tn ti mt im cng sut

cc i ng vi dng in v in p tng ng.

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Hnh 2.11. c tuyn I-V, P-V ca pin mt tri vi im cng sut cc i

Tuy nhin, im cc i ny li khng c nh, chng lun thay i theo cc

iu kin mi trng (Hnh 2.12). V vy, chng ta cn iu khin in p hoc

dng in thu c cng sut cc i t pin mt tri khi nhit v bc x thay

i s dng b tm im cng sut cc i.

Hnh 2.12. Cc im MPP di cc iu kin mi trng thay i

Hnh 2.13 gii thiu s khi ca h thng MPPT tiu biu. Hu ht cc b

MPPT hin nay gm c ba phn c bn: b chuyn i DC-DC, b phn o lng

v b phn iu khin

Khi pin mt tri c ni trc tip vi ti, im vn hnh ca pin mt tri

c iu khin bi ti. Tng tr ca ti c miu t nh sau:

HUTE

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oLOAD

o

VRI

(2.19)

Trong , Vo, Io l in p v dng in pht ra ca pin mt tri.

Tng tr ti u ca ti cho pin mt tri c miu t nh sau:

MPPOPT

MPP

VRI

(2.20)

Trong , VMPP, IMPP l in p v dng in pht ra ca pin mt tri ti im

ti u.

Khi gi tr RLOAD bng vi ROPT, cng sut cc i s c truyn t pin mt

tri n ti. Tuy nhin, trong thc t hai tng tr ny li khng bng nhau. Mc

ch ca b MPPT l iu chnh tng tr ti nhn t pha ngun bng vi tng tr

ti u ca pin mt tri.

Thng thng b bin i DC/DC (tng p, gim p) c phc v cho vic

truyn cng sut t pin mt tri ti ti. B DC/DC hot ng nh thit b giao tip

gia ti v pin mt tri. Bng vic thay i rng xung, tng tr ti nhn t pha

ngun s c thay i bng vi tng tr ngun ti im cc i, v vy cng sut

cc i c cung cp cho ti.

Hnh 2.13. S khi ca h thng MPPT tiu biu

Gi s, i vi mch gim p DC/DC (Buck converter), ta c:

VOUT = D.VIN (2.21)

HUTE

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Trong , VOUT l in p u ra, VIN in p u vo, khi :

ROUT = D2.RIN (2.22)

(ROUT l tng tr u ra, RIN tng tr u vo nhn t pha ngun)

RIN = ROUT/D2 (2.23)

V vy, tng tr ROUT c duy tr hng s bng vic thay i rng xung,

khi RIN nhn t pha ngun s c thay i.

Hnh 2.14. B DC/DC gip ht cng sut cc i t pin mt tri

Hay i vi mch tng p (Boost converter), mi quan h gia in p u

vo v u ra c miu t nh sau:

VIN = ( 1- D) VOUT (2.24)

Gi s, khng c cng sut tn hao, ta c:

IN OUT

OUT IN

I VI V

(2.25)

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IN OUT1I I

1 D

(2.26)

Tng tr u vo ca b bin i DC-DC l:

RIN = (1 - D)2ROUT (2.27)

V vy, tng tr ROUT c duy tr hng s bng vic thay i rng xung,

khi RIN nhn t pha ngun s c thay i.

HUTE

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2.4. Cc phng php tm im cc i ca pin mt tri ph bin

2.4.1. Phng php in p hng s Phng php ny s quan h gn ng gia in p ti im MPP (VMPP) v

in p h mch VOC vn thay i theo nhit v bc x:

VMPP k.VOC (2.28)

Trong k l hng s ph thuc vo c tuyn ca PV, c xc nh bng

cch xc nh VMPP v VOC ti cc bc x v nhit khc nhau. C nhiu nghin

cu xc nh rng k s nm trong khong 0.71 v 0.85

Vi mt hng s k bit, in p VMPP c th c xc nh bng cch o

VOC. o VOC, PV phi c ngt ti thc hin php o iu ny dn n tn

hao cng sut. Ngoi ra khi bc x mt tri thay i dn n sai s ln v vic xc

nh VMPP khng lin tc. Hn na y cng ch l phng php gn ng nn kt

qu s khng c chnh xc cao.

khc phc iu ny, c nhiu gii php c xut, chng hn nh

dng PV mu o VOC, PV ny khng dng pht in m ch dng xc nh

cc thng s ca PV nh VOC. PV mu phi c chn lc k cng v lp t

chung vi m un PV m bo c cng iu kin mi trng. Tuy nhin vic

dng thm PV mu c th s lm cho gi thnh ca h thng tng cao. Mc d vy,

y vn l mt phng php n gin bi v n khng yu cu mt phn cng qu

phc tp.

