A linear identification of diode models from single I-V characteristics of PV panels

This paper presents a novel approach on diode model parameters identification from the I-V characteristics of PV panels. Other than the prevailing methodology of solving a group of nonlinear equations from a few points on the I-V curve, the proposed one views the diode model as the equivalent output of a dynamic system. From this new viewpoint, diode model parameters are linked to the transfer function (after Laplace transform) of the same dynamic system whose parameters are then identified by a simple integral-based linear square. Indoor flash test shows the accuracy and effectiveness of the proposed method, and outdoor module testing shows its ability of online monitoring and diagnostics. Comparisons to the methods of Lambert W function and evolution algorithms are also included

Modelling and Parameter Identification Using Reduced I-V Data

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PV Parameter Identification using Reduced I-V Data

In this paper, possibility and accuracy of using reduced I-V data in PV parameter identification are discussed. Based on the linear identification method proposed in [1], six I-V points are used instead of the whole I-V curve to identify the PV parameters. The maximum power point (MPP) is then estimated using the identified I-V and P-V characteristics. Validation is done by using different sets of six points on the I-V curve. Experiment results show that the accurate curve fitting (with low RMSE and MPE) and good estimation of MPP can be achieved

An Improved Oblique Asymptote Method for Parameter Identification of PV Panels

A single-diode model is the most important and broadly used tool for PV module design and analysis. The model has 5 parameters to be identified from the I-V characteristics curves. However, due to the lack of explicit form of I or V with the unknown 5 parameters, parameter identification is very difficult. Recent progress in PV model identification are discussed in this paper with the simulation of MATLAB against the measured data from a real PV module. An improved Oblique Asymptote Method is then proposed and compared with existing identification methods. Test results show that the proposed method achieves lower RMSE with less knowledge of I - V data points

Non-Contact Measurement of POA Irradiance and Cell Temperature for PV Systems

This paper presents a non-contact measurement of irradiance on plane of array (POA) and cell temperature for PV systems. The idea is motivated from the diode model of PV, where POA irradiance and cell temperature are proportional to the photocurrent and modified ideality factor, respectively. Based on the recent progress of diode model identification, the photocurrent and modified ideality factor can be linearly determined from I-V characteristics, which makes it feasible to develop a non-contact measurement approach for POA irradiance and cell temperature, i.e., both of them will be derived completely from the diode mode parameter identification without the need of any sensors. The calibration of the proportional factors is done from the indoor module flash test and then applied to outdoor module testbed to show the accuracy and effectiveness of the proposed method

Transformada de Laplace y sus aplicaciones en sistemas dinámicos: una revisión

This paper presents a review of Laplace Transform (LT) applications in the analysis of linear dynamic systems. Is presented the importance of the transforms; the definition of the Transform; theorems and properties with applications and finally, the use of LT for the calculation of: steady state error, transfer functions, ordinary differential equations solution, frequency responses, signal analysis and block diagrams. The modeling and operational analysis with LT of a multipurpose reactor is proposed as a didactic situation for academic purposes.Este artículo presenta una revisión sobre las aplicaciones de la transformada de Laplace (TL) en el análisis de sistemas dinámicos lineales. Se presenta la importancia de la transformada; la definición de la transformada; los teoremas y propiedades con aplicaciones y por último, aplicaciones del uso de la TL para el cálculo de: error de estado estacionario, funciones de transferencia, solución de ecuaciones diferenciales ordinarias, respuestas en frecuencia, análisis de señales y diagramas de bloques. Se propone, como situación didáctica para propósitos académicos, el modelamiento y análisis operacional con TL de un reactor multipropósito

Metaheuristic Algorithm for Photovoltaic Parameters: Comparative Study and Prediction with a Firefly Algorithm

In this paper, a Firefly algorithm is proposed for identification and comparative study of five, seven and eight parameters of a single and double diode solar cell and photovoltaic module under different solar irradiation and temperature. Further, a metaheuristic algorithm is proposed in order to predict the electrical parameters of three different solar cell technologies. The first is a commercial RTC mono-crystalline silicon solar cell with single and double diodes at 33 °C and 1000 W/m2. The second, is a flexible hydrogenated amorphous silicon a-Si:H solar cell single diode. The third is a commercial photovoltaic module (Photowatt-PWP 201) in which 36 polycrystalline silicon cells are connected in series, single diode, at 25 °C and 1000 W/m2 from experimental current-voltage. The proposed constrained objective function is adapted to minimize the absolute errors between experimental and predicted values of voltage and current in two zones. Finally, for performance validation, the parameters obtained through the Firefly algorithm are compared with recent research papers reporting metaheuristic optimization algorithms and analytical methods. The presented results confirm the validity and reliability of the Firefly algorithm in extracting the optimal parameters of the photovoltaic solar cell

A Method for the Analytical Extraction of the Single-Diode PV Model Parameters

Determination of PV model parameters usually requires time consuming iterative procedures, prone to initialization and convergence difficulties. In this paper, a set of analytical expressions is introduced to determine the five parameters of the single-diode model for crystalline PV modules at any operating conditions, in a simple and straightforward manner. The derivation of these equations is based on a newly found relation between the diode ideality factor and the open circuit voltage, which is explicitly formulated using the temperature coefficients. The proposed extraction method is robust, cost-efficient, and easy-to-implement, as it relies only on datasheet information, while it is based on a solid theoretical background. Its accuracy and computational efficiency is verified and compared to other methods available in the literature through both simulation and outdoor measurements