Reduction of detent force in permanent magnet linear synchronous motor with double secondary side

In view of that detent force (DF) has great influence on thrust force ripple of permanent magnet linear synchronous motor (PMLSM), magnet-shifting method is introduced to suppress DF and its spatial harmonic. A double-sided PMLSM model is chosen as the object of research, finite element method (FEM) is adopted to build PMLSM model and Fourier transform (FT) is used to achieve its harmonic spectrum. The cases of DF are analyzed and total harmonic distortion (THD) is proposed to quantify spatial harmonic. The effects of different shift distance upon DF amplitude and spatial harmonic are analyzed in sequence, and then the optimal shift distance based on minimum ratio between DF amplitude and average thrust force is found. Results show that magnets-staggered technique can weaken DF amplitude drastically and improve DF spatial harmonic. The research provides an effective method for double secondary PMSLM detent force suppression.