Fuzzy-based Direct Power Control of Doubly Fed Induction Generator-based Wind Energy Conversion Systems

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Winfred Reed
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1 nd Intenational econfeence on Compute and Knowledge Engineeing (ICCKE), Octobe 8-9, Fuzzy-baed Diect Powe Contol of Doubly Fed Induction Geneato-baed Wind Enegy Conveion Sytem Mohammad Pichan, Haan Ratega Amikabi Univeity of Technology Tehan, Ian Mohammad Monfaed Fedowi Univeity of Mahhad Mahhad, Ian Abtact- Thi pape popoe a new fuzzy-baed diect powe contol (FDPC) fo doubly fed induction geneato ()- baed wind enegy conveion ytem. In the popoed method, the equied oto voltage ae diectly calculated baed on fuzzy contolle, tato voltage, oto peed and ome machine paamete. The witching table and hyteei compaato ued in conventional DPC ae eplaced by PWM modulato. Alo the convete witching fequency i contant. Futhemoe, the effect of machine paamete mimatche i found negligible. Simulation ae done to veify the effectivene of popoed method unde teady tate and tanient condition and alo machine paamete mimatche. Tubine Tanfome Roto ide Convete AC Filte ide Convete L g Keywod-doubly fed induction geneato (); diect powe contol (DPC); fuzzy logic contolle(flc) I. INTRODUCTION Wind enegy ha become an impotant ouce fo electicity geneation in many countie. It i expected that wind enegy will povide about % of the wold electical enegy in [].Nowaday, many wind fam ae baed on the doubly fed induction geneato () technology with convete ated at %-3% of geneato ating. Compaed with othe wind fam technologie it offe eveal advantage uch a inceaedpowe captue, decoupled and fat active and eactive powe contol, educed mechanical tee[]. A chematic diagam of the -baed wind enegy conveion ytem i hown in Fig.. Diect toque contol (DTC) wa fit intoduced in the middle of 98. DTCdiectly contol the developed toque by the machinewith the ue of toque and flux infomation and elect the bet voltage vecto uing witching look-up table [5]. Baed on the DTC technique, the diect powe contol (DPC) wa popoed fo thee phae pulewih modulated (PWM) convete and poven to have many advantage, uch a implicity, fat dynamic Wind Gea Box Slip Ring DC-link Figue.Schematic of a -baed wind enegy geneation ytem. and obutne againt paamete vaiation and gid ditubance [6-8].In DPC, the convete witching tate ae elected fom a witching table, baed on the active and eactive poweeo and the angula poition of the ac voltage [6, 7] o vitual flux [8]. Recently, the DPC i popoed fo the contol of acmoto [9] and moe ecently [].In the popoed method epoted in [], the convete witching fequency change due to the active and eactive powe eo and hyteei compaato bandwih. In thi pape a new fuzzy-baed diect powe contol (FDPC) tategy fo i popoed. In the popoed method, diect powe contol i achieved baed on the meaued active and eactive powe, tato voltage, oto peed and ome machine paamete. Powe eo and integation of powe eo ae fed a inputto a fuzzy logic contolle (FLC). The oto efeence voltage ae diectly calculated by adding output of FLC to the exta component namely theoto back emf. In the popoed method convete witching fequency i contant. The witching look-up table and hyteei compaato ae eplaced by PWM modulato. It i alo baed on tato voltage oientation not tato flux oientation which emove need of integation. II. MODELING AND EQUATIONS //$3. IEEE 66

