Research On Parameter Matching Optimization And Braking Energy Recovery Control Strategy Of Electric City Bus Power System

Nowadays,with the increasingly prominent energy crisis and environmental problems,pure electric vehicles have gradually become the mainstream representative of the current automobile industry.However,compared with traditional cars,pure electric vehicles still have short driving range,the charging infrastructure also has not been popularized.In the current research and development process of electric vehicles,the reasonable selection and parameter optimization of all parts of the vehicle’s system can effectively improve the vehicle’s power performance and economic performance,the recovery of braking energy can greatly improve the energy utilization rate,thus increasing the driving range of electric vehicles.Therefore,this thesis will conduct in-depth research from the following aspects:Firstly,based on the requirements of the vehicle performance index,the main components of the power system,including the transmission system,battery,motor,etc.,are selected reasonably and their parameters are matched.An optimization mathematical model with economic and dynamic performance as the objective function is established.The CRUISE simulation software platform was used to build vehicle models of different structural forms for simulation test.By comparing the simulation results of vehicle dynamic performance and economic performance before and after optimization,the rationality of parameter matching and optimization design scheme was verified.The influence of vehicle layout on vehicle performance was studied by comparing the simulation results of different powertrain models.By analyzing the braking force status of pure electric vehicles,a parallel braking energy recovery control strategy was designed based on ECE regulations,and the control strategy was analyzed and explained in detail.The control strategy model was built in MATLAB/Simulink,and the rationality and correctness of the control strategy design were verified by the joint simulation with CRUISE.By analyzing the factors affecting braking energy recovery,a fuzzy controller is introduced to reasonably allocate the power share of electric mechanism.The fuzzy control strategy of braking energy recovery is designed based on the membership function of input and output and the construction of fuzzy rule base.According to the results of joint simulation under the same working condition,the advantages and disadvantages of different braking energy recovery control strategies are analyzed.Finally,based on the fixed braking force distribution coefficient of front and rear axle in the braking energy recovery fuzzy control strategy,the braking force distribution coefficient of front axle is optimized.The front axle braking force distribution coefficient curve under full braking strength is obtained by fitting the optimization results.According to the distribution curve,the original strategy was modified,and the rationality of the optimal design scheme was verified by comparing the simulation results of the control strategy before and after optimization。...