Research On Control Strategy Of Hybrid Electric Vehicle Based On Dual-planetary Gear

Nowadays,with the rapid development of the automobile industry and the continuous improvement of people's living standards,the global vehicle ownership is growing increasingly.However,the ensuing energy crisis and environmental pollution have become more and more severe.As a new automobile product,new energy vehicle's power mostly comes from electric energy,which is of great significance to the improvement of environmental pollution and reduction of oil consumption.Limited by the short driving range,inadequate charging infrastructure and other factors,the pure electric vehicles are facing great challenges in the process of industrialization and marketization.Therefore,hybrid electric vehicle,especially power-split hybrid electric vehicle,has been favored by major automobile enterprises due to its advantages,such as energy saving,environmental protection,low using cost and so on.According to the requirements of the enterprise cooperation project "The configuration matching and key technology of the control system for the power-split hybrid electric vehicle",targeting at a proposed configuration of the hybrid electric vehicle based on the dual-planetary gear,this thesis has accomplished the research on its control strategy and has verified and evaluated it at the same time through the compare between the offline simulation results and the test results of a foreign hybrid electric vehicle which has the same configuration,so as to provide technical support for the self-directed development of the control system of the enterprise.The main research contents are as follows:(1)Based on the proposed configuration of the hybrid electric vehicle based on the dual-planetary gear and combined with analyses of relevant vehicles' literatures,this thesis has completed the research on control strategy.This thesis brings forward the drive mode recognition strategy which could automatically determine the drive mode,and the driver can manually select the drive mode according to the recognition results(SPO,NOR,or ECO);then the study focuses on the control features of accelerator pedal under every drive mode;this thesis also carries out research on the vehicle working mode and operation mechanism,as well as confirms the switch conditions among each working mode;in addition,in order to reduce the possible jerk when switching drive mode,this thesis puts forward the drive mode switch strategy by limiting the changing rate of torque in the process of switching.(2)This thesis has built the vehicle and control strategy model under Matlab/Simulink,and has carried out offline simulation.Whose result shows that this model can accurately carry out the proposed control strategy;the drive mode recognition strategy,the control features of accelerator pedal,the working mode classification strategy and the drive mode switch strategy can all achieve good control effect.(3)Through the analysis of the vehicle test results of a foreign hybrid electric vehicle which has the same configuration,this thesis has completed the verification of the control strategy,mainly including the driving cycle test,the accelerated test under different accelerator position and the drive mode switch test,and has emphatically verified the vehicle dynamic and economic performance and the validity of the control features of accelerator pedal,the working mode classification strategy and the drive mode switch strategy.Combining offline simulation and vehicle test results,this thesis verifies the validity and rationality of the control strategy.So before the breakthrough achieved in the battery technology,this study can provide certain reference and theoretical basis for the power-split hybrid electric vehicle research.