*2.1. PV Cell Model*

A PV cell model is usually combined in both series and parallel for the purpose of providing an output which is desired [24]. The current–voltage relationship can be given by [25,26]

$$I\_{\rm PV} = N\_{\rm P} I\_{\rm f} - N\_{\rm P} I\_{\rm s} \left( \exp \left[ \frac{q}{AKT\_{\rm c}} \left( \frac{V\_{\rm PV}}{N\_{\rm s}} + \frac{R\_{\rm s} I\_{\rm PV}}{N\_{\rm P}} \right) \right] - 1 \right) \tag{1}$$

where the meaning of each symbol is given in nomenclature. Here, *<sup>I</sup>*p<sup>h</sup> denotes the generated photocurrent that is mainly influenced by solar irradiation, which can be derived as

$$I\_{\rm ph} = \left(I\_{\rm sc} + k\_i (T\_{\rm c} - T\_{\rm ref})\right) \frac{s}{1000} \tag{2}$$

In addition, the saturation current *I*s of PV cells varies with the change of temperature on the basis of the below relationship:

$$I\_s = I\_{\rm RS} \left[ \frac{T\_{\rm c}}{T\_{\rm ref}} \right]^3 \exp\left[ \frac{qE\_{\rm g}}{Ak} \left( \frac{1}{T\_{\rm ref}} - \frac{1}{T\_{\rm c}} \right) \right] \tag{3}$$

Equations (1) to (3) denote that the current produced by the PV array is simultaneously dependent on the temperature and solar irradiation.