HUTE

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Set Vref

Start

Sense Vpv

Vpv > Vref

Increase Vref

Vpv < Vref

NO

NO

Decrease Vref

Return

YES

YES

Hnh 2.15. Gii thut MPPT da trn cc in p hng s

2.4.2. Phng php P&O (Perturb and Observe) B MPPT c xy dng da trn gii thut P&O l mt gii thut rt ph

bin bi tnh n gin trong gii thut cng nh cc thit b thc hin phng

php ny trong vic d tm im lm vic cc i ca pin mt tri.

HUTE

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Hnh 2.16. c tnh ca pin mt tri

T hnh 2.16 ta thy bn tri im MPP gia s cng sut v in p cng tng

trong khi bn phi ng cong gia s cng sut gim v in p tng. Nu tn

ti mt gia s cng sut, v hng ca gia s khng i (dng), khi nu cng

sut gim, hng ca gia s s i chiu (m). C nh vy cho n khi t c

MPP, v im vn hnh s lun lun dao ng xung quanh im MPP.

Tuy nhin phng php ny khng tnh ton chnh xc c khi c s thay

i nhanh chng ca bc x mt tri v coi n nh l mt s nhiu lon v dn n

kt qu tnh ton khng chnh xc ti im cc i.

Hnh 2.17. th PV khi bc x thay i v s lm vic tm im cc i ca

phng php P&O

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Trong hnh 2.17 th hin mt tnh hung m bc x mt tri thay i nhanh

chng, im cng sut cc i MPP cng di chuyn pha bn tay phi ca ng

cong th PV. Thut ton coi nh l mt s thay i do nhiu lon v lp i

lp li tip theo thay i hng ca nhiu lon v do ri xa hn cc im cng

sut cc i( im E,F v G ri xa cc im cc i B, C v D) nh c hin th

trong hnh. V th , hin nay khi s dng phng php ny phi tm kim thm cc

gii thut thc hin khc phc nhc im trn.

P = 0

Return

Inputs: V(t), I(t), V(t-t), P(t) &P(t-t) calculated from the inputs

V(t) = V(t) - V(t-t) P = P(t) - P(t-t)

P = 0 P> 0 P > 0

NO

P = 0

YES

V > 0

NO

NO NOYES YES

YES

P = 0

Decrease Vref

Decrease Vref

Increase Vref

Increase Vref

V > 0

Hnh 2.18. Gii thut P&O

HUTE

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Chng 3

CHN GII THUT B D TM IM CNG SUT

CC I CA PIN MT TRI

3.1 Phng php INC (Incremental Conductance) Qua trnh by nghin cu cc gii thut tm im cng sut cc i ca pin

mt tri (MPPT) ang c ng dng rng ri hin , bao gm gii thut in p

hng s, P&O trn. Tuy nhin cc phng php ny c nhng khuyt im l vi

mt hng s k bit, in p VMPP c th c xc nh bng cch o VOC. o

VOC, PV phi c ngt ti thc hin php o iu ny dn n tn hao cng

sut. Ngoi ra khi bc x mt tri thay i dn n sai s ln v vic xc nh VMPP

khng lin tc. Hn na y cng ch l phng php gn ng nn kt qu s

khng c chnh xc cao ( phng php in p hng s ) hay khng tnh ton

chnh xc c khi c s thay i nhanh chng ca bc x mt tri v coi n nh l

mt s nhiu lon v dn n kt qu tnh ton khng chnh xc ti im cc i

(phng php P&O)

Ta c mt trong nhng phng php c th khc phc cc khuyt im trn,

ng thi tnh n gin ca gii thut v hiu qu trong vic tm im MPP ca pin

mt tri, chi ph thp d p dng c a ra , l Phng php InC

(Incremental Conductance) da trn cc bi bo khoa hc nh : Jae Ho Lee ,

HyunSu Bae and Bo Hyung Cho Advanced Incremental Conductance MPPT

Algorithm with a Variable Step Size - Seoul National University School of

Electrical Engineering and Computer Science, Seoul, Korea v An investigation

of new control method for MPPT in PV array using DC DC buck boost

converter-Dimosthenis Peftitsis, Georgios Adamidis and Anastasios Balouktsis-

ectrical & Computer Engineering Department Democritus University of

Thrace,GREECE v mt s bi bo ti mc ti liu tham kho . Phng php InC

HUTE

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(Incremental Conductance) da trn o hm P-V ca ng cong PV c th c

miu t nh sau:

Hnh 3.1. dc (dP/dV) ca PV

Ta c:

dP/dV = 0, ti im cc i MPP ca PV

dP/dV > 0, bn tri im MPP

dP/dV < 0, bn phi im MPP

T:

dP d (IV ) dI II V I VdV dV dV V

(2.29)

Ta c th biu din nh sau:

dI/dV = - I/V, ti im MPP

dI/dV > -I/V, bn tri im MPP

dI/dV < -I/V, bn phi im MPP

im cc i c tm bng cch so snh gi tr tc thi I/V vi sai s dI/dV,

theo gii thut sau trn hnh 3.2

HUTE

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3.2 M hnh m phng gii thut

Hnh 3.2. Gii thut InC

Do ti ny chn phng php ny tm hiu xy dng gii thut b d im cc i ca pin quang in , t c th m phng thc nghim kim chng kt qu.

