## 3 Simulation Calculation Based on the Original Energy Management Strategy
### Simulation Results and Analysis  
Considering the previously introduced train parameters, energy storage device configuration, and energy allocation strategy, the circuit simulation was carried out based on the T1 line of Wuhan Guanggu. The T1 line has 23 platforms and 22 main parking spaces, as shown in Table 3. All intersections are considered in the calculation to ensure that the supplied energy storage device is equipped with sufficient energy. Due to the line speed limitation, the maximum train speed was controlled to be no more than 50 km/h. The initial SOC of the battery is 90%, and the initial voltage of the SC is 510 V. In this report, both the maximum discharge and charge currents of the battery are set as 4C, according to the experimental results. These two parameters were not changed in the optimization process to reduce the variables. The maximum charging power is about one third of the maximum discharge power. In order to speed up the optimization of the genetic algorithm, we assume that the maximum battery absorption power is one third of the maximum output power in the energy distribution strategy. \[\_ch\_bt=(1/3)\cdot P\_disch\_bt \tag{19}\]  
In the same way, due to the SC maximum output current being 700 A and the maximum absorption current being 300 A, the energy distribution strategy assumes that the maximum absorption power of the SC is three sevenths of the maximum output power. \[P\_ch\_uc=(3/7)\cdot P\_disch\_uc \tag{20}\]  
Figure 8 shows the train position-speed and time-power diagrams. The dashed line represents the expected value, and the solid line represents the actual running curve of the train. It seems that the train can travel at the desired speed and power with the configuration of the FC/battery/SC hybrid power 100% low-floor tramcar. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Station Number** & **Position (m)** & **Platform Length (m)** & **Stopping Time (s)** \\ \hline
1 & 164 & 64 & 0 \\
2 & 300 & 0 & 30 \\
3 & 805 & 64 & 30 \\
4 & 1231 & 64 & 30 \\
5 & 1295 & 0 & 30 \\
6 & 1715 & 0 & 30 \\
7 & 2070 & 0 & \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Station Number** & **Position (m)** & **Platform Length (m)** & **Stopping Time (s)** \\ \hline
31 & 11,230 & 0 & 30 \\
32 & 11,580 & 0 & 30 \\
33 & 11,687 & 64 & 30 \\
34 & 12,274 & 0 & 30 \\
35 & 12,424 & 64 & 30 \\
36 & 12,650 & 0 & 30 \\
37 & 13,440 & 0 & 30 \\
38 & 13,450 & 64 & 30 \\
39 & 13,857 & 0 & 30 \\
40 & 14,067 & 64 & 30 \\
41 & 14,628 & 64 & 30 \\
42 & 15,026 & 0 & 30 \\
43 & 15,226 & 64 & 30 \\
44 & 15,658 & 64 & 30 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: _Cont._  
Figure 8: Comparation of the expected and simulated values. (**a**) Position–Speed; (**b**) Time–Power. Figure 9 is the output power curves of FC, SC, and power battery versus time. We can see that the FC is not shut down in the whole working condition, and the maximum output power is 170 kW. In the practical engineering use condition, the fuel cell starts slowly with a slow dynamic response. Since the service life of the FC can be reduced when working in a high frequency start-stop condition, the FC does not shut down when the tramcar operates on certain rail tracks. The output power of the SC fluctuates between \(-125\) kW and \(250\) kW. This is the result of the maximum charge current of the SC is three parts of the maximum discharge current. Under the existing strategy, the battery has a low utilization rate, which means it neither exports nor absorbs much energy most of the time. Figure 10 shows the time-power state curve. The solid line is the battery SOC, and the dotted line is the SC SOC. It seems that the SOC of SC varies between 18% and 100%, while the battery SOC is limited by the energy management system (the battery SOC allows a range of 40-90%), and the whole operating process is basically maintained at about 90%. Figure 9: _Cont._  
By calculation, the hydrogen consumption of the train is 3.3469 kg, and the running time is 2178 s. The simulation results show that:  
1.