Research On Mode Switching Control And Energy Management Of Single Axis Parallel Hybrid Electric Vehicle

In order to achieve sustainable development of energy and cope with environmental pollution and global warming,the automobile industry has shifted from traditional fuel cars to hybrid electric vehicles,the core of hybrid electric vehicle research is the development of vehicle control strategy.Therefore,this paper studies the transient mode switching process and steady-state energy management strategy of single axis parallel hybrid electric vehicle,aiming at improving the smoothness of mode switching and vehicle fuel economy on the premise of guaranteeing the vehicle’s power performance.The main research contents are as follows:(1)Firstly,this paper summarizes the basic working principle and characteristics of petrolelectric hybrid electric vehicles with different configurations,and then selects the components of the driving system according to the vehicle parameters and power performance indexes.Finally,the single axis parallel hybrid electric vehicle model is built based on AVL Cruise software platform,which lays a foundation for the development of subsequent mode switching process and energy management strategy.(2)Secondly,the dynamic characteristics of power source and transmission system of hybrid electric vehicle are analyzed,and the evaluation index of mode switching effect is given.The dynamic analysis of switching between different modes is carried out in this paper,it is concluded that by pure electric switch to parallel mode is the main reason for the impact,a fuzzy controller is designed for the clutch engagement process during the mode switching,simulation results show that the controller can effectively restrain the impact,the smoothness in the process of mode switching is improved.(3)Thirdly,on the basis of the smoothness of mode switching,a mathematical model of ECMS algorithm was built for the steady-state process,and the energy flow of different operating modes was analyzed and modeled based on Matlab/Stateflow.Then,to obtain the parameters representing the vehicle state during the running process of hybrid electric vehicle,an adaptive control strategy based on SOC feedback was proposed,and different initial values of equivalent factors were selected to verify the effectiveness of the control strategy.(4)Finally,a joint simulation platform was built based on Isight and Cruise software,and the initial value of the equivalent factor was iteratively optimized by multi-island genetic algorithm with the power consumption of 100 kilometers as the optimization goal.Simulation results show that the control effect of the controller with the initial value of the optimal equivalent factor is compared with that of the logic threshold energy management strategy,and the engine operating points are distributed in the high-efficiency zone,so that the hybrid electric vehicle can effectively improve fuel economy while maintaining the power balance of the battery.