ROLE OF DVR IN MULTI-LEVEL CONVERTERS FOR SOLAR PV GRID INTERFACING SYSTEMS

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1 ROL OF DVR IN MULTILVL ONVRTRS FOR SOLR PV GRID INTRFING SYSTMS Rnder Snh, Mr. Desh Kumr M.Teh. Sholr ssstnt Professor & Supersor, Deprtment of letrl nneern, h Gurds Insttute of nneern & Tehnoloy, Snrur, Punj Ind strt The mn mpetus of the present reserh work s to hhlht the Power Qulty (PQ) ehor of the three fourleel modules onneted n prllel where, D soure lle t lod sde of eh module s repled wth kw SPV module. The trnsent ehor study hs een under tken n ll the three phses durn the fulted perod of smulton. The role of Dynm e Restorer (DVR) nto the PQ eluton hs een nestted. DVR ton hs een ontrolled y Proportonl Interl (PI) ontroller wherey ths ton hs een le to ontrol olteurrent weforms t three usrs. The study on rel power flow mon the three modules, utlty rd nd three phse lod hs een undertken durn the snle lne to round fult rd sde. ddtonlly, the rete power ompenston hs een demonstrted usn the three modules. Rete power requrement of the lod s lso met from the utlty rd opertn t unty power ftor. Fnlly, hrmons study hs een hhlhted usn the fst fourer trnsform tool of Mtl smulton t ll usrs. The hrmons leel hs een studed nd hs een found tht the leel of hrmons s less thn % t ll olte nd urrent leels. Keywords solr, ontrol, nerter, multleel, power, olte restorer I. INTRODUTION Renewle enery resoures re nresnly eomn populr due to the rdul depleton of fuel soures nd the dmes to the enronment due to ther use. s result of the nete mpts of lol wrmn nd lmte hnes, the nterest n renewle resoures hs een nresed rdully. nery from Solr Photoolt (SPV) s one of the potentl lternte enery soures. Ths s lrely enronment frendly nd does not enerte ny tox or hrmful sustne tht pollutes the enronment. Referene [] reports tht multleel nerters suppled from equl nd onstnt D soures lmost do not exst n prtl ppltons. The rton of the D soures ffets the lues of the swthn nles requred for eh spef hrmon profle, s well s nreses the dffulty of the hrmon elmnton s equtons. Ths pper presents n extremely fst optml soluton of hrmon elmnton of multleel nerters wth nonequl D soures usn noel Prtle Swrm Optmzton (PSO) lorthm. The penetrton of SPV s n eletr power enerton s ontnully nresn []. Trkn mxmum power pont n SPV systems s n mportnt tsk nd represents hllenn prolem. In Mxmum Power Pont Trkn (MPPT), the duty yle of DD onerter s djusted n wy tht mxmum hele power s extrted from SPV system. In [3], the ssessment on mpt of photoolt dstruted enerton onneton on the power qulty ndes of dstruton networks, suh s: lon term olte rtons (olte onformty ssues) nd olte unlne s done. Ths DOI :.3883/IJRTR.7.37.WIRU 469

2 Interntonl Journl of Reent Trends n nneern & Reserh (IJRTR) Volume 3, Issue 4; prl 7 [ISSN: 447] pper med to elute the use of photooltttery store systems to supply eletr power n the dstruton rd throuh multleel nerter [4]. In [], t s dsussed tht the power systems re sumtted to urrent nd olte hrmons due to the nresed presene of nonlner lods nd the wde use of power nerters to nterfe solr nd wnd power plnts. The pplton of SPV s soure, dsussed n [6], of eletrl enery n the Dstruted Generton (DG) systems re nn more ttenton wth the dnes n power eletrons tehnoloy. snle phse multleel nerter onfurton s proposed n [7] tht onjons three seres onneted