Design and thermal management of a novel eddy current retarder for electric buses

This paper proposes a novel eddy current retarder (NECR) and thermal management method, aiming to solve the problems of low electromagnetic utilization rate, serious thermal decay of braking torque, and waste of braking energy in traditional eddy current retarder. The structure characteristics and working principle of NECR are introduced. The braking model is analyzed and calculated by using the equivalent magnetic circuit method. The transient magnetic field and temperature field of NECR are numerically simulated by finite element method. A thermal management method of NECR is proposed. And the braking force distribution strategy based on fuzzy control system is designed. And the braking force distribution strategy based on fuzzy control system is designed. The simulation results show that the heat generated by NECR can heat the electric bus cabin temperature to 19 °C. And the energy consumption of the vehicle is reduced by 28.8% compared to the use of electric energy to heat the cabin. The experimental results show that the average error between the experimental value and the simulation analysis value of braking torque is <5.8%. When the excitation current is 100 A and the rotating speed is 1500 rpm, the braking torque can reach a maximum of 2410 N·m. After continuous braking for 10 min, the braking torque decreases by only 13.7% and the temperature is stable within 100 °C.