A Renewable Hybrid Wind Solar Energy System Fed Single Phase Multilevel Inverter

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1 SSN: ol. ssue, January - 04 A Reneable Hybr Wn Solar Energy Sysem Fe Sngle Phase Mullevel nverer P. Ganesh, Davaasrvaam. M & B. Arunha gnan s nsue of nformaon Technology/EEE (P&D), sakhapanam, na Absrac: Wh he ncreasng concern of global armng an epleon of convenonal resources e have o look a susanable energy soluons lke reneable energy sources. Ths paper proposes a reneable hybr n solar energy sysem fe sngle phase mullevel nverer. The hybr sysem s he combnaon of phoo volac (P) array an n generaor. Solar energy s generae by usng P arrays, n poer s generae by usng n generaor an boh he generae volages are boose up by boos converers. These boose volages are fe o he sngle phase mul level nverer. Due o he nermen naure of boh he n an solar energy sources, a fuel cell can be use as an unnerrupable poer source, hch s able o fee a ceran amoun of poer o he loa uner all conons. Smulaon moels are consruce for he boh sngle phase nverer, sngle phase mullevel nverer an s valae hrough expermenal resuls usng PC mcro conroller. Key ors: Phoo volac, n generaor, Fuel cell, mul level nverer. nroucon The reneable energy resources are omnpresen, freely avalable, an envronmenally frenly. A reneable hybr energy sysem consss of o or more energy sources an an oponal energy sorage sysem. These hybr energy sysems are becomng popular n remoe area poer generaon applcaons. Ths projec ll combne phoovolac an n o make hybr sysem. Wn an phoovolac energes can hol he mos poenal o mee our energy emans. Alone, n energy s capable of supplyng large amouns of poer bu s presence s hghly unprecable as can be here one momen an gone n anoher. Smlarly, solar energy s presen hroughou he ay bu he solar rraaon levels vary ue o sun nensy an unprecable shaos cas by clous, rees, ec. The common nheren raback of n an phoovolac sysems are her nermen naure ha makes hem unrelable. The combne ulzaon of hese o reneable energy sources, he poer ransfer effcency an relably of he sysem can be mprove sgnfcanly. When a source s unavalable or nsuffcen n meeng he loa emans, he oher energy source can compensae he fference. n hs sysem separae DC/DC boos converers are connece o reach maxmum eman from boh he reneable energy sources. The sysems consss passve npu flers o remove he hgh frequency curren harmoncs njece no n urbne generaors. These harmoncs n he generaor ecreases s lfespan an ncreases he poer losses. So an alernave mul-npu recfer srucure s connece o n energy sysem. The boh ens of each boos converer are connece o sngle phase mullevel nverer o ge relae ave forms o snusoal Fg (): Block agram of Reneable hybr n solar energy sysem fe sngle phase nverer.. CRCUT OPERATON The crcu agram of he reneable hybr energy sysem fe mullevel nverer s shon n belo fgure, here one of he npus s connece o he oupu of he P array an he oher npu connece o he oupu of a n generaor va brge recfer. Confguraon of sches allos each converer o operae normally or nvually n he even ha any source s unavalable. Fg (): Fron en crcu of hybr n solar energy sysem JERTS05 65

2 SSN: ol. ssue, January - 04 n he case hen only he n source s avalable, he npu o oupu volage relaonshp s gven belo c () On he oher han, f only he P source s avalable, hen he npu o oupu volage relaonshp s gven belo c () Here bello llusraes he varous schng moes of he converers. f he urn on uraon of M s longer han or equal o M, hen he schng saes ll be sae he moes,,. Smlarly, f he urn on uraon of M s longer han or equal o M, hen he schng saes ll be sae he moes,,. n he follong,,p s he average npu curren from he P source;,w s he RMS npu curren afer he recfer (n case); an c s he average sysem oupu curren. The mahemacal expresson ha relaes he oal oupu volage an he o npu sources n each moe are llusrae belo., T s << T s c c T s << T s c, T s << T s Moe- (M off, M on): Moe- (M on, M on):, c T s << T s c c T s << T s, T s << T s, 0<< T s c c c 0<< T s, 0<< T s Moe- (M on, M off): Moe- (M off, M off): c c T s <<T s c, T s <<T s JERTS05 66

