A new proposal for the extraction of the shunt resistance ( R _sh ) and saturation current ( I _sat ) of a current-voltage (I–V) measurement of a solar cell, within the one-diode model, is given. First, the Cheung method is extended to obtain the series resistance ( R _s ), the ideality factor ( n ) and an upper limit for I _sat . In this article which is Part 1 of two parts, two procedures are proposed to obtain fitting values for R _sh and I _sat within some voltage range. These two procedures are used in two simulated I–V curves (one in darkness and the other one under illumination) to recover the known solar cell parameters R _sh , R _s , n , I _sat and the light current I _lig and test its accuracy. The method is compared with two different common parameter extraction methods. These three procedures are used and compared in Part 2 in the I–V curves of CdS-CdTe and CIGS-CdS solar cells.

In this Part 2 of this series of articles, the procedure proposed in Part 1, namely a new parameter extraction technique of the shunt resistance ( R _sh ) and saturation current ( I _sat ) of a current-voltage ( I – V ) measurement of a solar cell, within the one-diode model, is applied to CdS-CdTe and CIGS-CdS solar cells. First, the Cheung method is used to obtain the series resistance ( R _s ) and the ideality factor n . Afterwards, procedures A and B proposed in Part 1 are used to obtain R _sh and I _sat . The procedure is compared with two other commonly used procedures. Better accuracy on the simulated I – V curves used with the parameters extracted by our method is obtained. Also, the integral percentage errors from the simulated I – V curves using the method proposed in this study are one order of magnitude smaller compared with the integral percentage errors using the other two methods.

In this Part 1 of this series of articles, the accuracy on the obtention of the shunt resistance (R_sh), the series resistance (R_s), the ideality factor (n), the light current (I_lig), and the saturation current (I_sat), via the use of the Co-content function CCV,I=∫0VI−IscdV (where Isc=IV=0 ) is investigated theoretically, as function of the number of measured points per voltage ( PV ) and percentage noise ( pn ). Reasonable values are obtained forR_sh,R_s, andI_lig, with PV = 11 measurement points perVif the pn is 0.1% or less. For a reasonable determinationofnat least PV = 101 measurement points perVare needed.I_satdetermination requires pn of 0.01% or lower with at least PV = 101 measured points perVand should be evaluated at large values ofV.The results given in this Part 1 are used in Part 2 to discuss the reported application of the CCV,I to obtain R_sh,R_s,n,I_lig, andI_satfound in the literature.

In this Part 1 of this series of articles, two iterative cycles are proposed to accurately determine the shunt resistance ($R_{sh}$), the series resistance ($R_s$), the ideality factor (n), the light current ($I_{\mathit{lig}}$), and the saturation current ($I_{\mathit{sat}}$) of solar cells, within the one diode model. First, $R_s$ and n are obtained linearly fitting $\frac{\partial V}{\partial ln{I}^{\prime }}$vs.$I^{\prime }$, where $I^{\prime }$ is a new defined current $I^{\prime }=I+I_{sat}+I_{lig}-\frac{V-I{R}_s}{R_{sh}}+\frac{nkT}{R_{sh}}$. Then, $R_{sh}$ and $I_{\mathit{sat}}$ are obtained using Procedure A and B proposed in [2]. Once these four solar cell parameters are obtained, a correction to $I_{\mathit{lig}}$ is deduced and applied. The deduction of these five solar cell parameters is reused to recalculate $I^{\prime }$ and the iterative cycles are redone till some convergence criteria is achieved. The accuracy and number of cycles necessary to achieve reasonable results are tested and discussed on ideal (noiseless) current voltage (IV) curves with measured points per voltage of $P_V=11$, 21, 51 and 101 $\frac{\mathit{\text{measured points}}}{V}$. These two cycles are compared with two different common parameter extraction methods. The results given in this Part 1 are used in Part 2 to calculate the five solar cell parameters of IV curves found in the literature.

In this Part 2 of this series of articles, the application of the iterative cycles CycleA and CycleB proposed in Part 1, to determine the solar cell parameters (the shunt resistance ($R_{sh}$), the series resistance ($R_s$), the ideality factor (n), the light current ($I_{\mathit{lig}}$), and the saturation current ($I_{\mathit{sat}}$)) on experimental current voltage (IV) and current density (JV) curves, is given. Several number of measured points per voltage ($P_V$) are attempted, from approximately $P_V=1\frac{measuredpoints}{V}$ to $P_V=52\frac{measuredpoints}{V}$. In one case, the application of the iterative cycles to IV curves showing the roll-over effect is discussed, while in another case, their application to solar panels is analysed, revealing that the iterative cycles can also be used in the case of solar panels, and not only for laboratory-made solar cells, in voltage ranges larger than [0 V,1 V]. Also, cases in darkness and under illumination are evaluated. In most cases, reasonable values are obtained for $R_{sh}$, $R_s$, $n,I_{\mathit{sat}}$ and $I_{\mathit{lig}}$, which simulated properly the IV or JV curves.