Published in: Proceedings of the 40th Annual Conference of IEEE Industrial Electronics Society, IECON 2014

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1 Aalbog Univeitet Lo Minimizing Opeation of Doubly Fed nduction Geneato Baed Wind Geneation Sytem Conideing Reactive Powe Poviion Zhang, Baohua; Hu, Weihao; Chen, Zhe Publihed in: Poceeding of the 4th Annual Confeence of EEE ndutial Electonic Society, ECON 4 DO (link to publication fom Publihe):.9/ECON Publication date: 4 Document Veion Accepted autho manucipt, pee eviewed veion Link to publication fom Aalbog Univeity Citation fo publihed veion (APA): Baohua, Z., Hu, W., & Chen, Z. (4). Lo Minimizing Opeation of Doubly Fed nduction Geneato Baed Wind Geneation Sytem Conideing Reactive Powe Poviion. n Poceeding of the 4th Annual Confeence of EEE ndutial Electonic Society, ECON 4 (pp ). EEE Pe. E E E ndutial Electonic Society. Annual Confeence. Poceeding Geneal ight Copyight and moal ight fo the publication made acceible in the public potal ae etained by the autho and/o othe copyight owne and it i a condition of acceing publication that ue ecognie and abide by the legal equiement aociated with thee ight.? Ue may download and pint one copy of any publication fom the public potal fo the pupoe of pivate tudy o eeach.? You may not futhe ditibute the mateial o ue it fo any pofit-making activity o commecial gain? You may feely ditibute the URL identifying the publication in the public potal? Take down policy f you believe that thi document beache copyight pleae contact u at vbn@aub.aau.dk poviding detail, and we will emove acce to the wok immediately and invetigate you claim. Downloaded fom vbn.aau.dk on: novembe 4, 8

2 Lo Minimizing Opeation of Doubly Fed nduction Geneato Baed Wind Geneation Sytem Conideing Reactive Powe Poviion Baohua Zhang, Weihao Hu, Zhe Chen Depatment of Enegy Technology Aalbog Univeity Aalbog, Denmak Abtact The pape deal with contol technique fo minimizing the opeating of doubly fed induction geneato baed wind geneation ytem when poviding eactive powe. The popoed method achieve it goal though contolling the oto ide q-axi cuent in the ynchonou efeence fame. The fomula fo the contol efeence i explicitly deduced in thi pape conideing the e of the geneato, the powe electonic device and the filte. Thee contol tategie ae compaed with the popoed method unde diffeent wind peed and diffeent eactive powe efeence. The imulation eult validate the effectivene of the popoed method. Keywod wind powe geneation; enegy efficiency; eactive powe contol; doubly fed induction genetao. NTRODUCTON Due to the inceaed integation of wind enegy into the powe ytem, eactive powe contol ha emeged a one of the main contol iue faced by wind fam opeato. One olution would be to commiion additional eactive powe compenation ouce to upply the eactive powe demand in the ytem. Howeve, fom the utility and the wind fam develope pepective, it i moe economical to optimize wind geneation ytem in ode to delive enhanced eactive powe pefomance []. Moeove, ome gid code aleady equie wind tubine to povide eactive powe ability, uch a Danih Gid Code Technical Regulation TF 3..6 []. Doubly fed induction geneato (DFG) baed Wind geneation ytem i one of the wind geneation ytem that can povide and abob eactive powe. Becaue of it advantage uch a high enegy contollability, educed powe convete ating, etc., DFG ha been widely ued in wind fam [3]. Howeve, the efficiency of the whole ytem would change unde diffeent opeating condition. Theefoe, it i impotant to minimize the oveall ytem e unde diffeent wind peed and eactive powe