| New energy vehicles are deeply loved by users due to their advantages of no contamination and low noise,and the government has given many preferential policies to promote their development.However,it also possesses some defects,such as imperfect charging facilities and short cruising range.Therefore,how to promote the overall performance of the vehicle to the greatest extent through reasonable power system parameter matching and efficient braking energy recovery control strategy,so as to reduce energy consumption and extend the cruising range,which is the focus of research by enterprises and university researchers.This paper takes the electric city bus as the research object,which is being developed by a company,and analyses the structural layout of the transmission system.According to parameters of the vehicle and criteria of performance,the parameter matching and selection of drive motor,battery and transmission system are completed.The model of whole vehicle is built with software of Cruise,then the simulation experiment and prototype testing are carried out.By comparing the simulation data with the measured data,it proved that the parameter matching scheme is reasonable and meets the design requirements.Considering the application scenario of electric city bus,the existing configuration of the whole vehicle is used reasonably to maximize the performance of the whole vehicle.In this paper,the transmission parameters are optimized on the basis of the preliminary parameter matching scheme,and a reciprocal simulation experimental platform of Isight and Crusie is built.Taking the energy consumption of 100 km and the acceleration time of 0-50km/h in CCBC as the optimization objective,the transmission ratio as the optimization variable,and performance criteria of the vehicle as the constraint condition,the NSGA-Ⅱ algorithm is used to carry out multi-objective optimization simulation analysis,and the results before and after optimization are compared,which proves that the feasibility of the optimization.In order to improve the economic performance further,the braking energy recovery control strategy is studied based on the optimized parameter matching scheme.The braking force of electric city bus is analyzed,and the braking force distribution strategy is improved based on ECE regulations and other curves,and the braking force of front and rear axles is initially distributed.Considering the driver’s braking intention,fuzzy control is introduced,and a multi-factor input fuzzy controller for braking intensity,state of charge and speed of the vehicle is designed.The weight coefficient of motor braking is adjusted.At the same time,considering the constraint of motor and battery,the braking force of front and rear axles is distributed again.The model of the regenerative braking control strategy is built by Simulink module,then the form of DLL is embedded to the Cruise vehicle model,which is realized the joint simulation of Cruise and Matlab.The effectiveness of the control strategy was verified by comparing the range before and after energy recovery. |
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