Design and Quantitative Analysis of Asymmetric Flux Reversal Permanent Magnet Linear Machine With Reduced Leakage Flux

This article introduces an asymmetric flux reversal permanent magnet linear machine (AFR-PMLM) designed to minimize the leakage flux. By employing asymmetric Halbach PM array, it effectively generates and fully exploits the second-order harmonic magnetomotive force (MMF), leading to substantial improvements in both thrust force density and power factor compared to conventional FR-PMLM. First, the machine topology and operation principle are introduced. Subsequently, the thrust force generation mechanism under multi MMFs is analytically calculated based on MMF-permeance model. Furthermore, various electromagnetic performances are thoroughly illustrated and comprehensively studied. It reveals that the proposed AFR-PMLM with Halbach PM array has the capability to provide 12.8% and 55.4% higher average force than that in AFR-PMLM with conventional asymmetric PM excitation and conventional FR-PMLM, respectively. Additionally, it achieves a power factor exceeding 0.77 under a current density of 6 A/mm2, representing a notable improvement of 36.8% compared to conventional FR-PMLM with symmetric PM excitation. Compared with conventional PMLM, it can provide nearly 72.1% of the thrust force density while consuming only 1/81 of the PMs over a 10 m distance.