The Research On The Drive System And Energy Management System Of The Electric Vehicle

With the global environmental pollution and energy problem are getting more and more serious,most countries have been trying to reduce the dependence on oil,the emergence of electric vehicles in order to solve this problem. However, the biggest problem of electric vehicles is that the ranges of their batteries are short. So, in order to develop electric vehicles, an important problem that how to effectively use the battery energy has to be faced. Besides, one defect of the power battery used in electric vehicles is low power density. As a new type of energy storage device, with the advantages of long life and high power density, super capacitors are increasingly used in the field of electric vehicles. By using super capacitors and a bi-directional DC converter as energy management system, this project can realize the purpose of power compensation and regenerative braking energy recovery. Moreover, the experimental platform is BLDCM, this project also designs the BLDCM drive system which realizing the control of the electric state and energy feedback braking state.In the introduction chapter, this paper succinctly introduce the development of electric vehicles、the power system and super capacitors. And then study the BLDCM control system,detailed analyze the operating principle of the electric state and energy feedback braking state and propose the phase change logic. Then through PSIM and MAX+PLUS II realize simulation analysis about BLDCM control system.Then, the energy management system and the bi-directional DC converter are analyzed. According to the application of electric vehicles’demand, non-isolated three-phase interleaved bi-directional DC converter is introduced. Through the PSIM simulation, the proposed topological structure is verified.Afterwards, this paper designs the BLDCM control module and the bi-directional DC converter control module as one controller, the core processor is TMS320F28335. The BLDCM control module realize the functions of current limit speed closed-loop control in electric state and directly brake torque closed-loop control in energy feedback braking state. The bi-directional DC converter control module realize the function of current closed-loop control in Boost pattern and voltage-current closed-loop control in Buck pattern. Through average switch of small signal modeling, the closed-loop parameters of bi-directional DC converter are designed.Finally, experiments are done to verify the effectives of the proposed control strategies of the BLDCM control module in electric state and energy feedback braking state and the bi-directional DC converter control module in Boost pattern and Buck pattern.