## 6 Conclusions  
In this paper, the poor anti-demagnetization performance of PMA-SynRM with asymmetric-rotor is investigated and optimized without changing the structure and usage of permanent magnets. Demagnetization simulations are carried out for the basic model at a temperature of 200 \({}^{\circ}\)C and 8 times the rated current. The results show that severe irreversible demagnetization of the permanent magnets in the second and third ribs of the flux barrier occurs, with maximum demagnetization rates of 82.69% and 24.46%, respectively. It is found that adding bypass bridges and changing the position of permanent magnets in the second and third layers of the flux barrier ribs of the basic model could effectively improve its anti-demagnetization performance. The maximum demagnetization rate of the permanent magnets is found to decrease significantly with the increase of the rib bypass magnetic bridge width \(d\) and height \(h\), as well as the flux barrier angle C3 and the drop height \(H\) of the permanent magnets, as analyzed by the demagnetization simulation. This allows the proposed model to have better anti-demagnetization performance without affecting its torque performance too much. In this paper, the sensitivity analysis and multi-objective optimization of the rotor flux barrier structure of the proposed model are carried out. After optimization, the no-load flux density, no-load Back-EMF, and average torque of the optimized model are basically the same as that of the basic model. The torque  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Maximum Demagnetization Rate** & **Unit** & **Basic Model** & **Opti. Model** \\ \hline Second layer of permanent magnets & \% & 82.69 & 15.35 \\ Third layer of permanent magnets & \% & 24.46 & 0 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Comparison of the maximum demagnetization rate of permanent magnets between the basic and optimized models at 200 \({}^{\circ}\)C and 8 times rated current condition.  
Figure 18: Distribution of demagnetization rate of the optimized model permanent magnets.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Item** & **Unit** & [26] & [27] \\ \hline Permanent magnet type & / & Ferrite & Rare-Earth-Less \\ Temperature & \({}^{\circ}\)C & \(-\)20 & / \\ Demagnetization rate before optimization & \% & 100 & 100 \\ Demagnetization rate after optimization & \% & 10 & 8 \\ Decrease rate of demagnetization rate & \% & 90 & 92 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Comparison of demagnetization data in other literatures.  
ripple of the optimized model is reduced by 44.14% compared with the basic model, and the maximum demagnetization rate of the permanent magnets are reduced by 81.44%. The anti-demagnetization performance of the optimized model is significantly improved, and it has better stability and reliability.  
Conceptualization, F.X.; methodology, J.Z. and F.Z.; software, J.Z.; validation, J.Z.; formal analysis, F.Z.; investigation, Y.G.; resources, F.X.; data curation, F.Z.; writing--original draft preparation, J.Z.; writing--review and editing, F.X. and Y.G.; visualization, F.X.; supervision, Y.G.; project administration, F.X.; funding acquisition, F.X. All authors have read and agreed to the published version of the manuscript.  
This research was in part supported by the 2024 Fundamental Research Project (No. IJ212410154011) of the Educational Department of Liaoning Province.  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The authors declare no conflicts of interest.