# Analysis of AC DC Four-Switch Boost-Buck Battery Charger Converter for EV Applications
## 10 Conclusions  
This study contributes to the advancement of AC/DC converter design for PFC applications, providing valuable insights into the analysis, control, and optimization of converter systems. The findings pave the way for improved converter performance, ultimately enhancing the efficiency and reliability of power conversion in various applications. The comprehensive evaluation of a power conversion approach using PSIM software simulations yields encouraging results, affirming the design's effectiveness and practicality. The simulations, integral for corroborating theoretical decisions and forecasting system behavior under diverse scenarios, utilized realistic parameters for enhanced accuracy. This included incorporating equivalent series resistances (ESRs) in inductors and capacitors, modeling switching elements with Level 2 characteristics to account for non-ideal behaviors and considering parasitic effects in diodes. Such meticulous modeling ensures a closer reflection of real-world conditions.  
Figure 20: Buck mode steady-state waveforms of output voltage \(v_{o}(t)\), output current \(i_{o}(t)\), input voltage \(v_{g}(t)\), and input current \(i_{g}(t)\) at full load.  
A significant outcome of the simulation is the effective harmonic suppression observed in both boost and buck modes. The Fast Fourier Transform (FFT) analysis of the intermediate voltage \(v_{c}\) demonstrates the snubber circuit's proficiency in mitigating high-Q oscillations and reducing unwanted harmonic frequencies. This is crucial as it implies minimal harmonic distortion in the voltage, a key factor for the efficient performance of the power stage and the load. Stability and efficiency are other highlights of the simulated design. The absence of internal dynamic stability issues in both operational modes, coupled with high PFs (0.99 in boost and buck mode), underscores the design's capability to dynamically manage the load without inducing instability or significant harmonic distortion. Additionally, the converter's ability to maintain stable and regulated output voltage under full load conditions, with a controlled output voltage ripple, is a critical aspect for reliable power converter operation.  
However, the introduction of a snubber circuit, while beneficial in eliminating the high-Q oscillations, brings additional losses, especially across the resistor \(R_{d}\). This necessitates an optimization trade-off to ensure minimal efficiency loss while maintaining desired performance and stability. In conclusion, these simulation results provide the vital confirmation of the proposed design's functionality, indicating that the power stage and control circuit work in harmony. They affirm the converter's ability to handle various load conditions effectively, maintaining stability, efficiency, and a controlled output voltage ripple, thus offering a reliable and practical solution for real-world applications.  
Conceptualization, M.N., E.V.-I. and J.C.; methodology, M.N.; software, M.N.; validation, M.N.; formal analysis, M.N.; investigation, M.N.; resources, M.N.; writing--original draft preparation, M.N.; writing--review and editing, M.N., E.V.-I. and J.C.; visualization, M.N.; supervision, E.V.-I. and J.C.; project administration, J.C. All authors have read and agreed to the published version of the manuscript.  
The research was supported by Universitat Rovira i Virgili and Diputacion de Tarragona under grant Marti Franques 2019 PMF-PIPF-95. Also this research was supported by Grant PID2021-124229 NB-I00 funded by MICIU/AEI/ 10.13039/501100011033 and by ERDF/EU.  
Not applicable.  
Data Availability Statement: Data are contained within the article.  
The authors declare no conflicts of interest.