Analysis Of Magnetic Field And Simulation Of Braking Efficiency Based On Permanent Magnet Retarder

Permanent magnet retarder, a new auxiliary braking device, is independent of the vehicle’s own braking and parking brake system. It is developed well in foreign countries because it can not only enhance the safety of the vehicle, extend the life of the main brake system to save money and protect environment, but also has many advantages of its own, such as lightweight, maintenance-free and non-consumption energy. But the application and research are just in its initial stage in China. In this context, in order to be able to provide theoretical methods for design, selection and use of permanent magnet retarder, main tasks in this paper are as follows:(1) First, the structure, installation and working principle of permanent magnet retarder were elaborated. Then the actual effects of the permanent magnet retarder were analyzed objectively. Finally, the problems to which should be paid attention when the retarder was installed were summarized.(2) In order to provide the basis for the determination of structural parameters, the relationship between the structural parameters and the air gap flux was analyzed by the parameter sweep function of Maxwell3D.(3) The braking process and efficiency indicators of vehicle were introduced in this chapter,which are the basis of establishing the model of braking and deciding braking effect.(4) In order to be able to predict the braking effect of the vehicle with permanent magnet retarder, select the ideal permanent magnet retarder, and promote the permanent magnet retarder’s reasonable process of serialization, first, a joint braking mathematical model was set up on the basis of considering many factors that affect the braking efficiency,such as air resistance, rolling resistance, transfer of vertical load, quality conversion coefficient, slip rates, the primary and secondary brake system. Then a simulation model was established with Matlab/Simulink, in which the characteristics of the vehicles and ground were taken as input parameters,and the parameters of braking efficiency were considered as output parameters. On the basis, various braking process was simulated, such as the straight road braking,ramp braking, emergency braking.Finally, the simulation results were analyzed and verified by experiments.The studies have shown that it plays a significant role in determining structural parameters of permanent magnet retarder to do three-dimensional parameter analysis with air-gap flux as the target parameter. In non-emergency braking, the retarder can consume a lot of energy of vehicle to reduce the frequency of the main brake. In emergency braking, the braking effect of retarders is not obvious. The correctness of this simulation model is verified by the comparison of the results between test and simulation. Therefore,the models can be used as an important basis to determine structural parameters and select retarders.