Đang tải... (xem toàn văn)
T4P CHl KHOA HOC & C6NG NGH^ CAC TRll''''dNG D Î HQC Ki THUAT * S6 89 2012 PHirONG PHAP TiM BltU C 6 N G SUAT Cl/C D^̂ I CClA PIN M^T T R 6 I DAP tnvG cAc Difeu KI? N M 6 I XRirdNC A MAXIMUM POWER POINT[.]
T4P CHl KHOA HOC & C6NG NGH^ CAC TRll'dNG D^I HQC Ki THUAT * S6 89 - 2012 PHirONG P H A P TiM BltU C N G SUAT Cl/C D^^I CClA PIN M^T T R I DAP tnvG cAc Difeu KI?:N M I XRirdNC A MAXIMUM POWER POINT TRACKING APPROACH FOR ADAPTING CHANGING ENVIRONMENTAL CONDITIONS Trirtfng ViftAnh Nguyin Thanh Thu^n Trifdng Dgi hgc Suphgm Ky IhudI Tp.HCM Trudng CDN Cdng ngh? cao Ddng An Nhgn ngdy 15 thdng ndm 2011, chdp nhgn dang ngdy thdng ndm 2012 T M TAT Bdi bdo trinh bdy phuxmg phdp tim diim Idm vl$c cd cdng suit eye 691 cda pin m$t tr&i (MPPT) ddp (mg cdc diiu kl$n mdi tnjf(mg thay dii Phuong phdp mCrl di xuit phdn chia vdng Idm viic trin dutmg d$c tuyin cua pin m$t triri thdnh ba vdng chinh, g6m vdng bdn trdi diim cgc d^l (MPP), vdng ciK d?/ vd vdng bdn phdi diim MPP B^ng vi$c xdc djnh diim Idm vide cOa pin m$t trdi dang & vOng ndo diu cd thi nhanh chdng dira pin vdo Idm vi$c & diim eye d^i thdng qua vi$c diiu chinh dd rdng xung cOa m^ch boost Kit qud md phdng vd thgc nghi$m cho thiy phuong phdp ndy d§ tim dux?c diim MPP nhanh hem, 6n djnh hon vd khdc phgc dux?v mdt s6 nhuoc diim cua gidi thudt P&O (Perturb and Observe) ABSTRACT This paper presents the Maximum PowerPoint Tracking (MPPT) technique of Photovoltaic to adapt changing enviromental conditions The author uses the new method by dividing the working point on the characteristics of solar cells into three major areas, including the left side of the maximum power point (MPP), the maximum area and the right of the MPP area By defining the working point of the solar cells we can quickly take the Photovoltaic to work at the MPP by adjusting duty pulse of the boost circuit Results of simulations and experimental measurements have shown that this method has found the MPP faster, more stable and overcomes some disadvantages of the algorithm P&O , GICflTHIfU Phat dien bdng pin quang dien (PV) edng trd nen quan trgng bdi vi nd dugc xem la ngudn nang lugng tdi tao cd nhieu uu diem nhu khong phat sinh chi phi nhien lieu, khdng gay nhiim mdi trudng, ddi hdi bdo tri it va khong phat tidng 6n so vdi cac nguon ndng lugng khac Tuy nhien, cac module PV Idm viec vdi tdng trd tai khdng thich hgp vdned hifu suat chuydn ddi thdp, dd,d6 tim diem cdng suat eye dai (MPPT) cho PV la didu cdn thidttrong mgt he thdng PV Lugng difn nang tao phy thugc vao dien dp ho^t dpng ciia PV Tren dac tuydn V(I) va P(V) ciia PV tdn tai nhdt mpt didm md d dd cong suat phat ciia PV dat cue dai (MPP), didm MPP thay ddi phu thugc vao buc xa va nhiet dp moi trudng Nhiem vu ciia bp MPPT id tim va U-i chd dp Idm viec hieu qua nhdt Vi vay,nhieu phuang phap MPPT da dugc nghien eiiu de xac dinh didm lam viec tdi uu Trong [l],vdi ky thugt MPPT diing bang tra tren may tinh nen ggp nhieu khd khan ve bg nhd bd vi xii ly.Giai quyet vdn de nay, mpt sd nghien cijm sir dung phuong phap thyc nghiem de chi quan he gi&a dien ap lam viec tdi uu va dien dp hd mach ciia PV [2],[3] nhung ehi dp dung dupe mdt so