Modeling of axial self-inductive displacement sensor considering fringing effects and eddy current effects

Axial self-inductive displacement sensor can be used in rotor systems to detect the axial displacement of the rotor. The design and analysis of the sensor are mostly based on the traditional ideal model, which ignores the influence of fringing effects and eddy current effects, resulting in significant discrepancies between theoretical analysis and experimental results. To take into account the influence of fringing effects and eddy current effects, this paper proposed the introduction of the fringing factor and complex permeability and then established an improved model. The results show that the prediction of the sensor's output voltage based on the improved model is in better agreement with the experimental results than the traditional ideal model, and the improved model can analyze the influences of the length of the air gap and excitation frequency on sensitivity. Therefore, the model could provide a significant reference for the design and analysis of the axial self-inductive displacement sensor.