An Integrated 5-DoF Displacement Sensor System of Magnetically Suspended Flywheel

The displacement measurement of the magnetically suspended flywheel (MSFW) on 5 degrees of freedoms (5-DoFs) is critical to the accurate position control of the flywheel (FW) rotor. Therefore, an integrated 5-DoF displacement sensor is designed to measure the dynamic displacements of the MSFW. First, the detection surfaces of the MSFW on 5-DoFs are introduced, and the displacement coordinates are established. Moreover, the detection principle and the dynamic responses of the integrated 5-DoF displacement sensor are analyzed. The single-winding probe is used as the radial displacement sensor, and the series-connection dual-winding probe is applied in the axial displacement sensor to measure the large displacement variation. Furthermore, the magnetic intensity and the quality factor of the integrated 5-DoF displacement sensor are simulated and tested. Finally, the measurements of the translational displacements and the deflection angles are conducted. The results show that the linear ranges of the radial single-winding probe and the axial series-connection dual-winding probe are 1.3 and 2.4 mm, respectively. The frequency bandwidth could be 10 kHz, and the maximum temperature drift is only 3.87%.