An Efficient Control of Induction Generator based Variable Speed Wind Power Plant with Power Optimization Capability

Transcription

1 International Journal of Applie Engineering Reearch ISSN Volume 1, Number 15 (017) pp Reearch Inia Publication. An Efficient Control of Inuction Generator bae Variable Spee Win Power Plant with Power Optimization Capability 1 Neha Gupta an Yauvir Singh Department of Electrical Engineering, School of Engineering, Harcourt Butler Technical Univerity, Kanpur (U.P.), Inia. 1 Orci I: X Abtract In thi work we have preente extremum eeking (ES) control for maximum power extraction in variable pee fixe pitch (VSFP) gri connecte win power plant. For moeling of win power plant we have coniere quirrel cage inuction generator (SCIG) a win generator (WG) an matrix converter (MC) a power electronic interface between WG an gri. Matrix converter facilitate the mechanim of ES cheme. Unlike other MPPechnique, ES i a non moel bae MPPT algorithm. In thi paper inuoial ignal ha been ue a a earch iturbance ignal. The performance of the ES algorithm ha been checke for ifferent win velocitie. In the latter ection of thi paper, we have eigne a non-linear controller bae on to prevent the magnetic aturation of inuction generator. Alo we mae a comparion between the reult obtaine with an without the non-linear controller. Keywor: Win generator, Extremum eeking, MPPT, tability, SCIG, Controller INTRODUCTION In lat few ecae ue to environmental iue, reearcher are more incline towar the non conventional an clean way of energy prouction. Of variou non conventional energy reource, the win energy i coniere to be mot promiing ource of energy becaue of it abunance cleanline, free availability an technical maturity [1-4]. The popular tructure in win power plant inclue quirrel cage inuction generator (SCIG) bae win power plant, oubly fe inuction generator (DFIG) bae win power plant an permanent magnet ynchronou generator (PMSG) bae win power plant [5-7]. All thee ytem offer goo efficiency, leer aeroynamic loa an eay regulation of active an reactive power. The SCIG provie flexibility uner varying win pee ue to it aynchronou operation, o here in thi work we have ue SCIG. SCIG alo offer economy, implicity an robutne in tructure againt iturbance an vibration. To extract maximum power from a win power plant at varying win pee, an MPPT eign i require which alter the haft pee of turbine uing varying win pee metho, which intern will alter the power output, ince the power output i proportional to the turbine angular velocity. Thi change in haft pee i one through a power electronic interface between WG an gri, for which we have to control the witching of power electronic converter. Here in thi paper we have ue matrix (ac-c-ac) converter intea of conventional rectifier inverter pair. The avantage of uing matrix converter i that it allow flow of power in both the irection an input power factor i alo controllable. In aition it ha no energy torage component [8-9]. By witching of matrix converter, we alter the tator electrical frequency, which lea to the change in turbine haft pee an rive SCIG to it maximum power point (MPP). The technique available until now, which inclue perturb an oberve (P & O) metho, fuzzy an neural network bae technique, are highly moel epenent. The main iavantage of moel bae optimization technique i that every time we ue a new moel, new controller ha to be eigne for MPPT, which i a teiou tak [10]. In thi work extremum eeking cheme ha been ue, which i a moel inepenent algorithm. Alo it offer eay tenability, eign implicity an performance toutne [3, 7, 15]. WIND POWER PLANT A general block iagram of win power plant contain win turbine, WG, power electronic interface to achieve MPPT at varying win pee an loa. Here in thi paper, we are uing matrix converter a power electronic interface an our win generator i SCIG. Since we are moeling gri connecte win power plant, we have utility gri in place of loa. In orer to know the ynamic of win turbine, we alo nee to moel the win turbine aeroynamic. The block iagram coniere in thi paper i hown in Figure.1. The power capture by the VSWT i expree in term power coefficientc P, which i a imenionle quantity. 4847

2 International Journal of Applie Engineering Reearch ISSN Volume 1, Number 15 (017) pp Reearch Inia Publication. C P i a meaure of the ratio of the rotor power to the win power a inicate by (1): Figure 1. Block iagram of Win power plant moel uner tuy. P T = 1 ρa rc P (λ, β)v ω 3 (1) Maximum torque extracte from the turbine rotor can be given a T T = 1 ω t ρa r C P (λ, β)v ω 3 () Where TSR (tip pee ratio) i efine a Figure. Power coefficient v. turbine pee curve. blae tip pee λ = win pee = ω t R V ω V ω = pee of win in m/ A = wept area of win turbine blae ω t = turbine angular pee. λ = TSR an β = Pitch angle of rotor blae C p i relate to λ, an β. Here, we have coniere C p curve to be []: Figure 3. Turbine power v. turbine pee curve. C p = V w Rω t exp ( V w Rω t 0.003) (3) From figure., it i clear that C p remain at the ame level, if the turbine pee i varie with each change in win pee. Figure.3 how the change in turbine power with each change in angular velocity for ifferent win pee. Figure.4. how that if we join the point of at which the turbine power i maximum, a curve of thir-orer efining the maximum power attaine by the win turbine i obtaine. Figure 4. Turbine pee v. win pee curve. 4848

