APPROXIMATION ALGORITHM FOR CURRENT-VOLTAGE CHARACTERISTICS OF PV MODULES UNDER SHADING CONDITIONS


Keywords: PV plants, PV modules, solar radiation, partial shading, approximation of CVC

Abstract

This work is devoted to modeling of current-voltage characteristic (СVC) of a PV module on the base of experimental data obtained using a measuring device with a variable load. The class of approximating functions is defined and the approximation algorithm is constructed. The developed method of processing data obtained from the microcontroller's analog-digital converter (ADC) via a PC serial interface is intended for building CVC and power characteristic under shading conditions. The technique is based on the construction of a model function, which approximate a multistage CVC of shaded PV modules (the CVC curves have been obtained for four levels of shading). The number of steps of the obtained experimental curve and the number of maximum power points are determined by the number of bypass diodes in PV module. As an example, the effect of vertical partial shading on the operating mode of a polycrystalline PV module in album orientation with two diodes is investigated. The total experimental curve is modeled by a corresponding piecewise polynomials: the CVC of the partially shaded module is represented as a superposition of two single-step I–V curves, which correspond to a single-diode equivalent circuit. The proposed algorithm for polynomial approximation of a multi-step CVC makes it possible to simulate the characteristics of shaded PV modules with high accuracy. The proposed class of approximating functions was tested on large arrays of raw experimental data. The obtained CVC allows one to estimate the real parameters of PV module. The speed and simplicity of the developed method give the possibility for calculating the PV module parameters on the base of experimental data obtained in field under shading conditions. The method allows to determine in real-time the operating maximum power point in changing of shading conditions, as well as predict the yield of PV module arrays and carry out their diagnostics. Ref. 24, fig. 6.

References

1. Kudrya S.O. Netradicіjna ta vіdnovlyuvana energetika. [Alternative and Renewable Energy]. Kyiv. NTUU “KPI”. 2012. 490 p. [in Ukrainian].

2. Daffi Dzh.A. Teplovye processy s ispolzovaniem solnechnoj ehnergii. [Heat processes using solar energy]. M. Mir. 1977. 420 p. [in Russian].

3. Markvart T., Castafier L. Practical Handbook of Photo-voltaics: Fundamentals and Applications. Oxford. UK. Elsevier. 2003. 988 p. [in English].

4. Mondol J.D., Yohanis Y.G., Norton B. The impact of ar-ray inclination and orientation on the performance of a grid-connected photovoltaic system. Renewable Energy. 2007. v. 32.

Pp. 118-140. [in English].

5. Gaevskij A.Yu., Gaevskaya A.N. Metod opredeleniya op-timalnogo ugla naklona i orientacii fotoehlektricheskih modulej na osnove ehksperimentalnyh dannyh solnechnoj radiacii. [Method for determining of the optimal title angle and orientation of PV modules based on solar radiations data]. Alternativnaya ehnergetika i ehkologiya. 2018. №13-15. Pp.15-29. [in Russian].

6. Gaevskij A.Yu., Demin D.A. Vliyanie ugla naklona i plotnosti raspolozheniya fotomodulej na ehffektivnost FES. [In-fluence of tilt angles and arrangement dencity of PV moduls on the efficiency of PV system]. Alternativnaya ehnergetika i ehkologiya. 2018. No. 25-27. Pp. 273-275. [in Russian].

7. Rauschenbach H.S. Electrical output of shadowed solar arrays. IEEE Trans. Electron Dev. 1971. v. 1. No. 8. [Electronic resource]. URL: http://dx.doi.org/. [in English].

8. Kawamura H. et al. Simulation of I-V characteristics of a PV module with shaded PV cells. Solar Energy Materials & Solar Cells. 2003. v. 75. Pp. 613-621. [in English].

9. Quaschning V., Hanitsch R. Numerical simulation of current–voltage characteristics of photovoltaic systems with shad-ed solar cells. Sol. Energy. 1996. v. 56. Pp. 513-520. [in English].

10. Deline C. A simplified model of uniform shading in large photovoltaic arrays. Solar Energy. 2013. v. 96. Pp. 274-282. [in English].

11. Abdullah Al Mamun M. Experimental investigation of the effect of partial shading on photovoltaic performance. IET Renewable Power Generation. 2017. v. 11. No. 7. Pp. 912-921. [in English].

