Simplified Control Method for Unified Power Quality Conditioner (UPQC)

Transcription

1 Euroean Assocaton for the Deeloment of Renewable Energes, Enronment an Power Qualty Internatonal Conference on Renewable Energes an Power Qualty (ICREPQ 9) Valenca (San), 5th to 7th Arl, 9 Smlfe Control Metho for Unfe Power Qualty Contoner (UPQC) Metn Kesler, Engn Ozemr, Techncal Eucaton Faculty Kocael Unersty, 48 Umuttee Kocael Turkey Phone number: e-mal: metnkesler@kocael.eu.tr, eozemr@kocael.eu.tr Abstract. Unfe Power Qualty Contoner (UPQC) for harmonc elmnaton an smultaneous comensaton of oltage an current, whch mroes the ower qualty offere for other harmonc senste loas. UPQC consst of combne seres acte ower flter that comensates oltage harmoncs of the ower suly, an shunt acte ower flter that comensates harmonc currents of a non-lnear loa. In ths aer a new control algorthm for the UPQC system s otmze an smlfe wthout transformer oltage, loa an flter current measurement, so that system erformance s mroe. The roose control technque has been ealuate an teste uner ynamcal an steay state loa contons usng PSIM software. The laboratory rototye exermental results for shunt acte flter art are gen. Key wors Unfe Power Qualty Contoner (UPQC), harmoncs, acte ower flter, ower qualty.. Introucton Unfe ower qualty control was wely stue by many researchers as an eentual metho to mroe ower qualty of electrcal strbuton system [-]. The functon of unfe ower qualty contoner s to elmnate the sturbances that affect the erformance of the crtcal loa n ower system. In other wors, the UPQC has the caablty of mrong ower qualty at the ont of nstallaton on ower strbuton systems. The UPQC, therefore, s execte to be one of the most owerful solutons to large caacty loas senste to suly oltage flcker/mbalance []. The UPQC, whch has two nerters that share one c lnk, can comensate the oltage sag an swell, the harmonc current an oltage, an control the ower flow an oltage stablty. Beses, the UPQC can also comensate the oltage nterruton f t has some energy storage or battery n the c lnk []. Turksh Energy Market Regulatory Authorty (EPDK) announce a new regulaton, number 569 an ate..4 namely Electrcty Transmsson System Suly Relablty an Qualty Regulaton an the ower factor was ncrease stewse. The reacte energy transmsson n Turksh electrcal strbuton system s arrange n ths regulaton gen n Table I. In Table I, reacte energy lmts are.98 n nucte an.988 n caacte regon [4]. Table I. Acte an reacte energy consumton ranges. Lmts Loas n strbuton system has ower lower than 5 kva Loas n strbuton system has ower hgher than 5 kva Energy Consumton /Month Acte Reacte (%) (%) Inucte Caacte 5 The new reacte energy rates cause nstallaton of new shunt caacte banks n Turksh electrcal strbuton system. The comensaton ower s ncrease an cause arallel resonance eent rsk at the utlty-consumer ont of common coulng (PCC). Howeer, n consequence of oer comensaton, generate harmoncs are ncrease. Hgher harmonc rates cause new roblems n facltes. In ths aer, the roose control algorthm for the UPQC s otmze an smlfe wthout transformer oltage, loa an flter current measurement, so that system erformance s mroe. The roose control technque has been ealuate an ynamcally teste uner fferent loa contons usng PSIM software. htts://o.org/.484/reqj RE&PQJ, Vol., No.7, Arl 9

2 . Unfe Power Qualty Contoner -q conerson Reference oltage calc. Fg. shows a basc system confguraton of a general UPQC consstng of the combnaton of a seres acte ower flter an shunt acte ower flter. The man am of the seres acte ower flter s harmonc solaton between a sub-transmsson system an a strbuton system; t has the caablty of oltage flcker/ mbalance comensaton as well as oltage regulaton an harmonc comensaton at the utlty-consumer ont of common coulng (PCC). The shunt acte ower flter s use to absorb current harmoncs, comensate for reacte ower an negate-sequence current, an regulate the c-lnk oltage between both acte ower flters. S abc Non-eal Suly R S T abc S abc L S R T L T SAPF T abc C DC SAPF L abc R L R C L C L abc Cabc L L Non-lnear Loa Fg.. Unfe Power Qualty Contoner confguraton.. The Proose UPQC Control Algorthm Z yük La Lb Lc PLL. (snwt coswt) -q transform. LPF q -q In. transform S Hysteress Ban Current control Fg.. Seres acte ower flter control block agram. () = + sn(wt) sn(wt - ) sn(wt ) q cos(wt) cos(wt - ) cos(wt + ) Voltage n axes ( ) gen n equaton () s comose from DC an AC comonents ( an s calculate by usng LPF (low ass flter). + ~ ~ ). GAH GAL GBH GBL GCH GCL Voltage = () bc reference oltages are calculate as gen n equaton (). The swtchng sgnals are assesse reference oltages ( bc ) loa oltages ( Labc ) an a hysteress ban current control. The roose UPQC control algorthm block agram n PSIM smulaton software s shown n Fg.. S sn(wt) = sn(wt - ) sn(wt + ) cos(wt) cos(wt + ) cos(wt + ) q () B. Shunt acte ower flter control algorthm The roose shunt acte ower flter control algorthm s shown n Fg. 4. Instantaneous reacte ower (-q) theory s use to control of shunt acte ower flter n real tme. In ths theory, nstantaneous three-hase current an oltages are transforme to -- from a-b-c coornates as shown n equaton (4) an (5). Fg.. The roose UPQC control algorthm block agram. -q conerson Reference current calc. A. Seres acte ower flter control algorthm The roose seres acte ower flter control algorthm s shown n Fg.. In equaton (), suly oltages bc are transforme abc to q. In aton, PLL conerson s use for reference oltage calculaton. - con. - con. o o Ins. Reacte ower calc. VDC V DC * V DC - + Σ + LPF q PI - Reference current calc. DC loss S S - In. Trans. Hysteress Ban Current control GAH GAL GBH GBL GCH GCL Fg. 4. Shunt acte ower flter control block agram. htts://o.org/.484/reqj RE&PQJ, Vol., No.7, Arl 9