HUTE

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3.2.1 M hnh Pin mt tri M hnh pin mt tri c xy dng trong Matlab/Simulink, trong cc

biu thc f(u) c xy dng da trn cc biu thc I-V ca pin mt tri, c th

dng quang in IPH c xy dng t biu thc (2.2), dng bo ha ngc IRS

c xy dng t biu thc (2.5), dng bo ha IS c xy dng da theo biu

thc (2.3), dng I c xy dng trn c s biu thc (2.6).

Hnh 3.3. M hnh pin mt tri c xy dng trong Matlab/Simulink

Hnh 3.4. M hnh pin mt tri thu gn

HUTE

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thc hin m phng, tc gi s dng pin mt tri thng mi MSX 60, c

thng s nh sau:

Bng 3.1. Thng s ca pin mt tri thng mi MSX 60 ti 1 kW/m2 , 25 oC

c tnh Thng s c tnh Thng s

Cng sut nh (PP) 60 W H s nhit ca VOC 80-90 mV/oC

in p nh (VPP) 17.1 V H s nhit ca ISC (KI)

3 mA/oC

Dng in nh (IPP) 3.5 A nh hng nhit ln cng sut

-0.38 W/oC

Dng ngn mch (ISC ) 3.8 A Nhit vn hnh bnh thng (NOCT)

49 oC

in p h mch (VOC) 21.1 V

Hnh 3.5. Bng thng s u vo ca pin mt tri

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c tuyn I-V ca pin mt tri khng tuyn tnh v n ph thuc vo nhit

vn hnh ca pin v bc x mi trng. Khi bc x mt tri tng, dng ngn mch

v cng sut tng theo, v in p h mch cng tng tng ng (hnh 3.6)

Hnh 3.6. c tuyn I-V, P-V vi cc bc x khc nhau (Nhit pin 25oC)

Khi nhit vn hnh ca pin mt tri tng cao, dng ngn mch cng tng

theo nhng khng ng k so vi khi bc x mt tri tng, nhng khi in p h

mch ca pin mt tri gim mnh, ko theo cng sut ca pin mt tri gim mnh

(hnh 3.7).

Hnh 3.7. c tuyn I-V, P-V vi nhit vn hnh khc nhau (bc x 1kW/m2)

HUTE

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3.2.2 Gii thut INC

Hnh 3.8. B phn o in p v dng in

Hnh 3.9. Gii thut INC c xy dng trong Matlab & Simulink

HUTE

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Hnh 3.10. M hnh m phng c tuyn pin mt tri

Hnh 3.11. M hnh m phng gii thut

HUTE

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Chng 4

KT QU M PHNG

4.1. M hnh pin mt tri

Trong qu trnh chy m phng m hnh pin mt tri Chng 3, u tin ta cho

bc x mt tri thay i theo thi gian ( ng thi khi bc x mt tri thay i th

nhit cng thay i theo ) cc mc 0,2 ; 0,4 ; 0,6 ; 0,8 v 1 . Nhm th hin

xem xt phn d tm im cng sut cc i khi bc x mt tri thay i tng dn

trong ngy. th bc x mt tri thay i tng cp th hin hnh 4.1

Hnh 4.1. Bc x mt tri

HUTE

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T s thay i bc x mt tri ta xc nh c cc ng c tuyn PV v IV ca

pin mt tri m phng theo tng thay i bc x mt tri trn. Ta thy trn c

tuyn PV hnh 4.2 , cng sut cc i pin mt tri tng dn khi bc x mt tri

tng ng thi in p ti cc im cc i gim. iu c ngha khi cng sut

cc i tng , in p gim th dng in ti cc im cc i cng tng theo th

hin qua ng c tuyn IV hnh 4.3

Hnh 4.2. c tuyn PV ca pin mt tri

HUTE

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Hnh 4.3. c tuyn IV ca pin mt tri

4.2. Gii thut MPPT

Kt qu khi m phng ta c th in p v dng in lm vic ca pin ng ra

khi qua b d tm im cng sut cc i ca pin m tri th hin qua hnh 4.4 v

hnh 4.5 , ta thy in p gim v dng in tng tng cp tng ng khi bc x

thay i xc nh c im lm vic cng sut ti u cc i ca pin mt tri

th hin th cng sut lm vic ca pin hnh 4.6 . iu ny ph hp vi kt

qu ca cc ng c tuyn PV v IV ca pin mt tri. Cho ta thy s hiu qu

lm vic ca gii thut a ra t c kt qu mong mun khi bc x mt tri

thay i trong ngy v kh nng p ng tt ca gii thut trn. Ph hp vi yu

cu t ra l xut phng php MPPT ti u vi kh nng p ng di cc iu

kin bc x v nhit thay i .

