Study On Control Strategy For Dual-motor Drive Pure Electric Vehicle Considering Motor Dynamic Characteristics

Pure electric vehicle(PEV),is one of the effective solutions to alleviate the energy and environmental problems,how to improve its driving range and reduce its cost has become an urgent problem to promote the market of PEV.From the aspect of vehicle system,the powertrain configuration,parameter matching of components and control strategy can directly affect the economic of PEV.Reasonable powertrain configuration and parameter matching for components can make full use of existing component technology to reduce the cost of PEV.In this paper,based on a dual-motor-driven pure electric vehicle powertrain configuration with centralized motor distribution,a complete vehicle model including the dynamic mathematical model of the drive motor is constructed,and then the drive control strategy of dual-motor driven PEV based on the dynamic characteristic of the drive motor is designed.The main research is as follows:(1)In-depth analysis of the structures of the dual-motor-driven powertrain configuration for PEV and its four drive modes,and setting up the dynamic modelling of the four drive modes;to explore the performance of the powertrain configuration,the key components of powertrain system and the vehicle dynamics are modeled;the boundaries of the four modes are divided based on the configuration characteristic of the powertrain system,and power distribution of the two drive motors during dual-motor coupling-drive modes is solved based on the static characteristic of the drive motors.(2)In order to obtain the dynamic characteristic of permanent magnet synchronous motor(PMSM),the dynamic mathematical model of PMSM is built,including its voltage model,fulx linkage model and torque model.To obtain the dynamic loss characteristic of PMSM,copper loss and iron loss of PMSM are analyzed and modeled.Then,the inverter loss model in the motor controller including conduction loss,switching loss and reverse loss of IGBT module is built.(3)In order to obtain the relationship between voltage,current and torque of PMSM,the current control strategy is deeply studied from the aspect of motor system control.A vector control strategy for PMSM considering DC bus voltage is optimized.Based on MATLAB software platform,a simulation that verifies the advancement and effectiveness of the vector control strategy is set up.(4)In order to explore the dynamic and economic characteristics of PMSM during transfer process of motor operating point,a dual-motor coupled-drive PEV model with PMSM dynamic mathematical model is constructed;Based on the vehicle model,the economic characteristics of the drive system in dual-motor coupling-drive modes are analyzed.Based on the torque and economic characteristics,a control strategy considering the dynamic characteristics of the motor is designed,which compared with the drive control strategy based on the static model of PMSM by simulation to verify its effectiveness.