MATLAB/Simulink Based Modelling of Solar Photovoltaic Cell

Transcription

1 MATLAB/Simulink Baed Modelling of Solar Photovoltaic Cell Tarak Salmi *, Mounir Bouzguenda **, Adel Gatli **, Ahmed Mamoudi * *Reearch Unit on Renewable Energie and Electric Vehicle, National Engineering School of Sfax, Tuniia **Department of Electrical and Computer Engineering, College of Engineering, Sultan Qaboo Univerity, Sultanate of Oman Correponding Author; Tarak Salmi, National Engineering School of Sfax, P.O.B: W, 3038 Sfax, Tuniia, ,[email protected], [email protected], [email protected], [email protected] Received: Accepted: Abtract-Thi paper focue on a Matlab/SIMULINK model of a photovoltaic cell. Thi model i baed on mathematical equation and i decribed through an equivalent circuit including a photocurrent ource, a diode, a erie reitor and a hunt reitor. The developed model allow the prediction of PV cell behaviour under different phyical and environmental parameter. The model can alo be ued to extract the phyical parameter for a given olar PV cell a a function of temperature and olar radiation. In addition, thi tudy outline the working principle of PV module a well a PV array. In order to validate the developed model, an experimental tet bench wa built and the obtained reult exhibited a good agreement with the imulation one. Keyword-Matlab, SIMULINK, PV, olar cell model, olar array model, olar radiation, maximum power point 1. Introduction The development of new energy ource i continuouly enhanced becaue of the critical ituation of the chemical indutrial fuel uch a oil, ga and other. Thu, the renewable energy ource have become a more important contributor to the total energy conumed in the world. In fact, the demand for olar energy ha increaed by 20% to 25% over the pat 20 year [1]. The market for PV ytem i growing worldwide. In fact, nowaday, olar PV provide around 4800 GW. Between 2004 and 2009, grid connected PV capacity reached 21 GW and wa increaing at an annual average rate of 60% [2]. In order to get benefit from the application of PV ytem, reearch activitie are being conducted in an attempt to gain further improvement in their cot, efficiency and reliability. With no pollutant emiion, Photovoltaic cell convert unlight directly to electricity. They are baically made up of a PN junction. Figure 1 how the photocurrent generation principle of PV cell. In fact, when unlight hit the cell, the photon are aborbed by the emiconductor atom, freeing electron from the negative layer. Thi free electron find it path through an external circuit toward the poitive layer reulting in an electric current from the poitive layer to the negative one. Fig.1.Photocurrent generation principle. Typically, a PV cell generate a voltage around 0.5 to 0.8 volt depending on the emiconductor and the built-up technology. Thi voltage i low enough a it cannot be of ue. Therefore, to get benefit from thi technology, ten of PV cell (involving 36 to 72 cell) are connected in erie to form a PV module. Thee module can be interconnected in erie and/or parallel to form a PV panel. In cae thee module are connected in erie, their voltage are added with the ame current. Neverthele, when they are connected in parallel, their current are added while the voltage i the ame. Three major familie of PV cell are monocrytalline technology, polycrytalline technology and thin film

