Study On Control Strategy Of Braking Energy Recovery For Pure Electric Bus

The problems of energy shortage and environmental pollution have become increasingly severe, and prompted the rapid development of electric vehicle industry. In recent years, our country attaches great importance to the independent research and development of electric vehicles, and increased the policy support and funding for the development of EV. Electric vehicles are bound to become the inevitable choice for people in the future.Braking energy recovery technology is a key and unique technology of electric cars. The basic principle of braking energy recovery techniques is that make the motor to run in generator mode by controlling during the vehicle braking. The motor will generate braking torque to achieve the vehicle braking. At the same time, part of the braking energy will be recovered. Therefore, the braking energy recovery technique has important research significance.The research object of this thesis is rear wheel drive pure electric bus. The research is focused on the formulation of control strategy. The purpose is that the braking effect of motor is full played, and braking energy is recovered as much as possible. The main research works are as follows:First, the composition of pure electric bus braking energy recovery system is analyzed. The research focuses on switched reluctance motor and Ni-MH power capacitor batteries, which are the key components of the braking energy recovery system. The purpose is to determine the impact of braking energy recovery from motor and battery. To analyze the regenerative braking principle and operating characteristics of switched reluctance motor. The working principle and charging characteristics of Ni-MH power capacitor batteries are studied, and to determine the charging influence factors.Then, on the basis of analyzing the basic theory of braking force distribution and ECE braking regulations, the range of the braking force distribution coefficients is determined. And brake force distribution range is further deduced. Based on the analysis of the braking energy recovery constraints, the size of the actual motor braking force was finalized. And through analyzing of three typical control strategy of braking energy recovery, the control strategy of optimal braking energy recovery for pure electric bus is proposed.Finally, vehicle model of pure electric bus is built based on the software AVL Cruise, and the parameters of all components are set. The control model of brake energy recovery is built based on Matlab/Simulink platform. And the two models are connected through MATLAB DLL interface. This thesis finishes offline simulation in China typical urban driving cycle and single braking condition of different braking intensity. The simulation results show that the control strategy of braking energy recovery proposed in this thesis can reclaim the braking energy effectively.