lo^i PV nhat dinh vi quan hf phu thupc vao vat lieu ehe tao, nhift dp moi trudng Cac giai thuat mdi [4],[5] su dung ky thuat P&O (perturb and observe)hay cai tien cua P&O da khdc phyc duge nhugc diem ndi tren Tuy nhien, cdng suat PV thu dugc bi dao dpng Idn va de tim sai diem MPP bde xa thay ddi Ngoai ra, hien cae phuang phap MPPT su dyng logic md hay m^ng Noron cung duge ehii trgng phdt trien nhung dp phiie tap cao [6]-[9] Bai bao tap trung nghien cuu xay dung gidi thuat MPPT cd tdc dp tim diem cue dai nhanh chdng va cd kha nang dap img dudi cac dieu kien moi trudng thay ddi dya tren nhung uu diem ciia phuang phap P&O va phuong T^lP CHl KHOA HQC & CflNG NCII$ CAC T RllftNG D»I HOC K^ THUiT * S6 89 - 2012 xa didm MPP phSp t h ^ nghiem PHDCyNGPHAPTlfePC^N 2.1M6Mh«thing I'll) St Iti-bit cfllculMadnomilw TAI PV t \' Hinh I Sadd khdi h4 thdng PVcd MPPT Cdng sudt eiia PV dugc xdc djnh bang tich s6 cua hai gid trj Ipv vd Vpv B$ MPPT xdc djnh gid trj di^n dp V„r (hogc d0 r^ng xung) nhdm didu khien b$ bidn ddi ndng lugng DCDC cho difn dp DC dgt Ifin tdi thay ddi dd thay ddi dugc cdng sudt tieu thy phii hgp vdi cdng sudt cue dgi ciia PV 2.2Phdn tich gidi thuSt P&O truydn thdng Hinh Dg doc dP/dV cua P V X6t hinh 2, gidi thugt P&Ovdn dya vdo quan hf V-P cua PV, bSn trdi didm eye dgi (MPP) dP/dV > 0, d ben phai didm MPP dP/dV < Ndu difn dp vgn hdnh ciia PV dugc di theo hudng dP/dV > 0, didu ndy cho thay PV dang di den diem MPP ngugc Igi ndu di theo hudng dP/dV < 0, diem 1dm vifc dd di qua didm MPP, dd giai Ihugl P&O se dao chieu (hinh 3) Vi vay giai thuat cd nhieu mat han che nhu luon ludn giao dgng quanh diem MPP, dap img cham, va cd the ddp img sai dudi cac dieu kifn mdi trudng thay ddi (HiNH4) Khi_ birc xa thay ddi PV chuydn dudng dgc tuyen thap len dgc tuyen cao Khi dd AP = (Pk,, - Pk) > vd AV > gidi thuat tidp tyc tang V,ef lam cho diem idm viec ngdy cdng Hinh Gidi thugi P&O tim sai diem MPP 2.3 Giai thu^tddxuSt I Vimg Idm vii>c hi^u qud cua PV Neu chia dgc tuyen ciia pin mat trdi thdnh ba viing nhu hinh 5, vdng ben trdi diem MPP (viing I), vung MPP (viing 2) vd vung ben phdi diem MPP (vimg 3) Cdc gid tri VLOW va VHIGH dugc xdc djnh dya tren phuang phdp thuc nghifm Theo [2],[3] VMPP^ ^ (0.75-0_.85)Voc Nhung dd dugc VQC can phdi ngat PV khdi hf thdng, nen chi phi mach dpng luc tang, that thodt cdng suat cung nhu dao dgng cdng suSt,cung cd the diing pin mdu dd xac djnh dien dp Voc- nhung khong chinh xac va Idm gid he thdng tdng cao Vi vay, dd dam bao dd diem MPP ludn ndm viing 2,cd thd chgn: TAP CHl KHOA HOC & CONG NCHf CAC TRUdNG D^I HOC K? THliAT * S6 89 - 2012 VLOW 0.8SVocrcf Trong dd: Vocrefld difn dp hd mgch tgi nhift dO chudn cua PV nhd sdn xudt cung cdp Xdy dimg gidi thugt dieu khiin chiing td rdng cdng sudt pin mgt trdi cd the cung cdp hon nOa, gidi thugt sS tdng gid trj Vrefbdng cdch gidm dO rf ng xung dd ddy cdng sudt PV ddn didm Idm vifc mdi cd cdng sudt cao hon didm Idm vifc cQ Sau xdc djnh dugc difn dp 1dm vifc Vpvciia hf thdn^, cdn so sdnh vdi hai gid trj VLOW vd VHIGH de xdc djnh gid trj Vref theo cdc quy lugt sau: Viing I: Vpv< VLOW, tdng nhanh VRLF vdi gia s6 Idn dd nhanh chdng dua PV vdo vimg - Vdng 2: VLOW< Vpv