Analytical Calculation of Leakage Flux Coefficient in Built-in Permanent Magnet Motor

Permanent magnet motors tend to adopt built-in permanent magnet motors to achieve miniaturization and lightweighting while improving torque density and efficiency, but this can lead to a decrease in the utilization rate of permanent magnets. Therefore, the reasonable design of rotor structural parameters is more important, especially the design of magnetic barriers. This paper uses a leakage coefficient analysis model to calculate the no-load leakage coefficient. The results indicate that the size of the magnetic barrier has a significant impact on the leakage coefficient, with the magnetic bridge thickness having the most prominent impact. For every 0.1mm reduction in magnetic bridge thickness, the leakage flux decreases by approximately $4 \%$. After optimization, the overall leakage flux was reduced by $13 \%$.This was verified through two-dimensional finite element analysis.