Structure Design and Simulation Analysis of Inductive Displacement Sensor

Inductive displacement sensor is one kind of the common sensors widely used in magnetic bearing system. In this paper, the output characteristics of the differential inductive sensor are analyzed. One radial inductive displacement sensor was designed for a magnetic levitated rotor. The magnetic field distribution and output characteristics of the designed sensor were simulated by using FEA software. Theoretical analysis and simulation results both show that there is a very good linear relationship between the output voltage and the rotor displacement of differential inductive displacement sensor. And when the displacement of rotor is in the range of -0.2 to 0.2(mm), the sensor sensitivity presented by simulation is 16.9V/mm, equal to 67.6% of the given theoretical value. The main reason is that it is assumed that the sensor iron core coils are ideal and have no magnetic flux leakage in the theoretical analysis, which does not fit with well the practical conditions. The main reason is caused by the ignoring leakage inductance of the coil in theoretical analysis.