| Range-extended electric vehicle is recognized as the most ideal hybrid vehicle in the transition from fuel vehicle to pure electric vehicle.Taking an Range-extended 4WD Electric SUV as the research object,combined with the structural characteristics of Range-extended electric vehicle,the research is carried out around its power system matching and modeling,distributed drive control strategy design,vehicle energy management control strategy development and so on:(1)According to the structural characteristics of the power system of the extended program electric vehicle,combined with the power and economic requirements of the whole vehicle formulated according to the benchmark model,the main performance parameters of the front and rear drive motors,power batteries,engines,generators and other key components are calculated,and the parts are matched and selected in combination with the calculation results.(2)After the key power system parts are determined,the forward simulation model of the whole vehicle is built on the AVL cruise platform,the digital modeling of the power system parts,driver model and whole vehicle dynamics model is carried out,the mechanical connection and signal connection of each controller are designed,and the verification of the power and economic indicators of the whole vehicle is preliminarily completed.(3)Aiming at the problem of electric energy consumption of 100 kilometers,combined with the characteristics of front and rear axle distributed drive electric vehicles,a distributed drive controller is designed with MATLAB Simulink.The driver demand torque analysis function,driving mode switching and a driving force distribution control strategy based on the optimal system efficiency are integrated.Compared with the common proportional driving force distribution strategy in AVL cruise simulation platform,the system efficiency is significantly improved and the electric energy consumption of 100 km of the whole vehicle is reduced by 5.3%.(4)Aiming at the problem of vehicle energy management,the working mode is defined,and the extender control strategy under hybrid mode and power holding mode is designed.The focus is to introduce the equivalent fuel consumption control strategy under power holding mode.On the basis of selecting the multi-point control strategy of extender,In order to reduce equivalent fuel consumption and improve battery cycle life,genetic algorithm is used for multi-objective optimization.Simulink and cruise are used to build the control strategy model and vehicle model respectively for joint simulation under NEDC working condition and composite working condition.The simulation results show that the control strategy has strong robustness.After optimization,the equivalent fuel consumption per 100 km is reduced by 13.2% and 8.8% respectively,reaching the set fuel economy index,and the energy flowing through the battery is reduced by 8.9% and 5%,which is helpful to improve the cycle life of the battery. |
