Magnetic force enhancement in a linear actuator by air-gap magnetic field distribution optimization and design

The focus of this paper is to show that the magnetic force generated by a linear actuator may be enhanced through the optimization and design of the devices air-gap magnetic field distribution. Specifically, the use of a periodic ladder structure is proposed for magnetic field manipulation, and a simplified finite element analysis is adopted in lieu of a higher cost computational model. The optimal magnetic field distribution that maximizes the actuator force is then found via structural topology optimization. This force enhancement is explained using a Maxwell stress tensor analysis and validated through experimental studies. Finally, a periodic-ladder structure is designed for an equivalent optimal magnetic field distribution, and the linear actuator force enhancement is confirmed.

► Magnetic force of actuator is enhanced by magnetic field manipulation.
► Simplified FE analysis reproduces field manipulation by periodic-ladder structure.
► Topology optimization finds that center-focused distribution maximizes force.
► Focused distribution increase force due to square terms in force calculation formula.