Study On Optimization Of Control Parameters And Development Of Control Strategy For Range-extended Electric Vehicle

Currently,automobile industry is rapidly transforming to the pure electric vehicle because of the increasingly prominent energy consumption and emission problems.However,due to the limitation of battery technology on the driving range of pure electric vehicles,it is difficult to fully realize the green transformation of the automobile industry in the short time.For this reason,this paper develops a range-extended electric vehicle equipped with auxiliary power device to effectively achieve energy saving and emission reduction and extend vehicle driving distance.In this paper,the range-extended electric vehicle is taken as the research object.The AVL Cruise and MATLAB/Simulink software are used to study on development of the control strategy and optimization of the control parameters after determining the design of vehicle structure and matching the components of powertrain system.The main research work in this paper is as follows:(1)The selection of motor,battery,engine and other components is studied based on design characteristics of the vehicle structure and driving condition of vehicle,meanwhile parameters of the components are calculated according to balance of the driving power and output characteristics of the battery.(2)To make full use of the battery and engine energy,the range-extended control strategy is developed combining the “three fixed working points” and “the optimal fuel consumption rate curve” according the dynamic transmission characteristics of vehicle,the battery state of charge and the working characteristics of engine.In addition,a regenerative braking allocation control strategy is developed to achieve the braking energy recovery and reduce the mechanical loss rate.(3)A vehicle simulation model is built in AVL Cruise software by using parametric modeling method,the Function model and regenerative braking control strategy model are built in MATLAB/Simulink software,and then the control strategy model is integrated into the whole vehicle model to obtain the joint simulation model.The design rationality of the power system and the control strategy is verified through co-simulation in AVL Cruise software.(4)At last,the three fixed working points of engine is optimized and analyzed by the AVL Design Explorer to obtain the best driving range and fuel consumption.The optimal solution set of the control parameters is obtained,and the simulation results are compared and analyzed before and after the optimization to obtain the optimal design of the control strategy.