Applicaton Of Differential Transformer Displacement Sensors In Active Magnetic Bearings

This thesis mainly concerns the application of a new differential transformer radial displacement sensor on Active Magnetic Bearing(AMB). As for the dynamic performance, the Linear Variable Differential Transformer (LVDT) displacement sensor using signal conditioner AD598 is not so good, so the differential rectifier is designed as the measuring circuit of the sensor so as to increase its cross-over frequency. Also, the static test and dynamic test is made for the sensor along with the LVDT. The experimental results show that the static performance of the new designed sensor is as good as that of the previous one, however, the dynamic performance is far better.A radial test-bed of AMB with two degrees of freedom is designed and manufactured for the practical use of the sensor in AMB system. With the use of the two design of the sensor, the static levitation of one and two freedom-degree is realized. Furthermore, the same levitation of AMB system is realized in which a non magnetic-conducting layer of material is installed between the stator and rotor.Additionally, the work of the thesis has made some theoretical and experimental preparations for the study on Self-sensing Magnetic Bearing(Sensorless Magnetic bearing). And the designed sensor can also be used to measure some other types of linear displacement or rotation angle.