Simulation Research On Power Management Strategy Of Fuel Cell And Battery Hybrid Vehicle

Fuel cell has the characteristics of high efficiency and environmental friendliness,and it can be combined with auxiliary energy to form a hybrid power plant.With the ability of effectively alleviating environmental pollution and energy shortage and other issues,fuel cell is an ideal power source for new energy vehicles.Hybrid electric vehicle not only has the advantages of electric vehicles,but also has the advantages of traditional vehicles.With the advantages good economy,good emissions and long journey,it has become the focus of research on new energy vehicles.The development of hybrid vehicle energy management system is also important.The energy management system can control the coordination of the various components in the hybrid vehicle based on the driver's driving intention.It optimizes the output of each component and improves the economy and emissions of the car.Therefore,it is very important to develop the energy management system of hybrid electric vehicle.In this thesis,the fuel cell hybrid vehicle of which battery as the auxiliary energy was taken as the research object.Based on the MATLAB/Simulink environment,the simulation model of hybrid power system and its components was built.The working principles of fuel cell,battery,motor and DC-DC converter were expounded,and their working characteristics were analyzed in consideration of the important factors that affect they working.According to the driving power demand of the hybrid electric vehicle,the parameters of each component were set,and the most important parameters of the hybrid electric vehicle were determined.Firstly,the six main working states of hybrid electric vehicle in the process of start and stop were studied,and the conditions of switching between each state were also formulated according to the requirements of each state.After analyzing and describing the function of the central controller of hybrid electric vehicle,the switching diagram between different driving modes was established against the planetary gear structure and the one-way clutch,in which the planetary gear structure is equivalent to a buncher.If necessary,the one-way clutch will look the generator to improve the efficiency of the system.In order to improve the computational speed,the dynamic programming algorithm was simplified and improved,and the grid points generated by the discretization of dynamic rules were reduced.Based on the analysis of the dynamic rules,the switching rules between the different driving modes of the planetary gear hybrid vehicles were obtained.The braking force of the traditional braking system was analyzed,and the distribution range of the front and rear axle power system of hybrid electric vehicle was defined according to the ECE regulations.On this basis,the factors that affect the distribution of regenerative braking force were analyzed.In order to ensure the safety and stability of the vehicle braking system,the distribution strategy of the front and rear axle power system and the logic threshold control strategy of the regenerative braking system were designed respectively.Based on the ADVISOR simulation software,the mathematical model of the brake force distribution strategy was established and the regenerative braking performance was simulated and analyzed.The effectiveness of the proposed model and the regenerative braking performance of the proposed control strategy were verified in the simulation results.