Axial Magnetic Bearing Displacement Detection Technology

At the booming developmental present time, Magnetic levitating bearing, with no friction, no wear, no lubrication, low power consumption, low noise, is being extensively demanded for application. Magnetic levitating bearing rotating shaft must, according to state of suspension, constantly adjust magnetic force to make axis suspension. The one key technique is the rotor displacement's detection in real-time. According to the developing of the system requirements, the main task is to make comparative study of three displacement detection technologies-the eddy current, inductance, and capacitor displacement detection technology used in magnetic levitating bearing system.By comparing with the various eddy current detection circuits, design the FM displace-ment detection circuit, do experiments and analyze the waveform and frequency. To improve the detection sensitivity of displacement, determine the incentive the signal frequency and waveform.Design a differential capacitor displacement system. Design PCB and detection circuit plate with electrodes, and then make up them an organic whole, join displacement changes, that is capacitance change, into electrical signal output directly, greatly reducing the capacitance interference, and adopt a shielding measure to overcome the influence of the external electromagnetic interference, so make the system detection reliabilities greatly improved, and then make the displacement detection sensitivity.Use the eddy current and differential capacitor displacement sensor in axial magnetic levitating bearing, carry on the actual contrast experiment. According to the actual effect, from installation convenience consideration, eddy current sensor volume is small, easy to install and capacitance sensor volume slants big, From sensitivity consideration, differential inductive sensor sensitivity is higher than the eddy current transducer, From the economic consideration, capacitance displacement detection systems are more cheaper than electricity eddy displacement detection system. So using differential capacitor displacement detection technology is more appropriate than electricity eddy displacement detection technology in axial magnetic levitating bearing the displacement detection.