| Hybrid Electric Vehicle(HEV: Hybrid Electric Vehicle) has been a new orientation for vehicle as it combines the two advantages of low emission and low fuel consumption. As a key technology to reduce energy consumption, regenerative braking has been paid more and more attention. Regenerative braking is a technology to change one part of the vehicle's kinetic energy to other forms of energy(such as electricity) or transfer this part of energy to other parts(such as Super High-speed Fly Wheel) to store it when braking. This part of the energy will be released when the vehicle drives or accelerates, so we can improve the vehicle's fuel economy effectively.At the present time, the research about Hybrid Electric vehicle in our country is just in the beginning, so the study of regenerative braking system is relatively weak. Considering the braking performance and braking stability, most HEV utilize both hydraulic braking system and regenerative system at the same time, which reserve the intrinsic hydraulic braking system and introduce the motor into braking, so how to make the hydraulic braking system cooperate with the regenerative braking system on condition of the braking stability is a key technology for HEV. The regenerative braking system applied on HEV presently in our country have many problems, such as the hydraulic braking force can not be controlled accurately, the reduced energy is limited and so on. There is a gap between domestic and foreign regenerative braking system.Based on the achievement of our laboratory in the national"863"program of hybrid electric vehicle, this paper did some research about the regenerative braking system, combining with the actual demand of the hybrid electric vehicle"CA7220E"in the"eleventh Five-Year". By consulting some domestic and foreign literature, we have acquired some results as following:1. Analysis was done about the working process of the regenerative braking system ,the HEV's structure and the basic theory of the energy reducing. 2. After doing some analyses about the braking process of hybrid electric vehicle, we consulted three typical braking force distribution control strategies, combining with the actual demand of the HEV, and then we finally proposed a braking force distribution control strategy, which can improve fuel consumption effectively on condition of the vehicle's braking stability. This strategy can meet the demand of the ECE braking law, and reduce braking energy effectively.3. A dynamic vehicle model for regenerative braking system has been built up based on AMESim in this paper, which includes some models for the key parts of the HEV braking system, such as the motor model, the battery model and the semi-empirical tire model and so on. The modeling course used theoretical modeling approach combined with mathematical modeling.4. An arithmetic model has been built under the environment of Matlab/Simulink, which include a braking force distribution control model and a sub-model for ABS hydraulic braking system.This are done based on the proposed braking force distribution control strategy. We can do a co-simulation with this arithmetic model and the dynamic vehicle model to assort the motor braking system with the ABS hydraulic braking system.5. Do simulation with the co-simulation model under different typical braking cycles(different initialized velocities,braking intensities and adherence coefficients). Adjust the parameters according to the simulation results. The results indicates that this HEV braking system can reduce the fuel consumption effectively on condition of the braking stability.It can reduce fuel consumption by 61.44% under condition of small braking intensity when the initialized velocity is 60km/h, and this validate that the model is reasonable and feasible.As one of the key technology of HEV, the regenerative braking system plays an important role in HEV study and research, the work of this paper will be a coaching significance for the further study of regenerative braking system.
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