Influence of Outer Diameter to Stack Length Ratio on the Output Performance of Brushless Permanent Magnet Motor

The outer diameter to stack length ratio or aspect ratio of a brushless permanent magnet (BLPM) motor has a big impact on its performance. Specifically, it affects both the power density and efficiency of the motor, which are important in most applications. Under the same volume, different aspect ratios will result in different output performances, so selecting the proper ratio for each requirement is necessary. This paper compares the performance of different aspect ratios of a BLPM motor with the help of finite element analysis (FEA). The most suitable model was chosen, and analysis results are validated with experimental data.