PV panel - wind turbine hybrid system modelling

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1 017 1st Intenational onfeence on ontol Systems and ompute Science PV panel - wind tubine hybid system modelling Mihaela Puianu 1, Ramona-Oana Flangea, Nicoleta Aghia 1, Segiu Stelian Iliescu 1 1 Dept. of Automatic ontol and Industial Infomatics Faculty of Automatic ontol and ompute Science Univesity Politehnica of Buchaest (UPB) Buchaest, Romania mihaelapuianu@gmail.com, nicoleta@shiva.pub.o, iliescu@shiva.pub.o ollective of Automation and Applied Infomatics, Faculty of Hidotehnics Technical Univesity of ivil Engineeing of Buchaest, Buchaest, Romania gigoiu.oana@gmail.com Abstact The wok poposes a hybid system famewok consisting of seveal sola panels and wind tubines, in ode to supply the electicity need fo small communities. The photovoltaic (PV) model consides as an output vaiable the active powe obtained fom the PV panel, which is diectly influenced by the sola adiation measuements duing a day. Based on wind speed, the output vaiable fo the wind tubine model is the active powe poduced by the wind tubine. Both models wee validated by computing the maximum elative eo on a peiod of one day and the esults showed a modelling eo of 1. % fo the wind tubine, espectively 6% fo the PV panel. Also, a hybid PV-wind tubine system achitectue is poposed in ode to minimize the consume supply fom the national gid. Keywods hybid RES supply system, PV panel model, wind tubine model, I. INTRODUTION Nowadays, solutions fo eplacing the conventional enegy souces such as coal, oil, natual gas ae moe and moe used. The use of RES (sola and wind) will suppot national enegy consumption fo an ecological envionment [4]. Renewable enegy esouces (RES) can help cuent heating needs in cetain aeas fo economic potential in competitive conditions of enegy maket. Due to highe envionmental equiements, the use of enewable enegy souces fo the supply of electicity in small communities is inceasing. The developments of smat gid into diffeent activities offe many benefits to utilities and consumes [5], [6]. Shaaf [1], poposed a hybid wind/photovoltaic (PV) system fo the supply of electicity in homes, consisting in fou subsystems: RES geneation fom sola panels and wind tubines, a convete fo the connection of geneatos to the common D bus, an invete D-A and a contol subsystem that uses PI contolles. Also, a hybid RES system fo ual electical netwok in Malaysia was designed by Fadaeenejad et al. []. The authos in [] consideed diffeent RES into the system, such as sola, wind, hydo and biomass and a PVwind-battey cost-effective system was obtained. A stand-alone hybid system was developed by Hashimoto et al. [3]. They poposed a model consisting of a wind tubine geneato and photovoltaic modules fo a adio station using a backup stoage battey. A hybid enegy system using wind and PV-sola was descibed by Nema et al. [1], in ode to eview the system equiements fo the design, opeation and contol. Thei wok also highlights the economic aspect fo futue developments of hybid wind-sola systems alongside with the conventional souces. Sun et al. poposed a hybid wind tubine system study in Wawick, UK [13]. This system was designed and implemented using a wind tubine that stoage the compessed ai enegy. Vaious contol methods wee applied to the hybid system and an analysis fo enegy efficiency was made, esulting a feasible system. This wok poposed a model consisting of seveal PV panels and wind tubines, in ode to supply the electicity need fo small communities. The pape is stuctued as follows: the fist pat intoduces the subject of hybid geneation systems, section two descibes the PV panel model, the thid pat pesents the wind tubine modeling and validation, section fou descibes the hybid system and the last one concludes the pape and highlights futhe impovements of the model. II. PV PANEL MODEL A. PV desciption This section descibes a model of a photovoltaic module with 36 sola cells, composed of semiconducto mateials. Sola panels ae compised of multiple photovoltaic cells connected in seies o in paallel, Fig.1. When the panels ae connected in seies, thei voltage inceases and the cuent is the same. PV cells ae connected in paallel to incease the cuent and fo constant voltage /17 $ IEEE DOI /SS