full rde nerter nd snle hlf rde nerter for renewle enery pplton espelly SPV system. In [8], proposl for n pproh of rd onneted SPV ontrol sheme, tht prodes optml SPV power nd hh qulty of urrent njeted nto the rd nd, therefore, hh power qulty s hhlhted. Ths pper mnly dsusses the mplementton of multleel nerters n smulnk enronment, wth emphss on the mportne of Power Qulty (PQ). The proedure of SPV modeln hs een dsussed usn the olte urrent nd power olte hrtersts. It lso presents the dsontnuous phse ontrol nerter [9] n rd nterte mode. ny retfer system n e mde to work s nerter y hnn the swthn nle. The topoloes re presented nd dsussed n detl. The mpt of snle lne to round fult t phse Y s presented for the deeloped system. ddtonlly, t hhlhts the mportne of Dynm e Restorer (DVR) n the mtton of PQ ssues. The DVR operton hs een reported y smultn the proposed system. Weforms re otned t rous ponts of Pont of ommon oupln (P) nd Totl Hrmon Dstorton (THD) nlyss s dsussed. II. N INTRODUTION TO SOLR PHOTOVOLTI LL solr ell s the s uldn lok of solr photoolt module. SPV ell n e onsdered s two termnl dee, whh onduts lke dode n the drk nd enertes photo olte, when hred y the sun. Inddul ells re usully onneted nto seres strn of ells (typlly 36 or 7) to hee the desred output olte. The omplete ssemly s usully referred to s module. The modules seres nother funton of protetn nddul ells from wter, dust et. s the solr ells re pled nto n enpsulton of snle or doule flt lsses. typl urrente (IV) hrterst of the SPV ell for ertn ment rrdton G nd ertn fxed ell temperture T, s shown n Fure. For resste lod, the lod hrterst s strht lne wth sope I/V=/R. It should e ponted out tht the power delered to the lod depends on the lue of the resstne only. Howeer, f the lod R s smll, the ell opertes n the reon MN of the ure, where the SPV ell ehes s onstnt urrent soure, lmost equl to the short rut urrent. On the other hnd, f the lod R s lre, the ell opertes on the reons PS of the ure, the SPV ell ehes more s onstnt olte soure, lmost equl to the openrut olte. Fure typl IV ure for Solr ell ll Rhts Resered 47

3 N Grd: ThreePhse Prormmle e Soure ThreePhse Soure Insolton4 reker reker reker ThreePhse Fult ns Susystem 3 ontnuous V_ I_ V_ I_ V_3 I_3 V I ThreePhse VI Mesurement Sope3 snl V I RMS rms To Workspe6 To Workspe7 To Workspe7 To Workspe6 3 To Workspe8 3 PQ 3phse Instntneous te & Rete Power To Workspe Dsply To Workspe8 VD Dsply onn onn Susystem Susystem onn Sope onn onn3 onn onn3 Susystem onn onn3 Three phse Inerter Output: te Rete Power Seres RL rnh Seres RL rnh urrent Mesurement Seres RL rnh urrent Mesurement urrnt To Workspe urrent Mesurement urrnt To Workspe3 urrnt3 To Workspe4 (W/m) (W/m^) (W/m) (W/m^) (W/m) (W/m^) PV rry PV rry PV rry 3 MPPT MPPT MPPT mp oost onerter ontrol (MPPT) mp mp oost onerter ontrol (MPPT) L oost onerter ontrol (MPPT) P_ IGT L L3 P_ IGT P_3 IGT3 Interntonl Journl of Reent Trends n nneern & Reserh (IJRTR) Volume 3, Issue 4; prl 7 [ISSN: 447] The Powere (PV) hrterst of SPV rry s nonlner nd tmeryn euse of the rton used y solr rdton nd temperture. Thus, the lner ontrol theory nnot e esly used to otn the olte for operton on the mxmum power pont MPP of the SPV rry []. To sole ths prolem, seerl methods he een deeloped to ontnuously trk the MPP [7]. These methods re lled MPPT methods, whh re the essentl prt of solr SPV rd onneted systems. The most