2 V R j j ( ) I d L Lm L I d R Figue. equivalent cicuit in the ynchonou efeence fame. The equivalent cicuit of in the ynchonou efeence fame otating at the peed of ω, i depicted in Fig.. Accoding to Fig., the tato and oto voltage and flux vecto of can be expeed a d V R I j d V () V R I j () LI LmI (3) LmI LI () In the above equation, L L Lmand L L Lm. The intantaneou active and eactive powe injected to the gid ae given by 3 P jq V I (5) The amplitude and otating peed of the tato flux ae contant unde ideal gid voltage. Conequently, d /.Auming that the tato coppe loe can be neglected, the tato voltage vecto equation will be implified a V j (6) If, by uing a PLL, the d-axi of the ynchonou efeence fame i fixed to the tato voltage vecto, Eq. (6) eult in, V / (7) d q d Baed on Eq.(3),(), (5)and (7), active and eactive powe can be expeed a P K Vd d (8) Q L Vd KV (. ) L (9) d q m whee K 3 Lm. LL Baed on (8) and (9), ince the tato voltage tay contant at nomal opeation, active and eactive powe change ove a fixed ample peiodt ae given P K V () d d Q K V () d q Accoding to () and (), ince change in active and eactive powe ae coeponding to the change in oto flux component in the d-q axi, the active and eactive powe can be contolled by adjuting d and q epectively. Equation () can be eaanged in each mall ample peiodt a follow T V R I j () Afte decompoing the () into d and q component and neglecting the oto eitance effect, the change in oto fluxe ae obtained a TV T ( ) (3) d d q TV T ( ) () q q d Subtituting (3) and () in () and (), the oto voltage in the ynchonou efeence fame ae obtained a P ( ) L Vd Q Vd (5) T K V ( k) K V L d d m V q Q P (6) T K V ( k) K V d d Thee equation ae the bae of popoed fuzzy-baed diect powe contol (FDPC) method. III. FUZZY-BASED DIRECT POWER CONTROL With caefully conideing (5) and (6), thee equation can be ewitten a follow whee Vd Ud Ed (7) Vq Uq Eq (8) Ud kp P (9) 67

3 Uq kq Q () TABLE. Rule of FLC E d Qk ( ) LV ( k) ( d lip ) k Vd ( k) Lm () Pk ( ) Eq lip k V ( k) () d Δe e PB PM PS PB PM PS Z NS NM PB PB PB PB PM PS Z PB PB PB PM PS Z NS PB PB PM PS Z NS NM Baed on (7)-(), it can be concluded that oto efeence voltage ae compoed of two component. The fit component i an output of popotional contolle and k p o k q ae the gain of thee contolle which ae adopted to educe the powe eo. Thee contolle can be eplaced by anothe pope contolle. The econd component i equivalent oto back emf which i popotional to the lip angula fequency ( lip ). In thi pape, the fuzzy logic contolle (FLC) i ued intead of popotional contolle mainly becaue of two eaon. Fit, it doen t equie any mathematicalmodel of the ytem o poce which i unde contolled. Second, it i widely accepted that the tuctue of FLC i imple and eay fo pactical implementation. The powe eo (e p and e q ) and integation of powe eo ( e p and e q ) ae ued a input of FLC. The output of the FLC i pope voltage (U d and U q ) to educe the powe eo which ae added to equivalent oto emf (E dq ) to geneate oto efeence voltage. Two independent FLC ae ued to contol active and eactive powe. Fo all input and output, even fuzzy et ae choen which ae negative big (), negative medium (NM), negative mall (NS), zeo (Z), poitive mall (PS), poitive medium (PM), poitive big (PB). Fo example, the fuzzy et of active powe eo i depicted in Fig.. The ange of thee vaiable in the hoizontal axi i depended on the opeating point of. Thee ae9 ule that fom the knowledge epoitoy of the FLC which ae ued to decidethe appopiate contol action.thee ule ae peented in Table.. The Sample ule of the FLC can be witten a follow if (e p (e q ) i x) AND ( e p ( e q ) i y) then (U d (U q ) i w)the pefomance of the fuzzy ytem i baed on Mamdani min max ule [, ]. When a et of input vaiable i ead, each ule i fied. Fo example, fo the FLC of active powe, the output of ith ule i a follow min ( ), ( ) i p ep e p p Z NS NM PB PM PM Z NM NM PM PS Z NS NM PS Z NS NM Z NS NM wheeμ p and μ p ae membehip function of each input and α i i the weighting facto (fiing tength) of ith ule. Aftewad, thi value hould be compaed with the membehip function of output in the ith ule. Thu O min, i i vi μ vi and O i ae output membehip function and final membehip value of ith ule. To complete the Mamdani min max ule, the maximum value of final membehip value of ule hould be choen. Baed on thi pinciple, the output that ha maximum poibility ditibutioni choen a the output. Thu the output i given a vmax Oi i,,... Finally the defuzzification method i ued to poduce the output voltage.baically, defuzzification i a mapping fom a pace offuzzy contol action defined ove an output univee ofdicoue into a pace of nonfuzzy (cip) contol action.it i employed becaue in many pactical application acip contol action i equied.the hematicdiagam of the FDPC i depicted in Fig.5. IV. SIMULATION To invetigate the pefomance of the popoed contol tategy unde diffeent condition, extenive imulation ae conducted uing Matlab/Simulink oftwae. The imulated ytem i hown in Fig. 6 and the ytem paamete ae given in Table. The i ated at MW. The gid ide convete i eponible fo balancing the powe exchange between the oto and gid though maintaining a fixed DC-link voltage. Degee of membehip NM NS Z PS PM PB e p Figue.Fuzzy et of active powe eo. 68

