Research On Control Strategy Of Regenerative Braking In PHEV

Hybrid Electric Vehicle (HEV) takes electric energy and fuel energy as double power sources, it belongs to Electric Vehicle (EV).Regenerative braking is the main feature of HEV ,which is noticeably different from traditional vehicle. Through the energy conversion devices of vehicle transmission, kinetic energy in the course of braking can be transformed to electricity energy into battery by regenerative braking and also can be utilized again when driving or accelerating, so the energy efficiency of vehicle is improved.In this dissertation, firstly, regenerative braking working principle and basic structure are analysed, besides, electro-mechanical brake is ensured and the priority should be regeneration braking force. After the main factors are analyzed which influence regenerative braking system, obtained by calculating the maximum regeneration braking force which the motor could supply to the wheel when braking. According to the ECE braking regulations, regeneration braking force and friction braking force get reapportioned at different braking intensity. Then, mathematical model of braking forces distribution are established in ADVISOR which based on ECE braking regulations. Comparing with the default control strategy, the new control strategy has advantages in energy recovery and motor efficiency by simulation.Secondly, aiming at the complex problems about mechanical coupling and power coupling of vehicle transmission, a fuzzy controller with double input variables and single output variable is designed, one input variable is battery State Of Charge (SOC), the other input variable is the difference between vehicle required torque and engine present torque, the output variable is engine torque. Choosed Particle Swarm Optimization (PSO) to optimize quantitative factor, the control precision of fuzzy energy management system are improved by optimizing.