HUTE

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Hnh 4.4. in p lm vic ca pin mt tri

Hnh 4.5. Dng in lm vic ca pin mt tri

HUTE

CH

37

Hnh 4.6. Cng sut lm vic ca pin mt tri

Hinh 4.7. in p lm vic ca pin mt tri tng ng vi cng sut thu c

HUTE

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Trn hnh 4.7 l th PV ta c kt qu in p lm vic ca pin mt tri tng

ng vi cng sut thu c khi bc x thay i t 0,2 ; 0,4; 0,6 ; 0,8 v 1, ta thy

b d tm cng sut cc i MPPT nhanh chng a in p lm vic t gn ti

cc im cng sut ti u p ng tt yu cu t ra.

Trn thc t do thi tit c th lm cho bc x mt tri thay i lin tc trong ngy

ch khng thay i theo tng cp ( theo gi nng trong ngy ) nh th nghim m

phng trn. Chng ti thc hin thm m phng xem s p ng ca phng

php ny khi bc x thay i th hin qua cc th bc x mt tri thay i nhanh

hnh 4.8 v kt qu m phng in p , dng in lm vic d tm tng gim

tng ng vi s thay i nhanh ca bc x th r nht c s thay i lin tc khi

ng cong th bc x khong 0,8 -1 v sau duy tr c in p lm vic

n nh v cng sut ti u ca pin mt tri c d tm nhanh trong thi gian

ngn v tin nhanh giai on u t bc x 0 -0,8 v t gn im cc i ti bc

x 0,8 -1 v sau cng sut gim tng ng khi bc x mt tri gim th hin qua

cc th ca cc hnh 4.9 ; hnh 4.10; hnh 4.11

HUTE

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Hnh 4.8. Bc x mt tri thay i nhanh

Hnh 4.9. in p lm vic ca pin mt tri

HUTE

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40

Hnh 4.10. Dng in lm vic ca pin mt tri

Hnh 4.11. Cng sut lm vic ca pin mt tri

HUTE

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41

Hinh 4.12. in p lm vic ca pin mt tri tng ng vi cng sut thu c

Hnh 4.12 th hin r s lm vic tt ca phng php ny khi bc x thay i lin

tc , b d tm cng sut cc i nhanh chng a in p lm vic ca pin mt tri

thay i tng ng b qua cc ng cong bc x thp tin nhanh gn vi im

cng sut ti u ca pin mt tri cao nht c th t ti.

.

HUTE

CH

42

Chng 5

KT QU THC NGHIM

5.1. M hnh thc nghim

Vic m phng trn phn mm matlab ch mang tnh l thuyt, thi cng mch

thc t t m hnh Matlab l gn nh khng th. V th, sau khi tm ra gii thut

mi v m phng thnh cng trn Matlab, lun vn tip tc xy dng m hnh

iu ny c ngha l thit k m phng chy trn m hnh thc t , trong chng

ny tin hnh thc nghim trn m hnh tht kim tra v so snh vi kt qu m

phng. Trong hnh 5.1 th hin m hnh v thit b tin hnh cng tc thc

nghim d tm im cc i ca pin mt tri theo gii thut Incremental

Conductance xy dng.

Hnh 5.1. M hnh thc nghim

HUTE

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43

M hnh thc nghim s dng loi pin th trng m s WN-15 , hnh dng v

thng s c th hin qua hnh 5.2 v bng 3.2

Hnh 5.2. Pin mt tri v thng s ca nh sn xut

Bng 3.2. Thng s ca pin mt tri thng mi WN-15 ti 1 kW/m2 , 25 oC

c tnh Thng s

Cng sut nh (PP) 15W

in p nh (VPP) 17.5 V

Dng in nh (IPP) 0.86 A

Dng ngn mch (ISC ) 1.31 A

in p h mch (VOC) 21.5 V

Trong h thng trn (hnh 5.1) gm m hnh pin mt tri, b chuyn i DC -

DC, gm : mch khuch i dng in , mch giao tip vi my tnh, mch cm

bin v mch iu khin . Mch cng sut v b phn o lng dng in c

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44

trnh by trong hnh 5.3 v 5.4. Thc hin thi cng mch in mch iu khin v

mch cng sut c trnh by trong hnh 5.5 v 5.6.

