## 4 Discussion  
The experimental results obtained in a laboratory prototype were similar to the theoretical results in both cases (Table 3), which means that the implementation of the switching angles in the microcontroller was correct. It can be seen that the THD was consistent in the output voltage waveform with all the tested loads as expected. Figure 28: Seven-level CHBMIL output current with R = 100 \(\Omega\). Figure 29: Fast Fourier Transform of the seven-level CHBMIL output voltage with the RL load. These outcomes were juxtaposed with findings documented in the literature in order to assess the effectiveness of applying the MFO algorithm. This comparison includes both metaheuristic and non-metaheuristic methods, as well as simulation and experimental results; the comparison for the five-level CHBMIL is shown in Table 4, while the comparison for the seven-level CHBMIL is shown in Table 5.  
In Table 4, compared with the five levels of the CHBMIL, the MFO algorithm obtained a better THD (lower THD value) in five of the eight reported cases, and the same THD was obtained in one case. The authors of references [11; 13] report a lower THD compared to the MFO algorithm implemented in this paper, and, interestingly, the MFO switching angles were the same as those reported in reference [11] with the PSO algorithm. However, the results reported in references [11; 13] were obtained through simulation, whereas this paper presents experimental results, where the inverter's real semiconductors and the microcontroller's processing time play an important part. Regarding the harmonic spectrum of references [11; 13], the authors consider up to the 49 th harmonic, the same harmonic spectrum considered in this paper. The results shown in reference [15] consider up to the 49 th harmonic, as in this paper, but in reference [15], the authors only present simulation results. Performing a more exhaustive comparison of this proposal with the presentation in reference [14] shows that both proposals were carried out experimentally with the same objective function. Similarly, the voltage waveform was implemented with a microcontroller, although in reference [14], a PIC16F628A microcontroller was used, while in this paper, the PIC16F877A microcontroller was used. This article and reference [14] considered the harmonic spectrum up to the 49 th harmonic. The same power quality analyzer (Fluke 435) is used in both papers. Due to the above, although reference [14] shows a better result, the \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Paper** & **Algorithm** & **Angle Values** & **THD** \\ \hline
[13] &
\begin{tabular}{c} Matlab fsolve \\ function \\ \end{tabular} & \(\begin{array}{c}\theta_{1}=12.00^{\circ}\\ \theta_{2}=48.00^{\circ}\end{array}\) & 16.2\% (Experimental) \\ \hline
[14] & PSO & \(\begin{array}{c}\theta_{1}=13.34^{\circ}\\ \theta_{2}=41.79^{\circ}\end{array}\) & 15.2\% (Experimental) \\ \hline
[15] & NR & \(\begin{array}{c}\theta_{1}=19.00^{\circ}\\ \theta_{2}=43.00^{\circ}\end{array}\) & 17.23\% (Simulation) \\ \hline
[15] & GA & \(\begin{array}{c}\theta_{1}=17.02^{\circ}\\ \theta_{2}=43.01^{\circ}\end{array}\) & 16.14\% (Simulation) \\ \hline
[11] & NR & \(\begin{array}{c}\theta_{1}=11.80^{\circ}\\ \theta_{2}=41.77^{\circ}\end{array}\) & 15.51\% (Simulation) \\ \hline
[11] & GA & \(\begin{array}{c}\theta_{1}=14.33^{\circ}\\ \theta_{2}=42.10^{\circ}\end{array}\) & 15.35\% (Simulation) \\ \hline
[11] & PSO & \(\begin{array}{c}\theta_{1}=13.40^{\circ}\\ \theta_{2}=41.91^{\circ}\end{array}\) & 15.29\% (Simulation) \\ \hline This paper & MFO & \(\begin{array}{c}\theta_{1}=13.40^{\circ}\\ \theta_{2}=41.91^{\circ}\end{array}\) & 15.3\% (Experimental) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparison of the literature for the five-level CHBMIL. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Levels in the CHBMIL** & **Theoretical \% THD** & **Experimental \% THD** \\ \hline Five & 15.29\% & 15.3\% \\ Seven & 10.43\% & 10.5\% \\ \hline \hline \end{tabular}
\end{table}