A Novel SVPWM Technology Used in PWM Rectifiers of WPGS

Transcription

1 Reserh Journl of Applie Sienes, Engineering n Tehnology 5(1): 4-45, 13 ISSN: ; e-issn: Mxwell Sientifi Orgniztion, 13 Sumitte: Otoer, 1 Aepte: Novemer 9, 1 Pulishe: April 3, 13 A Novel SPWM Tehnology Use in PWM Retifiers of WPGS 1, Zhng Junli, 1 i Yuren, 1 Fu ongfei n Zhng Wenjun 1 Northwestern Polytehnil University, Xi n 717, Chin Boji University of Arts n Sienes 7113, Chin Astrt: In orer to hieve the trnsformtion of eletril energy in rile Spee Constnt Freueny (SCF) Win Power Genertion System (WPGS), novel Spe etor Pulse With Moultion (SPWM) pulse trigger tehnology pplie in high effiient PWM retifier is propose. Retifier is n importnt prt of WPGS n its performne ffets the hrmoni ontent n power ftor of the power energy elivere to the gri. In orer to improve the performne of PWM retifier, novel SPWM pulse genertor tehnology is propose. Compre with other kins of PWM pulse genertor systems, Spe etor Pulse With Moultion (SPWM) hs mny vntges suh s ler physil onept, simple lgorithm, suitle for igitl implementtion, high voltge utiliztion, low hrmoni ontent, low swithes losses n simple hrwre iruit. Keywors: Hrmoni ontent, power ftor, PWM retifier, spe vetor pulse with moultion, vrile spee onstnt freueny, win power genertion system INTRODUCTION The prolems of tritionl power energy re environmentl pollution n the less n less ulity, so the evelopment n utiliztion of renewle energy soures suh s win power energy n solr power energy re ttrtinore n more ttention. As the lower ost n unntly glol energy, win power energy hs een one of the most promising renewle energy tht oul e pplie on lrge sle. In tritionl Win Power Genertion System (WPGS), Constnt Spee Constnt Freueny (CSCF) tehnology ws opte n win turine rn t fixe spee. The power genertor ouln t pture the optimum operting point y following the hnge win spee, leing to the elintion of genertor effiieny. The effiieny of opte win turine is lso low euse its wer n ter inreses with the hnging win spee. The win energy resoures re wste for not eine full use of. To overome the isvntges of CSCF tehnology mentione ove, the rile-spee Constnt Freueny (SCF) tehnology is pplie in moern n future WPGS. In SCF, Douly-fe Inution Genertor (DFIG) or Diret-Drive (DD) Permnent Mgnet Synhronous Genertor (PMSG) tehnology n e employe to pture mximum win energy n they oth hve wie pplition sle. By ontrolling its inner power eletronis evies, the SCF tehnology n not only provie high ulity power energy with the reuire freueny to the gri, ut lso flexily just the tive power n retive power sent to or sore from the gri. In WPGS se on SCF, retifier, whih is use to onvert AC voltges n urrents to DC ones, is the neessry evie hieve y power eletronis elements (i, 9; Zheng et l., 11). Hrmoni prolems in power system re minly use y the pplition of power eletronis euipments like ioe or thyristor retifiers, whih sor non-sinusoil urrents from the Common Connete Point (CCP) of the gri. High power ftor retifiers suseuently our n hve een use in mny osions. Pulse With Moultion (PWM) retifiers, whih n sent to or sor from lmost sinusoil AC urrent n relize unity power ftor, hve een wiely investigte n some of them se on oltge Soure Converter (SC) hve lrey een put into prtie (Zhng n Zng, 5; Zhng, 7; Zho n Hn, 1). For PWM retifiers se on SC, there re vriety of the trigger pulse genertion methos. These methos re pplie to improve the ulity of the voltges n urrents of the retifiers from ifferent perspetives. Referene (Go, 4) emonstrte the reliztion proess of SPWM pulse genertor se on CPD. Although it is reltively simple n esy, SPWM genertor tehnology hs mny isvntges suh s high hrmoni ontent n low voltge utiliztion rte. iu et l. () nlyze Seletive Hrmoni Elimintion (SHE-PWM) tehnology use in the SC pulse genertor system. SHE-PWM tehnology n eliminte the low-orer hrmonis of the AC output voltges n urrents, ut it elimintes lower orer hrmonis t the expense of pulsing high voltge hrmonis. For Seletive Hrmoni Elimintion (SHE-PWM) tehnology, the freuenies of Corresponing Author: Zhng Junli, Northwestern Polytehnil University, Xi n 717, Chin 4

