Optimal Design of Magnetically Levitated Permanent-Magnet Planar Motors Using THD 2D Method

In order to reduce the higher harmonic component of the magnetic field in magnetically levitated permanent-magnet planar motors (PMPMs), a sinusoidal index for 2-dimensional (2D) wave is proposed and verified by calculating the average total harmonic distortion (THD) of the discrete waveform. Based on this, a novel optimal design method using THD for 2-dimensional wave (THD2D) and fundamental amplitude is proposed for PMPMs. The finite element analysis and experimental results show that the higher harmonic component of magnetic field is reduced with average fundamental amplitude invariant, and the back-EMF is better. So the optimal design method can improve the electromagnetic performance of magnetically levitated PMPMs.