A novel approach for sensitivity improvement of axial inductive displacement sensor

Abstract

Nowadays, magnetic bearing has been used in more and more fields. Displacement sensor is one of the most important functional components of a magnetic bearing system and have attracted more and more attentions. Inductance displacement sensor, which shows merits in maintainability, lifetime, sensitivity, environmental interference ability, and cost, is a potential displacement sensor for magnetic bearing systems. While, usually, for a certain application, installation space of displacement is limited, increasing the difficulty of sensitivity improvement by stator structure optimization. This paper presents a novel approach for axial inductance displacement sensor to improve sensitivity by decreasing the armature depth. In the experiment part, three armature with different depth have been fabricated and their performance are tested. The results show that sensitivity is improved from 2.34 mV/µm to 3.15 mV/µm when the depth of armature decreases from 24 mm to 18 mm, validating the feasibility of sensitivity improvement by decreasing the armature depth. With the improvement of sensitivity, resolution also improves from 5.1 µm to 3.8 µm. Negative effect of this approach is that measuring range is decreased when the armature depth is reduced.