Design And Simulation For A Dual-Motor Powertrain Transmission System Of Electric Vehicle

With the increasing scarcity of oil resources and the continuous increase of environmental pollution problems, the pure electric vehicle has become the main direction of the future development of the automotive industry. Nowadays, the battery technology of pure clectric vehicle has not yet to break great through and innovation. So carrying out the parameters matching for the pure electric vehicle powertrain system and integrated vehicle control strategy research, aiming to raise pure electric vehicle driving range and reduce vehicle production cost, is one of the urgent needs for pure electric vehicle technology development and the main research direction. To solve the above problems, this paper based on Chongqing foundational science and frontier technology research special subject(project number: CSTC2015jcyjA60005) "The design theory and control method of pure electric vehicle power transmission system based on dual motor driving", proposed a novel dual motor power transmission system for electric vehicle(DMPTS) which cuopled by planetary gear and fixed gear based on power coupling transmission technology. The following aspects of the study are mainly carried out:(1) A novel dual motor power transmission system for pure electric vehicles whiche has four working modes such as mian/auxiliary motor drive respectively, mian/auxiliary motor torque coupling drive, mian/auxiliary motor speed coupling drive is put forward, through in-depth studying the configuration principle of multi power source coupling transmission technology, analysing the structural features and working mode of the existing dual motor power transmission system for electric vehicle.(2) Through giving full consideration to the various working modes corresponding to the vehicle driving conditions of dual motor power transmission system for pure electric vehicle, and the analysis of the frequency of vehicle speed, demand power and torque in several typical cycles, a kind of parameter matching method for power transmission system is explored, based on traditional power matching method, with the vehicle power performance as the constraint conditions, considering the frequency statistics of several typical driving cycle speed, power and torque requirements, based on the vehicle power performence constraint conditions, aiming to make the dual motor power transmission system for electric vehicle operate at high efficiency area, based on the statistical analysis of the characteristic parameters of the driving cycle. That solves the insufficient of general power matching for how to distribute two driving motor power for DMPTS. The Performance parameters of the main/auxiliary driving motor and gear ratio are confirmed.(3) The energy management strategy for the vehicle is proposed. The system efficiency of dual motor power transmission system for electric vehicle under four modes is studied. The mode switching control strategy and power allocation strategy under torque coupling and speed coupling based on the optimal system efficiency is proposed, and the mode conversion conditions based on rule-based is obtained.Simulation results show that, compared with the single motor deceleration drive system, the proposed novel dual motor power transmission system for electric vehicle has better energy saving potential and better acceleration performance and climbing ability in the low speed, the power performence of meet the design requirement of the vehicle.