Suppression of high-order detent force harmonics in motor structures using a double-sided asymmetric primary design

Abstract

In high-slot-count linear motors, mismatched end force and cogging force harmonics make high-order detent forces hard to suppress, leading to large thrust ripples. To address this, a double-sided, asymmetric primary structure is proposed that suppresses high-order detent force harmonics, reduces overall detent force, and enhances thrust performance. The motor's geometry and operating principles are first described, followed by derivation of a detent force model and detailed analysis of the harmonic suppression mechanism. Quantitative suppression criteria are then established, and a multi-objective optimization framework is developed to identify an optimal motor configuration for detent force minimization. Comparative analysis with a conventional symmetric primary confirms the proposed structure's effectiveness and robustness. A prototype motor is manufactured and tested, demonstrating a thrust ripple reduction to just 2.89 %. These results validate the design's efficacy and provide novel methodologies and insights for linear-motor structure design and detent-force suppression.