3 / / / = - / - / (4) / - / / / / = - / - / (5) / - / Loa se nstantaneous real an magnary ower comonents are calculate by usng loa currents an hase-neutral oltages as gen n equaton (6). q = Instantaneous real an magnary owers nclue AC an DC comonents as shown n (7). DC comonents of an q comose from oste sequence comonents ( an q ) of loa current. AC comonents ( ~ an q ~ ) of an q nclue harmonc an an negate sequence comonents of loa currents [5]. In orer to reuce neutral current, was calculate by usng DC an AC comonents of magnary ower an AC comonent of real ower; as gen n (8) f both harmonc an reacte ower comensaton s requre (6) = ; = + ~ (7) S - - ~ + + = + S -q loss s * an s * are reference currents of shunt acte ower flter n - coornates. These currents are transforme to three-hase system as shown below n equaton (9). = - / - / - / / S S The reference currents n three-hase system (* sa * sb e * sb ) are calculate n orer to comensate neutral, harmonc an reacte currents n the loa. The swtchng sgnals use n shunt acte ower flter control algorthm are generate by comarng reference currents an actual lne currents an usng hysteress ban current control algorthm [6]. (8) (9) 4. Smulaton Results In ths stuy, a new smlfe control algorthm for UPQC s ealuate by usng smulaton results gen n PSIM software. The roose an smulate UPQC system arameters are gen n Table II. In smulaton stues, the result are secfe before an after UPQC system s oerate. In aton, when UPQC system s oerate, loa has change an ynamc resonse of the system was teste. The roose control algorthm has conserably goo smulaton results as comare the conentonal control algorthms. Table II. UPQC smulaton arameters. System arameters Suly oltages bc 8V Suly frequency f S 5Hz DC lnk oltage V DA 75V Seres acte ower flter arameters Seres transformer Rate / AC flter R f C f 5Ω, µf AC nuctance L C.5mH Swtchng frequency f S khz Shunt acte ower flter arameters AC nuctance L LA mh DC resstance R LD Ω, DC nuctance L LD mh DC caactor C DC µf Total Harmonc Dstorton % (THD) Before Flter After Flter bc 6 6 Labc 6. bc Labc In the roose control algorthm, loa currents ( Labc ), mans currents ( bc ), mans oltages ( bc ) an loa oltages ( Labc ) waeforms are shown n Fg. 5, before an after UPQC system s oerate. The neutral current comensaton results are gen n Fg. 6. Loa-mans current an oltage waeforms n hase a are shown n Fg. 7. The roose UPQC control algorthm has ablty to comensate both harmoncs an reacte ower of the loa an neutral current s also elmnate. Fnally, the oltage an current harmonc comensaton caablty of the roose UPQC control technque s shown n Table II as THD leels. The obtane results show that the roose control technque allows the %. mtgaton of all harmonc comonents. htts://o.org/.484/reqj RE&PQJ, Vol., No.7, Arl 9

