**2. SPICE based PV cell and module modeling**

### **2.1 Equivalent circuit model of a PV cell**

To model the PV cell, a SPICE based 2-diode based equivalent circuit is used as shown in **Figure 1** [23]. All the parameters shown in **Figure 1**, are presented in **Table 1** [23]. Two diode-based PV cell modeling techniques are selected over single diodes since they are considered more accurate [24]. The resistance Rs and Rp as shown in **Figure 1** are the internal resistance of the PV Cell.

The current iPV *ge*nerated by the PV cell, as shown in **Figure 1**, can be computed by:

**21**

**Table 1.**

*Modeling of Photovoltaic Module*

*DOI: http://dx.doi.org/10.5772/intechopen.97082*

1 2 <sup>+</sup> =−−− *PV pv S*

*The parameters descriptions for modeling PV cells and module, their assumed constant value, and units.*

IS Diode saturation current IS1 = 10pA and IS2 = 1 nA G Solar irradiation data 1000 W/m2 GSh Shaded solar irradiation data 500 W/m2

**Symbol Description Value and units** VPV Output voltage across the PV module Volts IPV Output current across the PV module Amperes *v*pv Output voltage across a PV cell Volts *i*pv Output current generated from the PV cell Amperes VOV Open load voltage across PV module Volts *v*ov Open load voltage across PV cell 0.55 Volts IPH Total photon current of the PV module 2.17 Amperes *R*<sup>P</sup> Shunt resistor 1 mΩ *R*<sup>S</sup> Series resistor 0.1 MΩ *A*PV Area of PV cell 126.6 cm2 *J*SC Short-circuit current density 34.3 mA/cm2 *V*<sup>T</sup> Thermal voltage = *KT q*/ 26 mV *A* Diode ideality constant 1.2

> <sup>+</sup> <sup>×</sup> <sup>=</sup> <sup>−</sup> *PV pv S T v iR A V*

The total photon current of a PV cell is dependent on the area of the PV cell, short-circuit current density of the PV cell, and the solar irradiance. The following

*Ph PV SC* = ××

The current vs. voltage (I-V) and power vs. voltage (P-V) characteristics obtained for a single PV cell using SPICE-based equivalent PV cell are shown in

*P*

*<sup>R</sup>* (1)

*v iR*

1

*Sh*

*d s I Ie* (2)

*<sup>G</sup> IAJ <sup>G</sup>* (3)

*PV ph d d*

*i III*

equation can compute the total photon current for a given PV cell:

**Figure 2**. The SPICE simulation uses Eq. (1), Eq. (2), and Eq. (3).

Where the Id1 and Id2 can be computed by:

NS Number of PV cells in series NP Number of PV cells in parallel N Number of PV cells in a PV panel = NS x NP

**Figure 1.** *2-diode based equivalent PV cell model.*
