Design and Optimization of a Homopolar Permanent-Magnet Linear Tubular Motor Equipped With the E-Core Stator

In this study, a new homopolar permanent-magnet (PM) linear tubular motor is designed, analyzed and optimized. Firstly, a mechanical structure of the linear oscillating motor (LOM) is proposed and the main working principles are introduced. A basic dynamic mathematic model of the motor is given. Secondly, the magnetic circuit of the motor is analyzed and equivalent magnetic modes are obtained to estimate the magnetic characteristic and force outputs. Thirdly, optimizations including the tooth stricter of the E-core stator, the size of the PM and the air gap length are carried out to improve the force output performance of the motor, increasing force outputs and reducing force ripples during the stroke. Finally, the motor prototype is manufactured according to the design and experimental tests involving force outputs and working efficiency are measured. The average force output and efficiency of the motor can achieve 60 N and 67 %, respectively. Results obtained by finite element method (FEM) and experiments prove the correctness of the design and the effectiveness of the LOM.