Research on Improved Permanent Magnet Linear Synchronous Motor for Direct-Drive Application

This paper takes a Halbach permanent magnet linear motor (PMLM) without a core as the research subject; based on the traditional structure of a single-layer PM array, an improved PMLM with an optimized double-layer Halbach PM array is proposed to reduce the harmonic components of the air gap magnetic flux density (AGMFD) for direct-drive applications in the feeding system of the machine tool which need high force capability. The 3-D models of PMLMs with single-layer and double-layer Halbach PM arrays are established by using finite element (FE) software; the air gap magnetic field, the back electromotive force (EMF), and the electromagnetic thrust of the two types of motors are analyzed. The simulated results show that the PMLM with an optimized double-layer Halbach PM array can achieve better performances of the motor and reduce the cost of the PMLM. Finally, the experimental results verify that the proposed double-layer Halbach PMLM is effective and practical.