# Modeling and Control Simulation of Power Converters in Automotive Applications
## 4 Software-in-the-Loop Simulation Analysis
### AC/DC Converter Simulation Analysis  
The response of the AC/DC converter to a voltage step of magnitude \(V_{ref}=400\) V is shown in Figure 13. In particular, the DC bus's transient voltage is compared with various AC source circumstances. The following specifications are typical of single-phase AC power supply standards: (i) \(V_{g}=230V_{rms}\) & \(f_{g}=50\) Hz (standard in the EU); and (ii) \(V_{g}=110V_{rms}\) & \(f_{g}=60\) Hz (standard in the USA). Under both power supply scenarios, it is evident that the control system can manage the demand with a comparatively small steady-state mean error. As anticipated, the voltage transients are noticeably different, nevertheless. Since the controller must make up for the AC/DC conversion from drastically different absolute voltage levels, the overshoot is greater in the case of lower AC voltage. The transient voltage simulation results are shown in Figures 14-17. All of these results show comparable trends, and the intended DC-bus voltages are \(V_{ref}=500\) V, \(V_{ref}=600\) V, \(V_{ref}=700\) V, and \(V_{ref}=800\) V, respectively. It is crucial to remember that the simulations are run by first setting beginning conditions for the voltage \(V_{C}(0)\) of the active rectifier's output capacitor, which is always set to be around 50 V lower than the given \(V_{ref}\) value. Figure 12: Schematic representation of the software-in-the-loop simulation environment. Figure 13: Totem pole voltage control at \(V_{ref}=400\) V.  
Figure 16: Totem pole voltage control at \(V_{ref}=700\) V.  
Figure 14: Totem pole voltage control at \(V_{ref}=500\) V.  
Figure 15: Voltage control of the totem pole with \(V_{ref}=600\) V.  
Furthermore, it can be observed that the difference between the AC voltage instances that meet EU and USA requirements becomes less significant as the needed DC-bus voltage rises. This pattern highlights the role that greater DC-bus voltage requirements play in mitigating the effects of the differences in AC voltage between EU and USA standards. The current \(I_{L}(t)\) behavior under the EU-standard AC supply is depicted in Figure 18, which overlays the scenarios with the various needed DC-bus voltages. The current behavior is clearly influenced by the fluctuating \(V_{ref}\) it makes sense, based on the form of the current, in that the total harmonic distortion (THD) varies noticeably at lower DC-bus voltages. The alignment of \(I_{L}\) with \(V_{g}\), however, is still mostly steady despite the fluctuation in \(V_{ref}\). This illustrates the control mechanism's resilience and accomplishes the desired power factor adjustment goal. It is evident that the transient voltage behavior also has an indirect impact on the current's adjustment to align with the supply voltage. Specifically, for \(V_{ref}=400\) V, the effective current is in line with \(V_{g}\), and its effective value only makes sense in relation to the needed power flow when the transient voltage becomes closer to the end of the steady-state operation (see Figure 19). Figure 17: Totem pole voltage control at \(V_{ref}=800\) V.  
Figure 18: Under \(V_{ref}\), current control is applied in various circumstances, where \(V_{grid}=230V_{rms}\) & 50 Hz. Figure 20 displays the outcomes of a comparable study, with the current profiles corresponding to simulations run with the supply circumstances, \(V_{g}/f_{g}=110V_{rms}/60\) Hz. It is immediately noticed that the inductor current dynamics are far less sensitive to alignment with \(V_{g}\) with this setup. The transient voltage response for the scenario when \(V_{ref}=600\) V is shown in Figure 20, which also provides a robustness analysis of the variance in the beginning voltage of the active rectifier's output capacitor. While this change affects the transient voltage directly, the behavior is essentially the same, especially in the steady-state operation. The transient current behavior as it aligns with \(V_{g}\), as seen in Figure 21, is more sensitive to this fluctuation.