2 Res. J. Appl. Si. Eng. Tehnol., 5(1): 4-45, 13 voltge hrmonis onentrte ner the swithing freueny. This stuy presents the Spe etor Pulse With Moultion (SPWM) tehnology whih is novel pulse genertor strtegy n triggers the swithes in the retifiers to ontrol the AC urrents n the DC voltge. SPWM tehnology hs mny vntges suh s ler physil onept, simple lgorithm, suitle for igitl implementtion, high voltge utiliztion, low hrmoni ontent, low swithes losses n simple hrwre iruit. The DSP-se SPWM pulse genertor tehnology is introue n use to trigger PWM retifiers to improve its stti n ynmi properties. The propose SPWM tehnology is minly use in the three-phse PWM retifier. THE MATHEMATICA MODE OF PWM RECTIFIER The three-phse PWM retifier is onsiste of three legs, eh of whih hs two swithes with ntiprllele ioes s shown in Fig. 1. In orer to simplify nlysis proess, it is ssume tht the three-phse voltge of the CCP in the gri is symmetril, stle n interior resistne is zero, three-phse linking resistne R n re the sme vlues respetively, swithes loss n on-stte voltge is negligile, ffetion of istriuting prmeters is negligile, swithing freueny of the retifier is high enough (Zhng n Zng, 5; Zhng, 7). For PWM retifiers s].the mthemtil moe of the three-fze PWM retifier in Fig. 1 is shown in (1) n (). i Ri e ( vs v t i Ri e ( vs v t i Ri e ( vs v t v C t N N N v e is is is R ) ) ) (1) () Eution (1) n () is mthemtil moel of the three-phse PWM retifier in three-phse stti frme. In orer to simplify the ontroller esign of PWM retifier, the three-phse PWM retifier s mthemtil moel in two - rottion frme is shown in (3). i i Ri e vs t i i Ri e vs t v 3 C ( is i s ) i t (3) Eution (3) is nonliner moel system n it is reuire to e liner ze. Three new vriles suh s u, u, u re efine in (4) n the improve moel of three-phse PWM retifier is shown in (5). u v u e vs u e vs e e v v (4) i R e R1 i C e R1 i e e R1 ' ' ' Fig. 1: The min iruit of three-phse PWM Retifier 41

3 Res. J. Appl. Si. Eng. Tehnol., 5(1): 4-45, 13 Tle 1: The working time of eh vetor Setor t1 Z Y -Z -X X -Y t Y -X X Z -Y -Z Fig. : The lok igrm of SPWM (1 ) 3 (11 ) ( ) 4 (1 ) (111) 7 1 (1) Fig. 3: Mps of spe vetors i R 1 i i u t i R 1 i i u t u 3 3 u ei ei t RC C C THE PRINCIPE OF SPWM PUSE GENERATOR TECHNOOGY (5) For Spe etor Pulse With Moultion (SPWM) tehnology, two orthogonl voltge vetors, in the two-imensionl rotting oorinte system t s the rel time referenes, whih re trnsforme from the esire three phse voltges in retifier. The key of the SPWM tehnology is to etermine whih setor the vetors re in n how long eh vetor works (Tejs et l., 11; Kumr n Gokulkrishnn, 11). The lok igrm of SPWM tehnology is shown in Fig.. There re 8 workinoels in the swithing pttern of the retifier rms. The 8 working (11 ) (11 ) 5 moels orrespon to eight spe voltge vetors ( ) ~ 7 (111), wherein 1 ( 1 ) ~ (11 ) re lle effetive vetors n eh of their mplitues is U, ( ), 7 (111 ) re lle zero vetors n eh of their mplitues is zero, s shown in Fig. 3. The setor etermintion of vetors istriution n working time of eh min vetor n uxiliry vetor in SPWM re shown in Tle 1. When the setor of the reuire syntheti vetor n the working time of orresponinin vetor, uxiliry vetor n zero vetors re otine, SPWM wve n e generte. IMPROED SPWM FIXED-FREQUENCY CONTRO STRATEGIES The working priniple of improve SPWM ontrol strtegy is propose in this stuy, whih is sme to the tritionl SPWM ontrol strtegy. The funmentl freueny yle of three-phse AC voltge is ivie into six setors, eh of whih is eletril ngle. The voltge polrities in eh setor of improve SPWM n tritionl SPWM re ifferent euse the strting times of eh funmentl freueny yle of improve SPWM n tritionl SPWM re ifferent. As shown in Fig. 4, in the improve SPWM ontrol strtegy, the hrteristi of the setor ivision is tht in eh intervl, ny two phses re ensure to hve the sme signs n they re with ontrry to the thir one. In orer to ensure high power ftor, the phse ngles of the input urrents n the input voltges shoul e ontrolle to e eul. SPWM swithing lgorithm is shown in Tle. To the setor I for exmple, the v s, v s re positive n v s is negtive, so i s, i s re positive n i s is negtive. In this working 8 s s s I II III I I I Fig. 4: Distriution setor of power phse voltge in Improve SPWM 4

