Research On Active Electromagnetic Retarder For Automobile

Safety,environmental protection,energy saving,high-speed and comfort are the development direction of heavy vehicle now.The retarder will be an essential part of the heavy vehicle.Eddy current retarder(ECR)is widely used in heavy vehicles because of its advantages such as high torque at low speed,fast response speed and simple structure.However,ECR converts the kinetic energy of vehicle braking into heat energy and dissipates it in the air,which is bound to bring energy waste,especially for the heavy-duty vehicles which often go down the long slope on the mountain roads and the buses which often run on the urban roads with complex traffic,the frequent work of the ECR wastes a lot of energy.In view of the shortcomings of the existing ECR,based on literature reading,this paper proposed a new type of automobile retarder,active electromagnetic retarder(AECR),which combines eddy current braking and switched reluctance motor(SRM)regenerative braking technology.The design theory and key technology of active electromagnetic retarder are systematically studied,and a lot of bench experiments are carried out.The main contents of this paper include:The opening chapter introduces the function of automobile retarder,the necessity of installation,domestic and foreign laws and regulations,the existing problems and research significance of the retarder.By summarizing the research status of eddy current retarder,active retarder and energy recovery and reuse device,the development direction of active retarder is put forward.The research progress of eddy current brake theory is summarized,and the research method of active retarder design theory is put forward.Chapter ? proposed a structure and working principle of AECR.Based on the principle of eddy current braking and regenerative braking of SRM,two kinds of AECRs were proposed.By comparing the advantages and disadvantages of the two active retarders,the final structure of the AECR was determined.In addition,several structures suitable for passenger cars and heavy-duty trucks are proposed.According to the matching characteristics of the AECR and the whole vehicle in terms of electrical,heat dissipation and braking performance,the retarder electronic control unit and the whole vehicle cooling system water pipe layout scheme are designed.Chapter ? built the mathematical model of AECR.Through the formula of effective permeability,Faraday's law and Ampere's law,based on the method of equivalent magnetic circuit and subsection function,the mathematical model of air gap magnetic density and braking toruqe of eddy current brake part was established.The model considered the influence of the end effect and skin effect of electromagnetic field in the retarder on the permeability of eddy current disk,and the validity of the model was verified by finite element;based on the equivalent magnetic circuit and equivalent circuit The mathematical models of electromotion and generation of SRM are established.Chapter ? built the finite element analysis model of AECR system under different working conditions.The finite element analysis model of the eddy current braking system of the retarder was established.The distribution of the transient electromagnetic field,eddy current and the braking torque at different speeds of the retarder were predicted.The finite element analysis model of the SRM system was establish,the braking torque and generating current of the motor at different speeds were predicted,and the opening and closing angles of the motor were optimized.Chapter ? designed the electronic control unit of the AECR.According to the working requirements of AECR,an electronic control unit based on MC9S12XS128 and IGBT power output module was designed.The electronic control unit consists of microprocessor system module,system power module,input signal detection module,output driver module and can communication module.Then the circuits of each module are designed,including chip selection,interface circuit design,etc.Finally,the PCB was made after the integration of each module,and the experiment was carried out.Chapter ? studied the test method of AECR.The test platform of AECR was established.The AECR performance was tested by bench.The correctness of the mathematical model and the reliability of the system were verified.Finally,the dissertation conclusion and future research outlook are lodged.