Design and experiment study of digital eddy current displacement sensor used for displacement detection of magnetic bearing

Magnetic bearings are core components of magnetic flywheel and magnetic control moment gyroscope, which have strict requirements of size, weight and power consumption in space applications. The output of existing non-contact sensors used for displacement measurement in magnetic bearings is mostly analog signal, and separate signal lines are required for transmission of each detection points. This causes the size, weight and complexity of system to increase while reliability decreased and anti-jamming capability weakened. To solve this problem,a digital eddy current displacement sensor is proposed in this article, which according to the principle of Frequency Modulation and through the method of frequency measurement by CPLD, has achieved the high speed and high accuracy detection of the displacement as well as enhanced the reliability and anti-jamming capability of the system.