4 Before flter After flter Loa ste-own La Lb Lc DC. The oe-brge rectfer s consere a harmonc roucng loa entcal to a c ower suly that can foun n any ower electroncs base system. La Lb Lc The roose control technque s mlemente on the TMSF85 DSP boar. F85 DSP has an nternal 68 kb RAM, kb OTP ROM, 5 kb flash, 8 channels ulse wth moulaton (PWM), -bt 6 channels analog-to-gtal (A/D) conerters, exanson nterfaces an arallel ort JTAG nterface. It can erform arallel multly an arthmetc logc unt (ALU) on nteger or floatng ont ata n a 6.67 ns sngle cycle nstructon tme wth a eak comutaton rate of 5 mllon nstructon er secon (MIPS). Fg. 5. Mans-loa current an oltage waeforms when UPQC system s oerate. Fg. 6. Loa-mans currents an oltage waeforms. Fg. 7. Loa-mans current an oltage waeforms n hase a. 5. Exermental results La Lb Lc La Lb Lc NS NL The feasblty of harware mlementaton for the roose control algorthm was ealuate by esgn an exermentaton of three-hase three-wre UPQC. A three-hase oe-brge rectfer wth the R-L loa as the nonlnear loa s connecte to AC mans to emonstrate the effecteness of the UPQC wth the roose metho. The am of the UPQC system s not only to comensate for the current harmoncs rouce by a oe-brge rectfer of kva, but also to elmnate the oltage harmoncs contane n the receng termnal oltage from the loa termnal oltage. The UPQC conssts of a.5 -kva seres-acte flter an a.5-kva shunt-acte flter. The c lnks of both acte flters are connecte to a common c caactor of mcrofara an 7 V La La NS NL The source oltage an current sgnals are measure LEM hall-effect sensor. Semkron SEMIX GD8Ds IGBT moules an the CONCEPT 6SD6EI sx-ack IGBT rer moules are use for rng the IGBT swtches n ower art of the UPQC system. IGBT rer moule has short crcut an oer current rotecton functons for eery IGBT an roes electrcal solaton of all PWM sgnals ale to DSP. Fg. 8 shows source oltage an current waeform before flterng. After comensaton, source current becomes snusoal an n hase wth the source oltage; hence, both harmoncs an reacte ower are comensate smultaneously. Before harmonc comensaton the THD of the suly current was 9.% an after the harmonc comensaton, t was reuce to 5.75% whch comles wth the IEEE 59 harmonc stanars. The source current an flter current exermental results for roose control of shunt acte ower flter art of UPQC system are shown n Fg. 9- before an after flter oerate. Fg. shows exermental results for source current ( ) harmonc sectrum before flter an after flter. These exermental results gen aboe shows that the ower qualty comensaton features of UPQC, by arorate control of shunt APF can be one effectely. The exermental laboratory rototye seres acte ower flter art s nstallng an exermental results are lannng to ublsh n future aers. Source Voltage [V] Source Current [A] Fg. 8. Exermental results for source oltage ( ) an source current( ) before flter oeraton. htts://o.org/.484/reqj RE&PQJ, Vol., No.7, Arl 9

5 Source Voltage [V] Flter Current [A] Fg. 9. Exermental results for source oltage( ) an flter current( Ca ) after flter oeraton. Source Voltage [V] Source Current [A] Fg.. Exermental results for source oltage( ) an source current( ) after flter oeraton. 5. Concluson In ths stuy, a new smlfe control algorthm s roose for UPQC system n orer to comensate ower qualty roblems such as, unbalance oltages, harmoncs, reacte ower an neutral current of the nonlnear loas. The roose control algorthm smulaton results are gen n PSIM smulaton. In lterature, conentonal UPQC control algorthms requre measurements of loa, flter an mans currents an oltages an also DC bus oltage n orer to regulate DC bus. The roose control algorthm, the number of measurement s ecrease. In ths stuy successful smulaton results are gen n PSIM smulaton software. The laboratory rototye exermental results for shunt acte flter art are gen. Acknowlegement Ths stuy s suorte fnancally by TUBITAK research fun number 8E8 an Kocael Unersty entfc Research Fun. Ths work s also suorte by Concet Inc. (Concet IGBT Drer), Semkron Inc. (IGBT an IGBT Drer), LEM Inc. (Voltage an Current sensor) an TI Inc. (F85 ezs), whch s gratefully acknowlege. The authors gratefully acknowlege the contrbutons of Halm Özmen (from Semkron Turkey) an Robert Owen (from TI). References Fg.. Exermental results for source currents ( bc ) before an after flter oeraton. Fg.. Exermental results for source current( ) harmonc sectrum before an after flter oeraton. [] Akag, H. an Fujta, H., A new ower lne contonal for harmonc comensaton n ower systems, IEEE Trans. Power Del., ol., no., , Jul [] Fujta, H. an Akag, H., The unfe ower qualty contoner: The ntegraton of seres an shunt-acte flters, IEEE Trans. Power Electron., ol., no.,. 5, Mar [] H. Akag, E. H. Watanabe an M. Arees, Instantaneous Power Theory an Alcatons to Power Contonng. Wley-IEEE Press. Arl 7. [4] Turksh Energy Market Regulatory Authorthy (EPDK) regulaton, number 569 an ate..4 Electrcty Transmsson System Suly Relablty an Qualty Regulaton. [5] Dusan Graoac, Vlamr A. Katc an Alfre Rufer, Power Qualty Problems Comensaton wth Unersal Power Qualty Contonng System, IEEE Transacton on Power Delery, VOL., NO., (7). [6] B. Han, Senor Member, IEEE, B. Bae, H. Km, an S. Baek, Combne Oeraton of Unfe Power-Qualty Contoner Wth Dstrbute Generaton, IEEE Transacton on Power Delery, VOL., No., (6). [7] Kesler M., Desgn an DSP base control of a Shunt Acte Power Flter Kocael Unersty, M.. Thess, (July, 5). htts://o.org/.484/reqj RE&PQJ, Vol., No.7, Arl 9