Abstract: In this paper, the torque characteristics of an electromagnetic eddy current brake are studied by means of theoretical analysis and finite element method(FEM). First of all, the mechanical structure and working principle of the brake is introduced, and combined with the magnetic circuit analysis method and layered theory, the formulas of eddy current density and eddy current loss in brake disc are deduced, and the analytical calculation formula of braking torque is derived. The results show that the braking torque is positively correlated with the number of turns and the square of the product of exciting current, and is affected by the length of air gap, thickness of brake disc, permeability and conductivity of electromagnetic material. Then, the three-dimensional finite element model of the rotary eddy current brake is established, the validity of the theoretical results is verified. By using the finite element model, the influence of the geometric and electromagnetic parameters of the brake on the braking characteristics is studied, and the brake parameters suitable for the train emergency braking condition are obtained. Finally, the parameter model of the brake is established based on the braking characteristic curve, and the fuzzy controller of braking torque is designed to improve the stability of train braking in high-speed section. The proposed theoretical formula of braking torque, braking characteristic analysis and controller design method can provide reference for the overall design and optimization of eddy current brake.

Key words: eddy current brake, torque characteristics, parameter analysis, fuzzy control