Three-dimensional magnetic field analysis of micromotor by fast Fourier transform

An analysis method based on FFT (Fast Fourier Transforms) for the three-dimensional magnetic field of a micromotor is presented. The magnetic field and the static magnetic force between stator and rotor of the micromotor can be calculated by using a pair of Fourier transforms and some spatial filtering. Analysis results show that the field and the static magnetic force drop off sharply with increasing gap between rotor and stator, and the static magnetic force is much larger than the weight of rotor.