Pulsating Magnetic Field Effect and Detent Force Analysis of Double-Sided Asymmetric Primary Staggered Tooth Permanent Magnet Linear Synchronous Motor

Double-sided linear motors often encounter significant detent forces. To address this issue, a double-sided asymmetric primary staggered tooth permanent magnet linear synchronous motor (DSAPST-PMLSM) is proposed to suppress detent forces. This structure maintains equal lengths of the upper and lower primaries while having different tooth widths at the ends, forming staggered teeth. However, the staggered teeth introduce pulsating magnetic fields. This article first introduces the structure and principles of the motor for detent force suppression. Then, a magnetic field model that considers magnetic permeability is established by combining mirror imaging and conformal mapping techniques. The effects of the motor’s structural parameters on detent forces are analyzed. Furthermore, the influence of the motor’s structural parameters on the pulsating magnetic field effect is analyzed. The results show that the additional ripple force caused by the asymmetric structure is negligible. Finally, a prototype of the novel double-sided asymmetric primary staggered tooth motor is manufactured, and the motor’s back electromotive force and mechanical characteristics are tested. The results demonstrate that the motor can achieve a maximum acceleration of 60 m/s2 and a detent force of approximately 1.8 N, confirming the performance of the proposed motor structure and its effectiveness in suppressing detent forces.

I. Introduction

The double-sided linear synchronous motor comprises two primary elements and one secondary element (or one primary component and two secondary components). It is widely utilized in various transportation applications [1], [2], [3], [4]. Nevertheless, the motor’s primary, characterized by finite length and slots, introduces detent force and thrust fluctuations [5], [6], resulting in vibrations and noise. This, in turn, has a detrimental impact on the control precision and the overall reliability of transportation systems.