Research On Energy Management Strategy Of Power-split Hybrid Electric Vehicle

The combined hybrid electric vehicles have the advantages of high fuel economy and high cost-effectiveness,and Power-Split Hybrid Electric Vehicle(PS-HEV),as one of the combined,has a high degree of mixing,flexible adjustment,and could better adjust the engine operating point to achieve better fuel economy.In order to further improve the fuel economy of hybrid electric vehicles,the designed PS-HEV powertrain was taken as the research object in this paper.Design optimization and simulation analysis of PS-HEV energy management strategy were developed,mainly including:(1)The functions and connection methods of the main components of the PS-HEV transmission system,the working modes that the transmission system can form,and the motion relationships between various components within each mode were analyzed.The longitudinal dynamics of the whole vehicle was analyzed,and the relationship between the speed and torque of each power component was determined according to the dynamic balance equation,which provided the necessary data connection for the preparation and realization of the dynamic programming algorithm program in the following paper;which conducted dynamic modeling of the main power components to lay the foundation for the subsequent construction of the vehicle model.(2)A rule-based vehicle energy management strategy was design.Corresponding controller model,driver model,vehicle model,hybrid powertrain model,which formed the Complete vehicle simulation model were built.A simulation analysis was conducted on the fuel consumption of the entire vehicle based on the China World Transient Vehicle Cycle(C-WTVC).(3)Taking the optimal fuel economy as the objective function,the battery state of charge as the state variable,and the engine torque as the control variable,the dynamic programming algorithm was used to obtain the theoretical optimal solution of vehicle fuel consumption based on the given cycle conditions,and the optimal power distribution relationship between the engine and the battery,as well as the optimal working points of the engine and the two motors are obtained;By the further analysis of the results of dynamic programming,the allocation rules were extracted.the rule-based energy management strategy was improved and simulation analysis was conducted.Compared with the rulebased strategy,the fuel saving effect of the improved rule strategy was 4.802%,which verified the effectiveness of the improved rule.