A Practical Example of the Impact of Uncertainty on the One-Dimensional Single-Diode Model

Abstract

The state of health of solar photovoltaic (PV) systems is assessed by measuring the current-voltage (I-V) curves, which present a collection of three cardinal points: the short-circuit point, the open-circuit point, and the maximum power point. To understand the response of PV systems, the I-V curve is typically modeled using the well-known single-diode model (SDM), which involves five parameters. However, the SDM can be expressed as a function of one parameter when the information of the cardinal points is incorporated into the formulation. This paper presents a methodology to address the uncertainty of the cardinal points on the parameters of the single-diode model based on the mathematical theory. Utilizing the one-dimensional single-diode model as the basis, the study demonstrates that it is possible to include the uncertainty by solving a set of nonlinear equations. The results highlight the feasibility and effectiveness of this approach in accounting for uncertainties in the SDM parameters.

Figures (6)

• Figure 1: I--V curves samples representing two operational conditions. The maximum power point for each curve is highlighted in a red circle. The data set used corresponds to the solar module Cocoa_mSi460A8 marion_new_2014.
• Figure 2: Electrical diagram of the single-diode model. Four electrical elements compose this model: a DC current source of magnitude $I_\mathrm{ph}$, an ideal diode, D, a shunt resistance, $R_\mathrm{sh}$, and a series resistance, $R_\mathrm{s}$.
• Figure 3: Maximum power series resistance, $R_\mathrm{s}^\mathrm{mp}$, and shunt series resistance, $R_\mathrm{s}^\mathrm{sh}$ computed from the solar module Cocoa_mSi460A8 (data reported in marion_new_2014).
• Figure 4: Box plot extracted from the uncertainties of the cardinal points. The data was extracted from marion_new_2014.
• Figure 5: Maximum power series resistance, $R_\mathrm{s}^\mathrm{mp}$, and shunt series resistance, $R_\mathrm{s}^\mathrm{sh}$ computed for the low and high I--V curves. The solar module Cocoa_mSi460A8 is used as a basis and the data is reported in marion_new_2014.