3 International Journal of Applie Engineering Reearch ISSN Volume 1, Number 15 (017) pp Reearch Inia Publication. The overall moel for win energy converion ytem may be given by following eight nonlinear equation, which inclue the tate-equation of the mechanical haft, electrical generator, an the matrix converter [11-14]. t i α = a 0 i α + a 1 λ α + a ω r λ β + co θ 0 V 0m (4) t i β = a 0 i β + a 1 λ β + a 1 ω r λ α + in θ 0 V 0m (5) t λ α = a 3 i α a 4 λ α ω r λ β (6) t λ β = a 3 i β a 4 λ β + ω r λ α (7) t θ 0 = ω 0 (8) t ω r = 3p L m L r J t θ = ω t ω r pn ω t t = P t(v w,ω t ) (i βλ α i α λ β ) pk nj θ pb nj (ω t ω r pn ) (9) ω t (10) K θ B (ω t ω r pn ) (11) Now we preent the extremum eeking technique for WECS, which i a real time optimization technique an unlike conventional MPPT algorithm it oe not require ytem moeling an ientification. For imulation purpoe the moel of C p an turbine power are given eq. (3) an (4). Here it i aume that we can meaure & manipulate turbine power through MC. A, the turbine power map ha one MPP uner any win pee, we make the following aumption For V cut in < V w < V rate (Figure.5). EXTREMUM SEEKING FOR MAXIMUM POWER EXTRACTION IN WIND POWER PLANT A typical power curve of a WECS a hown in Figure.5 can be ivie into four major region. The firt region contain the velocitie below which turbine i not able to generate any power ue to inufficient win. The econ region contain the win velocitie from where the generation tart to the velocity up till which the power linearly increae with increae in win velocity. Thi region i known a ubrate power region. Thi i the region where MPPT cheme are applie to capture maximum power; hence power output i limite by win turbine. The fourth region contain the velocitie of win which are much tronger an may caue amage to win turbine, hence in thi region, the turbine i hut own [18]. Figure 6. Extremum eeking cheme for extraction of maximum power in win power plant (without inner loop). P t (V w, ω t ) ω t (ω t ) = 0 (1) P t (V w, ω t ) ω t (ω t ) < 0 (13) If, we carefully tuy the torque pee characteritic of an inuction machine, it i oberve that thi curve i very harp near the ynchronou pee (tator electrical frequency), ω 0. At thi point the rotor electrical pee ω r an ynchronou pee ω 0 will be nearly equal. Thi inicate that if we change the tator electrical frequency, the electrical rotor pee will change, which intern will change the turbine pee ω t [19].Thu by varying ω 0 through MC, we may change turbine pee ω t to track MPPT. Our ES cheme work on the ame line. CONTROL STRATEGY OF NON-LINEAR STATE FEEDBACK CONTROLLER Figure 5. Win pee v. power curve howing four operating region [18]. In cae of flux tranient the ynamic of ytem are non linear an couple. So we have ue a non-linear controller bae on fiel oriente control an feeback linearization to 4849