Hnh 5.3. S mch cng sut v b phn o lng dng in

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45

Mch iu khin:

Hnh 5.4.S nguyn l mch iu khin

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46

S mch in:

Hnh 5.5. S mch in mch iu khin

Hnh 5.6. S mch in mch cng sut

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47

B chuyn i cng sut DC - DC bao gm:mch khuch i dng in , mch

giao tip vi my tnh, mch cm bin v mch iu khin c th hin trong hnh

5.7

Hnh 5.7. Mch iu khin v mch cng sut thi cng

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48

Lu chng trnh chnh:

END

C IN P HIN TH LCD V TRUYN V MY TNH

DELAY (THI GIAN LY MU)

TNH TON CNG SUT

KHI TO LCD, RS232-PC, KHI TO B IU RNG XUNG

C DNG IN HIN TH LCD V TRUYN V MY TNH

GII THUT MPPT

BEGIN

CP NHT RNG XUNG

LU GI TR CNG SUT

Hnh 5.8. Lu chng trnh chnh

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49

Lu chng trnh tm im cng sut cc i MPPT

Hnh 5.9. Lu chng trnh MPPT

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50

Chng trnh MPPT c minh ho di y :

... if (deltaV=0)

{

if (deltaI = 0)

{

duty = duty;

}

else

{

if (deltaI>0)

{

if (duty > low_duty)

duty=duty - 1;

else duty = duty;

}

else

{

if (duty < high_duty)

duty=duty + 1;

else duty = duty;

}

}

}

else

{

if (delatI/deltaV = - ik1/vk1)

{

duty = duty;

}

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51

else

{

if (delatI/deltaV > - ik1/vk1)

{


duty=duty - 1;

else duty = duty;

}

else

{


duty=duty + 1;

else duty = duty;

}

}

}

vk = vk1;

pk = pk1;

ik=ik1;

//delay_ms(3);

//set_pwm1_duty(duty);

set_pwm1_duty(duty);

set_pwm2_duty(100);

}

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52

5.2. Kt qu thc nghim

in p lm vic, dng in v cng sut ca pin mt tri c theo di trong

qu trnh thc nghim trn m hnh thc t th hin hnh 5.10. Hinh 5.11 th

hin rng xung kch Mosfet cp nht rng xung b iu khin . Hnh

5.12 dng n 20W lm ti u ra b chuyn i cng sut DC- DC. Hnh

5.13 th hin in p v dng in trn ti.

Hnh 5.10. in p v cng sut v dng in

pin mt tri

Hnh 5.11. rng xung kch

Mosfet

Hnh 5.12. Cng sng ca ti l bng n

20W

Hnh 5.13. in p trn ti v

dng in chy qua ti

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53

Cc s liu thu thp trong qu trnh thc nghim ly c trn my tnh v c v

li th in p v cng sut pin mt tri trn phn mm excel th hin trn hnh

5.14 v 5.15 pha di y. Hnh 5.14 cho thy in p ca pin mt tri lun lun

vn hnh ti im ti u khong 13 V v cng sut ti u vo khong 11,5W t

khong 76% cng sut ca pin (hnh 5.15)

Hnh 5.14. in p pin mt tri

Cng sut lm vic ca pin mt tri

Hnh 5.15. in p pin mt tri

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54

Chng 6

KT LUN V HNG PHT TRIN CA TI

6.1. Kt lun

Tm quan trng ca pht trin nng lng ti to cng c thc y bi

nhn thc ca ngi dn v vn mi trng. Thc t, c ngun nng lng khc

thay th ha hn mt tim nng cung cp nng lng rt ln l nng lng ht

nhn. Nhng vic s dng ngun nng lng ny vn l vn tranh ci v s an

ton v nh hng n mi trng sng. n c gn y nht l v ng t, sng

thn ti Nht Bn ngy 11/3/2011 ph hy nh my in ht nhn Fukushima

Daiichi, gy thit hi v ngi v kinh t, tip theo mt s nc Chu u

quyt nh ng ca nh my in ht nhn.

V vy, nng lng ti to l s la chn tt nht, ngun nng lng xanh,

ngun nng lng thn thin vi mi trng. ng thi nhu cu ngy cng tng v

nng lng in v cc vn mi trng nh nhim v s nng ln ton cu

hiu lc, nng lng mt tri c coi l mt la chn cng ngh to ra nng

lng sch. Pin quang in (pin mt tri) tiu biu cho thit b chuyn i c bn

nng lng mt tri thnh nng lng in.

Tuy nhin, vic s dng rng ri ca nng lng mt tri t ra mt s thch

thc nh tng hiu qu ca nng lng mt tri trong qu trnh chuyn i, m

bo tin cy trong qu trnh chuyn i in in t v p ng cc yu cu k

thut khi kt ni vo li . Cng nng ( bc x mt tri), nhit ca t bo

quang in v in p vn hnh nh hng ln n c tnh cng sut v dng in

ng ra ca pin mt tri. Vi cc c tnh phi tuyn, m hnh pin mt tri u tin

c xy dng thit k b d tm im cng sut cc i (MPPT) cho cc ng

dng ca n. nng cao hiu sut ca pin mt tri c nhiu gii thut MPPT.

