Analysis and Reduction of Detent Force on a Novel Transverse Flux Permanent Magnet Linear Machine

Due to the influence of end effect, the air-gap magnetic density at both ends is seriously distorted, which results in high detent force. In this paper, a typical transverse flux permanent magnet linear machine (TFLM) is introduced to analyze the detent force in depth. The detent force of permanent magnet linear machines is composed of both end force and cogging force. It can be better analyzed and suppressed by separating the cogging effect from end effect. By using the proportional separation method, the end force and cogging force of TFLM are separately analyzed. By virtual displacement method, the influencing factors of cogging force are investigated. According to Maxwell tensor method, the variation law of end force is solved. To reduce the detent force of TFLM, the axial length of end boot is optimized, and the unequal-width boot and auxiliary pole are proposed. Finally, the proposed methods of reducing the detent force are validated to be effective by 3-D finite element simulation.