3 SSN: ol. ssue, January - 04 c c, T s <<T s The volage an nucor curren aveforms ha llusrae he schng moes of above moes n belo aveforms explane for conon he urn on uraon of M s longer han or equal o M. Where A C p, = ar ensy = roor sep area = poer coeffcen funcon = p spee rao = pch angle = n spee Fg (): aveforms of nucor currens for schng moes M s longer han or equal o M. To fn an expresson for he oupu DC bus volage c, he vol-balance of he oupu nucor, s examne accorng o above fgure h >. Snce he ne change n he volage of s zero, applyng vol-balance o resuls n eq (). The expresson ha relaes he average oupu DC volage ( c ) o he capacor volages (v c an v c ) s hen obane as shon n eq (4), here v c an v c can hen be obane by applyng volbalance o an. The fnal expresson ha relaes he average oupu volage an he o npu sources ( W an P ) s hen gven by eq (5). s observe ha c s smply conrolle by M an M nvually or smulaneously. T T T 0 () c c s c s c s c c c (4) c (5) To escrbe a n urbne poer characersc, belo equaon escrbes he mechancal poer ha s generae by he n. The poer coeffcen ( C ) s a nonlnear funcon ha represens he effcency of he n urbne o conver n energy no mechancal energy. s epenen on o varables, he p spee rao (TSR) an he pch angle. The TSR ( ) refers o a rao of he urbne angular spee over he n spee. The mahemacal represenaon of he TSR s gven belo. The pch angle ( ) refers o he angle n hch he urbne blaes are algne h respec o s longunal axs. R b Where, R = urbne raus = angular roaonal spee b Fgure 7 an 8 are llusraons of a poer coeffcen curve an poer curve for a ypcal fxe pch ( =0) horzonal axs n urbne. can be seen from fgure 7 an 8 ha he poer curves for each n spee has a shape smlar o ha of he poer coeffcen curve. Because he TSR s a rao beeen he urbne roaonal spee an he n spee, follos ha each n spee oul have a fferen corresponng opmal roaonal spee ha gves he opmal TSR. For each urbne here s an opmal TSR value ha correspons o a maxmum value of he poer coeffcen C ) an herefore he maxmum poer. ( p, max Therefore by conrollng roaonal spee, maxmum poer can be obane for fferen n spees. p P m, 0.5AC p Fg (4): Poer Coeffcen Curve for a ypcal n urbne JERTS05 67

4 SSN: ol. ssue, January - 04 The resulan eal volage-curren characersc of a phoovolac cell s gven as follo an llusrae by belo fg (6). q ph 0 exp kbt Fg (5): Poer Curves for a ypcal n urbne A solar cell s comprse of a P-N juncon semconucor ha prouces currens va he phoovolac effec. P arrays are consruce by placng numerous solar cells connece n seres an n parallel. The equvalen crcu s shon by belo fgure. The curren-volage characersc of a solar cell as follos ph D R R q s ph Ak BT 0 exp Where = phoo curren ph D = oe curren 0 = sauraon curren A = ealy facor q = elecronc charge.6x0-9 k B = Bolzmann s gas consan (.8x0-) T = cell emperaure R = seres ressance s R sh = shun ressance = cell curren = cell volage R sh s Fg (7): aveform of -ph seven level nverer crcu The ypcal oupu poer characerscs of a P array uner varous egrees of rraaon s llusrae an can be observe n belo fgure ha here s a parcular opmal volage for each rraaon level ha correspons o maxmum oupu poer. Therefore by ajusng he oupu curren (or volage) of he P array, maxmum poer from he array can be ran. Fg (8): P cell poer characerscs. -PH MUTEE NERTER Fg (6): P cell equvalen crcu Typcally, he shun ressance (R sh ) s very large an he seres ressance (R s ) s very small. Therefore, s common o neglec hese ressances n orer o smplfy he solar cell moel. The poer elecroncs evce hch convers DC poer o AC poer a requre oupu volage an frequency level s knon as nverer. The volage source nverers prouce an oupu volage or a curren h levels eher 0 or +ve or - ve c. They are knon as o-level nverers. Mullevel nverer s o synhesze a near snusoal volage from several levels of c volages. They ypcally synhesze he sar case volage aveform hch has reuce harmonc conen. n JERTS05 68