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55

ti nghin cu mt s gii thut MPPT ang c ng dng rng ri

hin nay, bao gm gii thut in p hng s, P&O v InC. Trong , gii thut

P&O v Inc l hai gii thut ph bin nht do bi tnh n gin ca gii thut v

hiu qu trong vic tm im MPP ca pin mt tri.

Qua kt qu m phng khi bc x thay i chm v thay i nhanh lin tc

nhm m phng st iu kin thi tit thc t lun thay i , ta chng minh c

gii thut ca phng php INC p ng c yu cu mong mun t ra l nhanh

chng t c im cng sut ti u khi c xt n s thay i bc x mt tri v

nhit lm vic ca pin cng vi s thay i tng ng in p v dng in lm

vic ca pin mt tri . V ng thi gii thut ny khng qu phc tp thc hin

m hnh vt l chng minh tnh ng dng vo thc t ca phng php ny

Kt qu m phng trong Matlab & Simulink cho thy gii thut INC c th

tm c im MPP ca pin mt tri nhanh hn nhanh chng v lm vic n nh

Kt qu thc nghim cho thy s cn thit phi s dng b MPPT nng

cao hiu sut ca pin mt tri v bng vic s dng gii thut MPPT, h thng thc

nghim ht c cng sut cc i t pin mt tri nh vic a in p lm vic

ca pin mt tri v in p MPP thng qua b chuyn i DC/DC (mch boost).

Nhn c kt qu t m hnh, gii thut bm st theo iu kin mi trng

t pin, thng s ca pin.

Vi kt qu nhn c, c th ng dng rng ri phng php xut vi

mc tiu ti a ha hiu sut pin mt tri. Gip cho cc nh nghin cu c thm ti

liu tham kho trong vic d tm im cng sut cc i

6.2. Hng pht trin ca ti

- Thc hin m phng trong cng mt iu kin tng t i vi phng

php P&O v phng php in p hng s so snh vi phng php xut .

- Nng cao hiu sut b MPPT thng qua vic thit k ci tin mch chuyn

i DC/DC.

- Tch hp b MPPT trong h thng Pin mt tri lm vic c lp (np cho

acquy) v h thng pin mt tri ha li.

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56

TI LIU THAM KHO

TING VIT 1. Vin kh tng thy vn: http://www.imh.ac.vn/

2. First Solar Vit Nam d n cng ngh cao u nm 2011,

http://www.hepza.hochiminhcity.gov.vn

3.ng nh Thng C s nng lng mi v ti to Nh xut bn khoa hc k

thut. 2006

TING NC NGOI 4. Jeyraj Selvaraj and Nasrudin A. RahimMultilevel Inverter For Grid-Connected

PV System Employing Digital PI Controller IEEE TRANSACTIONS ON

INDUSTRIAL LECTRONICS, VOL. 56, NO. 1, JANUARY 2009 .

5. Syafrudin Masri, Pui-Weng Chan Development of a microcontroller based

boost converter for photovoltaic system ISSN 1450-216X Vol.41 No.1 (2010).

6. Ahmed A. A. Hafez Simple maximum power point contronller for single

phase grid connected PV system Cairo University, Egypt, December 19-21, 2010,

paper ID 123.

7. Jae Ho Lee , HyunSu Bae and Bo Hyung Cho Advanced Incremental Conductance MPPT Algorithm with a Variable Step Size - Seoul National University School of Electrical Engineering and Computer Science, Seoul, Korea-2009 8. Marcio Mendes Casaro*, Denizar Cruz Martins Power Electronics Institute,

Federal University of Santa Catarina Grid-Connected PV System: Introduction to

Behavior Matching

9. A.P.S Ramalakshmi Comparision of solar panel power under varying load and

irradiance conditions

10. Jing Li , Fang Zhuo , Xianwei Wang , Lin Wang , Song Ni A Grid-Connected

PV System with Power Quality Improvement Based on Boost + Dual-Level Four-

Leg Inverter

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57

11. Samatcha Phuttapatimok, Anawach Sangswang, Member, IEEE, and

Krissanapong Kirtikara Effects on Short Circuit Level of PV Grid-Connected

Systems under Unintentional Islanding

12. Fei Wang, Chengcheng Zhang, Zengqiang Mi Anti-islanding Detection and

Protection for Grid connected PV System Using Instantaneous Power Theory

13. Fei Wang, Zengqiang Mi Passive Islanding Detection Method for Grid

Connected PV System 2009 International Conference on Industrial and

Information Systems.

14. M.B. Bana Sharifian Single-Stage grid connected photovoltaic system with

Reactive power control and adaptive predictive current controller Journal of

applied sciences 9 (8): 1593-1509, 2009.

15. N. Hamrouni and A.Cherif Modelling and control of a grid connected

photovoltaic system Revue des Energies Renouvelables Vol. 10 No3 September

2007).