condition in ode to povide moe powe to the gid. n ode to impove the oveall efficiency, egulating eactive powe flow fo minimizing the electical e of the geneato and the convete ha been popoed in peviou wok. The optimal oto eactive cuent value wa deived fo minimal coppe e in [4-8]. Thee method only conide coppe minimization, but the eactive powe fom the tato i not zeo, o the equied powe facto at the geneato teminal i egulated by the gid-ide convete, which will caue on the convete. Theefoe, thee method cannot each an optimal efficiency fo the whole ytem. n [9, ], the e of convete ae taken into account and the optimal plitting of the eactive powe buden ove the oto and gid ide convete i iteatively calculated, which fom a et of look-up table. n the contol poce, the contolle hould look up the table to decide the optimal eactive powe cuent, which would be time conuming. The optimal oto eactive cuent fomula wa deived in []. The of convete i piecewie lineaized in ode to deive the optimal oto eactive cuent. Howeve, it only analyzed the condition when DFG i cloe to the ated opeation and the condition when DFG ae equied to povide eactive powe to uppot the gid wa not conideed. n thi pape, an optimal contol tategy i popoed to minimize the e of the whole ytem (the geneato, convete and the filte) when poviding eactive powe to the gid. The fomula of the whole ytem ae modeled fit and the optimal oto eactive cuent fomula i deived late conideing eactive powe efeence povided by the gid o the wind fam contolle. The cuent and e in evey pat of the ytem ae calculated and thei chaacteitic ae analyzed in detail. The popoed tategy i compaed with thee othe tategie unde diffeent wind peed and eactive powe efeence. Compaative imulation eult validate the effectivene of the popoed method. Thi pape i oganized a follow: Section decibe the analytical fomula fo calculation. Optimal eactive cuent contol tategy conideing eactive powe poviion wa popoed in Section. The effect of the new tategy i illutated in Section V, and finally concluion ae dawn in Section V.. ANALYTCAL FORMULAS FOR LOSS CALCULATON The powe e of a DFG wind geneation ytem ae compoed of fiction of the mechanical pat, coe and Thi eeach wok i uppoted by the Danih Stategic Reeach Cente (Gant DSF ), Development of a Secue, Economic and Envionmentally-fiendly Moden Powe Sytem (SEEMPS)

3 coppe of the DFG, witching and conducting of convete, and eitant of the filte. The fiction and coe can be conideed contant unde a cetain opeation point [8], theefoe they ae not conideed in thi pape. A. Wind Tubine Chaacteitic The mechanical powe extacted fom the wind can be expeed a follow [4], 3 Pmec R v Cp(, ) () whee P mec i the powe extacted fom the wind, ρ i ai denity (kg/m 3 ), R i the blade adiu (m), v i the wind peed(m/) and C P i the powe coefficient which i a function of the pitch angle θ (deg) and the tip peed atio λ. The tem λ i defined a R v () t whee ω t i the wind tubine peed (ad/). B. Lo Model of DFG Baed on the cuent diection hown in Fig., the teadytate tato and oto voltage ae peented in the following fomula [5, ]. Note that all of vaiable ae in pe unit (pu) ytem in the following expeion. Vd R X Xmd X R Xm q V d X m R X d V q X m X R q Whee: X Xl Xm, X Xl Xm, X l : tato leakage inductance, X m : mutual inductance, X l : oto leakage inductance; : oto lip. Subcipt:, and g fo tato, oto and gid-convete cicuit; l, m fo leakage and mutual inductance; d, q fo diect and quadatue axe; ' fo oto value efeed to the tato. V R X l Fig.. Equivalent cicuit fo teady tate opeation of DFG [] The tato and gid convete cuent hould be expeed a