Three-dimensional electromagnetic model and performance analysis of eddy current brake for rail transit
LYU Gang
HAN Tianyu
Abstract：To address the challenge of accurately calculating the braking force of eddy current brakes(ECBs)in rail transit,this study proposes a three-dimensional electromagnetic model and analyzes the effects of various parameters on braking performance.First,the expression for static air-gap magnetic flux density is derived using the equivalent magnetic circuit method and Maxwell's equations.The influence of the transverse edge effect on braking force is examined,and a correction coefficient for the conductivity of the conductor plate is derived.An equivalent eddy current density model is then estab-lished,leading to analytical expressions for both air-gap flux density and eddy current density.Subse-quently,the impact of the longitudinal end effect on braking force is analyzed,and an expression for the additional air-gap flux density is derived.Based on the relationship between eddy current density and air-gap flux density,an analytical ex-pression for braking force is obtained.Finally,a three-dimensional finite element model is constructed using the design parameters of the Shanghai TR-08 high-speed maglev train's ECB to verify the accuracy of the proposed model.The three-dimensional electromagnetic model is also used to analyze the influence of different parameters on braking perfor-mance.The results indicate that the maximum error between the three-dimensional electromagnetic model and the three-dimensional finite element model is 5.18%,with an average error of 2.35%,validating the accuracy of the three-dimensional electromagnetic model.The braking force in-creases initially and then decreases with rising speed,exhibiting four distinct characteristics in its variation curve:linearity,criticality,attenuation,and stabilization.The additional braking force increases with speed.Properly widening the conductor plate can effectively mitigates the influence of the transverse edge effect.The braking force increases with higher ampere-turns of the excita-tion winding and a wider primary core,while it first increases and then decreases with increasing conductivity and permeability of the conductor plate and with greater primary pole distance.The braking force decreases as the air-gap thickness increases,and the speed corresponding to peak braking force also increases.A thinner conductor plate slows the growth of braking force.Both in-creasing the air-gap thickness and reducing the conductor plate thickness contribute to a more stable braking performance.
Keywords：eddy current brakethree-dimensional electromagnetic modelfinite element methodbraking performance
Publication Date：2025-08-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 52-62 )