Analysis and Optimal Design of Relative Position Detection Sensor for High Speed Maglev Train

The relative position detection sensor provides the information about position, speed, direction and magnetic phase for high-speed maglev train, by detecting the varying inductance of coils along the long stator with tooth-slot structure. Actual processing technique can´t ensure the identity of two differential coils, which will make the direct current (DC) component of differential voltage drift and reduce the accuracy of sensor. In this paper, the effect of tooth-slot is equivalent to varying relative permeability. The wave distortion of differential voltage is analyzed, and algebraic expression of DC drift is derived. Based on that, some optimized methods are proposed. Experiment proves that they can effectively eliminate DC drift and improve the accuracy of sensor.