function of oto cuent. Baed on (3), tato cuent ae peented a follow: X m d BA Xm q V Xm d q BXm q V AXm d Whee A R / X, B X / X R X l R V (3) (4) Unde table opeation, oto d-axi cuent can be calculated a [3]: X d Pmec (5) VX m / u (6) d Whee i the angula fequency of the voltage and cuent of the oto winding, i the angula fequency of the voltage and cuent of the tato winding, u i the tun atio. The electic powe on the tato ide and on the oto ide ae calculated a follow: P dvd qvq Q qvd dvq (7) P Vd Q V d q The coppe e in the geneato winding, P Cu, can be expeed a: P R R (8) Cu d q d q C. Lo Model of Convete and Filte Each witch of a convete conit of a tanito (T) and a evee diode (D). The e of the convete can be divided into witching e and conducting e. The conduction and witching e can be expeed a [4]. Pc VGBT m GBT m (9) m P E E f (), T ON OFF w C,nom, D w C, nom m P E f () whee P c i the conduction e in T and D, P,T i the witching e in T, P, D i the witching e in D, m i the m value of the inuoidal cuent to the gid o the machine, V GBT i the voltage aco the collecto and emitte of the GBT, GBT i the lead eitance of GBT, EON EOFF i the tun-on and tun-off e of the GBT, C,nom i the nominal collecto cuent of the GBT, f w i the witching fequency, E i the tun-off (evee ecovey) e of the D. Now, the total e become P 3 P P P () con c, T, D

4 Equation () can be expeed a P a b (3) con l m l m Whee a l and b l ae the powe module contant and can be expeed a 6 EON EOFF E a V f f l GBT w w Cnom, Cnom, (4) b 3 (5) l GBT Given the convete chaacteitic data fo the GBT module (ABB 5SND 8M7) [5], the convete i etimated a: P (6) con m m Whee f w i choen a.khz. Fig. depict the convete vaiation with the quae of the m convete cuent. Typically, the elation in Fig. can be epeented by piecewie lineaization, a illutated by lineaization cuve. The lineaization cuve can be expeed a follow: con con m P P R x (7) All the value in thi equation ae pu value, the paamete ae elected a: P, Rcon.38, x m.7 P.3, Rcon.4, x.7.7 m.5 (8) P.55, Rcon.6, x.5.5 m So, the e of Roto Side Convete (RSC) and Gid Side Convete (GSC) can be calculated a: Convete Lo (Watt) P P R x RSC con d q GSC con gd gq P P R x The of the filte can be calculated a: 3.5 x 4 eal cuve 3 lineaization cuve filte filte gd gq (9) P R () m (A ) x 6 Fig.. Piecewie lineaization fo P con with m. D. Calculation of gid ide cuent The powe flow of DFG wind ytem i hown in Fig. 3, fom which we can get: P P P P P () g RSC GSC filte Qef Qg Q () whee P g i the active powe abobed fom the gid, Qg i the eactive powe poduced by gid ide convete, Q ef i the eactive powe efeence given by the gid o wind fam contolle. V P mec P, Q P RSC P, Q P GSC Fig. 3. Powe flow of DFG wind ytem P g P filte V, Q The coelation of gid ide d-axi cuent gd and oto ide q-axi cuent q i vey mall, o it i neglected in thi pape when deiving (6). Gid ide q-axi cuent i: gq Qef V q (3) So, the total, P tl, can be expeed a follow: P P P P P tl Cu RSC GSC filte P Rcon d q gd gq x R R R d q d q filte gd gq Q g ef (4). LOSS MNMZNG OPERATON STRATEGE Peviou pape [4-8] popoe a contol tategy to minimize the geneato coppe. The optimal eactive cuent contibution ( qopt ) of the oto-ide convete can be found by making the deivative of the geneato coppe with epect to q equal to zeo, PCu / q, the optimal eactive cuent contibution qopt can be expeed a: qopt A B R X V (5) R A B X R m m Howeve, thi tategy doe not conide the e of convete and filte, which i a ignificant pat of the total and could not be neglected. Theefoe, an optimal contol tategy conideing the e of the whole ytem i popoed heeafte.

