Research And Implementation Of Braking-Energy Recovery System Based On Pure Electric Vehicle

The research on Electric Vehicle (EV) is getting more and more attentiondue to the serious environmental pollution and energy shortage. The keyresearch areas of EV include control and management system of vehicle,driving systems, battery and battery management system. Braking energyrecovery belongs to the field of control and management system of vehicle andit plays a significant role to improve the efficiency of energy use in EV. During the braking process of EV, driving motor can run on the stateregeneration and supply electric energy outside. If some kinetic energy ofvehicle can be recovered and charge the storage battery, it would be a crucialway to elongate the driving miles of EV. Braking energy recovery involvestransmission mechanical system of EV, driving motor and battery, and it isnecessary to synthetically consider the characteristics of vehicle kinetics,generating motor, charging of battery and its safe guarantee. Currently, thestudy on braking energy recovery in China is still on the preliminary stage. Thepaper makes some positive explore about this problem and achieve somevaluable outcomes. The first part of the paper introduces the technical principles of brakingenergy recovery in EV, and reviews the last research results in this domainhome and abroad. By analyzing the whole process of vehicle braking andcombining with the specialties of generation of driving motor, charging ofbattery and its safe guarantee, the paper sorts three braking modes andconcludes some constraint conditions of braking energy regeneration. The second part of the paper analyzes the open-loop and close-loop controlsystem of vehicle. On the base of driver model and constraint conditions ofbraking energy recovery, taking the transmission efficiency of mechanicalsystem, generation efficiency of motor and charging efficiency of battery into - II -account, the paper puts forward an optimization control algorithm of energyrecovery base on nonlinear programming model. In addition, the simulationmodel is also constructed with Simulink. The third part of the paper thoroughly introduces the hardware of thebraking energy recovery controller and the software implementation of controlalgorithm. In order to evaluate the effect of the control algorithm, driving cycleof SAEJ227a in United States and 1015 in Japan are employed. Finally, thealgorithm response speed, the improvement on control algorithm and otherpertinent problems are also discussed.