Study On The Control Strategy Of Electric Driving And Regenerative Braking For Pure Electric Vehicle With Dual-Energy Storage System

This paper considers the pure electric vehicles (PEV) control system driven by brushless direct current motor (BLDCM). In order to develope the control strategy of electric driving and regenerative braking system with high-performance, high efficiency, high standard for PEV, the dynamic model of PEV, the mathematic model of BLDCM and the model of speed and current double closed-loop control system are constructed at first. After that, the bi-directional DC/DC converter, electric driving and regenerative braking system are mainly present respectively. The above work accumulated a lot of invaluable experience for the follow-up search of PEV.Firstly, since BLDCM has many advantages such as high efficiency, high power density and good speed regulation performance, the dynamic model of PEV driven by BLDCM is obtained by analyzing the equation of PEV and the mathematic model of BLDCM. Therefore, it is combined reasonably in PEV control system.Secondly, an adaptive fuzzy PID control system in which the control objective is the vehicle speed can be designed for PEV with sole-energy storage system. In addition, the principle of regenerative braking for PEV driven by BLDCM is analyzed detailedly, and the control strategy for energy recycling is studied and simulated in Matlab7.0. The simulation results show that the control strategy is correct.Thirdly, the main circuit of the dual-energy storage system (DESS) and the adaptive fuzzy PID control strategy for bi-directional DC/DC converter are designed based on the structure of ultra-capacitor and battery in parallel. On this condition with constant current and voltage, simulation model of this system can be confirmed. The simulation results proved that the control strategy is correct and effective.Finally, on the basis of braking mechanism and energy recycling principles of PEV, a braking force distributing scheme is obtained. By utilizing the simulation software ADVISOR2002, modeling and simulation of the braking energy recycling system is conducted. The simulation results show that the recycling efficiency of regenerative braking energy for PEV is improved. Therefore, the consumption of the limited energy of the dual-source energy storage system is more rational, and the PEV's driving range can be extended as well.