ResearchofPVModelandMPPTMethodsinMatlab-solarbe文库

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Notice of Retraction After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE s Publication Principles. We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper. The presenting author of this paper has the option to appeal this decision by contacting TPIIieee.org .Research of PV Model and MPPT Methods in Matlab Wang NianCHun, Sun Zuo School of Electrical Engineering SouthEast University Nanjing, 210096, China E-mail wxy01seu.edu.cn Kazuto Yukita, Yasuyuki Goto, Katsuhiro Ichiyanagi Department of Electrical and Electronic EngineeringAichi Institute of Technology Nagoya, 470-0392, Japan E-mail itiyaaitech.ac.jpAbstract The power generated by the PV generator depends on the irradiance, temperature, and surface conditions. The PV generator has a nonlinear characteristic, and the power has a maximum power point or multi-local maximum power points under different conditions. Various MPPT methods have been reported, in order to confirm the effectiveness of each control method, experimental or simulation analysis is used, from economical point of view, simulation analysis is more effective. In this paper, a versatile, accurate Matlab/Simulink PV model suitable for use by power electronics specialists has been developed, and has been designed for easy implementation on Matlab/Simulink platform; conventional MPPT methods and MPPT methods suitable for partial shading conditions can be simulated by using this PV model.Keywords- Maximum power point tracking; PV model; shading PV characteristic curves; dP/dV; Matlab/Simulink I. INTRODUCTIONOCVMPPVPV VoltageV0 5 10 15 20 25 30PVPowerW0408012016020021000 /G W m25CT C °MPPdP/dV0dP/dV0 dP/dV02600 /G W m2200 /G W m / ConstantMPP OCV V ≈Figure 1. SPG1786T-02E PV modules with different irradiation P-Vcurves calculated by modelThe power delivered by the PV generator depends on the environmental factors irradiance, temperature, and shadowing conditions, it is never constant over time. Whatsoever stand-alone system or connected-grid system, and whatsoever two stages of PV converter system or single stage PV converter system, it is very important to operate PV energy conversion systems near maximum power point MPP to obtain the approximately max power of PV generator. Many maximum power point tracking MPPT methods have been developed, such as [1]-[5] 1Constant Voltage method CV; 2Perturbation and Observation method P 3Incremental Conductance method IncCond etc. The CV method is based on the fact that generally the ratio VMPP/VOC≈ 0.76 Fig. 1. In this algorithm, the MPPT controller periodically sets the PV generator current to zero to allow a measurement of the PV ’ s open circuit voltage. A problem with this algorithm is that the available energy is wasted when the PV generator current is set to zero, and at the same time power supply is interrupted, also the MPP is not always located at 76 of the PV ’ s open circuit voltage. The last two methods are so called “ hill-climbing ” methods, and they using the fact that the PV power-voltage curve having only one peak value along with whole scope voltage Fig. 1. The advantages of the P complicated computation and more computational time; confused in rapidly changing environmental factors. II. PV M ODULE M ODEL IN M ATLAB /SIMULINKThe mathematic equations described PV model can be divided into four aspects [6] 1Relations between solar cell temperature and ambient temperature 22 0.03c a a2Km /WT T C GC 1 2Expressions of PV photocurrent I PH 1 1, 1,1 / aPH c c sc c nom sc c noma nomGI T T I T I TGα - 2 3Expressions of PV open circuit voltage V OC1 13 2.3 10OC OC c c cV/KV V T T Tββ - - - 3 Strictly speaking, V OC is not only affected by solar cell temperature, but also by irradiance, especially at low irradiation strength. This research was partly supported by the Ministry of Education, Science,Sports and Culture of Japan, Private University Scientific Study AdvancementPromotion Work in 2006, Social Cooperation Promotion Work,“ Development of New Electric Power Supply System by Micro-grid Network ” . 