Research On Long Stroke Secondary Moving Permanent Magnetic Linear Eddy Current Brake

Eddy Current Brake is an electromagnetic device that effectively utilizes eddy current effect,and can realize braking by transforming kinetic energy of the moving devices into electrical energy and being consumed in the form of heat.This type of braking device has no contact interface between the primary and the secondary,and it enjoys high reliability,long working life,no pollution and little noise.Compared to the electrically excited eddy current brake,the permanent magnetic eddy current brake saves the copper usage of the winding and huge amount of excitation power loss,and has high reliability and high force density.It has a wide application prospect in the braking and vibration elimination field.This paper targeting at the long stroke secondary moving Permanent Magnetic Linear Eddy Current Brake(PMLECB),performs the analytical analysis and Finite Element Method(FEM)simulation,proposes the design approaches accordingly,studies its mechanical dynamic characteristics,manufactures the prototype and conducts the corresponding experiments.Firstly,theory of hierarchies is applied to deduce the magnetic vector potential distribution and the magnetic distribution;through eddy current loss and Maxwell Tension Equation,it derives the braking force expression and normal force of eccentricity respectively;the 2D model is extended to 3D domain by taking the edge effects into account;thus,the complete analytical electromagnetic model is established.Secondly,the FEM simulation model of PMLECB is established,the magnetic and eddy current distribution is studied,and the former analytical model is validated by the FEM simulation results;upon the main purpose of maximum force density,the FEM is applied to optimize the main structural parameters of the PMLECB.Then,based on the former analytical model and optimization process,a design approach of such PMLECB is developed;the relation between the main structure dimensions is deduced and the selection of the main structural parameters is determined.The prototype is designed and manufactured,the corresponding experiment is conducted,which verifies the correctness of the analytical and FEM model.Finally,the mechanical dynamics analysis of the PMLECB is performed.FEM is applied to study the modal analysis,harmonic response analysis and etc.of the secondary plate;the effect of the secondary structure on its natural frequency is explored and the means to improve its natural frequency can be found,which provides practical reference to the engineering application.