4 International Journal of Applie Engineering Reearch ISSN Volume 1, Number 15 (017) pp Reearch Inia Publication. prevent magnetic aturation of inuction generator an improve the performance of the ytem [14]. x 3 = η 1 co φ (5) x 4 = η 1 in φ (6) x 5 = arctan ( Υ β Υ α ) (7) x 6 = Υ α + Υ β (8) x 7 = pn (y 1 + y + a 8 Δ + ) (9) x 8 = Δ (30) x 9 = y 1 (31) Ψ = η +a 4 η 1 a 3 (3) Figure 7. Extremum eeking for MPPT in WECS with inner loop. y 1 = Ψ 1 (x) = x 9 (14) y = L f Ψ 1 (x) = (x 9 x 7 pn ) a 8x 8 (15) y 3 = L f Ψ 1 (x) = b 0 ξ q + b 1 L f Ψ 1 (x) + b x 8 + b 3 - (16) y 4 = L f 3 Ψ 1 (x) = b 4 L f Ψ 1 (x) + b 5 L f Ψ 1 (x) + b 6 x 8 b 0 x 6 λ q x 7 (b 7 Ψ (x) + b 8 L f Ψ (x)) +b 9 (17) η 1 = Ψ (x) = x 3 + x 4 (18) η = L f Ψ (x) = a 3 ξ a 4 Ψ (x)) (19) η 3 = L f Ψ (x) = b 1 Ψ (x) + b 11 L f Ψ (x) + b 13 x 7 (L f Ψ (x) b 1 L f Ψ (x) b x 8 + b 3 + ) + a 3 i + a 3 x 6 (0) = x 8 (1) φ = arctan ( x 4 x 3 ) () where ξ = x 1 x 3 + x x 4, ξ q = x x 3 x 1 x 4,i = i α + i β an [ λ λ q ] = [ co x 5 in x 5 in x 5 co x 5 ] [ x 3 x 4 ] (3) Ψ q = 1 b 0 (y 3 b 1 y b Δ b 3 + ) (33) With Φ a 3 (η 3 + a 4 η a 1 a 3 η 1 a 3 i ) (34) Φ q = (y b 4 b 1 y 3 + a 8 0 a y + a 8 9 a + b 0 (a 0 + a 4 )Ψ q + 9 b 0 x 7 (Ψ q + a η 1 ) + a 8 a 9 b 3 + ) (35) Aigning a new variable for each ifferential, we obtain: y 1 = y (36) y = y 3 (37) y 3 = y 4 (38) y 4 = G 1 + b 0λ x σl 6 u 1 b 0λ q u σl (39) η 1 = η (40) η = η 3 (41) η 3 = G + a 3λ q x σl 6 u 1 a 3λ u σl (4) With [ i iq ] = [ co x 5 in x 5 in x 5 co x 5 ] [ x 1 x ] (43) Defining the ignal a follow [ x 6u 1 u ] = [ co (φ θ 0) in(φ θ 0 ) η 1 in( φ θ 0 ) co(φ θ 0 ) ] [ Aigning new et of variable again, we get: v 1 G 1 b 0 v G a 3 ] (44) z = [y 1 ω t ref, y, y 3, y 4 ] T (45) The invere tranformation of (14)-() [ x 1 x ] = 1 η 1 [ co φ in φ in φ co φ ] [Ψ Ψ ] (4) q ζ = [η 1 ( λ ref ), η, η 3 ] T (46) 4850

5 International Journal of Applie Engineering Reearch ISSN Volume 1, Number 15 (017) pp Reearch Inia Publication. We obtain z 1 = z (47) z = z 3 (48) z 3 = z 4 (49) z 4 = v 1 (50) ζ 1 = ζ (51) ζ = ζ 3 (5) ζ 3 = v (53) Δ = z a 8 Δ (54) Figure 8. MPPT without inner loop, (otte green line), MPPT with inner loop, (otte blue line) φ = ω r + a 3 b 0 η 1 (z 3 b 1 z b b 3 + ) (55) Linear tate feeback v 1 = k 1 z 1 k z k 3 z 3 k 4 z 4 (56) v = k 1 ζ 1 k ζ k 3 ζ 3 (57) Where b 0 = a 5, b pn 1 = a 8 + a 7 pn, b = a 8, b 3 = a 8 + a 7 pn, b 4 = b 1 a 0 a 4, b 5 = a 0 b 1 + a 4 b 1 b, b 6 = a 0 b + a 4 b a 8 b, b 7 = a b a 4 b 0 a 3, b 8 = b 0 a 3, b 9 = a 0 b 3 + a 4 b 3 b, b 10 = b 3 a 0 a 4, b 11 = a 0 +3a 4, b 1 = a 1 a 3 a 0 a 4 a 4, b 13 = a 3 b 0 Figure 9. Power coefficient variation with inner loop control SIMULATION RESULTS The propoe extremum eeking feeback cheme for MPPT in WECS ha been evaluate by teting it for ifferent iturbance i.e. variation of win pee in ubrate power region uing MATLAB m-file. The reult are preente below. To check the performance of inner loop we applie a win velocity 0f 10 m/ for 30 an then change it uenly to 11 m/. Figure.8. how the repone of the propoe WECS incorporating the ES bae control of SCIG with an without inner loop control, for uen win pee variation. It i een clear from Figure. 9 & 10 that without inner loop the power coefficient greatly varie with change in win pee but with inner loop the variation of Cp with change in pee i very le, while with increae in win pee the power level increae. Figure 10. Power coefficient variation with inner loop control CONCLUSION We have preente extremum eeking feeback algorithm for maximum power extraction in win power plant. ES cheme etimate the tator electrical frequency to teer the win turbine to it maximum power point. We have checke the performance of thi control ytem for uen 4851