2 technologie. The monocrytalline and polycrytalline technologie are baed on microelectronic manufacturing technology and their efficiency i in general between 10% and 15% for monocrytalline and between 9% and 12% for polycrytalline. For thin film cell, the efficiency i 10% for a-si, 12% for CuInSe2 and 9% for CdTe [3]. Thu, the monocrytalline cell that ha the highet efficiency i the focu of thi paper. Thi paper carried out a Matlab/SIMULINK model of monocrytalline PV cell that made poible the prediction of the PV cell behaviour under different varying parameter uch a olar radiation, ambient temperature, erie reitor, hunt reitor, diode aturation current, etc. The focu of thi paper i on olar cell modelling which i dicued in ection two. Section three preent the effect of the variation of the olar radiation. In ection four, the influence of temperature on the PV cell output are invetigated. The effect of the erie reitance have been preented in ection five. Section ix focue on the effect of the hunt reitance. In ection even, the effect of the diode revere aturation current are tudied. The model feature and it experimental validation are dicued in ection eight through ten. While concluion and future work are preented in ection eleven. and R h, the I-V and P-V curve are generated a hown in Fig.4. Fig. 3. PV cell Matlab/SIMULINK model. 2. PV cell model The equivalent circuit of a PV cell i hown in Fig. 2. It include a current ource, a diode, a erie reitance and a hunt reitance [4, 5]. Fig. 4.I-V curve and P-V curve for a given PV cell 3. Effect of Solar Radiation Variation The above model include two ubytem: one that calculate the PV cell photocurrent which depend on the radiation and the temperature according to equation (2) [3]. I ph I c K i T (2) Fig. 2.PV cell equivalent circuit. In view of that, the current to the load can be given a: [6,7,8] R I V R I q V I I I ph exp 1 (1) NKT R h In thi equation, I ph i the photocurrent, I i the revere aturation current of the diode, q i the electron charge, V i the voltage acro the diode, K i the Boltzmann' contant, T i the junction temperature, N i the ideality factor of the diode, and R and R h are the erie and hunt reitor of the cell, repectively. A a reult, the complete phyical behaviour of the PV cell i in relation with I ph, I, R and R h from one hand and with two environmental parameter a the temperature and the olar radiation from the other hand. Baed on equation (1), the Matlab/SIMULINK model of Fig.3 wa developed. For a given radiation, temperature, R where K i = A/ C i the cell' hort circuit current temperature coefficient and β i the olar radiation (W/m 2 ). Baed on the above equation, the ubytem of Fig. 5 i obtained and the model imulation reult are hown in Fig. 6 and 7. Fig. 5. I ph Matlab/SIMULINK ubytem for varying cell temperature and olar radiation. A it can be een from Fig.6 and 7, the PV cell current i trongly dependent on the olar radiation. However, the 214

3 voltage ha a 50 mv increae a the olar radiation increaed from 400 W/m 2 to 1000 W/m 2. In general, for a given olar radiation, when the cell temperature increae, the open circuit voltage V oc, drop lightly, while the hort circuit current increae. Thi behaviour i validated and preented in Fig. 9 and 10. Fig.6.I-V curve for different olar radiation. Fig.9.I-V curve for different cell temperature. Fig.7.P-V curve for different olar radiation. 4. Effect of Varying Cell Temperature The diode revere aturation current varie a a cubic function of the temperature and it can be expreed a: I 3 T T E g T I exp 1 T T N V nom nom. t where I i the diode revere aturation current, T nom i the nominal temperature, E g i the band gap energy of the emiconductor and V t i the thermal voltage. The revere aturation current ubytem hown in Fig.8 wa contructed baed on equation (3). (3) Fig.10.P-V curve for different cell temperature. 5. Effect of Varying R The erie reitance of the PV cell i low, and in ome cae, it can be neglected [3]. However, to render the model uitable for any given PV cell, it i poible to vary thi reitance and predict the influence of it variation on the PV cell output. A een in Fig.11 and 12, the variation of R affect the lope angle of the I-V curve reulting in a deviation of the maximum power point. Fig.11.I-V curve for different R. Fig. 8. Matlab/SIMULINK temperature effect ubytem on diode revere aturation current. 215

4 7. Effect of Varying I. The model ait in expecting the behaviour of the PV cell for different revere aturation current of the diode. The curve of Fig.15 and 16 were plotted for three different value of I : 100nA, 10nA and 1nA. The influence of an increae in I i evidently een a decreaing the open-circuit voltage V oc. 8. PV Module Fig.12.P-V curve for different R The imulation wa performed for three different value of R, namely 1mΩ, 4mΩ and 8mΩ. It wa hown that higher value of R reduce the power output of the PV cell. According to equation (4), the fill factor, given by equation (4), decreae a R increae. P FF V max oc I c (4) A previouly mentioned, a PV module i a connection of ten of PV cell. Figure 17 how the bloc diagram of Matlab/SIMULINK model of a PV module. Thi model contain an external control block permitting an uncomplicated variation of the model parameter. In thi model, 36 PV cell are interconnected in erie to form one module. A a reult, the module voltage i obtained by multiplying the cell voltage by the cell number while the total module current i the ame a the cell one. The reult are hown in Fig.18 and Effect of Varying R h The hunt reitance of any PV cell hould be large enough for higher output power and fill factor. In fact, for a low hunt reitor, the PV cell current collape more teeply which mean higher power lo and lower fill factor. Thee reult can be een in Fig.13 and 14. Fig.15.I-V curve for different I Fig.13.I-V characteritic for different Rh Fig.16.P-V curve for different I Fig.14.P-V curve for different Rh Fig.17. SIMULINK model for the PV module. 216

