The performance of a photovoltaic (PV) module is represented by a single-diode-model circuit with the five parameters for a given environmental condition. However, the model characteristic equation which is implicit in nature makes the parameters’ extraction computationally complex. In addition, for finding the five parameters from the specifications of the PV module datasheet, one can formulate only four equations. To complete the solution, the formulation of the fifth equation is really tricky. Therefore, the researchers have attempted several approximations to complete the problem formulation, but the obtained results have low accuracy in many cases. This paper specifically focuses on the formulation of the fifth equation without any approximation, which considers an exact area under the current–voltage ( I – V ) curve of a PV cell/module. The method is employed for different cells as case study-I and for the experimental data of a silicon cell and a module as case study-II commonly available in the literature. The numerical results are highly accurate with respect to the existing methods.

Accurate Expressions for Single-Diode-Model Solar Cell Parameterization

Photovoltaic (PV) systems are subject to nearby lightning strikes that can contribute to extremely high induced overvoltage transients. Recently, the authors introduced a 3D semi-analytical method to study the electromagnetic transients caused by these strikes in a PV module. In the present paper we develop an improved model of the PV module that: (a) takes into account high-frequency effects by modelling capacitive and inductive couplings; (b) considers the electrical insulation characteristics of the module; (c) includes the connection to a DC/DC converter. The whole process involves three major steps, i.e., the magnetic-field computation, the evaluation of both common-mode- and differential-mode-induced voltages across the PV module, and the use of the calculated voltages as input to a lumped equivalent circuit of the PV module connected to the DC/DC converter. In such a framework, the influence of the PV operating condition on the resulting electrical stresses is assessed; moreover, the relevance or insignificance of some parameters, such as the module insulation or the frame material, is demonstrated. Finally, results show that the induced overvoltage are highly dependent both on the grounding of the conducting parts and on the external conditions such as lightning current waveforms and lightning channel (LC) geometry.

Modeling of PV Module and DC/DC Converter Assembly for the Analysis of Induced Transient Response Due to Nearby Lightning Strike

Solar energy has become a popular renewable energy source, leading to wide use of photovoltaic (PV) cells/modules in energy production. For this reason, realistic modeling of PVs and determining the equivalent circuit parameters is of great importance in terms of planning and operation. Hence, in this study, an analytical model for identifying the single-diode equivalent circuit parameters; series resistance (Rs ), shunt resistance (Rp ), diode ideality factor (a), diode reverse-saturation current (Io ), and photon current (Ipv ) for PV cells/modules is developed without neglecting any term. In order to test the accuracy of the model, a number of PV modules from different manufacturers are taken into account and the results are compared with those obtained by using such analytical models given in the literature. Current-voltage (I-V ) characteristics of the PV modules, which are studied here, are also simulated by comparing with the experimental I-V curves provided by the manufacturers. Results show that the values of the parameters obtained for the PV modules are consistent with those extracted by using other analytical models. In addition, I-V curves created by using the obtained parameters are in full agreement with the experimental data. The curves also show a high degree of compatibility with the ones created by using the optimal parameters of the two-diode models given in the literature. Moreover, the proposed model provides a great advantage in estimating equivalent circuit parameters in terms of ease of use, requirements for input data, dependency on initial conditions as well as considering the parameters which are neglected in such methods given in the literature.

https://journals.tubitak.gov.tr/elektrik/issues/elk-19-27-4/elk-27-4-46-1805-161.pdf

A new approach for parameter estimation of the single-diode model for photovoltaic cells/modules

Solar Photovoltaic is a very promising solution that can greatly contribute in solving the increasing global energy demand. In both rural and urban areas, photovoltaic modules are in some instances installed close to telecommunication antennas or voltage transformers which generate important magnetic fields in their vicinity. The question is whether or not these magnetic fields affect the performances of the photovoltaic installations. This article presents a modelling study of external magnetic field effect on the electrical parameters of a photovoltaic module. The photocurrent, the photovoltage, the electric power, the series and the shunt resistances of the photovoltaic module, made up of ideal cells, are deduced from those of a silicon solar cell. Then, the I-V and P-V curves are plotted and the theoretical values of the electrical parameters of the photovoltaic module are deduced. The series and shunt resistances of the photovoltaic module are calculated using well known equations and the previous electrical parameters. The results show the negative effect of magnetic field on the performance of a solar photovoltaic module.

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Modelling Study of Magnetic Field Effect on the Performance of a Silicon Photovoltaic Module

An enhanced two diode photovoltaic (PV) model is proposed to estimate accurately the current-voltage (I-V) characteristic curves of the PV modules. In the proposed method, only four parameters of the two diode PV model are needed to calculate from seven parameters with reasonable computational effort. In this paper, a new expression is developed to find the value of reverse saturation current (Isat) using two diode PV model's I-V characteristic curve equation considering the effects of temperature and irradiation on the value of shunt and series resistances. A Numerical technique is used to determine the value of output current, series and shunt resistance of the proposed PV model. For validating the proposed PV model, five different PV modules are tested at various weather conditions. The proposed PV model is simple and accurate and it is useful to design the suitable MPPT converter.

An enhanced analysis of two diode model PV module under various weather conditions

The objective of this paper is to estimate the values of five parameters (A , Rse , Rsh , ILG , and Isat) of a PV module more accurately and to extract the maximum power point (MPP) accurately under varying environmental conditions. Suitable new equations are proposed, by which the values of the series and shunt resistances are initialized in order to obtain good convergence speed in the Gauss–Seidel method. In this work, two new equations are proposed to find the ideality factor and shunt resistance and to obtain accurate MPP of the PV model under varying environmental conditions. The proposed PV model is validated at standard test conditions and under varying environmental conditions. Current–voltage and power–voltage characteristics of different PV modules are simulated using MATLAB. Accuracy of the proposed model is validated by comparing with the results of an adaptive neuro-fuzzy inference system and experimental data taken under varying environmental conditions.

https://journals.tubitak.gov.tr/elektrik/issues/elk-16-24-4/elk-24-4-3-1312-268.pdf

A new method for accurate estimation of PV module parameters and extraction of maximum power point under varying environmental conditions

In this paper, an improved mathematical model of a single-diode photovoltaic (PV) module has been developed to predict the maximum power of the PV modules produced by different PV technologies, suc...

Mohamed Saleem Abdul Kareem

Papers

A new method for accurate estimation of PV module parameters and extraction of maximum power point under varying environmental conditions

A novel modeling approach to predict the output performance of photovoltaic modules under different environmental conditions