4 P ef, Q ef fuzzy logic contolle + j( ) t e V + Edq calculation SVM modulato RSC ω ω P,Q calculation DC-Link PLL GSC Figue 5.Schematic of popoed fuzzy-baed diect powe contol. I V The oto ide convete i intended to contol the tato active and eactive powe. The contol tategy of the gid ide convete ipactically the ame a VSC tanmiion ytem [3] and gid-connected ectifie []. In thi pape, the popoed method in [] i ued and the DC-link voltage i adjuted at V. A high fequency RC filte i connected to the tato ide to abob the witching hamonic and high fequency noie geneated by the two convete. Duing the imulation, the ampling peiod wa et to 5μ. To geneate the witching pule, the pace vecto modulation (SVM) technique with the witching fequency fixed at - khz i utilized. hown in Fig. 7 fo oto peed of.pu. Initially the oto ide convete i enabled with the active and eactive powe efeence at MW and -.5 MVa, epectively. The active and eactive powe efeence jumped fom to MW at. and fom -.5 to.5 MVa at., epectively. Then, tep change of active powe efeence fom MW to MW at.6 i caied outto evaluate both iing and falling pefomance. The popoed contol tategyeveal a fat dynamic epone and the active and eactive powe tack the efeence value within a few milliecond. To veify that paamete vaiation don t make conideable effect on pefomance of contol tategy, a imulation with % vaiation in mutual inductance and oto peed vaiation wa done. The eult ae depicted in Fig.8. A een in Fig. 8, even with uch lage inductance eo and oto peed vaiation the ytem epone i good enough and the ytem maintain upeio pefomance unde both teady-tate and tanient condition. a 3 - Vaiou tep change in the active and eactive powe efeence ae caied out to evaluate the dynamic pefomance of the popoed DPC tategie. The eult ae.5mva/5% 69/KV.5 mh KV/MVA ω 6mF RC Filte 3~ = = R=.5Ω 3~ C=3μF Roto Side Side Convete Convete Figue 6.Configuation of the imulated ytem. TABLE. Paamete of the imulated b c d time() Rated powe MW Stato voltage 69V Stato/oto tun atio.3 R.8pu R.pu(efeed to the tato) L m 3.36pu L σ.pu L σ.pu(efeed to the tato) Lumped inetia contant. Numbe of pole pai Figue 7. Tanient pefomance of the popoed DPC unde vaiou active and eactive powe tep change at oto peed of.pu: a) active powe (MW) b) eactive powe (MVa) c) tato cuent (ka) d) oto cuent (ka). 69

