## 6 Results and Discussion
### Reliability Assessment
Similarly, the Euclidean distance from the negative ideal solution can be obtained by:  
\[S_{i}^{-}=\sqrt{\sum_{j=1}^{\text{m}}\left(V_{ij}-V_{j^{-}}\right)^{2}} \tag{30}\]
5 Calculate the relative closeness for each alternative as the performance score by dividing its positive ideal solution by the summation of its ideal solutions:  
\[P_{i}=S_{i}^{-}/\left(S_{i}^{-}+S_{i}^{+}\right) \tag{31}\]  
A higher value of the closeness coefficient indicates that the alternative is closer to the positive ideal solution. Thus, in the final stage, the alternatives must be ranked based on the calculated relative closeness that will make the alternative perform the best. In this research, the considered weights for the Norris-Landzberg parameter (\(N_{j}\)) for the maximum junction temperature of switches (\(T_{jmax(D)}\)), maximum junction temperature of diodes (\(T_{jmax(D)}\)), number of total components, and cost are 0.2, 0.2, 0.2, 0.1, and 0.3, respectively. From these selected weights, it is clear that the total cost is more significant compared to a single lifetime criterion, but by assuming all three reliability factors, these reliability indicators will play a critical role in selecting the most proper topology. In the meantime, the number of circuit components is important because it influences the size, weight, and complexity of the circuit. The above procedure has been implemented in a MATLAB environment in which the obtained closeness coefficients (or performance score) and ranks are listed in Table 3.  
As can be seen from Table 3, the best ranking is by far related to the floating interleaved converter because this converter performs the best in terms of both reliability and thermal behavior. Interestingly, the conventional boost converter is ranked fourth by considering the factors such as the number of components, simplicity, and cost. Although the cost is significantly important, this converter could not gain a high-performance score. The multi-switch converter is in the second place due to its superiority (less cost and number of components) to the interleaved converter. The Cuk converter also gets the worst rating and comes in the last place, with a performance score of 0.11. To clarify that if the overall performance (reliability and thermal conditions) is the highest-priority indicator rather than the cost, another scenario is considered here in which it is assumed that the cost weight is 0.2 instead of 0.3; and the Norris-Landzberg parameter weight increases from 0.2 to 0.3. The rest of the weights remain unchanged. The newly generated data according to the assigned weights are presented in Table 4. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Converters** & **Performance Score (\(P\))** & **Rank** \\ \hline Conventional Boost & 0.2631 & 4 \\ Interleaved Boost & 0.3782 & 2 \\ Floating Interleaved Boost & 0.7369 & 1 \\ Multi-switch Boost & 0.3690 & 3 \\ Cuk & 0.0579 & 5 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The determined performance scores and ranks for the candidates (second scenario). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Converters** & **Performance Score (\(P\))** & **Rank** \\ \hline Conventional Boost & 0.3306 & 4 \\ Interleaved Boost & 0.3553 & 3 \\ Floating Interleaved Boost & 0.6694 & 1 \\ Multi-switch Boost & 0.3679 & 2 \\ Cuk & 0.1092 & 5 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The determined performance scores and ranks for the candidates (first scenario). In this scenario, it is evident that all the scores have become completely different so that the interleaved converter moved to second place. The multi-switch converter is in third place, ahead of the conventional boost. The Cuk converter has the lowest performance score and is still in the last place, as expected. Considering that the number of cycles is always known as a crucial factor in determining the suitable converter for the fuel cell systems, the floating interleaved converter will not lose its place at the top of the list.