## 3 Results  
The simulation model proposed in this paper was subjected to preliminary verification. The comparative material was the nominal parameters of the CX-75/200 module, given in Table 2, which were tested under the conditions given by the manufacturer (850 W/m\({}^{2}\), cell  
Figure 4: The simulation model of the C3 PV module in Matlab/Simulink.  
temperature 25 \({}^{\circ}\)C, and AM 1.5). The simulation results obtained for the nominal parameter values are shown in Figure 5.  
After the positive initial verification of the proposed model shown in Figure 5, simulation studies were conducted, the results of which are presented in Figures 6-10. The simulation studies determined the essential characteristics for the modeled C3 PV CX-75/200 module at a constant irradiance level of 300 W/m\({}^{2}\) and a variable angle of incidence of direct radiation in the range of 0-10\({}^{\circ}\). The irradiance (300 W/m\({}^{2}\)) was assumed to be the same as in the experimental determination of the applicability range of the model, when a value of 5\({}^{\circ}\) angle was set as the limit after which the power generated by the cell dropped significantly. The irradiance was obtained using a solar radiation simulator built with halogen lamps [25].  
Complete verification of the developed simulation method by measuring actual I-V characteristics for the CX-75/200 module is not possible due to measurement limitations of the meters. An attempt to use the I-V 400 w [26] current-voltage characteristic meter for this purpose was unsuccessful because this meter and others like it cannot take measurements at such low current values of the PV module.  
The simulation results shown in Figure 6 for irradiance of 300 W/m\({}^{2}\) and a module temperature of 21 \({}^{\circ}\)C showed a proportional decrease in value for the short-circuit current in the I-V characteristic curve.  
Figure 5: Simulation results for nominal parameters of CX-75/200 module: (a) current–voltage characteristic curve I = f(U); (b) power diagram P = f(U).  
Figure 6: Simulation results for irradiance 300 W/m\({}^{2}\) and temperature 21 \({}^{\circ}\)C for modeled CX-75/200 module: (a) current–voltage characteristic curve I = f(U); (b) power diagram P = f(U).  
Figure 8: Simulation results for irradiance of 300 W/m\({}^{2}\) deflected by an angle \(\Delta\theta\) = 4\({}^{\circ}\) from the direction of perpendicular incidence and a temperature of 21 \({}^{\circ}\)C for the modeled CX-75/200 module: (**a**) current–voltage characteristics I = f(U); (**b**) power graph P = f(U).  
Figure 7: Simulation results for irradiance of 300 W/m\({}^{2}\) deflected by an angle \(\Delta\theta\) = 2\({}^{\circ}\) from the direction of perpendicular incidence and a temperature of 21 \({}^{\circ}\)C for the modeled CX-75/200 module: (**a**) current–voltage characteristics I = f(U); (**b**) power graph P = f(U).  
In the following Figures 7-10, for the same radiation and temperature conditions, the incident direction of the radiation measured by the deviation (\(\Delta\theta\)--per Figure 3b) from the perpendicular direction was changed. For angle deviations from 5\({}^{\circ}\), a sharp decrease in short-circuit current values was observed.  
Figures 9 and 10 clearly show that radiation concentration no longer works. A small amount of energy is generated from diffuse solar radiation.  
Table 3 shows the numerical results of the current-voltage characteristics and power values for each bias angle used in this simulation for a fixed irradiance of 300 W/m\({}^{2}\) and an assumed module temperature of 21 \({}^{\circ}\)C. The given numerical values of these three current-voltage characteristic points allow comprehensive further considerations on the efficiency or fill factor of the considered module.