Physical Design And Research On Mechanical-permanent Magnet Bearings For High-speed Flywheels

Storing energy through high-speed flywheels has many advantages: high energy-storage density,quickly charging and discharging,and high power input and output;long service life,and being capable of recycle for several times;high conversion rate,and making the best of energy.However,due to the revolving speed of high-speed flywheels is extremely high,its supporting system becomes a key problem.Under the application background of high-speed energy-storage flywheels in vehicles,and based on the present research on permanent magnet bearings,this thesis improves the traditional permanent magnet bearing corresponding to its drawbacks which are low bearing capacity,low radial stiffness and poor ability of automatic center-alignment,and designs a system of mechanical-permanent magnet bearing for high-speed flywheels,as well as investigates the bearing characteristics through simulation.This thesis mainly carries out the research on the following three aspects:(1)This thesis studies a new rad ial permanent magnet bearing.Dividing the magnet ring of traditional permanent bearing stator into six permanent magnets,with each permanent magnet having a driving device,it can be dynamically controlled corresponding to the displacement of the stator.Based on the working principle of permanent magnet bearings,a parallel differential control method is designed to improve its ability of fast center-alignment.With the assistant of electromagnetic filed analysis software Ansoft Maxwell,the finite element model of the new radial permanent magnet bearing is constructed.Through theoretical analysis and simulation,this thesis investigates the factors that influence the bearing capability of the permanent magnet bearing and designs a new radial permanent magnet bearing which has compact structure,high bearing capability and high radial rigidity.(2)To control the permanent magnet stator dynamically,this thesis designs a driving device for the permanent magnet stator of the new radial permanent magnet bearing.The driving device is composed of a piezoelectric ceramic actuator and a secondary leverage micro displacement amplifier.As the micro displacement amplifier is a kind of flexible hinge mechanism,ANSYS Workbench is utilized to analyze the impact of the flexible hinge parameters on the micro displacement amplifier.(3)To enhance the working stability of the permanent magnet bearing,this thesis designs a soft assistant supporting system.Based on the deformation of the suspending stand,the pre-loaded pressure and contract stress between the suspending small bearing and axle cover are calculated,respectively.And a soft assistant supporting system with reliable function and reasonable structure is obtained after the simulation and structure optimization with the assistant of finite element analysis software Workbench.