## 4 Results and Discussion
### POVC Test  
To begin, independent POVC tests were performed without the boost converters connected to the MLI. One module of the PV panel with the specifications listed in Table 3 was linked to a single boost converter with a switching frequency of 20 kHz in the simulation. The temperature was maintained at a constant of 31 \({}^{\circ}\)C. With a fixed V\({}_{\text{ref}}\) of 40.66 V and a load of 58 \(\Omega\), the POVC was first evaluated for its reaction to rapid variations in irradiance; Figure 8 depicts the outcome. The value of 40.66 V was chosen since it is the value for V\({}_{\text{DC}}\), which will be addressed further in the upcoming section. The POVC successfully maintained the desired output voltage at all times, as shown in Figure 8. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Values** \\ \hline Power at MPP, P\({}_{\text{mpp}}\) (W) & 132.21 \\ \hline Voltage at MPP, V\({}_{\text{mpp}}\) (V) & 26.39 \\ \hline Current at MPP, I\({}_{\text{mpp}}\) (A) & 5.01 \\ \hline Open Circuit Voltage, V\({}_{\text{OC}}\) (V) & 40.16 \\ \hline Short-Circuit Current, I\({}_{\text{SC}}\) (A) & 5.614 \\ \hline Temperature Coefficient of V\({}_{\text{OC}}\) (\(\%/^{\circ}\)C) & \(-\)0.35 \\ \hline Temperature Coefficient of I\({}_{\text{SC}}\) (\(\%/^{\circ}\)C) & 0.05 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: PV panel characteristics at STC. Figure 7: Experimental setup. In the experimental analysis, since the actual PV module was used, it was impossible to adjust the irradiance and temperature manually, as in the simulation. Therefore, the POVC was tested at several different times of the day. At the irradiance of 838 W/m\({}^{2}\), temperature of 32 \({}^{\circ}\)C, and load of 58 \(\Omega\), the experimental results for voltage regulation, including all the measured values, is shown in Figure 9. A complementary simulation analysis to study the POVC start-up characteristic was conducted under the same environmental conditions to test the theory given in Figure 5. The simulation result is given in Figure 10. By comparing Figure 10 with Figure 5b, it can be seen that at the beginning of the operation, the POVC tracked MPP and stayed at the MPP region for a brief moment until V\({}_{\text{B}}\) reached the targetted V\({}_{\text{ref}}\). Afterwards, the system proceeded into the reference power tracking stage before finally reaching the steady-state operation at the targetted V\({}_{\text{B}}\) = V\({}_{\text{ref}}\). Table 4 presents the voltage regulation experimental results obtained at several other tested irradiance levels. Figure 8: Boost converter voltage (V\({}_{\text{B}}\)) vs. time under varying irradiances. Figure 9: Experimental voltage regulation at 838 W/m\({}^{2}\) and 32 \({}^{\circ}\)C.  
Next, the POVC was tested under the condition where the reference value was changed at several points during the operation. The irradiance and temperature were set at 582 W/m\({}^{2}\) and 31 \({}^{\circ}\)C, respectively. The selected environmental conditions and the moment they changed were based on the experimental results. The results obtained from both the simulation and experiment are shown in Figure 11. As can be observed, the experimental results were highly similar to the simulation findings, supporting that the proposed POVC was capable of accurately tracking all the specified reference values. In terms of the voltage regulating range, as briefly described in Section 3.1, the voltage regulating range of the boost converter was not fixed and was directly affected by the solar irradiance and temperature. For instance, using the PV panel given in Table 3, at the irradiance of 800 W/m\({}^{2}\) and temperature of 31 \({}^{\circ}\)C, the theoretical maximum V\({}_{\text{B}}\) was 262.12 V if the maximum D was set at 0.9, according to (16). If the maximum allowable value of D was limited to 0.6, the maximum boost converter voltage was only 67.03 V. Differently; the theoretical minimum boost converter voltage would always be 0, regardless of environmental conditions.