Research On The Optimization Of 4WD Hybrid Electric Vehicle Energy Management Strategy

The development of electric vehicles become a consensus of the whole society due to energy and environmental problems in recent decades.Hybrid electrical vehicle(HEV)is widely recognized with superior dynamic performance and fuel economy.It is an important topic in the HEV technology research that coordinating all power components and improving fuel economy through designing reasonable energy management strategy in this form of complex structure with several power sources.In this paper,a vehicle longitudinal dynamics model is established according to the special structure form of 4WD HEV and the rule-based energy management strategy was designed based on the hybrid energy management of the existing research results.In order to improve fuel economy,mode distribution rules are subdivided.In order to acquiring the optimal fuel consumption and the global optimal torque distribution of Energy management in theory,energy management strategy based on dynamic programming(DP)that is suitable for 4WD HEV is designed.Its energy management results is a guide for other energy management strategy optimization.In order to avoiding the energy management algorithm into local optimization and considering the influence of the power battery changes on energy consumption,the equivalent fuel consumption minimum strategy(ECMS)suitable for 4WD HEV is designed.ECMS is improved by referring to the global optimal results of the energy management based on DP.In order to make the total fuel consumption become minimized,genetic algorithm(GA)is used to optimize the key parameters which have an impact on total energy consumption of ECMS.The last,Energy management strategies simulation test is completed to verifying the control performance of these energy management strategies.Results show that the control performance of optimized ECMS is best.The design and optimization of 4WD HEV energy management strategy are studied in the paper,which have a certain guiding significance for 4WD HEV energy management strategy development.