In this Part 1 article of this series of articles, a new methodology to refine the Co-Content function \(\left(CC\left(V,I\right)\right)\) is proposed, consisting on fitting the current minus the short-circuit current \((I-{I}_{sc})\) , to an \(N-1\) order polynomial, where \({N}_{points}=N\) , is the number of measured current–voltage \(\left(IV\right)\) points, and integrating it to calculate \(CC\left(V,I\right)\) . The shunt resistance \(\left({R}_{sh}\right)\) , the series resistance \(\left({R}_{s}\right)\) , the ideality factor \(\left(n\right)\) , the light current \(\left({I}_{lig}\right)\) , and the saturation current \(\left({I}_{sat}\right)\) , are then deduced, in the case of a constant percentage noise or a percentage noise of the maximum current \(\left({I}_{max}\right)\) . In the former case, \({R}_{s}\) , \({R}_{sh}, n, \text{and } {I}_{lig},\) can be deduced with less than 10% error, using only \({P}_{V}=\) 51 \(\frac{number\, of \,points}{V}\) , even if the noise is as large as \({p}_{n}=0.1\text{\%}\) , with a computation time around 80 ms. \({I}_{sat}\) needs \({p}_{n}=0.05\text{\%}\) or less, and \({P}_{V}\) equal or larger than 501 \(\frac{number\, of\, points}{V}\) . For the latter case, \({R}_{s}\) , \(\text{and } {I}_{lig},\) can be obtained with less than 10% error, using only \({P}_{V}=\) 251 \(\frac{number\, of\, points}{V}\) , and \({p}_{n}=0.1\text{\%}\) , or smaller, with total computation time around 49 s. \({R}_{sh}, {I}_{sat}, \text{and } n\) needs that \({p}_{n}\le 0.05\text{\%}\) , and \({P}_{V}=\) 751 \(\frac{number\, of \,points}{V}\) or larger. A computation time expression of the form \(time=E{{N}_{points}}^{m}\) , is deduced. The methodology proposed in this article is appliable to unevenly/randomly distributed IV data points, and it is implemented in Part 2 in solar cells’ and photovoltaic modules’ experimental \(IV\) reported in the literature, to deduce their five solar cell parameters.
