Radial and axial integrated inductive displacement sensor used for magnetic bearing system

This paper presents a small size and high-integration inductive displacement sensor used for magnetic bearings. This sensor is a circular ring structure fixed on radial direction of a magnetic bearing and can measure radial and axial displacement at the same time. Sensitivity results show that displacement detection along each direction will not be affected by others. Then, the proposed sensor is applied in closed-loop control of a magnetic bearing when the rotor is levitated and rotates at 40k, 50k, and 60k r/min. According to experiment results, radial and axial displacement vibrate noise can be controlled within ±10 μm and about ±10 μm, respectively, evaluating the feasibility of inductive displacement sensor in closed-loop control. Contribution of this paper is to explore application boundary and provide a guide of applicable speed for inductive displacement sensor, which will help to promote application of magnetic bearing in more fields. And based on the experiment results present in this paper, inductance sensor can be used for magnetic bearing control when the rotation speed is below 60k r/min.