Research On Energy Management Strategy Of Hybrid Electric Vehicle Based On Traffic Prediction

The energy management strategy of hybrid electric vehicle is the main factor that affects the performance of hybrid system.The goal is to coordinate the working status of the various components in the hybrid system,to distribute the power of the battery and the engine reasonably and chieve the best vehicle economic performance indicators.Plug-in Hybrid Electric Vehicle can use the external power grid to charge the battery,use electricity in the process of driving as much as possible,reduce fuel consumption and improve exhaust emissions.Driving traffic directly affects the fuel economy of hybrid vehicles,so consider the driving traffic into the hybrid vehicle energy management strategy.Based on thses,this paper presents a PHEV energy management strategy based on traffic prediction.Firstly,determine the PHEV system structure and work modes.The structure adopts the uniaxial hybrid structure to realize the coupling of the driving torque.According to the dynamic battery SOC(State of Charge)change trajectory,the PHEV basic operation modes are defined as three kinds,namely,pure electric driving mode,hybird driving power charge depleting mode and hybrid driving charge sustaining mode.Secondly,identify and predict the future traffic conditions.According to the traffic characteristics,the road conditions are divided into three categories: urban conditions,suburban conditions,highway conditions.And then according to the past periods of time between the speed and time,extract three characteristics of the parameters: the average speed,Idle time ratio and maximum speed.Finally,the traffic condition recognition fuzzy controller is designed to identify the current road condition.The recognition result is used as the traffic type of the next time interval.It lays the foundation for energy management strategies for the next step.Then,formulate PHEV energy management strategies.We use the dynamic programming global optimization control strategy to obtain the optimal trajectory of the SOC of the power battery under different off-road conditions.In order to facilitate the practical application,the SOC optimal trajectory is obtained as the SOC reference trajectory.According to the predicted traffic type,combined with the SOC reference trajectory,the PHEV energy management strategy is established.In order to achieve global optimization and achieve rational use of energy and energy saving purposes,theSOC is close to and follow the SOC reference trajectory change.Finally,the simulation model of dynamic system is established by Matlab /Simulink and Advisor simulation software,and the simulation analysis is carried out.The results show that the designed fuzzy controller can identify the traffic conditions well.The energy management strategy based on traffic prediction can improve the fuel economy of the vehicle.