# Modeling and Control Simulation of Power Converters in Automotive Applications
## 5 Final Discussion and Conclusions  
In the pursuit of a scientific article, simulations were conducted to evaluate the performance of control algorithms and the sizing of passive components within the framework of an onboard charger (OBC) power electronic system. The investigation comprised separate simulations for the AC/DC conversion stage, implemented via a single-phase PFC circuit. Notably, a detailed analysis of the voltage step response for various DC-link reference values was undertaken, yielding noteworthy outcomes. For \(V_{ref}=400\) V, the steady-state error was 0, with settling times ranging between 1.36 and 1.65 s, contingent on the AC voltage being 230 V/50 Hz or 110 V/60 Hz. Similarly, for \(V_{ref}=550\) V, a steady-state error of 0 was achieved, with nearly identical settling times for both AC input configurations (approximately 1.2 s). For \(V_{ref}=600\) V, \(V_{ref}=700\) V, and \(V_{ref}=800\) V, behaviors in both AC input configurations were practically overlapping, exhibiting a steady-state error trending toward 0 and a voltage ripple consistently below 2%. The evaluation of the AC/DC converter included an assessment of the power factor (PF), reaching approximately 97% after the voltage transient for 230 V/50 Hz AC input and even reaching 98% for  
Figure 31: SOC behavior of the battery during the charging phase, in the three different protocols. 110 V/60 Hz. This performance aligns with market supplier declarations and surpasses the declared design in some industrial products. Furthermore, in the 230 V/50 Hz configuration, current harmonic distortion was lower compared to the 110 V/60 Hz configuration, never exceeding 5%. Robustness analysis of the feedback system concerning variations in circuit parameters within a 20% range from the nominal case demonstrated acceptable performance degradation. This involved maintaining a voltage ripple consistently below 2.5%, a current ripple below 10%, a steady-state error below 2%, a PF consistently above 90%, and total harmonic distortion (THD) consistently below 6.5%. A parallel analysis was performed on the DC/DC conversion stage, employing a DAB converter. The output voltage response, evaluated at a constant output power of 7 KW, yielded distinct performances for various \(V_{ref}\) values. For \(V_{ref}=250\) V, there was a maximum overshoot of 15%, with zero steady-state error and a maximum settling time of 3.2 ms. Similarly, for \(V_{ref}=350\) V, a maximum overshoot of 15% was observed, along with zero steady-state error and a settling time below 6 ms. For \(V_{ref}=450\) V, the overshoot was below 10%, the steady-state error was below 1%, and the settling time was below 52.5 ms. These performances were assessed while varying the input voltage at the DC/DC primary. Additionally, feedback robustness was evaluated concerning variations in passive parameters within a 50% uncertainty range from the nominal value, revealing slight performance degradation limited to a worst-case 25% overshoot. Thermal performances were also scrutinized to ensure that the junction temperature of switching components remained within the operational limits declared in the supplier data sheets. This comprehensive investigation into the intricacies of OBC system design and control, encompassing both AC/DC and DC/DC conversion stages, sets the stage for future advancements. The study highlights the adaptability and resilience of control algorithms, emphasizing the critical importance of precision in component sizing and algorithmic design. The findings pave the way for optimizing OBC efficiency and reliability through advanced control strategies and thermal management. Future developments could explore the implementation of feedback from thermal models, leveraging adaptive or predictive controllers for enhanced precision. However, careful consideration of computational challenges, especially in resource-limited embedded systems, is imperative for practical implementation in automotive environments.