An Inductive Sensor for the Angular Displacement Measurement of Large and Hollow Rotary Machinery

This article presents an inductive sensor for angle measurement of the large and hollow rotary machinery. The sensor consists of the magnetic core, primary coils, and secondary coils. Three-phase alternate current signals are applied to the primary coils. Then, the traveling wave electrical signal is obtained by combining three roads of amplitude-modulated electrical signals modulated by permeability, and the phase difference reflects the spatial angular displacement directly. Furthermore, the angular displacement is acquired by high-frequency pulse interpolation. In this article, the structure and the measurement principle of the sensor is introduced first. Then, a model is simulated by the finite element analysis software to verify the feasibility of the sensor. The sensor structure is optimized according to the simulation analysis. Finally, a sensor prototype is fabricated and the experimental platform is built up for experiment. The experiment results show that the measurement accuracy of the sensor prototype is $\pm 40^{\prime \prime }$ during the measurement range of 0°–360°.