The Effect of Frequency on Double-Coil Inductive Displacement Transducer

Double-coil inductive displacement transducer is a noncontact-type high-precision displacement measurement element, which is widely used in industrial manufacturing and large power equipment systems. Since the inductive displacement transducer has a parasitic capacitance, the frequency of the excitation signal has a great influence on the performance that has been little studied so far. In this article, the method of determining the optimal excitation frequency of double-coil inductive displacement transducer is studied. The working principle and characteristics were analyzed, a signal conditioning circuit was proposed, and a circuit simulation model was established. According to the simulation results, the influence law of the frequency of excitation signal on the double-coil inductive displacement transducer is obtained. The effect of frequency on the displacement transducer was analyzed in five aspects: frequency characteristics, output signal, sensitivity, the residual voltage at zero, and linearity. Finally, the effectiveness of the simulation results was verified through experiments. The simulation and experiment show that the proposed signal conditioning circuit can realize the demodulation of the double-coil inductive displacement transducer signal. Taking DIPT14 displacement transducer as the research object, the frequency of excitation signal has influence on the sensitivity, residual voltage at zero, and linearity. When the frequency is low, the parasitic parameters have little effect on the performance of the transducer and can be ignored. However, when the frequency is high, the parasitic parameter has a great influence on the performance of the transducer. The method presented in this article is of great significance for the study of the characteristics, signal conditioning circuit, and the determination of the optimal frequency of the excitation source of double-coil inductive displacement transducers.