Design and Performance Analysis of a Novel Liquid-Cooled Electromagnetic Retarder

Abstract

In order to solve the problems of serious deterioration of braking efficiency of traditional eddy current retarder (ECR) in continuous operation and poor braking characteristics of hydraulic retarder (HR) at low speed, a novel four salient poles liquid-cooled electromagnetic retarder (FSP-LER) is proposed. The downhill dynamics model of medium and heavy vehicles is established to analyze the braking demand, the FSP-LER is designed according to the braking demand, and its braking characteristics are predicted by the equivalent magnetic circuit (EMC) method and the finite element method. Hierarchical variable domain fuzzy control strategy combined with retarder is utilized for braking control, and MATLAB is used to establish the controller and the long downhill braking model of the whole vehicle and perform joint simulation. The actual braking characteristics of the retarder prototype were tested by bench test and vehicle road test, and the results showed that the braking torque of the FSP-LER decreased by only 13.49% for 10 min of continuous operation, and the braking efficiency was still maintained by about 86% at a low speed of 500 r/min. The average error between the actual measured value of braking torque and the analyzed calculated value is less than 5%, and the braking torque can reach 2213 N $\cdot $ m when the rotational speed is 1250 r/min, which meets the braking demand of medium and heavy vehicles.

Keywords

• Four salient poles
• dynamics model
• equivalent magnetic circuit
• finite element
• variable domain