5 The deivative of the total e, expeed in (4), with epect to q hould be zeo, Ptl / q. Afte implification, the optimal oto eactive cuent i given by total qopt * * Ru RB A Xm RB g Xm * (6) RB XmA B XmRg uv * * AB X mrg d RgBX muqef V * * whee R R RRSC, Rg RGSC Rfilte. The optimal oto eactive cuent total qopt can be calculated in evey contol tep and will be et a the contol efeence of the oto eactive cuent. V. CASE STUDES To tetify the popoed optimal contol tategy, an example wa ued to calculate the value of the ytem. The paamete ae hown in Table. TABLE. PARAMETERS OF DFG WND GENERATON SYSTEM [3] Paamete Value Bae wind peed (m/) Maximal output powe (pu) at the bae wind peed.73 Geneato otational peed (pu) at bae wind peed. Rated powe (kw) Rated fequency (Hz) 5 Rated line-to-line tato voltage (V m) 69 Rated tato cuent (A m) 76 Roto/tato tun atio.34 V bae (V) bae (A m) 76 Stato eitance (pu). Stato leakage inductance (pu).7 Roto eitance (pu).8 Roto leakage inductance (pu).7 Mutual inductance (pu) Filte eitance (pu).3 A. Change of q Cuent and e wee calculated in the condition when wind peed v= m/, eactive powe efeence Q ef = and the eult wee peented in Fig. 4 and Fig. 5. The coppe take a lage potion of the total. The coppe (the black line in Fig. 5) eache the minimum value (at point A) when q i.436 pu, which i exactly the ame value calculated fom (5). Note that q i the eal value of the oto ide cuent. When efeed to the tato ide, it hould be divided by the tun atio u, which i.34 in thi pape. So, q i.8 pu, which i cloe to the abolute value of q (the yellow line in Fig. 4) at point A (.436,-.569). Actually, when X X m, R R, it can be deived fom (4) and (5) that qopt q, which mean that the coppe i minimum when magnetizing cuent i equally haed by tato ide q-axi cuent q and oto ide q-axi cuent q (efeed to the tato ide q ). Thi i the ame with the eult fom [6]. The of the gid ide convete (the geen line in Fig. 5) eache the minimum value (at point B) when q i.988 pu, whee the of the filte (the ed line in Fig. 5) and gid ide cuent g (the black line maked with cicle in Fig. 4) ae alo the minimum. The total (the cyan line in Fig. 5) of the contol tategy uing (5) i eached at point D, while the total of the popoed tategy uing (6) i eached at point C. t i obviou that the popoed tategy can minimize the total. Cuent (pu) B(.988,) d d q gd gq g A(.436,-.569) q (pu) P (pu) Fig.4. Cuent tend with the change of q when v=, Q ef= A(.436,.5) C(.763,.86) D B(.988,.9) Ptl Pcoppe Ptato Poto Pfilte Pgc Pc q (pu) Fig.5. Loe with the change of q when v=, Q ef=

6 The e wee alo calculated in the condition when v= m/ and Q ef =.3 pu. Reult wee peented in Fig. 6, fom which one can ee that the total (the cyan line in Fig. 6) of the contol tategy uing (5) i eached at point D, while the total of the popoed tategy uing (6) i eached at point C. The total diffeence of the two tategie become moe obviou while Q ef inceae. P (pu) D A(.436,.5) C(.48,.8) Ptl Pcoppe Ptato Poto Pfilte Pgc Pc B(.988,.9) q (pu) Fig.6. Loe with the change of q when v=, Q ef=.3 The coppe (the black line in Fig. 6) eache the minimum value at point A, whee q i.436 pu, which i exactly the ame value a the eult in Fig. 5. Thi mean no matte what value Q ef i, the optimal q of contol tategy uing (5) i contant. Thi concluion can alo be een fom (5), when the paamete of the geneato i fixed, the optimal cuent qopt i contant. The of the gid ide convete (the geen line in Fig. 6) eache the minimum value (at point B) when q i.89 pu, whee the of the filte (the ed line in Fig. 6) i alo the minimum. t can be een fom Fig. 5 and Fig. 6 that the value of q fo minimum coppe and the value of q fo minimum of the gid ide convete and the filte ae quite diffeent, and when Q ef inceae, the diffeence become geate. Thi i the eaon that the value of q fo minimum total inceae fom.763 to.48. Theefoe, it can be concluded that the optimal q i a compomie value between the attempt to minimizing the coppe and the attempt to minimizing the e of convete and filte. B. Change of wind peed Fig. 7 and