populr MPPT methods n SPV systems re Pertur & Osere (P&O) nd Inrementl ondutne (I). III. SIMULINK SYSTM ONFIGURTION s depted n smulnk drm, Fure, the three four leel sumodules multleel onerter systems re mde to operte s nerter when the swthn nle of eh thyrstor s mde to operte t n nle reter thn 9. On the D sde of eh module, kw SPV rry s onneted, whh s ontrolled y I MPPT tehnque to extrt the mxmum rel power output under hnn temperture nd solr rdton leels. lso, mult wndn trnsformer hs een employed, whh ntrodues n pproprte solton etween the prmry wndn nd seondry wndns. Indutne ptne Indutne (LL) flter s mplemented to redue the leel of hrmons t the P. snle lne to round fult s ntrodued t phse Y etween the swthn perod t=.4 s to t=. s. norml seres RL lod s onneted t the P etween the three phse rd nd supply omn from modulr mult leel onerter systems. In order to estmte the olte nd urrent mesurement leels t P, threephse VI mesurement lok s mplemented n Mtl smulton t P. three phse te power nd rete power mesurement lok n Mtl s lso mplemented t P for rd, lod nd modulr mult leel onerter systems. Fure omputtonl smulnk lok drm for three modulr multleel onerter systems, wth three SPV rrys under snle lne to round fult IV. SIMULTIONS RSULTS ND DISUSSION Tle shows the enerl speftons hosen for the snle SPV rry. kw rry ple to enerte rel power of ths pty s mplemented wth eh of module onerter system. The eluton of the proposed system hs een done t 9 kw rel power t 44 V nd Hz fundmentl frequeny. Further, the lod enertes no extr pte rete power for mproement of olte profle, howeer, sors 3 kw ndute rete ll Rhts Resered 47

4 Interntonl Journl of Reent Trends n nneern & Reserh (IJRTR) Volume 3, Issue 4; prl 7 [ISSN: 447] Tle Speftons dopted for snle SPV rry System nme wth omponents Rtn lues No. of solr ells per module 96 No. of seres onneted modules per strn No. of prllel strns 66 Module speftons under ST [64. V,.96, 4.7 V,.8 ] [ Vo, Is, Vmp, Imp] Model prmeters for one module [ Rs, Rp, Ist, Iph, Qd ] Mxmum power Pmp [.38 Ω, 993. Ω,.73e8,.96,.3] =.7 kw Fure 3 ) shows the per unt urrent ehor of the three modules onneted n prllel n the proposed system. Sne the fult n phse Y hs een ntrodued t t=.4 s to t=. s, shrp trnsent s sle n phse t t=.8 s. In ddton, unlned nture s lso edent n other two phses. Fure 3 ) shows the per unt ehor of the lod urrent n whh nonunform dsturne s osered from t=.4 s to t=.6 s. Smlrly, Fure 3 ) shows the ehor of per unt rd urrent. It s found tht I MPPT hs een le to dere the power from SPV rrys whh s dded up t the P for ll the three modules onneted. Modules urrent mpere Phse Threephse lod urrentmpere... Phse Utlty urrentmpere () () () Fure 3 Wthout DVR ontrol unompensted ) 3φ modulr output urrent ) 3φ lod urrent ) 3φ output rd urrent, wth I MPPT ontrol durn fult Fure 4 ) shows the ehor of the output olte n per unt of the three modules onneted n prllel, where the trnsent ehor n e osered n ll the three phses. The mpt of fult t phse Y n e seen n the tme perod t=.49 s to t=.8 s. Smlrly, Fure 4 ) nd Fure 4 ) shows the threephse lod olte nd rd olte t P, respetely. From Fure ), the mxmum lue of the rel output power enerted y utlty s 8 kw (shown y red lne). The rel power requrement of the lod (reen lne) ondes wth tht of utlty durn the mpt of fult. It my e noted tht no rel power s en enerted y the three modules (lue lne). Smlrly, Fure ) shows the rete power ehor where t s shown tht rete power s en sored y the three modules. Mxmum lue of rete power enerted y the lod nd utlty rd s 3 kw nd 8 kw, respetely. The mpt of the fult s sle n the tme durton t=. s to t=.78 ll Rhts Resered 47