978-1-4244-4813-5/10/25.00 2010 Crown4Expressions of PV I-V 1111 1, 1,3 1 11 /1 1 / 11gc cOC c scScac c sc c nom sc c noma nomqVnnk T Tsc c cqV T NcnkTq V IRnkT SSHGI T T I T I TGI T T eTeV IReRα - - - - - - - 4 The model of the PV module was implemented using a Matlab/Simulink Level 2 s-function. The model parameters are evaluated during execution using the equations 1 4. There are 24 input parameters in the model. The model considers the series resistance and shunt resistance, by set the input parameter TestRp greater than 1, the influence of RSH is calculated. Because equation 4 is non-linear, so it only can be solved using numerical methods, the Newton-Raphson method was used in this paper model. Symbols in equations refer to [6]. The I-V, P-V curves under various irradiance and constant temperature calculated by Matlab/Simulink model show good correspondence to the manufacturer ’ s published curves [6]. Figure 2. Equivalent circuit diagram of the PV model III. M PPT M ETHODS SIMULATION U SING PV M ODEL IN M ATLAB /SIMULINK A. IMPP /ISC Constant Method CI Method Like V MPP/V OC≈ constant at MPP, I MPP/I SC at maximum power point is also nearly constant; the curve shape is almost smooth along with whole scope irradiation, the ratio of VMPP /V OC is affected mainly by solar cell temperature Fig. 3. In this algorithm, if the ratio of I MPP/I SC is calculated or tested at different temperature first, then the MPPT controller need a temperature sensor to detect solar cell temperature to realize a simple, speed and accurate MPPT. In fact, temperature sensor is not necessary, the MPPT controller periodically close a short-circuit switch to allow a measurement of the PV ’ s short circuit current, and considers the ratio of IMPP/ISC is nearly constant. A problem with this algorithm is that the available energy is wasted when the short-circuit switch turns on, and at the same time power supply is interrupted. 100 200 300 400 500 600 700 800 900 1000I MPP/I SCMPP.90.92.94.96.981.001.022 / Irradiation W m20cT C - °5cT C - °25cT C °10cT C °40cT C °Figure 3. I MPP/I SC at MPP versus irradiation curve calculated by model B. dP/dV Versus I Control Method The P 2Short-circuit current pulse method [13]; 3Fibonacci search method [14]. This method gives fast response, and it is able to handle multi-local maximum points, but it requires powerful digital microcontroller to calculate the process; 4State-based space approach [15]; 5Compound MPPT methods combined with conventional MPPT methods [16]. IV. CONCLUSIONSMPPT methods are very important for PV generator, many papers have been reported various MPPT control techniques, most of them are brought forwards and verified by experiments. In this paper, a versatile, accurate Matlab/Simulink PV model suitable for use by power electronics specialists has been developed, and has been designed for easy implementation on Matlab/Simulink platform. By using the model, several MPPT methods are verified, the simulations results show good correspondence to the results of theoretic analysis. Most of MPPT methods are based on hill-climbing algorithms, but the method can ’ t work correctly if some panels of PV generator are partially shaded. This paper gives a simple overview of MPPT methods suitable for partially shaded PV generator, and the P-V characteristics of PV generator under partial shading conditions are simulated by model, MPPT methods under partial shading conditions will be examined in later research. A CKNOWLEDGMENTThis research was partly supported by the Ministry of Education, Science, Sports and Culture of Japan, Private University Scientific Study Advancement Promotion Work in 2006, Social Cooperation Promotion Work, “ Development of New Electric Power Supply System by Micro-grid Network ” . Authors would like to greatly appreciate for this grant program. REFERENCES[1] Z. Salameh, F. Dagher and W. A. Lynch, “ Step-Down Maximum Power Point Tracker for Photovoltaic System, ” Solar Energy, Vol. 46, No. 1, pp. 278-282, 1991. [2] K. H. Hussein, I. Muta, T. Hoshino, and M. Osakada, “ Maximum Photovoltaic Power Tracking An Algorithm for Rapidly Changing Atmospheric Conditions, ” IEEE proc. Gener. Transm. Distrib, Vol. 142, No. 1, pp. 59-64, Jan, 1995. [3] E. Koutroulis, K. Kalaitzakis, and N. C. Voulgaris, “ Development of a Microcontroller-Based Photovoltaic Maximum Power Point Tracking Control System, ” IEEE Trans. On Power Electronics, Vol. 16, No, 1, pp. 46-54, Jan, 2001. [4] K. 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