4 Tle : SPWM swithing lgorithm Setor etor Conution Rte I II III I I ' 1 moe, s the urrent oes not flowing through S, S, S, D `, D ` n D, the voltge vetor n e synthesize through ontrolling the stte of S `, S `, S. In orer to reue swithes losses, the two-phse moultion metho is opte. The working length of eh phse in one yle is one thir, on whih the swithes mintin turn-on or turn-off n o not hnge n the working time of zero vetor is ontrollle. The propose moultion metho is superior to onventionl moultion metho in reuing swithes losses. It n e seen tht the onution rtes n the si vetors use for the synthesis of the reuire voltge vetor re onsistent whtever PWM retifier opertes in retifier or inverter stte (Yin, ). IMPEMENTATION OF THE SPWM PUSE GENERATOR Digitl Signl Proessor (DSP) hs some vntges suh s goo ury n stility. The funtions of DSP-se igitl ontroller re hieve Res. J. Appl. Si. Eng. Tehnol., 5(1): 4-45, 13 ' vi softwre progrms n hrwre onstrution. When the hrwre iruits re esigne orretly, severl ontrol lgorithms n e progrmme respetively. Moifying softwre progrms to meet the reuirements hs some hrteristis of lower osts, shorter evelopment yles n goo effiieny. To etermine simple, resonle n effetive ontrol lgorithm to effiiently ompenste retive power, ifferent ontrol lgorithms re vlite. The ie of only moifying softwre progrms gives room to the improvement n optimiztion of ontroller n it n reue osts n sve evelopment eugging time. DSP use in SPWM tehnology: The TMS3F47 hip, memer of the TMS3C genertion of igitl signl proessor ontrollers, is one of the fixe-point DSPs. The 47 offers the enhne TMS3 DSP rhiteturl esign of the Cxx ore CPU for low-ost, low-power n high-performne proessing pilities. Severl vne peripherls, optimize for igitl motor n motion ontrol pplitions, hve een integrte to provie true single-hip DSP ontroller. While oe-omptile with the existing C4x DSP ontroller evies, the 47 offers inrese proessing performne (3 MIPS) n higher level of peripherl integrtion. The 47 offers n rry of memory sizes n ifferent peripherls tilore to meet the speifi prie/performne points reuire y vrious pplitions. Flsh evies of up to 3K wors offer ost-effetive reprogrmmle solution for volume proution. Note tht Flsh-se evies ontin 5-wor oot ROM to filitte iniruit progrmming. The 47 lso inlues ROM evies tht re fully pin-to-pin omptile with their Flsh ounterprts. The 47 offers two event mnger moules whih hve een optimize for igitl motor ontrol n power onversion pplitions. In orer to generte SPWM signls, mny registers shoul e set. The register ACTRA is use to efine the output moe of the ompre output pin. The register COMCONA is use to enle the omprison opertions n etermine SPWM moe n set the reloing onitions of CMPR1,, 3 to unerflow. Mny prmeters in eh PWM yle shoul e etermine y AC sie voltges. For two jent vetors Ux n Ux +, prmeters T1, T, T3, re loe to the 14th~1th its of ACTTRA oring to Ux n the vlue 1 is lo to the 15th it of ACTRA n then hlf of T1 is loe to register CMPR1, the hlf of (T1+T) is loe to register CMPR. Generlly, the formul CMPR1 CMPR T1PR shoul e stisfie in Spe etor PWM. The register CMPR3 is not use in SPWM tehnology n it n e use in other time events. Aury of the min ontroller: The ury of ontroller is minly relte with the hrwre

