**4. Results and discussions**

## **4.1 Current voltage characteristics of solar module**

 To find out various current–voltage points of the PV module, resistances R of different values must be connected with the PV module. For such variable resistance requirement, a rheostat (200R, 2.5 A) was used. Before doing the connections,

#### *Dual Axis Solar Tracker DOI: http://dx.doi.org/10.5772/intechopen.81083*

the open circuit voltage (VOC) is to be measured by connecting voltmeter across PV module's terminals (without connecting any load or rheostat). In the same manner, the short circuit current (ISC) is to be measured by connecting ammeter in series with PV module (without connecting any load).

 Current versus voltage characteristics were studied by connecting the rheostat to a low resistance value. For the lowest resistance value, current and voltage values were recorded. After that, the knob of rheostat was slightly moved and voltage and current were noted down for this new position. This was repeated until the highest value of resistance in rheostat was reached. The tabulated I-V points were plotted. Experimental set up is shown by **Figure 4**.

#### **4.2 Maximum power point tracking (MPPT)**

 **Figures 5** and **6** show the current-voltage and power-voltage characteristics of the solar module in the tracking mode condition respectively. It is observed that the maximum power Pm varies with time. The average power generated is 51.54 W.

**Figure 4.**  *Experimental set up for I-V characteristics of solar module.* 

**Figure 5.**  *I-V characteristics of PV module.* 

#### **Figure 6.**  *P-V characteristics of PV module.*

 The three main parameters derived from the characteristics of current voltage and power voltage graphs are:


The factors affecting electricity generated by solar PV module are conversion efficiency (η), amount of incident light, operating temperature, solar cell area and angle (θ) at which light falls.

It is the percentage of radiation input power converted into electrical power:

$$\eta = \frac{P\_{\text{max}}}{P\_{in} \times A} \times \mathbf{100} \tag{1}$$

Where Pin = Input Power (W/m2 ), η = efficiency (%), Pmax = Maximum power (W), A = Area (m2 ).

The insolation available for the month of January was between 800 and 900 W/m<sup>2</sup> during 10 am–3 pm. The power generated in tracking mode is more than 50 W throughout the day (11 am–5 pm) but for non-tracking mode, the power generated varies from 10 to 55 W. If the panel is kept in tracking mode, there is an increase in its efficiency.
