Research On Power Matching And Control Strategy Of Electro-hydraulic Hybrid Electric Vehicle

In the sustainable development of the traditional automobile industry,energy problems and environmental problems have always been its biggest obstacles.The emergence of new energy vehicles has effectively alleviated the above two problems.As an important branch of new energy vehicles,the development of pure electric vehicles has been restricted due to the failure of key battery technology.The hybrid electric vehicle,which combines the good power of traditional vehicles with the advantages of energy saving and environmental protection of pure electric vehicles,has developed rapidly.Therefore,the development of hybrid power systems is becoming increasingly important in the automotive industry.Based on the systematic study of the power systems of pure electric vehicles and hybrid electric vehicles,this paper designs a new type of vehicle electro-hydraulic hybrid power transmission system.Conducted research.The basic driving conditions of the vehicle are divided according to the driving characteristics of the electro-hydraulic hybrid vehicle,and the main power components such as hydraulic pump / motor,power battery,motor generator,hydraulic accumulator,etc.Type selection and parameter matching have been carried out so that the hydraulic system and electric power generation system can be well coordinated and coordinated.Analyze the working mode of the electro-hydraulic hybrid car and the energy flow under different working modes,study the control strategies under different working modes,and complete the design of the vehicle control strategy.Using AMESim software as a vehicle modeling tool,based on the selection of power components and parameter matching,physical models of motors,battery pack models,drivers,wheels and roads,hydraulic motors and hydraulic accumulators are established.The mechanical connection,hydraulic connection and electrical connection between the various components were established,and a complete vehicle model of the electro-hydraulic hybrid vehicle was built.Analyze the working mode of the electro-hydraulic hybrid vehicle and the energy flow under different working modes,study the control strategies under different working modes,and complete the design of the vehicle control strategy.The control strategy model is built based on MATLAB / Simulink software,focusing on analyzing the construction process of the control strategy in drive mode and regenerative braking mode.Integrate the vehicle model in AMESim and the control strategy model in Simulink into a joint simulation model.Simulate and analyze the built control strategy through joint simulation to verify the accuracy of the power system parameter matching,and the actual vehicle speed and expectations under the NEDC(New Europe Driving Cycle)cycle conditions and UDDS(Urban Dynamometer Driving Schedule)cycle conditions The simulation results of the vehicle speed and the actual output torque and expected output torque of the power system are analyzed.The results show that the vehicle model and control strategy built are feasible.Based on the multi-objective genetic algorithm to optimize the hydraulic accumulator parameters,comparative analysis of the optimization results,the vehicle dynamics have improved,in line with the requirements of vehicle design.