5 Fig.18.I-V curve of the PV module model Fig.21.I-V curve for the PV array model 9. PV Array Fig.19.P-V curve of the PV module model In order to get benefit from thee developed model, an array of 6 PV module ha been contructed. In fact, thee PV module were interconnected in erie and all of them are connected to the external control block a hown in Fig.20. Fig.22.P-V curve for the PV array model 10. Experimental Reult and Validation In order to validate the Matlab/SIMULINK model, The PV tet bench of Fig.23 wa invetigated. It conit of a rheotat, a daytar-meter to meaure the olar radiation, two digital multi-meter and a olar panel that ha the key pecification lited in Table 1. Fig.20. PV array model. The PV array model wa imulated imilarly to the model of the PV module and the obtained reult are hown in Fig.21 and 22, repectively. Fig. 23. Setup of the PVL-124 olar laminate panel. 217

6 Current (A) Power(W) INTERNATIONAL JOURNAL of RENEWABLE ENERGY RESEARCH Table 1. Electrical pecification for the tet panel Solar Laminate PVL-Serie Model: PVL-124 Maximum power 124 W Voltage at P max 30 V Current at P max 4.1 A Open circuit voltage 42 V Short circuit current 5.1 A The Matlab/SIMULINK model wa evaluated for the PVL-124 olar panel. The reult are hown in Fig.24. On the other hand, the experimental reult for a olar radiation of 540 W/m 2 are hown in Fig. 25. The I-V and P-V imulation and experimental reult how a good agreement in term of hort circuit current, open circuit voltage and maximum power. In thi tudy, the Matlab/SIMULINK model not only help to predict the behavior of any PV cell under different phyical and environmental condition, alo it can be conidered a mart tool to extract the internal parameter of any olar PV cell including the ideal factor, erie and hunt reitance. Some of thee parameter are not alway provided by the manufacture. 11. Concluion A Matlab/SIMULINK model for the olar PV cell, module and array wa developed and preented in thi paper. Thi model i baed on the fundamental circuit equation of a olar PV cell taking into account the effect of phyical and environmental parameter uch a the olar radiation and cell temperature. The module model wa imulated and validated experimentally uing the high efficient PVL-124 olar laminate panel. A a reult of the tudy, one can benefit from thi model a a photovoltaic generator in the framework of the Sim- Power-Sytem Matlab/SIMULINK toolbox in the field of olar PV power converion ytem. In addition, uch a model would provide a tool to predict the behaviour of any olar PV cell, module and array under climate and phyical parameter change Iim Voltage (V) Pim Pmax=101.8 W Voc=39.4 V Fig.24.MATLAB imulation reult Current (A) Fig. 25.PVL-124 olar laminate panel experimental reult. Reference Iexp Pexp Pmax=99.5 W Voc=40 V Voltage (V) [1] Jeyraj Selvaraj, Narudin A. Rahim, Multilevel Inverter For Grid-Connected PV Sytem Employing Digital PI Controller, IEEE Tranaction On Indutrial Electronic, vol. 56, No. 1, pp , [2] Renewable Energy Policy Network for the 21t Century (REN21), Renewable 2010 Global Statu Report, Deutche Geellchaftfür Techniche Zuammenarbeit (GTZ) GmbH, pp. 19, [3] Savita Nema, R.K. Nema, Gayatri Agnihotri, MATLAB/Simulink baed tudy of photovoltaic cell / module / array and their experimental verification, International journal of Energy and Environment, vol.1, No.3, pp , [4] Huan-Liang Tai, Ci-Siang Tu, Yi-Jie Su, Development of Generalized Photovoltaic Model Uing MATLAB/SIMULINK, Proceeding of the World Congre on Engineering and Computer Science WCECS, San Francico, USA, [5] Francico M, González-Longatt, Model of Photovoltaic Module in Matlab, 2do congreoı beroamerı cano de etudıante de ıngenıeríaeléctrı ca, electrónıca y computacıón pp.1-5, [6] S. Rutemli, F. Dincer, Modeling of Photovoltaic Panel and Examining Effect of Temperature in Matlab/Simulink, Electronic and Electrical Engineering, ISSN , no. 3(109), pp , [7] Kinal Kachhiya, Makarand Lokhande, Mukeh Patel, MATLAB/Simulink Model of Solar PV Module and MPPT Algorithm, Proceeding of the National Conference on Recent Trend in Engineering and Technology, [8] I.H. Atla, A.M. Sharaf, A Photovoltaic Array Simulation Model for Matlab-Simulink GUI Environment, International Conference on Clean Power, pp , Power(W) 218