## 4 Simulation and Analysis
### Siemens Simcenter Flomaster Simulation Environment  
This program provides more possibilities than the ADVISOR program in changing the motor, battery, and outdoor parameters. It can also be integrated with the Matlab program. In this way, the fuzzy logic controller was integrated into the system, and driving cycles were realized. Values are defined for 40 different components used in the modeling and the properties of these components. While the model for the EV is created automatically in line with the data entered on the vehicle data entry screen, the EV battery model is designed for the hybrid storage system. In this model, data can be obtained from all units of the EV, such as the brakes, wheels, engine, and battery. In the HESS, the battery and SC are connected in parallel and a fuzzy logic controller is integrated as the control system. Figure 18 shows the EV blog diagram modeled in the Simcenter Flomaster program. In this program, outdoor and in-cabin temperatures can be adjusted to obtain the closest-to-reality results on battery usage values. It also allows changes to the battery's initial SoC and battery capacity. The Simcenter Flomaster program allows customization of all battery parameters. In this context, it creates an internal resistance model, which is the most important variable for battery health. The three-dimensional relationship of the internal resistance created in the program for the battery used in this study is shown in Figure 19.  
In the simulation environment, the vehicle's road conditions in Europe (NEDC driving cycle) were simulated at different outdoor temperatures and different battery SoC values, and then the current values that passed through the battery and HESS were examined. The battery data of the EV that was modeled in the simulation is defined as 4560 battery  
Figure 18: EV control blog diagram modeled in the Simcenter Flomaster program. units with 95 series and 48 parallel connections. In this study, 2900 mAh batteries were tested at \(-10\)\({}^{\circ}\)C, \(0\)\({}^{\circ}\)C, \(10\)\({}^{\circ}\)C, \(20\)\({}^{\circ}\)C, \(20\)\({}^{\circ}\)C, \(30\)\({}^{\circ}\)C, \(40\)\({}^{\circ}\)C, and \(50\)\({}^{\circ}\)C outdoor temperatures. At all these outdoor temperatures, the EV cabin temperature was kept constant at 20 \({}^{\circ}\)C. The current values obtained from the Simcenter Flomaster program at a 20 \({}^{\circ}\)C outdoor temperature are calculated as the C value per battery (Figure 20). The regenerative braking rate was defined as 80%, and the battery's initial SoC was defined as 70%. When the current values through the battery and the current values from regenerative braking are analyzed, the battery in the hybrid storage system is exposed to 28.7% lower current values than the battery storage system. The Simcemter Flomaster program was tested at a 70% battery charge and a 50% SC charge. The hybrid storage system completed the driving cycle with a 4.15% battery loss, whereas the battery storage system completed the driving cycle with a 5.02% battery loss. Figure 21 shows the SoC change in the systems during the driving cycle. Figure 22 shows the battery SoC values obtained after the driving cycle at a 20 \({}^{\circ}\)C outdoor temperature and different SoC values of the battery. Figure 19: Internal resistance changes depending on battery temperature and SoC in the Simcenter Flomaster program. Figure 20: Current values in the NEDC driving cycle in the Simcenter Flomaster program. Different percentage gains were obtained by starting the driving cycle with different SoC ratios of the battery. This is because fuzzy logic protects the battery's health by selecting different storage methods at different SoC ratios. The same is true for different temperature values. Figure 23 shows the battery SoC values obtained because of the driving cycle at 70% battery and a 50% SC SoC ratio and different outdoor temperatures. When the battery SoC was 10%, the system used the SC more to prevent the battery from deep discharging.