Torque and Radial Force Optimization of Arc Flux Switching Permanent Magnet Linear Motor Used for Large Scanning Equipment

This paper deals with the analysis and comprehensive optimization of the torque and radial force ripples in the arc flux switching permanent magnet linear motor, which is equipped in the large scanning equipment. The torque ripple is caused by the no-load torque including cogging torque and end force. Specially, a worth noting problem of unbalanced radial forces is caused by the discontinuity of the arc stator, which is easily behaved as the rotor and load vibrations. In this paper, an analytical model based on the magnetic permeance function is established to analyze the principle of the no-load torque and radial force. Based on it, the optimization goal of force harmonics can be determined, and the feasible optimization approach can be predicted. It demonstrates the harmonic distribution of the torque is completely opposite to that of the radial force. Pure structural parameter optimization can not achieve the satisfactory results. To effectively suppress the no-load torque and radial force at the same time, a novel structure with two sets of specially arranged three-phase stator is proposed. An obvious optimization effect is verified according to the detailed FEM and experiment analysis.