Study And Realisation Of Temperature Compensation For Gap Determination Sensor Based On FPGA

The gap determination sensor, is one of the most important parts of High-speed Maglev Vehicle system. Actually, the temperature varies in a large range in the place where the gap determination sensor works, so the detect voltage of the coil is direct relevant to the temperature and the gap value. The stability of the gap determination directly influence the control stability of maglev vehicle and the operation security, as the result of temperature drift, the gap sensor cannot performance higher accuracy. It’s necessary to reduce the temperature drift, in order to enhance the sensor’s temperature stability.This gap determination can partly eliminate the tooth-groove-effect from special structure of track in linear synchronous motor (LSM) by using a new stereoscopic probe coil. According to the analysis on the temperature drift of gap sensor, we get a conclusion that the detecting coil is the key point which results in temperature drift.Although the accurate mathematics model of the planner rectangualar inductor have not been established in theory, this article compares several existing traditional hardware and software compensation plans, according to the environment analysis on probe coil of the sensor, how the parameters of coil influence its inductance, and how the alternating-current resistance of the detecting coil changes, especially when the temperature changes, the Skin effect on the inductor coil is rised by high frequency current, is discussed in this paper.This paper establish the model of detect voltage of the planner rectangualar inductor coil, which is relevant to the temperature and the gap value,and propose a new compensation plan. We design a program based on FPGA, gather the gap signals in several temperature under real-time operation, obtain the survey data to the compensation plan. According to the experiment, the compensation plan improve the temperature stability of the gap sensor. Combined with the calibration system, the sensor provide more precise and effective signal for the following controller.