## 4 Simulation Results  
In this section, a comparative simulation between the proposed strategy and previous methods is conducted to evaluate the strategy's effectiveness for the hybrid PEMFC-BAT-SC tramway system under different operating conditions. In detail, the proposed fuzzy EMS (F-EMS) was implemented and compared with the two other strategies: an RB-EMS in [18], and an ECMS in [44]. To comprehensively investigate EMS approaches with various operating situations, the load profile as in Figure 5 was considered with several load levels such as acceleration, deceleration, and regeneration in practical working conditions. In addition, the modeling of the hybrid tramway was deployed in Matlab/Simulink 2019b environment with a sampling time for displaying simulation results at 0.1 ms. By reasonably selecting components, characteristics of energy sources and parameters of the proposed EMS are listed in Tables 2-5. The system qualification is described in Figures 9-13. Firstly, simulation results of load power adaptation by using three EMSs are shown in Figure 9 in which a continuous black line represents the required power of load, a continuous red line depicts the output power of the proposed F-EMS, the power of RB-EMS is shown by a dashed-dot blue line, and the power of ECMS is described as a dashed-dot green line. As can be seen in Figure 9a, the required power of the proposed F-EMS satisfies load requirements better than the RB-EMS \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Nominal operation point \([\text{U}_{\text{nom}},\text{I}_{\text{nom}}]\) & [568 V, 265 A] \\ Maximum operating point \([\text{U}_{\text{max}},\text{I}_{\text{max}}]\) & [550 V, 300 A] \\ Number of cells & 762 \\ Rated power & 150 kW \\ Nominal efficiency & 60\% \\ Nominal hydrogen pressure & 2.24 bar \\ Nominal air pressure & 2.06 bar \\ Nominal air mass flow & 3653 lpm \\ Maximum stack temperature & 57 \({}^{\circ}\)C \\ Cooling & Air \\ \hline \hline \end{tabular}
\end{table} 
Table 2: PEMFC specifications. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Number of series capacitor bank & 5 \\ Rated voltage & 625 V \\ Capacitance & 126 F \\ Operating temperature & 25 \({}^{\circ}\)C \\ \hline \hline \end{tabular}
\end{table} 
Table 3: SC bank parameters. and ECMS at each time of transient peak power. Although the PEMFC, with the lowest dynamics, cannot instantly react to the load change, the load tracking effort can still be ensured due to the compensation from the BAT and SC during various working modes. In Figure 9b, the ECMS takes an insufficient power in the range of \((-1.2\to 3.8)\) kW, while the RB-EMS obtains a smaller error approximated \((-2.1\to 2.3)\) kW, and the proposed F-EMS achieves the highest distributed accuracy within \((-1.7\to 2.5)\) kW. Furthermore, the proposed F-EMS has the lowest average inadequate power on the driving cycle of the hybrid system. This reveals that the suggested methodology is able to guarantee the load power demand under different operating conditions. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Rated capacity & 68 Ah \\ Nominal voltage & 450 V \\ Internal resistance & 0.066 O \\ Number of batteries & 1 \\ Maximum discharge current & 180 A \\ \hline \hline \end{tabular}
\end{table} 
Table 4: BAT parameters. Figure 9: The comparison power released of load. (**a**) The power released for the hybrid tramway system from three strategies; (**b**) The comparison of power tracking error. Figure 10: The comparison of power distribution from energy sources. (**a**) PEMFC; (**b**) BAT; (**c**) SC.