Study On Regenerative Braking System Of Hybrid Electric Car

Regenerative braking is one of the ways for hybrid electric vehicles (HEV) to reduce energy consumption, is a remarkable advantage of hybrid electric vehicles to current"conventional"vehicles. Using it can effectively improve fuel economy. But in our country, the research for hybrid electric vehicles is just in the beginning, so the study of regenerative braking, which is one of the key techniques for HEV, is relatively weak. In recent years, domestic research institutes and automotive companies have investigated on regenerative braking system, and have acquired some achievement, but the technology is not mature. Presently, the regenerative braking systems applied in HEV have many problems, for example, the hydraulic braking force is always operated, the hydraulic braking force cannot be controlled, the recycled braking energy is limited. There is a gap between domestic and overseas regenerative braking system.On account of the present state, this paper made use of the achievement of our lab in the "863" Plan of Electric Vehicle, and based on the requirement in the eleventh Five-Year, the author proposed a hydraulic regenerative braking system with the"baking by wire"system in theory.First of all, this paper analyzed the commonly used control strategy of regenerative braking system, and then proposed a braking force distribution control strategy which is suitable for the hybrid electric car. Using the strategy in hybrid electric car can effectively improve fuel economy and can ensure the stability of the car when braking. But the conventional hydraulic braking system cannot implement this strategy. So, this paper proposed a hydraulic electric braking system with the"baking by wire"system, which can realize the digital distribution of the braking force.When developing this new type braking system, Firstly, this paper mainly designed the structure of the regenerative braking system and chose the components. Secondly, the mathematics models of the system were summarized, based on this, the dynamic model was constituted. Then, the author did thesimulation in the environment of MATLAB/SIMULINK, The author carried on many drive cycles, and compared with the other strategy, and analyzed the result of the simulation. The results verified the rationality and the feasibility of the hydraulic electric braking system, and proved the braking force distribution control strategy which proposed in this paper can effectively improve fuel economy and can ensure the stability of the car when braking.