Best-Fit Mathematical Operator for Power Equation of Solar Photovoltaic Module

The solar photovoltaic (PV) module is designed to convert the solar radiation directly into electricity which can be calculated through the mathematical equation of PV power output that will be influenced by the cell temperature. However, two different mathematical operators, namely the addition and subtraction operator, can be found in the equations of power output and cell temperature, respectively. These inverse mathematical operators can lead the same equation to produce two different calculation results. Thus, this paper conducts a series of result analyses on the mathematical equations of PV power output and cell temperature to determine the best-fit mathematical operator to avoid any problematical calculation results that can influence the accuracy in estimating the size of a PV system. As to problematical results, the equation of power output with the unfit mathematical operator will produce the results in opposite operational characteristics, and cell temperature will produce the results that exceed the standard range of operational temperature of a PV module. Namely, these problematical results will cause an underestimation or overestimation of the size of a PV system and negatively impact any grid-connection systems, especially the large-scale PV system. In summary, the basic mathematical equation of power output is recommended to adopt the addition operator, and cell temperature adopts the subtraction operator.