Force Characteristics Studies On Permanent Magnet Electrodynamic Wheel Stucture Of Annular Halbach Array

Permanent magnet electrodynamic suspension(PMEDS)technology has received much attention on recent years due to the application of Nd Fe B material and the demand for highefficiency transportation.While traditional PMEDS structure has a high cost and low lift to drag ratio caused by sizeable magnetic resistance,which limits its widespread use.Hence,an annular Halbach structure of permanent magnet electrodynamic wheel(EDW)is studied in this paper,which is able to convert the magnetic resistance into the thrust force and avoid extra energy consumption.Based on the principle of PMEDS,this thesis studies an annular Halbach structure of permanent magnet electrodynamic wheel(EDW)that could convert magnetic resistance force into propulsion force,and avoid additional energy consumption.This thesis adopts the study route of the EDS principle of exploration,Finite Element Method(FEM)simulation and electromagnetic force analysis.It aims to explore and master the characteristics of the suspension force and propulsion force of PMEDS under static and dynamic operating conditions.By analyzing the steady-state stiffness terms and damping terms of the permanent magnet EDW,the levitation stability of the system is studied,and the suggestions for the stable operation condition of the system are given.Firstly,a two-dimensional model of permanent magnet EDW system for maglev vehicle is established in ANSYS Maxwell software.The quasi-static and dynamic levitation characteristics of permanent magnet EDW system are analyzed under different suspension air gaps,rotational speeds and relative slip speeds,meanwhile,the influence of different parameters on suspension force and propulsion force.When the levitation air gap is 10 mm and the rotational speed is 7000 rpm,the maximum levitation force is 47 N,the maximum propulsion force is 17 N,and the system transition rotational speed is 1050 rpm.Then,Electromagnetic Induction law is applied to expound the qualitative analysis of the levitation principle,and the distribution of induced current at different rotational speeds was obtained.Besides,the existing analytical methods of permanent magnet magnetic field are summarized,and then the magnetic charge method is used to calculate the magnetic field and electromagnetic force of the EDW system,and the correctness of the analytical model is verified by comparing with the three-dimensional FEM model and experiments.Based on the three-dimensional analytical force model,the vertical and translational stiffness and damping terms of the levitation force and thrust force are further calculated.The stiffness and damping characteristics of the permanent magnet EDW under different operating conditions are studied.In addition,the operating levitation stabilities of the permanent magnet EDW are analyzed,and some suggestions on the control of the working operations corresponding to the unstable stiffness and damping terms are also proposed.