Study on Signal Processing Technology of Relative Position Detection Sensor for High Speed Maglev Train

Relative position detection sensor is critical component for High Speed Maglev Train (HSMT) as they provide direction, speed, tooth-slot count and phase angle for traction system which drives maglev train. The traction system has higher requirements on the accuracy and stability of the phase angle signal. The demodulated wave signal directly affects the precision of the phase. In order to obtain higher accuracy of the demodulation signal, a demodulation approach based on an analog switch is proposed. The difference between early and present signal generating circuit is compared. Then the proposed demodulation method is analyzed mathematically. Moreover， the comparison between demodulation of the early sensor based on the analog multiplier and that based on the analog switch is implemented. A series of tests have been adopted to validate the performance of the proposed demodulation method and show that a more stable and accurate demodulation signal can be obtained.