Fig. 8 how the oveall e fo Q ef = and =.3 epectively when wind peed ange fom 7m/ to Q ef 3.33 m/, which i the nomal opeation egion unde the ated wind peed. The eaon fo thi choice i that when wind powe i geate than ated powe, the wind tubine can captue moe enegy to compenate the e. The blue cuve i the total of the whole ytem when the geneato i opeating unde a nomal contol tategy, whee no magnetization eactive powe i povided by the oto cicuit ( q =). The ed cuve how the ituation in which magnetization eactive powe i olely povided by the oto cicuit ( q =). The total unde MinCoppeLo contol tategy uing (5) which only conideed the coppe minimization i depicted in black cuve while the total unde popoed MinTotalLo contol tategy i hown in cyan cuve maked with cicle. t can be een fom Fig. 7 and Fig. 8, a wind peed inceae, the total gadually ie and the lope inceae. Alo, at evey wind peed, the MinTotalLo tategy alway get the lowet total. t alo can be een fom Fig. 7 that, when Q ef =, MinCoppeLo contol tategy i bette than q = contol tategy when wind peed i below.5 m/, while when wind peed i above.5 m/, q = contol tategy i bette than MinCoppeLo contol tategy. Howeve, the MinTotalLo tategy i alway the bet. Total (pu) Total (pu) MinTotalLo MinCoppeLo q= q= Wind peed (m/) Fig.7. Total Lo with the change of wind peed when Q ef= MinTotalLo MinCoppeLo q= q= Wind peed (m/) Fig.8. Total Lo with the change of wind peed when Q ef=.3 C. Change of Q ef Fig. 9 and Fig. how the oveall e fo v=7 and v= epectively at diffeent eactive powe efeence, ange fom

7 -.33 to.33, which i the eactive powe opeating ange fo wind powe plant with a powe output geate than 5 MW in Danih Gid Code [7]. t obviouly can be een in thee two figue that MinTotalLo contol tategy i optimal unde evey Q ef, while the othe thee only cloe to the optimal in cetain egion. The lowet total eache when Q ef i about -.5, which mean when DFG abob a cetain eactive powe fom the gid fo magnetization, the total of the ytem will be the leat. Total (pu) 4 x MinTotalLo MinCoppeLo q= q= continually. The laget elative deceae i 9.6% when Q ef i.3 pu and wind peed i 7 m/. TABLE. RELATVE LOSS DECREASE PERCENTAGE BETWEEN PROPOSED STRATEGY AND MNCOPPERLOSS STRATEGY v (m/) Q ef (pu) % 5.3%.9%.4% 3.% 3.6% 3.5% %.4%.3%.9%.7%.5%.4% -..6%.%.6%.%.7%.6%.4% 3.%.3%.6%.%.5% 3.% 3.%. 8.6% 6.6% 6.7% 5.% 4.% 3.%.4%. 4.5%.7%.6% 9.3% 7.4% 5.8% 4.6%.3 9.6% 8.% 6.8% 4.%.% 8.9% 7.% Fig. how the eduction of popoed tategy againt MinCoppeLo tategy with the change of wind peed and Q ef. The eduction i inceaing with the inceae of wind peed. The laget eduction i.3 pu when Q ef i.33 pu and wind peed i 3.3 m/ Qef (pu) Fig.9. Total Lo with the change of Q ef when v=7 x -3 3 Total (pu) MinTotalLo MinCoppeLo q= q= Lo eduction (pu).3.. Qef (pu) Wind peed (m/). Fig. Lo eduction between popoed tategy and MinCoppeLo tategy Qef (pu) Fig.. Total Lo with the change of Q ef when v= D. Change of wind peed and Q ef Table how the elative deceae between popoed tategy and MinCoppeLo tategy with the change of wind peed and Q ef. A can be een, the total of popoed tategy i alway lowe than the of MinCoppeLo tategy in evey opeating condition. At fixed Q ef condition, a the wind peed inceae, the elative deceae pecentage goe down. At fixed wind peed condition, a the Q ef inceae, the elative deceae pecentage fitly goe down when Q ef i le than -. pu, then the elative deceae pecentage goe up V. CONCLUSON Thi pape intoduce an optimal eactive powe contol tategy to minimize the of the whole DFG baed wind ytem when poviding eactive powe to the gid. The modeling of the whole ytem i caied out in pe unit ytem. On the bai of the peented model, cuent and e in evey pat ae analyzed in detail. Diffeent tategie fo eactive powe contol ae compaed unde diffeent wind peed and eactive powe efeence. t can be concluded fom the imulation eult that the popoed tategy i effective in minimizing opeating of wind geneation ytem. n the futue, minimization opeation of a wind fam may be developed by egulating eactive powe between wind tubine.

