Study On The Control Strategy Of Master And Auxiliary Motor Coupled Driving System For Pure Electric Vehicle

With the increasing attention to environmental pollution,cleaning and energy saving electric vehicles(EVs)have become the research hotspot recently.As one of the important component of EVs,the performance of Powertrain impact the electric vehicle’s overall performance seriously.However,the development of EVs were restricted by the low motor load factor in traditional single-motor driving mode seriously.Dynamic coupling technology which can combine multiple power sources through coupler and achieve a series of function,is one of the future powertrain development directions and has broad application prospects for dynamic transmission system.This paper according to the research of dynamic coupling technology which maturely applied to Hybrid Electric Vehicle(HEV)and existed coupler,completed the main motor and the auxiliary motor coupling which can be applied to EVs to improve the economy without loss of dynamic performance of the original car.This paper focuses on driving configuration and control strategy studying and a few jobs have been done mainly in the following aspects.Firstly,the coupling mechanism of multi power is analyzed.The analysis of dynamic system of the dual-motor coupling powertrain(DMCP)on torque coupling and speed coupling and the coupling mechanism is studied.What’s the important,completed the analysis of dynamic characteristic through lever diagram and energy saving potential of configuration from the theoretical analysis.Secondly,several typical dual-motor coupling driving systems were analyzed and compared in cost,power performance and economic performance.Based on the original vehicle parameters,dynamic index and the mathematical statistics on the driving cycles match the suitable parameters includes Master and Auxiliary Motor,coupling mechanism and main reducer mechanism.Thirdly,the control strategy of steady-state control is studied which mainly divided into driver module,demand torque calculation module and energy management module three parts.Using the instantaneous optimization algorithm based on the results to determine the logic threshold in the energy management module,so as to formulate the power allocation strategy in different modes.Finally,The simulation model is built based on the MATLAB/Simulink platform,whose reliability could be verified by building the bench test of the original motor.Through the simulation to verify the energy-saving potential of the main motor and the auxiliary motor coupling drive system by studying the simulation analysis of the system with the original motor dynamic performance and economic performance.