16. Roberto F. Coelho, Filipe M. Concer, Denizar C. Martins A MPPT Approach

Based on Temperature Measurements Applied in PV Systems Electrical

Engineering Departament, Power Electronics Institute, Federal University of Santa

Catarina, P.O. 5119 - Florianpolis, SC 88040-970, Brazil

17.Vocational School of Technical Studies, Marmara University, Kadkoy, 34722

Istanbul, Turkey Recent Developments inMaximumPower Point Tracking

Technologies for Photovoltaic Systems

18. Ibrahim, H. E.-S. A. and Houssiny, F. F., Microcomputer Controlled Buck

Regulator for Maximum Power Point Tracker for DC Pumping System Operates

from Photovoltaic System, Proceedings of the IEEE International Fuzzy Systems

Conference, August 22-25,Vol. 1, pp. 406-411 (1999).

19. Jawad Ahmad, and Hee-Jun Kim A Voltage Based Maximum Power Point

Tracker for Low Power and Low Cost Photovoltaic Applications World Academy

of Science, Engineering and Technology 60 2009

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58

20. Masoum, Mohammad A. S. Dehbonei, Hooman, Design, Construction and

Testing of a Voltage-based Maximum Power Point Tracker (VMPPT) for Small

Satellite Power Supply SSC99-XII-7

21. Enslin, J. H. R. and Snyman, D. B., Simplified Feed-Forward Control of the

Maximum Power Pont in PV Installations Proceedings of the IEEE International

Conference on Power Electronics Motion Control, Vol.1, pp. 548-553 (1992).

22.Sree Manju B, Ramaprabha R, Mathur B.L Design and Modeling of

Standalone Solar Photovoltaic Charging SystemInternational Journal of Computer

Applications (0975 8887) Volume 18 No.2, March 2011

23. Mayssa Farhat, Lassad Sbita Advanced Fuzzy MPPT Control Algorithm

for Photovoltaic Systems Science Academy Transactions on Renewable Energy

Systems Engineering and Technology Vol. 1, No. 1, March 2011

24. Mohamed Salhi, Rachid El-Bachtri Maximum Power Point Tracker using

Fuzzy Control for Photovoltaic System International Journal of Research and

Reviews in Electrical and Computer Engineering (IJRRECE) Vol. 1, No. 2, June

2011, ISSN: 2046-5149

25. R. Belaidi, M. Fathi, A. Haddouche, A. Chikouche, G. Mohand Kaci and Z.

Smara, Study and Simulation of a Mppt controller based on Fuzzy logic

controller for photovoltaic system IGEC-VI-2011-208

26.Theodoros L. Kottas, Athanassios D. Karlis, New Maximum Power Point

Tracker for PV Arrays Using Fuzzy Controller in Close Cooperation With Fuzzy

Cognitive Networks IEEE TRANSACTIONS ON ENERGY CONVERSION,

VOL. 21, NO. 3, SEPTEMBER 2006

27. Huan-Liang Tsai Insnolation oriented model of PV using Matlab/Simulink

Solar Energy 1318-1326

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PH LC

Chng trnh chnh thc hin m hnh tm im cc i ca pin mt tri :

#include

#fuses HS,NOWDT,NOPROTECT,NOLVP,NODEBUG,NOBROWNOUT

#use delay(clock=4000000)

#use rs232(baud=9600, parity=N,xmit=PIN_C6, rcv=PIN_C7,bits=8)

void ADC_Init_V(void);

void ADC_Init_I(void);

void congsuat(void);

void TraCommand(int8 comm);

void TraData(int8 data);

void dich(int8 digital);

void xuat_vitri();

void xuatkytu();

void start_LCD();

void write_data(int data);

void write_command(int command);

void dich(int digital);

void write_string(char* chuoi, int line, int index);

int32 a=0;

int32 b=0;

int32 g=0;

int32 h=0;

int32 m=0;

int32 k=0;

int32 n=0;

int32 p=0;

int32 u=0;

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int32 i=0;

int32 Vhigh = 170;

int32 Vlow = 90;

int32 bien = 0;

int32 pk = 0;

int32 pk1 = 0;

int32 deltaP = 0;

int32 vk = 0;

int32 vk1 = 0;

int32 ik = 0;

int32 ik1 = 0;

int32 deltaV = 0;

int32 deltaI = 0;

int32 thoigian = 500

int32 g1=0;

int32 g2=0;

int32 g3=0;

int32 g4=0;

int32 g5=0;

int32 g6=0;

int32 r=100;

int32 rr=100;

int32 z=0;

int32 dd=0;

int32 amp=0;

int32 gan=0;

int32 xp=0;

int duty = 2; //50

int low_duty = 2;

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int high_duty =90;

void main()

/////////////////////////////////////

set_tris_c(0x0);

//set_tris_b(0x06);

setup_ccp1(CCP_PWM); // Configure CCP1 as a PWM

setup_ccp2(CCP_PWM); // Configure CCP2 as a PWM

setup_timer_2(t2_div_by_16,93,16);//1500hz




/////////////////////////////////////

set_tris_a(0xff);

start_LCD();

output_high (pin_b1);






