Electromagnetic Normal Force Characteristics of a Permanent Magnet Linear Synchronous Motor with Double Primary Side

The large normal force of the permanent magnet linear synchronous motor (PMLSM) is caused by the PM group shifting. This is the significant drawback which will deteriorate the performance of the drive system in high-precision applications. In the optimization design process, when the PM group shifting length is not zero the normal force will be changed into a pulsation curve with large amplitude. To solve this problem, this paper proposes that the PMLSM is divided into two symmetrical PMLSMs. The effectiveness of this proposed structure is verified by the simulation and experiment according to the comparison of the electromagnetic force characteristics between the conventional and proposed structures.