**7. PV cells of module**

and increase when output voltage away from maximum power voltage. The PV cell character‐

Also, model PV cell can be used to study number of PV cells need to supply energy to the system, for example figure 14 show *16 PV cells* for simple circuit supply of *5V* source formed by: block diode (*D1*) and a regulator circuit (*LM140*).Then, change number of PV cells and configure climatic conditions (Irradiance and temperature) can see if has enough or need more PV cells, too if has more PV cells that is need. On figure 14 show: output voltage (*V\_load.V*), output current (*I\_load.I*) and voltage cells (*V\_cells.V*), to different values of irradi‐ ation, therefore study irradiance needs to obtain *5V* on load resistor. Conclusions on figure

obtain *5V* and *0,5A* output (on load). The PV cell characteristics used on figure 14 is: *1A* for

or higher to

14 is than needs *16 PV cells* on series and irradiance value around *500-550 W/m2*

istics used on figure 13 is: *150mA* for *ISC* and *0,62V* for *VOC* on *SCM*.

**Figure 13.** Used model to study circuit control of PV cell

**Figure 14.** Study irradiation for simple regulator circuit

*ISC* and *0,6V* for *VOC* on *SCM*.

134 New Developments in Renewable Energy

Some case has available information of PV module on *SCM* to emulate PV module (figure 15), then needs calculate values for PV cells: division between module open voltage (*VOC\_MODULE*) and number PV cells series (*NCELLS\_SERIES*) to obtein open voltage of cell (*VOC\_CELL*), division between module current short (*ISC\_MODULE*) and number of strings cells connection (*NCELLS\_STRINGS*) to obtain current short of cell (*ISC\_CELL*), and repeat by module maximum val‐ ues of voltage (*VMAX\_MODULE*) and current (*VMAX\_MODULE*) to obtain maximum values of voltage (*VMAX\_CELL*) and current (*VMAX\_CELL*) of cell; equations 13 to *16* respectively.

$$V\_{OC\_{\text{\\_CEEL}}} = \frac{V\_{OC\_{\text{\\_MODELL}}}}{N\_{\text{\\_CEELS\\_SERIES}}} \tag{13}$$

$$I\_{\text{SC\\_CELL}} = \frac{I\_{\text{SC\\_MODEL}}}{N\_{\text{CEL\\_STERMGS}}} \tag{14}$$

$$\left| V\_{\text{MAX\\_CEIL}} = \frac{V\_{\text{MAX\\_MODEL}}}{N\_{\text{CELS\\_SERIES}}} \right. \tag{15}$$

$$I\_{MAX\\_CEIL} = \frac{I\_{MAX\\_MODEL}}{N\_{CESLS\\_STERINGS}}\tag{16}$$

Values obtained on equations 1*3 and* 14 used to obtain: *voc*, *RS*, *IL*, and *I0*, on *equa‐ tions*: *6*, *8*, *9* and *10*. The values obtained on equations 13 to *16* used to obtain *FF* on equation 7. This approximation is based on a PV module is union of PV cells connect‐ ed in series and parallel strings. Model of PV module included connections cells loss inside module.

On figure 15 shows an example for PV module based on subcircuit on PV cells, char‐ acteristic of PV module on *SCM* is: *150W* to *PMAX*, *22,6V* to *VOC*, *8,7A* to *ISC*, *18,5V* to *VMAX* and *8,12A* for *IMAX*. The module used in figure 15 used 36 cells connected in ser‐ ies on a string.

Advantage to use model PV cells on model PV module is that change parameter of ir‐ radiation and temperature by cell (figure 7), and so study effects: partial shading, num‐ ber pass diode, different connections of pass diode, hot cells, etc. Also can be study effect on mismatch on module used PV cell with different electrical characteristics. For example on figure 16 show effects of partial shading on module using 2 diodes pass (figure 9): figure 16a without shadow, figure 16b shadow affect to same number of cell connects on parallel by diode and figure 16c shadow affect only to cells connects on par‐ allel with 1 diode pass.

**Figure 16.** Partial shading on PV module use model PV cell.

In this chapter show a equivalent circuit for simulate PV Cell, then show equation to obtain all parameters to circuit based on PV cell datasheet. To check model is implemented on free software and compare results of output PV Cell model represented on IV Curve and output measurements with datasheet information. The software application selected is QUCS be‐

Modeling of Photovoltaic Cell Using Free Software Application for Training and Design Circuit in Photovoltaic...

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137

**8. Conclusion**

**Figure 15.** Simulate PV module based on PV cell model

Modeling of Photovoltaic Cell Using Free Software Application for Training and Design Circuit in Photovoltaic... http://dx.doi.org/10.5772/51925 137

**Figure 16.** Partial shading on PV module use model PV cell.

#### **8. Conclusion**

**Figure 15.** Simulate PV module based on PV cell model

136 New Developments in Renewable Energy

In this chapter show a equivalent circuit for simulate PV Cell, then show equation to obtain all parameters to circuit based on PV cell datasheet. To check model is implemented on free software and compare results of output PV Cell model represented on IV Curve and output measurements with datasheet information. The software application selected is QUCS be‐ cause can be include equations to calculate circuit parameters and a real representation of subcircuit.

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The PV cell model can modelled any PV cell using datasheet information, also the model in‐ clude variations of temperature and irradiance for output PV cell. Therefore used PV cell model connected in series and parallel can modelled a PV module. In section 4 shows all necessary equations to obtain parameters of circuit to PV cell model and section 7 shows process and equations to obtain PV module cell.

Using *QUCS* to model a PV cell allows subcircuit and a real representation to a attractive presentation for teaching. In section 5 show examples of practices used on formation, further can be used on: courses of photovoltaic, online formation or distance learning, because only need download *QUCS* application, and is a good complement to a previous works on labo‐ ratory or concepts review for theory. Advantage to used *QUCS* is that allow several PV cells with a few mouse click, also does not needs buy additional PV cells to used on laboratory because can be modelled the PV cell available on laboratory. Further, is not a problem the availability material on laboratory, because the material of PV system can be expensive, then is best provide a good photovoltaic devices that a devices for all student in a class.

Other application for model of PV cell or module is used to design of supply circuits, for example in a network sensors node, to design power control. In section 6 shows examples to used electronic devices available on *QUCS* library to control output PV cell, with the ad‐ vantage to change weather condition to study operation circuit and is surer for designer and electronic devices. Also, can emulate various conditions to which the PV cell work (irradi‐ ance and temperature), which can reduce design time, detecting errors. Further, the availa‐ bility of weather conditions that need for tested circuit.
