Analytical solutions for the rapid extraction of single- and double-diode model parameters from experimental data are described. The resulting parameters' values are shown to have less than 10 percent error for most solar cells. Error contours are also illustrated to define the range of validity of these methods.

Analytical methods for the extraction of solar-cell single- and double-diode model parameters from I-V characteristics

A nonlinear least-squares optimization algorithm based on the Newton model modified with Levenberg parameter, is described for the extraction of the five illuminated solar cell parameters from the experimental data. An initialization routine based on the reduced nonlinear least-squares technique in which only two parameters have to be initialized, is introduced to overcome the difficulty in initializing the cell parameters. The program when incorporated into a microcomputer-based data acquisition software, allows an in-situ theoretical modelling of solar cells in laboratories. Results obtained for a commercial solar cell and a module are given.

Nonlinear Minimization Algorithm for Determining the Solar Cell Parameters with Microcomputers

Simulated Annealing algorithm for photovoltaic parameters identification

Parameter identification for solar cell models using harmony search-based algorithms

Artificial bee swarm optimization algorithm for parameters identification of solar cell models

The influence of minority carrier recombination in the depletion region of silicon solar cells on their current-voltage characteristics has been investigated. Starting with cells which exhibited a clear double-exponential dark characteristic of the form j = j_{01}[\exp (\frac{qV}{(A_{1}kT})-1] + j_{02}[\exp (\frac{qV}{A_{2}kT})-1] + \frac{V}{R_{sh}} with values A_{1} \approx 1 , A_{2} \approx 2 , and R sh large, depletion region recombination was studied by subjecting the cells to proton irradiation of 20- to 80-MeV energy at fluences of 1012to 1015cm-2, so as to introduce further recombination centers in the depletion region. A significant change of j 01 resulted rather than the expected change in j 02 which would be caused by the introduction of deeplying levels. It could be shown that this effect, included inthe Sah, Noyce, Shockley formulation of diode current resulting from recombination in the depletion region, Was caused by the introduction of shallow levels in the depletion region by the proton irradiation. The analysis required an accurate measurement of the I-V Characteristics over a range of temperatures and an evaluation of them with a least squares Curve fitting computer program in order to separate the effects. As a result of this study it is found that the saturation current j 01 is not necessarily attributable Only to diffusion current from outside the depletion region and that solely its temperature dependence can clarify its origin.

Investigation of the double exponential in the current&#8212;Voltage characteristics of silicon solar cells

Investigation of the double exponential in the current-voltage characteristics of silicon solar cells. [proton irradiation effects on ATS 1 cells]

A theoretical analysis is presented of certain peculiarities of the current-voltage characteristics of silicon solar cells, involving high values of the empirical constant A in the diode equation for a p-n junction. An attempt was made in a lab experiment to demonstrate that the saturation current which is associated with the exponential term qV/A2kT of the I-V characteristic, with A2 roughly equal to 2, originates in the space charge region and that it can be increased, as observed on ATS-1 cells, by the introduction of additional defects through low energy proton irradiation. It was shown that the proton irradiation introduces defects into the space charge region which give rise to a recombination current from this region, although the I-V characteristic is, in this case, dominated by an exponential term which has A = 1.

G. T. Noel

Papers

Investigation of the double exponential in the current—Voltage characteristics of silicon solar cells

Investigation of the double exponential in the current-voltage characteristics of silicon solar cells. [proton irradiation effects on ATS 1 cells]

Investigation of the double exponential in the current-voltage characteristics of silicon solar cells

G. T. Noel

Papers

Investigation of the double exponential in the current&#8212;Voltage characteristics of silicon solar cells

Investigation of the double exponential in the current-voltage characteristics of silicon solar cells. [proton irradiation effects on ATS 1 cells]

Investigation of the double exponential in the current-voltage characteristics of silicon solar cells

Investigation of the double exponential in the current—Voltage characteristics of silicon solar cells