## 3 Results
### Model Validation
#### 3.1.2 Saturation Current  
A second analysis was performed regarding the maximum current admitted during regenerative braking conditions (i.e., saturation current) at the AC/DC converter level. Recalling Section 2.2, a fixed AC/DC converter efficiency was assumed, whereas four different values of the saturation current \(I_{sat}\) admitted in the system were considered. The details of the tested scenarios are reported in Table 6. In the first three scenarios, typical saturation current values were imposed on the BEV model despite the driving mission  
Figure 14: Comparison of the battery state of charge trajectories estimated by the model considering different vehicle masses with respect to the experimental battery state of charge of DM15.  
\begin{table}
\begin{tabular}{c c c} \hline \hline  & **Scenario** & **Vehicle Mass** \\ \hline
1 & Driver only & 720 kg \\
2 & Driver w/light payload (30 kg) & 750 kg \\
3 & Driver and Passenger & 790 kg \\
4 & Driver, Passenger w/light payload & 820 kg \\
5 & Gross vehicle mass & 898 kg \\ \hline \hline \end{tabular}
\end{table}
Table 5: Vehicle masses considered in the tuning operation.  
profile. In the fourth (Table 6, last row), the value of \(I_{sat}\) was set to the indirectly estimated value using the experimental battery SoC trajectories of the different driving missions. As an example, the actual values of the recharging current obtained throughout DM25 are reported in Figure 15.  
The blue curve is representative of the actual values of the current flowing into the battery during any regenerative braking event, whereas the dashed red curve is representative of the vehicle velocity profile. The recharging current assumed a positive value only in a sub-set of the entire driving mission time steps, since it was activated only when braking scenarios occurred. Specifically for DM25, the maximum recharging current seen by the system was roughly 120 \(A\). Recalling the saturation currents considered in Table 6, the experimental saturation current for DM25 in the last scenario (#4) was set to 120 \(A\).  
The comparison between the experimental battery SoC profile and those produced by the model when applied to DM25 in case of the four different recharging currents is reported in Figure 16.  
Of note, the difference between the battery SoC curves throughout the mission is quite negligible. Two reasons may account for this result: first, the share of breaking events (and their related time) with respect to the entire driving duration is relatively small (-8%); second, the variation of the charge consumed calculated by the integral of (22) according to the ECC method is mostly mitigated and its effects are reduced. In the case of DM25, the final battery SoC value fluctuated in the range (0.705, 0.695) (-1% of maximum relative variation). Since the final battery SoC variation can be considered as irrelevant and that the same results occur for the entire dataset, the experimental \(I_{sat}\) values have hence been considered for any further analysis.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Scenario** & **Saturation Current** \\ \hline
1 & 25 A \\
2 & 50 A \\
3 & 75 A \\
4 & experimental \\ \hline \hline \end{tabular}
\end{table}
Table 6: Saturation currents considered in the tuning operation.  
Figure 15: Recharging current during DM25.