8 REFERENCES [] L. Meegahapola, B. Fox, T. Little, D. Flynn, Multi-objective eactive powe uppot fom wind fam fo netwok pefomance enhancement, ntenational Tanaction on Electical Enegy Sytem, vol. 3, pp. 35 5, Januay 3. [] Wind tubine connected to gid with voltage below kv, Document no 77899, Technical Regulation TF 3..6, Eneginet.dk, 4. [3] T. Lund, P. Soenen, and J. Eek, Reactive powe capability of a wind tubine with doubly fed induction geneato, Wind Enegy, vol., pp , 7. [4] K. Chen, P. Delaue, A. Boucayol, P. Vidal, and M. Pietzak-David, Minimum Coppe Lo and Powe Ditibution Contol Stategie of Double-nvete-Fed Wound-Roto nduction Machine Uing Enegetic Macocopic Repeentation, EEE Tan. Enegy Conveion, vol. 5, no. 3, pp , Sep.. [5] H. Li, Z. Chen, and J. K. Pedeen, Optimal powe contol tategy of maximizing wind enegy tacking and conveion fo VSCF doubly fed induction geneato ytem, in EEE ntenational Powe Electonic and Motion Contol Confeence 6. PEMC'6, 4-6 Augut 6, pp. -6. [6] Y. Tang and L. Xu, A flexible active and eactive powe contol tategy fo a vaiable peed contant fequency geneating ytem, EEE Tan. Powe Electonic, vol., pp , July 995. [7] A.G. Abo-Khalil, H. Pak, and D. Lee, Lo Minimization Contol fo Doubly-Fed nduction Geneato in Vaiable Speed Wind Tubine, the 33d Annual Confeence of the EEE ndutial Electonic Society (ECON), Taipei, Taiwan, Nov. 5-8, 7. [8] K. Kajangpan, W. Sdaa, B. Neemmanee, Contol tategie fo maximum active powe and minimum coppe of doubly fed induction geneato in wind tubine ytem, ntenational Confeence on Powe Sytem Technology (POWERCON), Hangzhou, China,, pp.-7. [9] B. Rabelo and W. Hofmann, Contol of an optimized powe flow in wind powe plant with doubly fed induction geneato, in EEE 34th Annual Powe Electonic Specialit Confeence 3, PESC '3, 5-9 June 3, pp [] B. Rabelo, W. Hofmann, and L. Pinheio, Lo Reduction Method fo Doubly-Fed nduction Geneato Dive fo Wind Tubine, in ntenational Sympoium on Powe Electonic, Electical Dive, Automation, and Motion, SPEEDAM'6, 6, pp. S3-6 - S3-. [] A. H. Kaem, E. F. El-Saadany, H. H. El-Tamaly and M. A. A. Wahab, Pefomance enhancement of DFG-baed wind tubine cloe to the ated opeation, 4th Noth Ameican Powe Sympoium, NAPS 8, 8-3 Septembe 8, Univeity of Calgay, Calgay, Canada. [] R. Pena, J. C. Clae, and G. M. Ahe, Doubly fed induction geneato uing back-to-back PWM convete and it application to vaiablepeed wind-enegy geneation, Poc. nt. Elect. Eng. Elect. Powe Appl., vol. 43, no. 3, pp. 3 4, May 996. [3] G. Abad, J. Lopez, M. Rodiguez, L. Maoyo, andg. wanki, Doubly Fed nduction Machine: Modeling and Contol fo Wind Enegy Geneation Application, Hoboken, NJ: Wiley-EEE Pe,. [4] A. Peteon, Analyi, modeling and contol of doubly-fed induction geneato fo wind tubine, PhD thei, Sweden: Chalme Univeity of Technology, 5. [5] ABB HiPak TM, 5SND 8M7, GBT Module, Data Sheet, available online, DocumentD=5SYA589- &LanguageCode=en&DocumentPatd=&Action=Launch [6] J. Jia, J. Liu, Y. Zhang, Novel eactive powe optimization contol tategy fo doubly fed induction wind powe geneation ytem, Poceeding of the CSEE, Vol. 3, No. 3, Oct.5,, pp [7] Wind powe plant with a powe output geate than kw. Document no 55986/, Technical Regulation 3..5, Eneginet.dk,.