Obtaining small photovoltaic array operational curves for arbitrary cell temperatures and solar irradiation densities from standard conditions data

The paper presents a simple approach to deriving I-V curves of photovoltaic panels and small arrays for arbitrary environmental conditions on the basis of three points of a single operating curve data and short current temperature coefficient only. The proposed method does not employ fitting of any type and is solely based on a numerical solution of a system of transcendental equations. The equations are expressed in a dimensionless form, simplifying both the solution and photovoltaic panel parameters' representation. The solution is used to find the values of normalized equivalent circuit elements for the available data and then perform an appropriate adjustment to obtain the operating curves for arbitrary conditions. The proposed method was applied to monocrystalline and polycrystalline commercial solar panels and was compared with both manufacturer-provided and experimentally measured operating curves to analyze the approach applicability and accuracy.