Study of the shielding of angular position sensors with magnetic transduction

Abstract

Over the past few years, magnetic position sensors have increasingly been chosen over other products and technologies as a result of their high durability, reliability and their ability to be integrated into very small form factors. However, the use of magnetic based sensors is susceptible to interferences when placed in electric vehicles, due to the increasing number of cables. As the electric cables generate stray magnetic fields, especially the ones carrying the high currents from battery to the motor, wrong readings from the magnetic sensors occur, since the amount of external magnetic fields is greater than the maximum disturbance supported by the sensor [1]. The effect of magnetic shielding on an angular position sensor is studied here using an electro-magnetic FEM model (ANSYS Workbench [2]). Permanent magnet, magnetic sensor and disturbance source are modeled and the effect of shielding is extracted from the simulations. Simulation results show that shielding can be achieved using a highly permeable plastic casing.