Research On Energy Control Strategy For Parallel Hybrid Electric Vehicle

With the development of industry,the use of fossil fuels is also increasing.Not only energy consumption increased dramatically,but also caused serious pollution to the environment.The traditional fuel vehicle brings convenience to people's life,but the vehicles consume a lot of fossil fuel.At the same time,there are also problems of non-renewable energy consumption and environmental pollution.Therefore,it is urgent to solve the fuel consumption and emission problems of fuel vehicles.At present,for this problem,there are mainly two kinds of solutions,one is to improve the work efficiency of the engine so that fuel consumption can be reduced.The other one is to use the renewable energy to replace fossil fuels.Nowadays,hybrid electric vehicle(HEV)has become the most effective way to solve the energy consumption and environmental pollution,it is also a research hotspot.Taking hybrid electric vehicle as the research object,the parameter seleting,energy control strategy and optimization of hybrid electric vehicle are studied in this paper.(1)This paper introduces the research background and significance of the project,and introduces the operation modes of three types of HEV,series HEV,parallel HEV and series-parallel HEV.Then the development of the domestic and foreign hybrid electric vehicles is summarized,and the power distribution strategy and the energy recovery strategy are emphatically introduced.(2)The simulation model of engine,motor and battery is analyzed.Then the parameter matching of parallel HEV is carried out,and the appropriate parameters of engine,motor,battery and transmission ratio are selected.Considering the influence of mixing degree on the performance of the vehicle,using orthogonal test to select the best mixing degree.Then simulating by using ADVISOR,the results show that the selected mixing degree can improve fuel economy.(3)Because fuzzy control strategy is suitable for highly nonlinear system,and has strong adaptability and robustness,the power distribution strategy of parallel HEV is designed based on fuzzy control strategy.Firstly,this paper introduces the theory of fuzzy control,and then the working mode of HEV power distribution are analyzed,according to the working mode,the fuzzy controller is designed.The fuzzy controller is embedded into the simulation model,and the simulation results show that the power distribution strategy based on fuzzy logic theory significantly improves the fuel economy and emissions of the vehicle.(4)In view of energy recovery,the fuzzy control theory is used to make further optimization.Firstly,this paper introduces the energy recovery work mode of HEV in the process of braking deceleration.Speed,SOC,front wheel brake torque are selected as the input of the fuzzy controller,the regenerative braking force distribution coefficient is selected as the output of fuzzy controller.The simulation results show that the vehicle can recover more energy after the fuzzy control strategy is added.(5)Because the design of fuzzy energy control strategy is based on the experience of experts and strong subjectivity.Therefore,the genetic algorithm is used to optimize it.First,the basic theory of genetic algorithm(GA)is introduced,and the control rules in the fuzzy controller are optimized by GA.After GA optimized,the fuel consumption and emission are improved.(6)In order to verify the design of the HEV energy control strategy,the dynamic programming(DP)is selected to get the global optimal results.The simulation results of control strategy in this paper are similar with those after DP optimization,which the design of energy control strategy in this paper is verified.