5 SSN: ol. ssue, January - 04 Where, = evel of nverer n = number of cascae nverers For example here number of cascae nverers s hree ( n =) s subsue n equaon e ge =7 means he level of he nverer s seven. n hs paper smulaon moel of sngle phase Seven-level nverer has been evelope usng MOSFETs. Gang sgnals for hese MOSFETs have been generae by pulse generaors. n orer o manan he fferen volage levels a approprae nervals, he conucon me nervals of MOSFETs have been manane by conrollng he pulse h of gang. 4.SMUATON MODE Fg (): Smulaon moel for hybr n solar energy sysem Smulaon resuls: Fg (9): -ph seven-level nverer crcu (a) (b) Fg (0): aveform of -ph seven-level nverer crcu (c) JERTS05 69

6 SSN: ol. ssue, January - 04 () Fg (4): Drver crcu agram use n Harare (e) (f) Fg (): smulaon resuls for (a) Solar generae volage (b) Wn generae volage (c) Pulses for M&M () nverer ncomng c volage aveforms (e) nverer oupu ac volage (f) Oupu ac volage of mul-level nverer Fg (5): Expermenal seup of Reneable hybr n solar energy sysem fe sngle phase nverer. Harare resuls: 5.HARDWARE MPEMENTATON Fg (6): Oupu volage of nverer CONCUSON Fg (): Conrol crcu agram use n Harare n hs paper a reneable hybr n solar energy sysem fe sngle phase mullevel nverer presene. The feaures of hs crcu are: Aonal npu flers are no necessary o fler ou hgh frequency harmoncs. Boh reneable sources can be seppe up/on. nvual an smulaneous operaon s suppore. Smulaon resuls have been presene. Smulaon moels are consruce for he boh sngle phase nverer an sngle phase mullevel nverer, harare s mplemene for sngle phase nverer. JERTS05 60

7 SSN: ol. ssue, January - 04 REFERENCES [] Joanne Hu, EEE Suen Member, Alreza Bakhsha, EEE Senor Member, an Praveen K. Jan, EEE Fello A Hybr Wn-Solar Energy Sysem: A Ne Recfer Sage Topology /00 EEE. [] Debosma Das, Reza Esmal, ongya Xu Dave Nchols An Opmal Desgn of a Gr Connece Hybr Wn/Phoovolac/Fuel Cell Sysem for Dsrbue Energy Proucon / EEE. [] Mul-npu nverer for Gr-Connece Hybr P/Wn Poer Sysem Yao-Mng Chen, Senor Member, EEE, Yuan-Chuan u, Shh- Cheh Hung, an Chung-Sheng Cheng EEE TRANSACTONS ON NDUSTRA EECTRONCS, O. 55, NO. 4, APR 008 B.Arunha born on 9 h March 968 as receve BE from Unversy college of Engneerng, Burla, Sambalpur, Orssa, na n 99, M.Tech n he year 005 from JNTU, Hyeraba an pursung Ph.D from JNTU, Hyeraba. Presenly orkng as Asso.Professor an HOD- EEE of gnan s nsue of nformaon & echnology, sakhapanam, na. Her research neress are near moors & conrol sysem applcaons o poer elecroncs an machne rves. [4] An negrae Hybr Poer Supply for Dsrbue Generaon Applcaons Fe by Nonconvenonal Energy Sources Sachn Jan an vek Agaral, Senor Member, EEE EEE TRANSACTONS ON ENERGY CONERSON, O., NO., JUNE 008 BOGRAPHY Ganesh Ponnana as born on 08 h June 988 as receve B.Tech from Aya nsue of Technology an Managemen (JNTUK), Tekkal, A.P, na of n 009. He s pursung M.Tech gnan s nsue of na. nformaon & echnology (JNTUK), sakhapanam, Davaasrvaam.M as born n 987. He receve hs M.Tech (Compuer Conrolle nusral Poer) Degree n Elecrcal an Elecroncs from NT, Calcu. Receve B.Tech (EEE) GET engneerng college of JNTU Hyeraba. Presenly he s orkng as Asssan Professor n gnan s nsue of nformaon & echnology, sakhapanam, na JERTS05 6