5 N Grd: ThreePhse Prormmle e Soure Three phse Inerter Output: te Rete Power V_ I_ ThreePhse Soure V_ I_ V_3 I_3 Insolton4 V I Lod : te Rete Power V I Grd: te Rete Power V I reker reker reker ThreePhse Fult ns Susystem M_V_I P_Q M_V_I P_Q M_V_I P_Q 3 ontnuous K K K V_ I_ V_ I_ V_3 I_3 V I ThreePhse VI Mesurement Sope3 relp To Workspe9 snl V I RMS D e Soure reteq rms To Workspe To Workspe6 To Workspe7 To Workspe7 To Workspe6 3 To Workspe8 3 PQ 3phse Instntneous te & Rete Power To Workspe Dsply To Workspe8 VD Dsply onn onn Susystem Susystem onn Sope onn onn3 onn onn3 Susystem onn onn3 Three phse Inerter Output: te Rete Power Seres RL rnh 3phse IGT Inerter Seres RL rnh urrent Mesurement urrent Mesurement Seres RL rnh urrnt To Workspe urrnt To Workspe3 urrnt3 To Workspe4 urrent Mesurement Uref Dsrete PWM Genertor n _re dlt Susystem6 onstnt4 Sutrt PI Dsrete PI ontroller PV rry Sope Lner Trnsformer Lner Trnsformer Lner Trnsformer (W/m) (W/m^) (W/m) (W/m^) (W/m) (W/m^) M Phse PV rry PV rry 3 MPPT 3Phse Sequene nlyzer MPPT MPPT mp From V_3 oost onerter ontrol (MPPT) mp mp oost onerter ontrol (MPPT) L oost onerter ontrol (MPPT) P_ IGT L L3 P_ IGT P_3 IGT3 Interntonl Journl of Reent Trends n nneern & Reserh (IJRTR) Volume 3, Issue 4; prl 7 [ISSN: 447] Phse Phse Phse Modules olte s Threephse lod oltes Utlty oltes () () () Fure 4 Wthout DVR ontrol unompensted ) 3φ output olte snle module ) 3φ output lod olte ) 3φ output utlty olte, wth I MPPT ontrol durn fult x 4 3 x 4 8. Rel powerwtts 6 4 module power lod power utlty power Totl rete powervr.. Module power lod power Utlty power () () Fure ) Rel nd ) rete power output weforms from snle module, onneted lod nd utlty 4. Smulnk System onfurton wth DVR Fure 6 depts the proposed system n whh PI ontrolled DVR s onneted t utlty sde throuh mult wndn trnsformer. In order to rry the study of the proposed system, the smulton hs een performed n Mtl [8] erson usn rous loks of lle lrry. The s funton of DVR ( seres te flter) s to njet the seres olte omponent of desred mpltude, frequeny nd phse, [9] etween P nd rd n seres wth the utlty or lod olte. The essentl prt for wellperformne of ontroller n DVR s the sdeteton rut []. e s must e deteted fst, nd orreted wth mnmum of flse opertons. fored ommutted e Soure onerter (VS) s onsdered n the DVR lon wth enery store to mntn the ptor olte. The DVR s onneted t us r3 throuh mult wndn lner trnsformer. The utlty rd s mntned t 44 V Hz nd workn t unty power ftor. Fure 6 omputtonl smulnk lok drm wth DVR nd three modulr multleel onerter systems, wth three SPV rrys under snle lne to round ll Rhts Resered 473

6 Interntonl Journl of Reent Trends n nneern & Reserh (IJRTR) Volume 3, Issue 4; prl 7 [ISSN: 447] Fure 7 ) depts sne nture of the oerll per unt module urrent t us r. Ths nture of per unt urrent s otned when the se lue of power s mntned t 9 kv t 44 V nd Hz. Smlrly, the Fure 7 ) nd Fure 7 ) depts sne nture of lod urrent nd utlty urrent, respetely. It s edent tht the dstorton hs een remoed whh hd erler een sle n these weforms due to the presene of snle lne to round fult. Ths s due to the ft, tht DVR ton hs resulted