Design and Analysis of Double-Sided U-Shaped Linear Primary Permanent Magnet Vernier Motor

This paper introduces a new double-sided U-shaped linear primary permanent magnet Vernier (U-LPPMV) motor, whose most important feature is a U-shaped Halbach structure in which the magnetization direction of five permanent magnets is concentrated at the center point, which provides more than twice the thrust density compared with existing single-sided motors. The secondary stage adopts a convex pole structure consisting of laminated silicon steel sheets, which has the advantages of a simple structure and low cost. The no-load counter-electromotive force and magnetic chain are made more sinusoidal by changing the side end structure at both ends of the primary. Next, the air-gap magnetic density of the motor is analyzed analytically by establishing the magnetomotive force potential-magnetic conductance model, and the accuracy is verified by simulation analysis. In addition, a global optimization of the motor is performed to increase the average thrust and improve the electromagnetic performance based on the optimized structural parameters. Finally, the accuracy of the theory is demonstrated by prototype design and fabrication as well as by building a test platform, and the motor is more suitable for long-stroke, high-load, and high-precision application scenarios. © 2025 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.