Study, analysis and development of a linear stepper motor with permanent magnetis.

Abstract

This work presents a linear stepper motor with permanent magnetics with high energy product – MLP – for planar movements where the combination of precision and speed are required. Thus, this study present a MLP consist of a linear and static structure of ferromagnetic material, which are mounted six coils and a mover structure, U-shaped, in which two permanent magnets are fixed. Mechanical suspension systems allow a linear movement between static and mover part, maintaining a constant air gap. The operating principle is based on the Lorentz Force, which provides that when a conductor, excited with electric current, is immersed in a magnetic field it acts an electromagnetic force, so, in the MLP, the relative motion between the static and mover parties, as well as the speed and intensity of the force is conditional to the sequence of switching the six coils and the intensity of the electrical current applied on them. The study of this device is still based on the use of numerical analysis, from a virtual prototype, and an experimental analysis, from a physical prototype, investigating and comparing quantities such as: electromagnetic force and magnetic flux density. Preliminary results realize that the driving force of the linear device is 2.63 N / A (Newton per Ampere), when the coils are completely aligned with the permanent magnets and 1.55 N / A when the coils are only 50% aligned.