the njeton of olte rd sde, wherey hs ts effet on ll urrent weforms t P due to unty power ftor operton of utlty.... Phse. Phse. Phse Modules urrentmpere.... Lod urrentmpere.. Utulty urrentmpere () () () Fure 7 Wth DVR ontrol ompensted ) 3φ modulr output urrent ) 3φ lod urrent ) 3φ output rd urrent, wth I MPPT ontrol durn fult Fure 8 ), Fure 8 ) nd Fure 8 ) depts sne nture of oerll modules olte, lod olte nd utlty olte, respetely. It n e seen tht the mxmum mpltude of these weforms remns t per unt, wth no dstorton. Thus, DVR ton hs een justfed n the mtton of unlned ss, swells, nd trnsents.. Phse. Phse. Phse Modules oltes.. Lod oltes.. Utlty oltes () () () Fure 8 Wth DVR ontrol ompensted ) 3φ output olte snle module ) 3φ output lod olte ) 3φ output utlty olte, wth I MPPT ontrol durn fult Fure 9 ) shows the rel output power of the utlty rd hn mxmum power of 8 kw. Thus, the dp n the weform of rel output power hs een remoed. There hs een the onsumpton of the rel power on RL lod of eh module due to whh the rel power enerted y the three modules hs een round 8 W. Howeer, from Fure 9 ), the rete power s en enerted y the three modules round VR. Ths shows tht the ojete of rete power ompenston s heed y the pplton of three modules onneted n prllel. lso, the rete power requrement of the lod s met from the rete power from the ll Rhts Resered 474

7 Interntonl Journl of Reent Trends n nneern & Reserh (IJRTR) Volume 3, Issue 4; prl 7 [ISSN: 447] x 4 3. x Rel powerwtts 6 4 Modules power lod power utlty power Rete powervr. Modules power lod power utlty power () () Fure 9 ) Rel nd ) rete power output weforms from oerll three modules, onneted lod nd utlty Fure ) shows the rel output power of the snle module. It n e seen tht the nture of the rel power s snusodl wth mxmum mpltude of 7 W. Howeer, s dsussed oe lso, the rete power enerted y eh module s reter more thn the rel power wth mxmum mpltude of 7 VR, Fure ). Fure ) shows the leel of the totl D olte ross the three SPV modules. The nture of ths D lnk olte ross the ptors s rle n nture due to the ft tht the nput to the SPV module res wth hne n the solr rdton nd ment temperture leels. Rel power of module Wtts Rete power VR 3 Totl D oltes () () () Fure ) Rel output power nd ) rete output power weforms from snle module ) Totl D lnk olte Tle shows the hrmons leel t eh pont of P. It s ler tht the leel of hrmons s elow % s spefed n the I stndrd9/99. The I stndrd9/99 stpultes tht the leel of the hrmon njeted nto utlty should e less thn %. Thus, DVR ton s justfed n ontrolln the hrmons t ll ponts of P. Tle THD nlyss of PIDVR Prmeter nme PIDVR Module (s) olte.8% Module (s) urrent.34% Lod olte.8% Lod urrent.3% Utlty olte.8% Utlty ll Rhts Resered 47

8 Interntonl Journl of Reent Trends n nneern & Reserh (IJRTR) Volume 3, Issue 4; prl 7 [ISSN: 447] V. ONLUSION Ths pper hs mnly hhlhted the PQ ehor of the three fourleel modules onneted n prllel where, the D soure lod sde of eh module s repled wth kw SPV module. t P, the olte nd urrent ehor hs een osered durn the presene of snle lne to round fult t one phse. In ddton, the rel power nd rete power study hs een rred out. It hs een found tht there s no rel power en enerted y the three modules. The trnsent ehor exsts n ll the three phses durn the fulted perod of smulton. The purpose to rry out the present study s to demonstrte tht ny D soure when repled wth