2 γ IS is the shot cicuit cuent coefficient [A/K], G enegy band-gap mateial. ε the The I-V elationship can be obseved in the above equation, Eq. (1) fo a given values fo sola adiation, cell tempeatue and othes cell paametes. [7] The sola adiation measued at efeence condition is G = 1000 W/ m and the efeence cell tempeatue is T = 5 0 [10]. Fig. 1. PV panel desciption [11] The above schema descibes the cuent-voltage chaacteistic fo a PV panel that contains seies and paallel PV cells [11]. The paametes N S and N P epesent the numbe of seies/paallel cells. N PI L is the total light cuent which is influenced by sola adiation and cell tempeatue, (N S/N P) R S is the total seies esistance [11]. The output paametes ae the teminal voltage, V, and the teminal cuent of a PV cell, I, which is defined as the diffeence between the light cuent, I L and the diode cuent, I D [11]. One of the models used to simulate sola cells was conducted by Bellia et al. in [8]. They pesented a detailed simulation and modeling fo photovoltaic panels that can be used fo any type of photovoltaic panel. The output vaiables used ae cuent and powe and as input vaiables, tempeatue and iadiation ae consideed. B. PV panel modelling Mathematical modeling of the photovoltaic cell can be epesented by diffeential equations, state equations o tansfe functions. Based on [7], [8] and given the necessay conditions fo achieving a model fo photovoltaic cells, the following set of equations was obtained: q( V + IRs ) I = I L I 0 exp 1 γkt γ = A N S G I L = [ I L, + μ IS ( T T ] (1), ) G 3 T = qε G I I , exp T, ka T, T Whee I is cuent [A], cuent [A], I I O O, electon change [], Boltzmann constant [J/K], tempeatues [K], I I L L,, the light absobed, the satuation cuent [A], q is the R is the seies esistance [ Ω ], k is S G T T,, ae photovoltaic cell G, is the sola adiation [W/ m ],. Model simulation esults Figue descibes the modeling diagam fo a photovoltaic panel which is composed of 36 photovoltaic cells. Fig.. PV model diagam The model was implemented in Matlab/Simulink. The sola adiation input G [W/m ] is based on eal egisteed data fo the day of May 016, in a plain aea of Romania (Tagoviste). Iadiance data was povided by [9]. The output vaiables ae the electic cuent I [A] and the powe [W]. Othes paametes wee consideed constant. The PV panel model simulation esults ae shown in Figue 3. The two cuves define a photovoltaic panel powe vaiation fo both simulated model and actual egisteed data in the same day of May 016. This compaison was made on an houly basis. Fig. 3. PV cells vaiation in time: simulation vs eal data As a validation index, the maximum elative eo was computed duing a day (4 hous) with the following equation: 637

3 y ( i) yc( i) ε = max 100[%], i = 1,4 () i y ( i) Whee y is the eal powe esulting fom actual data fo the photovoltaic panel and y c is the esulting powe of the model. Afte calculating the eo fo the data in question, a maximum eo of 6% was obtained. III. WIND TURBINE MODEL A. Tubine desciption This section pesents the mathematical model of a wind tubine and its compaison with a pedefined block model of Matlab / Simulink. Wind tubines ae systems that convet kinetic enegy povided by wind speed into mechanical enegy though the blades. Then, the mechanical enegy is conveted into electical enegy though an electic geneato. Wind tubines ae also called wind enegy convetes o wind enegy units. Whee Pw = powe [W]; = ai density [kg / m3]; p = powe coefficient; = tip-speed atio; = blade pitch angle; A = the aea of the blade suface [m ]; = length of the blade; V W = wind speed [m / s].. Model simulation esults The mathematical model was implemented in Matlab 015a/Simulink. The wind speed was consideed vaiable fo a full day (4 hous). The pitch angle was consideed constant (45 degee), as well as the tip-speed atio. In these conditions, the powe coefficient was also consideed constant. Figue 5 depicts the modeling diagam fo a wind tubine and the paametes of the model ae valued based on the data in Table I. Fig. 5. Wind tubine model diagam TABLE I. WIND TURBINE PARAMETERS Symbol Table Paametes Paamete Values Unit P powe coefficient 0.4 p.u. ai density 1.3 kg/m3 tip-speed atio 1 p.u. blade pitch angle 0 p.u. Fig. 4. Wind tubine schematic desciption The powe geneated by wind tubine is diectly popotional to ai density [kg/m 3 ], the aea coveed by a full otation of the oto blades and the squae of wind speed v W[m/s], Fig. 4. The tubines can be used fo electicity supply alone o in hybid systems togethe with any othe enewable souce of electicity, such as sola panels. A wind tubine known model is pesented by Bimayak Bhandai [3]. He also pesented a hybid system consisting of photovoltaic panels and wind powe. B. Tubine Model Stating fom the model pesented by Bimayak Bhandai [3] and given the necessay conditions fo achieving a model fo a wind tubine the following equations wee obtained: P W ρ = P A = π ( λ, β ) A v 3 W (3) The wind tubine powe esulting afte model simulation is shown in Figue 6. A 600W wind tubine was consideed fo simulation. Fig. 6. Wind tubine powe vaiation in time D. Poposed model vs. Matlab/Simulink tubine model Since eal egisteed data fo a 600W wind tubine wee not available, the poposed model was compaed to a 638