// delay_ms (3000);

while(1)

{

///////////////

/////////////////

write_command(0x80);

write_data('V');//1

write_data('o');//2

write_data('l');//3

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write_data('t');//4

write_data(' ');//5

write_data(' ');//6

write_data('A');//7

write_data('m');//8

write_data('p');//9

write_data('e');//10

write_data(' ');//11

write_data('P');//13

write_data('(');//14

write_data('W');//15

write_data(')');//16

write_command(0xc0);

ADC_Init_V();

ADC_Init_I();

for (i=0;iVOLT

a = amp;

b = b + a;

}

b = b/r;

amp = b;

amp = amp/15;

amp=amp*10;

z = amp;

ik1=z;

gan = amp/1000;

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/// putc(gan+0x30);

write_data(gan+0x30);

amp = amp%1000;

gan = amp/100;

write_data(',');

/// putc(',');

/// putc(gan+0x30)


amp=amp%100;

gan = amp/10;

n = gan;

/// putc(gan+0x30);


amp=amp%10;

k = gan;

/// putc(amp+0x30);

/// putc('A');

/// putc(' ');

write_data(' '); //thuan

write_data(' '); //thuan

//********CONG SUAT********************

//***********************************

congsuat();

}

}

//*************************************

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//chuong trinh con

void ADC_Init_V(void)

{

setup_adc(ADC_CLOCK_DIV_2);

setup_adc_ports(sAN0);

set_adc_channel(0);

for (i=0;iVOLT

g3 = g2;

g4 = g4 + g3;

}

g4 = g4/rr;

g5 = g4/100;

g5=g5*46;

g5=g5/10;

vk1=g5;

g6 = g5/1000;

/// putc(g6+0x30);

// write_data(g6+0x30);

g5 = g5%1000;

g6 = g5/100;

/// putc(g6+0x30);

write_data(g6+0x30);

g5=g5%100;

g6 = g5/10;

/// putc(g6+0x30);


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g5=g5%10;

write_data(',');

/// putc(',');

/// putc(g5+0x30);


/// putc('V');

/// putc(' ');

// putc('\n');

// write_data(' ');//5

write_data(' ');//6

}

void ADC_Init_I(void)

{

setup_adc(ADC_CLOCK_DIV_2);

setup_adc_ports(sAN1);

set_adc_channel(1);

}

//xuat string ra LCD

void write_string(char *chuoi, int line, int index)

{

switch(line)

{

case 1: write_command(0x80 + index);

break;

case 2: write_command(0xC0 + index);

break;

}

while (*chuoi)

{

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write_data(*chuoi++);

delay_ms(100);

}

}

void start_LCD()

{





write_command(0x0c);//0x0e


}

void write_data(int data)

{

output_high(pin_c5);

output_high(pin_c4);// muc 1->la du lieu xuat len LCD

output_d(data);

output_low(pin_c5);

delay_ms(2);

}

//RS->pinA1, Enable->pinA2

void write_command(int command)

{

output_high(pin_c5); //set EN len mot

output_low(pin_c4); //muc 0 -> nhu mot lenh va ko hien thi len LCD

output_d(command);

output_low(pin_c5); //tao mot canh xuong

delay_ms(2);

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}

void congsuat(void)

{

u = g*10 + h;

i = m*10 + k;

p = vk1*z;

p=p/100;

pk1 = p;

xp = p/1000;

putc(xp+0x30);

write_data(xp+0x30);

p = p%1000;

xp = p/100;

putc(xp+0x30);


write_data(',');//1

putc(',');

p = p%100;

xp = p/10;

putc(xp+0x30);


p = p%10;

putc(p+0x30);

write_data(p+0x30);

/// putc('W');

putc(' ');

//putc('F');

//putc(bien+0x30);

//putc(' ');

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//putc (duty+0x30);

putc('\r');

putc('\n');

delay_ms(thoigian);

//////////SO SANH///////////////

deltaP = pk1 - pk;

deltaV = vk1 - vk;

deltaI = ik1-ik

//GUAI THUAT MPPT

if (deltaV=0)

{

if (deltaI = 0)

{

duty = duty;

}

else

{

if (deltaI>0)

{


duty=duty - 1;

else duty = duty;

}

else

{


duty=duty + 1;

else duty = duty;

}

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}

}

else

{

if (delatI/deltaV = - ik1/vk1)

{

duty = duty;

}

else

{

if (delatI/deltaV > - ik1/vk1)

{


duty=duty - 1;

else duty = duty;

}

else

{


duty=duty + 1;

else duty = duty;

}

}

}

vk = vk1;

pk = pk1;

ik=ik1;

//delay_ms(3);


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set_pwm2_duty(100);

}

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Tim Diem Cong Suat Max