5 Res. J. Appl. Si. Eng. Tehnol., 5(1): 4-45, () Fig. : Phse voltge of SC () Fig. 5: The wveform of symmetri spe vetor PWM -1 - omponents. The ury of A/D onverter in TMS3F47 is 1 its n the onverting results store in the high 1 of 1 its. As n exmple of the smpling urrent: while urrent is sinusoil mount, the onverting results store in the high 1 of 1 its fter left-move 1 times. The urrent is trnsforme to smple vlue in the rnge of ~14 n then the vlue is in the rnge of -51~+51 fter sutrting 51, expresse s FD~1FF. The smpling results n e expresse s Q15 formt to improve the proess preision. The speifi proess is s follows. The mximum vlue of smpling urrent is 15.A (orresponingly the smpling resistne is 3Ω). The enhmrk of urrent is 4A when it is stnrize. The output of ADC is expresse s Q15 formt s follows: i RES 51 4 where, RES = The vlue of ADCRESUTn. () In the ourse of progrmming K RES K is the vlue of 51 4 ADCRESUTn in Q15 formt. In orer to improve the ury of set points multiplition, the vlue of K is lso expresse in Q15 formt. The enhmrk of K is Fig. 7: oltge n urrent in phse A 5 = 3 when it is stnrize. 5 K RES is hieve when K K ' is multiplie y RES fter it is left-move 5 times. Then ADCRESUTn n e expresse s Q15 formt. SIMUATION RESUTS AND ANAYSIS Aoring to setting the registers in the previous setion, the resulting SPWM wveform is enter symmetril in eh PWM yle n this metho is lle the symmetri SPWM metho, shown in Fig. 5. Hump wveform is otine through filtering PWM output voltge wveform, whih inites tht the pulses generte y the propose pulse system to trigger the min iruit retifier rms is proper n resonle n the esire sinusoil voltges n e otine. The propose pulse system is pplie to PWM retifier n mny results re otine. Figure is the phse voltge of retifier AC sie. Figure 7 is the wveform of voltge n urrent filtere in the sme phse. After three yle times, the voltge n urrent re in the sme phse n the power ftor is very high.

6 Res. J. Appl. Si. Eng. Tehnol., 5(1): 4-45, 13 CONCUSION To overome the isvntges of CSCF tehnology, the rile-spee Constnt Freueny (SCF) tehnology is pplie in moern n future WPGS. In SCF, Diret-Drive (DD) Permnent Mgnet Synhronous Genertor (PMSG) tehnology n e employe to pture mximum win energy n hve wie pplition sle. A pulse trigger system se on TMS3F47A DSP is esigne n the use DSP hip ontins hrwre PWM pulse genertor iruit. Compre with other kins of PWM pulse genertor systems, Spe etor Pulse With Moultion (SPWM) hs mny vntges suh s ler physil onept, simple lgorithm, suitle for igitl implementtion, high voltge utiliztion, low hrmoni ontent, low swithes losses n simple hrwre iruit. ACKNOWEDGMENT This stuy ws supporte in prt y grnt from Projet Supporte y Ntionl Nturl Siene Fountion of Chin (517).Projet Supporte y Boji University of Arts n Sienes (ZK1117, ZK118) n Projet Supporte y Boji City Siene n Tehnology Bureu (11KG-4). REFERENCES Go, M., 4. Reserh on utonomous triggering system for STATCOM. MA Thesis, Xi n University of Tehnology, Xi n, Chin. Kumr, N.S. n J. Gokulkrishnn, 11. Impt of fts ontrollers on the stility of power systems onnete with ouly fe inution genertors. Int. J. Eletr. Power Energy Syst., 33(): i, J., 9. The reserh on topology n ontrol strtegy of onversion system for iret-rive win power genertion. Ph.D. Thesis, Shnghi University. iu, W., J. u n Z. Zheng,. Controller n pulse genertor se on SHE -PWM for D-STATCOM. J. Tsinghu Univ. Si. Tehnol., 4(9): Tejs, Z., B.R. Bhlj n Z. Nimish, 11. A novel pproh of referene urrent genertion for power ulity improvement in three-phse, three-wire istriution system using DSTATCOM. Int. J. Eletr. Power Energy Syst., 33(1): Yin, Z.,. Reserh on PWM retifier se on the spe voltge vetor. MA Thesis, Xi n University of Tehnology, Xi n, Chin. Zhng, J., 7. The nlytil stuy for DSTATCOM through the mthemti moel se on swithing trnsfer funtions. Eletr. Mes. Instru., 44(1): Zhng, C. n X. Zhng, 5. PWM Retifier n its Control. Beijing: Mehnil Inustry Press, Chin. Zho, G. n M. Hn, 1. DC voltge esign n orresponing ompenstion performne nlysis for stti vr genertor. Int. J. Eletr. Power Energy Syst., 43(1): Zheng, Z., G. i n N. Wng, 11. Reserh on ontrol strtegy of three-phse high power ftor PWM retifier. Int. J. Digitl Content Tehnol. Appl., 5(8):