Research On Structure And Control Strategy Of Dual Motor Drive System

Vehicle ownership has increased significantly in recent years with the continuous improvement of travel requirements.The problems of environmental pollution and energy consumption caused by a large number of internal combustion engine vehicles are increasingly acute.Under the vigorous advocacy of the government,the development of electric vehicles has become the only way for auto companies to deploy future strategies.Compared with internal combustion engine vehicles,electric vehicles have significant advantages in terms of emissions,noise and energy utilization.However,the current development of single-motor direct-drive electric vehicles has a short driving range and poor power performance,which makes it difficult to replace internal combustion engine vehicles.In order to improve this situation,this article focuses on the drive system,designing the drive system with dual power sources as the core,and completing the following studies:(1)Introduce the structure of dual-motor independent drive and coupled drive,and explain their respective advantages and disadvantages.After analysis and comparison,this paper selects the research focus as the coupling drive structure,and analyzes its energy-saving principle from a theoretical perspective.Breaking through patent protection,a new dual-motor drive system with simple structure and four drive modes is designed.Its mode conversion mechanism takes roller clutches as the core.In view of the advantages of the large torque transmission ability of the roller clutch and the low drag torque,the size of the entire mechanism can be well controlled.The realization process and applicable working conditions of various working modes in this system are introduced in detail,and the characteristics of torque and speed are analyzed.(2)According to the performance requirements of the vehicle and the vehicle dynamics equation,the power parameters of the dual-motor drive system are matched,and the power distribution of the two motors is completed based on the required power distribution of various standard working conditions.Considering that the parameters of the system will be correlated with each other,in order to coordinate allaspects of the impact to obtain the best overall performance,with a 100 km acceleration time and energy consumption ratio as the research goals,genetic algorithms are used to further optimize the matching parameters.The results show that the optimized parameters can improve the vehicle’s acceleration performance and economic performance.(3)Analyze the control structure of the new dual motor configuration.Considering the influence of driving style on vehicle performance,fuzzy control is adopted for the driver model,and the relationship between the torque load factor and the pedal opening degree is corrected in the required torque module.In the energy management module,with the minimum energy consumption of the system as the goal,a pattern recognition model is established,and working mode switching conditions are formulated.At the same time,increase the time threshold to solve the problem of frequent switching of working modes.In order to reduce the impact caused by the mode switching process,analyze the dynamic characteristics of the motor in the power system and formulate a reasonable mode switching control strategy.(4)A complete vehicle model is built in Matlab / simulink to verify the dynamic and economic performance of the dual-motor dynamic coupling system under standard operating conditions,and the performance is compared with the single-motor direct-drive structure.The simulation results show that with the structure and control strategy designed in this paper,the performance of the vehicle is superior to the original model in all aspects.In the case of little change in cost,it can effectively improve the driving range of the vehicle,and the impact degree is low when the mode is switched,which will not affect the comfort.