| Faced with increasingly severe environmental problems,new energy vehicles have become the recognized development direction in the automotive field.As one of the types of new energy vehicles,plug-in hybrid vehicles that can charge the battery by an external power grid combine the advantages of both pure electric cars and hybrid vehicles.It can greatly reduce the consumption of fossil fuels while increasing the mileage of pure electric power,which makes it one of the key research contents under the current level of the technology.Therefore,it is necessary to study the energy management strategy and hybrid configuration optimization of plug-in hybrid electric vehicles.And this paper relies on the national key research and development plan sub-project "plug-in/extended-program hybrid system multi-physics coupling mechanism and configuration optimization method research and software tool development",equipped with a continuous variable transmission(CVT),a plug-in hybrid vehicle with configuration of single motor and single planetary has been studied.The main content of this paper includes the following sections:(1)According to the experimental data,the engine model,motor model and battery model were built successively.Research on the structure and working mode of the plug-in hybrid vehicle,analyzed,the vehicle dynamics model under different working modes is established.Taking torque and SOC as mode switching conditions,a rule-based vehicle energy management strategy was put forward.(2)Based on Principal Component Analysis(Principal Component Analysis),nine characteristic parameters that can retain the working condition information as much as possible are used for working condition identification.Constructing working condition identification library by using composite equal division method for existing typical cycle conditions.Based on the generalized regression neural network,the working condition recognizer is built,and the comprehensive test conditions are constructed,and the working condition recognition results are analyzed.Establish a vehicle energy management strategy based on working condition identification.Based on Matlab,the two energy management strategies are compared and simulated.The results show that the proposed energy management strategy can reduce the energy consumption of the whole vehicle by 6.46%.(3)According to the national standard,the fitness function is used to unify the power consumption and fuel consumption of the whole vehicle;the shifting law under different modes is set according to the optimal system efficiency;after the gear is initially divided based on the equal ratio,the genetic algorithm is used for the different modes.The number of bits and the gear ratio of each gear are optimized at the same time,and the CVT grading optimized speed ratio under different driving modes is obtained.The simulation results show that the energy consumption of the vehicle can be reduced by 1.07% based on the proposed CVT speed ratio grading control strategy.(4)In order to further improve the comprehensive driving performance of single-motor hybrid vehicles,a single-motor double-planetary hybrid power system configuration scheme is proposed.A topological design method is used to characterize the constraint relationship between the power source components and the planetary row nodes.All feasible alternative configurations are systematically explored,and the dynamic relationships of all alternative configurations are automatically obtained.Based on the dynamic programming algorithm,the global optimal control strategy is used to simulate the fuel economy and dynamic performance of the alternative configuration.The single-motor double-planetary hybrid system configuration with excellent comprehensive performance is selected and compared with the original structure.This configuration can reduce the energy consumption of the whole vehicle by 11.26%. |
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