A review of topology deign and drive control in arc-linear motors for direct-drive application

This study provides a comprehensive overview of the ALMs for direct-drive applications, mainly focusing on their topology structures, working principles, performances evaluation and control techniques. Moreover, a comprehensive performance comparison of several typical ALMs. Finally, the application areas, main challenges and future trends of the ALMs are highlighted.

The ALMs can be classified into two categories, i.e., induction and synchronous ALMs. Further, the synchronous ALMs are classified into RPM, SPM and DPM ALMs. The RPM-ALMs include radial flux, axial flux and tubular ALMs. The SPM-ALMs are divided into double salient, FR and flux switching ALMs. Then, the major merits and demerits of various ALM topologies are identified and summarized. The RPM type ALMs illustrate high torque capability. However, the PM utilization rate is relatively low. On the contrary, the SPM type ALMs can improve PM utilization rate, but the average torque is lower than the RPM type counterparts. The DPM type ALMs can be regarded as a combination of RPM and SPM type ALMs, thus are tradeoffs between the RPM and SPM ALMs. The study can promote a more comprehensive understanding for ALM.

Focusing on the core challenges of “torque density increase and torque ripple decrease” of the ALMs, this paper intends to summarize the following three future trends from the motor design and control strategy level:

1) Novel ALM topologies will continue to emerge, which attempt to improve torque density and reduce torque fluctuation. The axial flux ALMs and DPM type ALMs seem to be more suitable for direct-drive applications. At present, there are few researches on these two types of ALM designs.

2) Workable data-driven surrogate model-based optimization design methods having high precision and good generalization ability as well as considering the electromagnetic, thermal and mechanical multiphysics are highly required to facilitate the optimization design process of ALMs.

3) Effective approach to suppress the radial force and temperature rise is still a major challenge for ALM in the future direct-drive applications.

The complete study is accessible Via DOI: 10.30941/CESTEMS.2025.00018