Search

This paper presents the analyses and experimental results of a single-sided linear induction motor (SLIM) thrust and normal force for the propulsion of semi-high-speed magnetic levitation (maglev) trains. These trains are composed of a levitation system that uses electromagnetic suspension and a propulsion system that uses SLIMs. The propulsion system of maglev trains using SLIMs has better low noise and dynamic characteristics compared with those using rotators. However, it has nonlinear characteristics due to the effect of slip that occur in the secondary eddy-current induction process; the normal force generated by the SLIM can negatively affect the levitation control. Therefore, a new slip-control algorithm is proposed for the safe operation of maglev trains, reflecting the normal force of the motor in propulsion control. First, the SLIM thrust and normal force are analyzed through the finite-element method (FEM) for a precise analysis of the slips. Furthermore, a slip range with a low normal force was derived based on the FEM analysis results, and these results are reflected in the propulsion control algorithm. Finally, the new algorithm was validated by an application to a full-sized testing apparatus. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM PUBLISHER]

The large normal force of a single-sided linear actuator may cause vibration, noise and reduce the positioning accuracy. To overcome these disadvantages, a new H-module linear actuator (HMLA) is proposed to reduce effectively the normal force without using expensive air suspension system or assisted guide. Compared to the existing HMLA, the teeth on the two opposite sides of the stator of this new HMLA are shifted by a tooth-shift-distance tsd. With a proper choice of tsd, the electromagnetic design and the force characteristics of the HMLA may be greatly improved. The finite element method (FEM) is employed to analyze the magnetic performance and the force characterization of an optimized HMLA with varying tsd. The performances when the HMLA is excited by rectangular and sinusoidal waveform currents are investigated. The result presented in this paper has shown that the total average tangential force of this new HMLA could be improved by 51% in comparison to the existing HMLA. [ABSTRACT FROM AUTHOR]

In this paper, a new linear synchronous motor—permanent magnet double-sided linear synchronous motor with perpendicular arrangement (PMDLSM), was proposed. This motor was designed to account for the drawbacks of conventional linear motors, such as the problems with normal force and end effects. It was designed by analyzing the detent force and the thrust of different models, and optimizing the design variables of the machine. The characteristics of the perpendicular PMDLSM were analyzed by finite element method, and a comparison of the results was made in the experiments. [ABSTRACT FROM AUTHOR]

This paper describes a method to compute the normal force that acts on the mover of an electromagnetic planar actuator. The method is based on the Maxwell Stress Tensor and depends on the resulting magnetic field. The actuator has a mover with two permanent magnets and a ferromagnetic stator covered by two orthogonal armature coils. The mover is hold by a suspension system with linear bearings that enable bi-directional motion. A normal force is present and it depends on the magnetic flux density distribution produced by the permanent magnets and on the armature magneto motive force, since the latter contributes to that distribution. This paper focuses the analysis of that normal force in order to assess its effects on the actuator and in a way that allows the proper design of the mechanical parts that will be affected by it. [ABSTRACT FROM AUTHOR]