Design of a flat-type magnetic position sensor using a finite-difference method

Abstract

This study presents an analysis and the design of a new flat-type position sensor with an external armature. One excitation coil and two antiserially connected pickup coils are used in the stationary part. Solid iron segments or steel lamination segments are used for the moving armature. The proposed position sensor was modelled using linear movement. A two-dimensional finite-difference method was developed and was used for fast analysis for optimising the sensor. The induced eddy currents in the solid armature were taken into account in the finite-difference analysis. The finite-difference calculations were compared with 2D and 3D finite-element method simulations and with experimental results. The sensor has a total error of 0.23 mm root-mean-square for 36 mm range without any compensation. Unlike previous designs, the authors’ new sensor has no moving coil.