6 International Journal of Applie Engineering Reearch ISSN Volume 1, Number 15 (017) pp Reearch Inia Publication. win variation an foun that a oon a we change the win velocity the ES cheme teer the win turbine to it correponing MPP. Further we have applie a non linear controller to the ame ytem, which i bae on fiel oriente control an feeback linearization. The non linear controller i ue for the tranient performance improvement of the propoe win power plant. The avantageou feature of thi work i that it i inepenent of the knowlege of win pee, turbine or generator parameter. So, once we have eigne the controller, it can be applie to any WECS moel. We have alo one the tability analyi of E cheme for WECS an foun that it uccefully converge at MPP. REFERENCES [1] Jiawei Chen, Jiechen, chunying Gong, On optimizing the tranient loa of variable pee win energy converion ytem uring MPP tracking proce, IEEE tranaction on Inutrial Electronic, Vol-61, Iue-9, 013,pp [] S. M. Barakati, Moeling an controller eign of a win energy converion ytem incluing a matrix converter, Ph.D. iertation, Dept. Electr. Comput. Eng., Univerity of Waterloo, Waterloo, ON, Canaa, 008. [3] X. She, A. Q. Huang, F. Wang, an R. Burgo, Win energy ytem with integrate function of active power tranfer, reactive power compenation, an voltage converion, IEEE Tran. In. Electron., vol. 60, no. 10, pp , Oct [4] L. Barote, C. Marinecu, an M. N. Cirtea, Control tructure for ingle-phae tan-alone win-bae energy ource, IEEE Tran. In. Electron., vol. 60, no., pp , Feb [5] N. Wang, K. E. Johnon, an A. D. Wright, Comparion of trategie for enhancing energy capture an reucing loa uing LIDAR an fee forwar control, IEEE Tran. Control Syt. Technol., vol. 1, no. 4, pp , Jul [6] L. Shuhui, T. A. Hakew, K. A. William, an P. R. Swatloki, Control of DFIG win turbine with irect-current vector control configuration, IEEE Tran. Sutain. Energy, vol. 3, no. 1, pp. 1 11, Jan. 01. [7] M. F. M. Arani an E. F. EI-Saaany, Implementing virtual inertia in DFIG-bae win power generation, IEEE Tran. Power Syt., vol. 8, no., pp , May 013. [8] T. H. Nguyen an D.-C. Lee, Avance fault riethrough technique for PMSG win turbine ytem uing line-ie converter a STACOM, IEEE Tran. In. Electron., vol. 60, no. 7, pp , Jul [9] S. Zhang, K. J. Teng, an T. D. Nguyen, Moeling of AC-AC matrix converter for win energy converion ytem, in Proc. IEEE Conf. In. Electron. Appl., May 009, pp [10] A. I. Bratcu, E. C. Iulian Munteanu, an S. Epure, Energetic optimization of variable pee win energy converion ytem by extremum eeking control, in The International Conference on Computer a a Tool, 007. [11] P. C. Kraue, O. Waynczuk, an S. D. Suhoff, Analyi of Electric Machinery an Drive Sytem. New York, NY, USA: Wiley, 00. [1] A. D. Luca an G. Ulivi, Dynamic ecoupling of voltage frequency controlle inuction motor, in Proc. 8th Int. Conf Anal. Optim. Syt., 1988, pp [13] A. D. Luca an G. Ulivi, Deign of exact nonlinear controller for inuction motor, IEEE Tran. Autom. Control, vol. 34, no. 1, pp , Dec [14] R. Marino, S. Pereaa, an P. Valigi, Aaptive input-otput linearizing control of inuction motor, IEEE Tran. Autom. Control, vol. 38, no., pp. 08 1, Feb [15] M. Komatu, H. Miyamoto, H. Ohmori, an A. Sano, Output maximization control of win turbine bae on extremum control trategy, in Proc. of American Control Conference, 001. [16] V. Kumar, R. R. Johi, an R. C. Banal, Optimal control of matrixconverter- bae WECS for performance enhancement an efficiency optimization, IEEE Tranaction on Energy Converion, vol. 4, pp , 009. [17] T. Pan, Z. Ji, an Z. Jiang, Maximum power point tracking of win energy converion ytem bae on liing moe extremum eeking control, in Proc. IEEE Energy 030 Conference, 008. [18] A. Ghaffari, M. Krtic, S. Sehagiri, Power optimization an control in win energy converion ytem uing extremum eeking, IEEE Tranaction on Control Sytem Technology, Vol-, Iue 5,014. [19] M. Krti c an H.-H. Wang, Stability of extremum eeking feeback for general nonlinear ynamic ytem, Automatica, vol. 36, no. 4, pp , 000. [0] Khalil, H.K. (1996). Nonlinear ytem (n e.). Englewoo Cli!, NJ: Prentice Hall. 485

7 International Journal of Applie Engineering Reearch ISSN Volume 1, Number 15 (017) pp Reearch Inia Publication. APPENDIX TABLE-I CONSTANT PARAMETERS a 0 a a 3 + R, a 1 a a 4 a L m L r a 3 a 4 L m R r L r R r L r a 5 a 6 a 7 a 8 3p L m /JL r pk /Jn pb/jn K / B/ 4853