4 Matlab/Simulink tubine model. The pedefined block in Simulink is also based on Eq. (3) and the powe coefficient p is vaiable based on the otational speed, and pitch angle. p eaches its maximum value fo a null pitch angle. The poposed model consides a constant powe coefficient, the vaiable input of the model is consideed the wind speed v w. The esults fo the two wind tubine models simulation in tems of active powe (P W) ae shown in Figue 7. The two cuves consideed the vaiation of wind speed fo a day. with Eq. (). The validation of the model is based on a 1.% elative eo. IV. HYBRID PV-WIND TURBINE SYSTEM FRAMEWORK A. Hybid system This section poposed a PV-wind tubine hybid system which consists of a 36 sola cells PV panel and a wind tubine, in ode to supply the electicity needs fo a small community. Fig. 8. PV-wind tubine hybid supply system diagam Fig 7. Active powe vaiation: poposed vs Matlab/Simulink model To compae simulated data model wind tubines and data fom pedefined model we calculated maximum elative eo B. Hybid PV-wind tubine supply achitectue Figue 9 depicts a new famewok fo contolling a subsystem in the powe system whee the poposed hybid PV-wind tubine geneation povides electicity fo consumes. The system efeence is the consume electicity need (load ef.) that is continuously compaed to the electical geneation in ode to assue adequacy of the system. PV panels and wind tubines ae depending on weathe conditions and they cannot geneate duing an entie day. The powe contolle commands the S1 switch closed when the RES systems ae not poducing enough to cove the load. In this situation, the enegy consumption is povided by the national gid. + Load efeence Σ PV panels Powe ontolle - Σ wind tubines Σ Geneation S1 National Gid Geneation Fig. 9. PV-wind tubine hybid system famewok V. ONLUSIONS AND FUTURE WORK The use of enewable enegy souces fo electicity supply continues to gow. The pape popose a PV-wind tubine hybid system which consists of 36 sola cells PV panel and a wind tubine, which is able to supply the electicity needs fo a small community. 639

5 The system achitectue was modelled gadually: fist the PV panel model, then the wind tubine model was validated. The validation index was computed as the maximum elative eo duing a day (4 hous). The PV panel model was simulated in Matlab 015a/Simulink and the cuent and powe outputs wee achieved. In compaison with eal egisteed data fo a 1000W panel, an eo of 6% was obtained, which shows a good appoximation of the eal system. The wind tubine model was also simulated in Matlab 015a/Simulink and in this case, an eo of 1.% was obtained afte the compaison of the poposed model and a pedefined Simulink block model. The advantages of these models ae epesented by scalability and ease of use since the input paametes ae meteoological and constuctive, compaed to moe complex models. Still, the simulation pefomance is within accepted theshold (eo), as seen above. The highlights of this wok ae as follows: the PV model, the wind tubine model, both validated using eal data and the poposed achitectue of hybid PV-wind tubine system in ode to minimize the consume supply fom the national gid. Futhe wok will consist in simulating the hybid PV-wind tubine system using Matlab/Simulink with vaious scenaios, then stoage and diffeent components will be added to the poposed achitectue. AKNOWLEDGEMENT This wok was patially suppoted by the Romanian Ministy of Education and Reseach unde gant PNDI/PTE/016. ERENES [1] A. M. Shaaf, M.A.H. El-Sayed, A Novel Hybid Integated Wind-PV Mico o-geneation Enegy Scheme fo Village Electicity, Pocedings of IEEE Intenational Electic Machines and Dives onfeence, pp , 009. [] M. Fadaeenejad, M. A. M. Radzi, M. Z. A. AbKadi, H. Hizam, Assessment of Hybid Renewable Powe Souces fo Rual Electification in Malaysia, Renewable and Sustainable Enegy Reviews, Vol. 30, pp , 014. [3] S. Hashimoto, T. Yachi, T. Tani, A New Stand-Alone Hybid Powe System with Wind Tubine Geneato and Photovoltaic Modules fo a Small-Scale Radio Base Station, IEEJ Tansactions on Powe and Enegy, Vol. 15, No. 11, pp , 005. [4] Z. Altinkaya, A. Aslan, ompaison of enewable and conventional enegy costs by wavelet techniques, Intenational Jounal of Electonics, Mechanical and Mechatonics engineeing, vol., pp. [5] G F. Dagomi, O.E. Dagomi, Impovement of enegy consumed fom hybid systems integating enewable enegy souces, Advanced Mateials Reseach, Vol , pp: , 01 [6] I. Stamatescu, N. Aghia, I. Fgan, G. Stamatescu, S. St. Iliescu and V. alofi, Decision Suppot System fo a Low Voltage Renewable Enegy System, Enegies 017, 10(1), 118; doi: /en [7] R. henni, M. Makhlouf, T. Kebache, A. Bouzid, A detailed modeling method fo photovoltaic cells, Enegy, Vol. 3, Issue 9, Septembe 007, Pages [8] H. Bellia, R. Youcef, M. Fatima, A detailed modeling of photovoltaic module using MATLAB, NRIAG Jounal of Astonomy and Geophysics, Vol., Apil 014, Pages [9] accesed [10] S. S. Dihab, K. Sopian, Electicity geneation of hibid PV/wind systems in Iaq, Renewable Enegy, Vol. 35, pp ,010. [11] A. Jalilvand, R. Nooozian, M. Daabian, Modeling and contol of multi-level invete fo thee-phase gid-connected photovoltaic souces, Intenational Jounal on Technical and Physical Poblems of Engineeing, Issue 15, Vol. 5, No., pp , 013. [1] P.Nema, R.K. Nema, S. Rangneka., A cuuent and futue state of the at development of hybid enegy system using wind and PV-sola: A evie, Renewable and Sustainable Enegy Reviews, Vol. 13, 009. [13] H. Sun, X. Luo, J. Wang, Feasibility study of a hybid wind tubine system Integation with compessed ae enegy stoage, Applied Enegy Jounal, Vol.137, pp ,