Analysis and experimental study of a novel self-differential eddy current sensor for high-speed magnetic electrical machine

With the increasing rotated speed of the magnetic electrical machine with active magnetic bearings (AMBs), improving the dynamic response and the resolution of the displacement sensor turn into a key problem. In this paper, a novel self-differential eddy current displacement sensor (ECDS) based on the Hartley principle for high-speed electrical machine was proposed. First, the integrated structure of the ECDS probe and the novel design scheme were presented. Then a method of phase advance network to improve the dynamic characteristic of the sensor was described in detail. Finally, the detailed procedure was given to suppress the sensor-to-sensor crosstalk noise to improve the resolution of the sensor. Experimental results showed that the ECDS with high dynamic response and resolution is valid in the application to high-speed maglev rotating machinery in industry.