5 a b c d time() Fig.8. Simulated eult unde vaiou tato active and eactive powe tep and oto peed vaiation and % vaiation in R and L m. (a) Roto peed(p.u) (b) Stato active powe (MW) (c)stato eactive powe (MVa) (d) Thee-phae oto cuent (ka). V. CONCLUSION In thi pape, a new diect powe contol method baed on a fuzzy logic contolle i popoed. At fit, the mathematical model of in the ynchonou efeence fame i deived. Then, baed on thi model, the oto efeence voltage ae diectly calculated uing fuzzy logic contolle and feed fowad tem namely back emf. In the popoed method, the hyteei compaato and witching look-up table ae eplaced by PWM modulato. Alo, the convete witching fequency i contant. The extenive imulation wee done which confimthe effectivene and upeb pefomance of popoed method unde teady tate and tanient conditionand alo machine paamete and oto peed vaiation. [] L.M. Fenandez, C.A. Gacia, F. Juado, Opeating capability a a PQ/PV node of a diect-dive wind tubine baed on a pemanent magnet ynchonou geneato, Renew. Enegy 35 () [5] I. Takahahi and T. Noguchi, A new quick-epone and highefficiency contol tategy of an inductionmoto, Int. Elect. Eng. Tan. Ind. Appl., vol., no. 5, pp. 8 87, 986. [6] T. Noguchi, H. Tomiki, S. Kondo, and I. Takahahi, Diect powe contol of PWM convete without powe-ouce voltage eno, IEEE Tan.Ind. Appl., vol. 3, no. 3, pp , May/Jun [7] G. Ecoba, A. M. Stankovic, J. M. Caaco, E. Galvan, and R. Otega, Analyi and deign of diect powe contol (DPC) fo a thee phae ynchonou ectifie via output egulation ubpace, IEEE Tan. PoweElecton., vol. 8, no. 3, pp , May 3. [8] M. Malinowki, M. P. Kazmiekowki, S. Hanen, F. Blaabjeg, and G. D. Maque, Vitual-flux-baed diect powe contol of theephae PWM ectifie, IEEE Tan. Ind. Appl., vol. 37, no., pp. 9 7, Jul./Aug.. [9] X. Luo, Diect powe contol of AC moto, Mate thei, Univeity of Nevada, Reno, 9, [online].available:\ul{ /fulltextpdf/3ebd9556d8dbaa/?accountid=56} []L. Xu and P. Catwight, Diect active and eactive powe contol of fo wind enegy geneation, IEEE Tan. Enegy Conve., vol., no. 3, pp , Sep. 6. []C.C. Lee, Fuzzy logic in contol ytem: fuzzy logic contolle. Pat I, IEEE Tan. Syt. Man Cyben. vol., no.,pp. - 8,Ma/Ap. 99. []C.C. Lee, Fuzzy logic in contol ytem: fuzzy logic contolle. Pat II, IEEE Tan. Syt. Man Cyben. vol., no.,pp. 9-35,Ma/Ap. 99. [3]J. L. Thoma, S. Poullain, and A. Benchaib, Analyi of a obut DCbu voltage contol ytem fo a VSC-Tanmiion cheme, in Poc. 7th Int.Conf. AC-DC Powe Tan., London, U.K.,,pp. 9. []M.Monfaed, H.Ratega, H.M.Kojabadi, High pefomance diect intantaneou powe contol of PWM ectifie, Enegy Conveion and Manage (5): REFERENCES [] Wold Wind Enegy Aociation (online), Available: [] R. W. De Doncke, S. Mulle, and M. Deicke, Doubly fed induction geneato ytem fo wind tubine, IEEE Ind. Appl. Mag., vol. 8, no. 3,pp. 6 33, May/Jun.. [3] L.M. Fenandez, C.A. Gacia, F. Juado, Compaative tudy on the pefomance of contol ytem fo doubly fed induction geneato() wind tubine opeating with powe egulation, Enegy 33 (8)

7. Inverter operated induction machines

7. Inverter operated induction machines 7. Invete opeated induction machine Souce: Siemen AG, Gemany Dept. of Electical Enegy Conveion Pof. A. Binde 7/1 Invete-fed induction machine Fequency convete (invete) geneate thee-phae voltage ytem with