SPV soure, the deeloped system s le to enerte the multple olte leels t the output due to the ft, tht the there s ontnuous enerton of enery from ny SPV soure under hnn tmospher ondtons. The nestton hs een rred y the role of DVR nto the PQ eluton for three four leel modulr multleel onerter systems. DVR ton ontrolled y PI ontroller hs een le to ontrol the olte nd urrent weforms t ll ponts of P. RFRNS [].K. lothmn nd H. T. delhmd, lmnton of hrmons n multleel nerters wth nonequl D soures usn PSO, nery onerson nd Mnement, ol., pp , 9. []. R. Jordeh, Mxmum power pont trkn n photoolt (PV) systems: reew of dfferent pprohes, Renewle nd Sustnle nery Reews, ol. 6, pp. 7 38, 6. [3]. N. M. Sl,.. Rodrues, nd M. G. Sl, Stohst ssessment of the mpt of photoolt dstruted enerton on the power qulty ndes of dstruton networks, letr Power Systems Reserh, pp. 9, 6. [4] K. Hmour, K. Ghedms, nd. M. erkouk, Superson nd ontrol of rd onneted PVStore systems wth the fe leel dode lmped nerter, nery onerson nd Mnement, ol. 77, pp. 98 7, 4. [] L. S. Xer,. F. upertno, J.T. Resende, V. F. Mendes, nd H.. Perer, dpte urrent ontrol strtey for hrmon ompenston n snlephse solr nerters, letr Power Systems Reserh, ol. 4, pp. 84 9, 7. [6] M.. Ltrn, nd. Teke, Inestton of multleel multfuntonl rd onneted nerter topoloes nd ontrol strtees used n photoolt systems, Renewle nd Sustnle nery Reews, ol. 4, pp ,. [7] N. Prhrn, nd K. Plnsmy, nlyss nd nterton of multleel nerter onfurton wth oost onerters n photoolt system, nery onerson nd Mnement, ol. 8, pp , 6 [8] N. Hmroun, M. Jrd,. Dhou, nd. herf, Desn of ommnd sheme for rd onneted PV systems usn lssl ontrollers, letr Power Systems Reserh, ol. 43, pp. 3, 7. [9]. Srwr, nd M. S. J. shr, Smulton nd nlyss of Multleel onerter Topoloy for Solr PV sed Grd onneted Inerter, Smrt Grd nd Renewle nery, ol., pp. 66,. [] S. Rusteml, nd F. Dner, Modeln of Photoolt Pnel nd xmnn ffets of Temperture n Mtl/Smulnk, letrons nd letrl nneern, ol. 9, pp. 3 4,. []. Hu, J. Ln, nd. Shen, Roust ontrol for mxmum power pont trkn n photoolt power system, In: Pro. of Power onerson onf., pp ,. [] N. Fem, G. Petrone, G. Spnuolo, nd M. Vtell, Optmzton of pertur nd osere mxmum power pont trkn method, I Trns. Power letron., ol., no. 4, pp ,. [3] J.. Gow, nd.d. Mnnn, Deelopment of photoolt rry model for use n powereletrons smulton studes, In: Pro. of I letr. Power ppl., ol. 46, no., pp. 93, 999. [4] W. Xo, W.G. Dunford, nd. pel, noel modeln method for photoolt ells, In: Pro. of I Power letrons Spelsts onf., ol. 3, pp. 9 96, 4. []. Mtne, R. henn, nd R. l htr, photoolt ell model sed on nomnl dt only, In: Pro. of Int. onf. on Power nneern, nery nd letrl Dres, pp. 6 6, pr. 7. [6] G. J. Yu, Y. S. Jun, J. Y. ho, I. ho, J. H. Son, nd G. S. Km, noel twomode mppt ontrol lorthm sed on omprte study of exstn lorthms, In: Pro. of I Photoolt Spelsts onf., pp. 334,. [7] S. Lu, nd R.. Doul, Dynm multphyss model for solr rry, I Trns. nery oners., ol. 7, no., pp. 8 94,. [8] Mtl/Smulnk, The Mthworks, In (R), [9] P. oonhm, nd N. Mthulnnthn, Dode lmped multleel olte soure onerter sed on medum olte DVR, Interntonl Journl of letrl Power nd nery systems nneern, pp. 667, 8. [] H. zoj,. Shekholeslm, M. Reznezhd nd H. Ln, new ontrol method for dynm olte restorer wth symmetrl nerter les sed on fuzzy lo ontroller, Journl of Smulton Modelln Prte nd Theory, ol. 8, pp. ll Rhts Resered 476