A study on the effect of excitation frequency on eddy current sensor coil inductance and signal conversion circuit design

Eddy current sensor are widely used in various industrial applications among many non-contact measurement methods because of their excellent performance, low cost, and simple operating conditions. In the field of micro-nano manufacturing, the realization of high-precision online nondestructive measurement is the premise of ensuring the quality of processing, and the eddy current testing method also has great advantages in the thickness of nano-scale metal films. The detection coil and signal conversion circuit of eddy current sensors are very important for its performance the detection coil is used as the sensitive element to receive the external physical quantity change, and the signal conversion circuit is responsible for converting the impedance change obtained by the detection coil into the voltage change. As a kind of electromagnetic sensor, eddy current sensors need a high excitation frequency to achieve good measurement results, so the influence of excitation frequency on the performance of the eddy current sensor should be considered comprehensively when designing the eddy current sensor. In this paper, the influence of excitation frequency on the detection coil and electrical parameters of the signal conversion circuit is studied by the coupling simulation of the electromagnetic field and circuit.