12. Bishop J.W. Computer simulation of the effects of elec-trical mismatches in photovoltaic cell interconnection circuits. Solar Energy Mater. Solar Cells. 1988. v. 25. Pp. 73-89. [in Eng-lish].

13. Andreev V.M., Grilihes V.A., Rumyancev V.D. Fotoeh-lektricheskoe preobrazovanie koncentrirovannogo solnechnogo izlucheniya. [Photoelectric Conversion of Concentrated Solar Radiation]. L. Nauka. 1989. 310 p. [in Russian].

14. Ma J., Man K. Approximate Single-Diode Photovoltaic Model for Efficient I-V Characteristics Estimation. The Scientific World Journal. 2013. v. 2013. 7 p. Article ID 230471. [in Eng-lish].

15. Tamrakar V.L., Gupta S.C. et al. Single-diode and two-diode pv cell modeling using matlab for studying characteris-tics of solar cell under varying conditions. Electrical & Computer Engineering: An International Journal (ECIJ). 2015. v. 4. No. 2. Pp. 67-77. [in English].

16. Miceli R., Orioli A., Di Gangi A. A procedure to calcu-late the I–V characteristics of thin-film photovoltaic modules using an explicit rational form. Applied Energy. 2015. v. 155. Pp. 613-628. [in English].

17. Jia Q.X., Ebiharaand K., Ikegami T. Analytical solution for solar cell model parameters from illuminated current-voltage characteristics. Philosophical Magazine B. 1995. Vol. 7. Pp. 375-382. [in English].

18. Ortiz-Conde A., Garcıa Sanchez F.J., Muci J. New method to extract the model parameters of solar cells from the explicit analytic solutions of their illuminated I–V characteristics. Solar Energy Materials & Solar Cells. 2006. v. 90. Pp. 352-361. [in English].

19. Zhang C. Zhang J., Hao Y. et al. A simple and efficient solar cell parameter extraction method from a single current-voltage curve. Journal of Applied Physics. 2011. v. 110. p. 064504. [in English].

20. Gaevskij A.Yu. Opredelenie parametrov fotoehlektrich-eskih modulej na osnove tochnogo resheniya uravneniya dlya VAH. [Determination of the PV modules parameters based on the exact solution of CVC equation]. Vіdnovluvana energetika. 2012. No. 4. Pp. 32-39. [in Russian].

21. Woyte A., Nijs J., Belmans R. Partial shadowing of pho-tovoltaic arrays with different system configurations: literature survey and field results. Solar Energy. 2003. v. 74. Pp. 217-233. [in English].

22. Ferhat-Hamida A., Ouennoughi Z., Hoffmann A., Weiss R. Extraction of Schottky diode parameters including paral-lel conductance using a vertical optimization method. Solid-State Electronics. 2002. v. 46. Pp. 615-619. [in English].

23. Kong K.C., Mamat M., Ibrahim M.Z. New Approach on Mathematical Modeling of Photovoltaic Solar Panel. Applied Mathematical Sciences. 2012. v. 6. No. 8. Pp. 381-401. [in Eng-lish].

24. Karatepe E., Boztepe M., Colak M. et al. Development of a suitable model for characterizing photovoltaic arrays with shaded solar cells. Solar Energy. 2007. v. 81. Pp. 977-992. [in English].

Author Biography

A Gaevskaya, NTUU «Ihor Sikorsky Kyiv Polytechnic Institute» 03056, 37, av. Peremogy, Kiev, Ukraine

gaevskaia.pngAutor information: Senior Lecturer of the Department of RES.
 Education: National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute», Faculty of Electricity, specialty "Electrical Insulation and Cable Engineering".
Research area: renewable energy, computer simulation.
Publications: 25.


Abstract views: 19
PDF Downloads: 14
Published
2019-09-25
How to Cite
Gaevskaya, A. (2019). APPROXIMATION ALGORITHM FOR CURRENT-VOLTAGE CHARACTERISTICS OF PV MODULES UNDER SHADING CONDITIONS. Vidnovluvana Energetika, (3(58), 21-29. https://doi.org/https://doi.org/10.36296/1819-8058.2019.3(58).21-29