3D Modeling and Simulation of the Electromagnetic Field in Eddy Current Sensor

A 3D electromagnetic simulation of an eddy current sensor with an air-cored cylinder coil was studied by Finite Element Method. Based on the characters of structure and boundary conditions, two finite element models of eddy current sensor were built. Then the influences of eddy current sensor performance caused by its parameter changes were simulated with the better model. The simulating results indicate that the longer lift-off, which is the distance between the bottom of the coil and the top of the tested conductor, is given, the weaker density of eddy current is got as well as the higher inputting frequency is given, the thinner skin depth and the better energy reflecting effect in tested conductor are got. The relationship between the real and the image part of equivalent coil impedance is almost linear.