Obtention of solar cell parameters, through convergence of iterative cycles. Part 1: Theoretical analysis and cycles proposal

Abstract

In this Part 1 of this series of articles, two iterative cycles are proposed to accurately determine the shunt resistance (Rsh), the series resistance (Rs), the ideality factor (n), the light current (Ilig), and the saturation current (Isat) of solar cells, within the one diode model. First, Rs and n are obtained linearly fitting ∂V∂lnI′vs.I′, where I′ is a new defined current I′=I+Isat+Ilig−V−IRsRsh+nkTRsh. Then, Rsh and Isat are obtained using Procedure A and B proposed in [2]. Once these four solar cell parameters are obtained, a correction to Ilig is deduced and applied. The deduction of these five solar cell parameters is reused to recalculate I′ 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 PV=11, 21, 51 and 101 measured pointsV. 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.