Study On The Dual Mode Braking System Of A 4wd Hybrid Electric Vehicle Based On The Dual Rotor Motor

The braking system of HEV is generally composed of hydraulic braking subsystem and regenerative braking subsystem. The hydraulic braking subsystem is the same to the hydraulic braking system of traditional vehicle, which starts braking by human power and produce hydraulic braking force with some delay. With the development of electronic control technology, the control unit of braking system also promotes the trend of electronic, such as electrical hydraulic braking system, it can achieve more accurate and efficient braking. During the process of braking, the regenerative braking subsystem can store part of kinetic energy in the form of electrical energy in the battery, and generate braking force to brake the vehicle. How to make the hydraulic braking system assorts with the regenerative braking system, to get more regenerative energy under assurance of braking safety is a key technique for HEV research.Based on a four-wheel drive HEV of joint development, an electrical hydraulic barking subsystem is put forward, which is defined as the dual mode braking system. The appropriate braking force distribution strategy, braking performance and energy recovery efficiency of the dual mode braking system are studied in detail. The research contents are as follow:Firstly, an electrical hydraulic braking subsystem is promoted, its structure and working principle are studiede carefully, and the control method of the dual mode braking system is also carried out.Secondly, a braking force distribution strategy is presented, which not only meets the requirements of braking performance, but also achieves better energy recovery efficiency. The limitations of regenerative braking force of the motor are analysed, and the control algorithm of the braking force distribution is also formulated.Thirdly, the mathematical model of the various parts of the dual mode braking system are established, including the driver intention model of brake pedal, the high-speed switch valve model, the model of electrical hydraulic braking subsystem, the model of vehicle energy consumption, the dual rotor motor model, the battery model and the braking force distribution model, etc.Fourthly, according to the mathematical model of each part, the simulation model of the dual mode braking system is built up in the Matlab/Simulink. The simulation under several typical duty cycles are carried out and the results are compared with those from the Advisor commercial software. In order to vetify the rationality and availability of the electrical hydraulic braking subsystem and the braking force distribution strategy, and the efficiency of energy recovery, the simulating results are analysed in detail.Finally, corresponding conclusions have been summarized and the further researching directions are proposed.