Research On Parameters Matching And Optimization Of Powertrain System For Range Extended Electric Vehicle

With environmental pollution becoming increasingly serious,the development of electric vehicles has got more and more attention.The range-extended electric vehicle can effectively compensate for the shortcomings of the lower driving range of the pure electric vehicle.It can effectively increase the driving range by properly controlling the start or stop of the range extender and the power.battery changes.Reducing emissions and pollution has became one of the hottest researching topics in the field of new energy vehicles.This article probes into parameter matching for key components of the power system of a certain range-extended urban bus and designs for a suitable control strategy to meet the requirements of the vehicle performance.Meanwhile,the simulation and verification of vehicles' parameter matching and control strategy were carried out through AVL-Cruise simulation platform.Finally,the non-dominated sorting genetic algorithm(NSGA-?)with elite strategy was used to optimize the vehicles' properties of dynamics and economy.The main research contents of this article are as follows:1.Analyzing and studying the structural form,dynamic performance,power composition and the operating mode under different operating conditions of the range-extended urban buses and then based on the performance indicators and related requirements of the vehicle,matching and designing parameters of the range extender,motor and battery of the power system.2.According to the characteristics of frequent start-stops and simple operating conditions of the range-extended urban buses,the constant power control strategy was selected as the energy management strategy and based on the shortcomings of which,the speed threshold was increased to prevent over-discharge of the battery.3.The AVL-Cruise platform was used to build a model of the range-extended urban vehicle and its performance was simulated.The vehicle control strategy model.was built in Matlab/Simulink and which was embedded into the vehicle model through the DLL module.Based on the established simulation model,the vehicle was simulated and analyzed from two aspects of dynamics and economy and whose results meet the requirements of the vehicle design,indicating that the parameter matching of the power system and the building of the vehicle model are reasonable and effective.4.Based on the aim for increasing two properties of dynamics and economy of a range-extended electric bus and the optimal variables including the speed threshold,the upper and lower limits of battery SOC and the final drive ratio of the main decelerator,NSGA-? was used as the optimization algorithm.The optimization results in an increase of the economic performance of the overall bus.For example,climbing performance is increased by 43.77%and fuel consumption is increased by 17.43%.