An essential requirement for a long-stroke linear motion system is a low-cost and robust track. To allow the implementation of a linear motor topology in such application, passive tracks, consisting no rare-earth material, are recommended to reduce the price. This paper presents a comparison between two linear motor topologies with permanent magnet (PM)-less tracks: e.g., linear induction motor (LIM) and linear flux-switching permanent magnet motor (LFSM). These motors are benchmarked to a linear permanent magnet synchronous motor (LSM), which merits itself for high force density. The LIM and the LFSM are optimized for maximized continuous force while considering the same footprint as the LSM. The optimization is based on a multiphysical model containing an analytical representation of the magnetic field distribution, force production, power losses, and thermal the behavior of both structures. The obtained parameters are used to compare different configurations of both motors to the LSM. The results of the comparison show that at the price of higher losses, both topologies have comparable thrust force to the LSM.

A semianalytical model is derived for the description of the three-dimensional magnetic fields, generated by an array of air-cored rectangular coils above a ferromagnetic plate with cavities, or bounded slots, in the xy-plane. The magnetic fields are described with a double Fourier series and are obtained by solving the Maxwell equations using a combination of the magnetic vector and scalar potentials. Mode-matching of the double Fourier series is applied to obtain the description of the magnetic fields inside the cavities. Therefore, the mode-matching technique is extended for two dimensions. The semianalytical model is compared with three-dimensional finite element analysis and a good agreement has been found.

In the paper a novel actuator is presented for a magnetically suspended ceiling actuator. The actuator consists of several stator segments which contain the coils and the magnets. The armature, therefore, has a totally passive design. Because of its salient structure, a translational force can be produced for motion of the armature. The magnets create a passive attraction force for failsafe operation, which can be controlled for magnetically suspending the armature. Decoupling of the attraction and translational force, however, is complex, because they are strongly coupled. Therefore, position and current dependent force models are created based on curve fitting of inductances. It is shown that using these models, decoupling of the attraction and translational force in the ceiling actuator is possible.

This paper presents a 2D hybrid steady-state magnetic field model, capable of accurately modeling the electromagnetic behavior in a linear induction motor, including primary slotting, finite yoke length, and longitudinal end-effects by primary motion. This model integrates a complex harmonic modeling technique with a discretized magnetic equivalent circuit model. The Fourier model is applied to regions with homogeneous material properties, e.g., air regions and the track of the motor, while the magnetic equivalent circuit (MEC) approach is used for the regions containing non-homogeneous material properties, e.g., the primary of the linear induction motor (LIM). By only meshing the domains containing highly-permeable materials, the computational effort is reduced in comparison with the finite element method (FEM). The model is applied to a double-layer single-sided LIM, and the resulting thrust and normal forces show an excellent agreement with respect to finite element analysis and measurement data.