2-Dimensional analysis approach method of outer-rotor type brushless DC motor considering 3-dimensional effect of housing

In general, motor is designed through a two-dimensional (2-D) Finite Element Analysis (FEA) for better accuracy. However, in the case of outer-rotor type motor, housing part is designed to take function of rotor at the same time by using magnetic material. Therefore, the design based on three-dimensional (3-D) FEA should be conducted essentially since 2-D analysis is not capable of considering end part of housing. For this reason, this study suggests a novel method that reflects 3-D effect of end part of housing in the 2-D model FEA by changing the material property of the rotor core to have a linear characteristic. By applying a suggested method, we can determine the optimal motor size.