Design Of Power Coupling Mechanism And Its Control Strategy For Electric Vehicle With Double Motors

Faced with increasingly depleted oil resources and poor air quality,people gradually realize the seriousness of the problem.The automobile industry has shifted from petrol vehicles to hybrid cars to electric cars.The government has also given great support to the electric vehicle industry.It has provided a a favourable turn for the development of electric vehicles,which has sprung up like bamboo after a spring rain.However,at present the power of the high-power single motor for most electric vehicle is not proportional to its mass and volume.Its power system has low power density per unit mass.Compared with low-power motor,it has lower performance/price.In addition,the paper takes the high-speed light-load electric vehicle as an example.The working area of single motor in original vehicle is generally in the high torque with high efficiency area.The utilization rate of low torque with low efficiency is low.Therefore,the paper would have a research to replace the high-power single motor with several low-power motors.Performance advantages of low-power motors is greatest in effect,so as to improve the power and economy of the vehicle.The specific process is as follows:Firstly,a novel dynamic coupling mechanism of double planetary row with double input and single output was designed and put forward,and different working patterns modes were divided.The power system of a single motor electric vehicle was modified,matching parameters of motor and coupling mechanism in dual motor vehicle.The model was established and multi-body dynamics analysis were carried out to prove the feasibility of the mechanism.Secondly,combining the MAP diagrams of high-power and low-power motors,the output maps of the power system were drawn.in contrast with the original single motor,the coupling characteristics of the new mechanism and its advantages over the output of speed and torque were analyzed.Finally,mathematical models of single motor and dual motor electric vehicle with mode switching control strategy were established in MATLAB/Simulink.The dynamic performance and economy under different cycle conditions were simulated.At the same time,In Simulink/Simscape,the physical model of dual-Motor electric vehicle was established with the control strategy for a mode switching.The purpose were to simulate its mode switching process.It can be obtained by simulation.The climbing degree of the new dual-motor electric vehicle has been improved obviously.The acceleration of 100 Km has been increased by 29.4%,and the maximum speed has been increased by 6.4%.In terms of economic performance,the vehicle economy under UDDS and NEDC conditions increases by 10.4% and 2%,respectively.On the mileage per unit energy,dual motor driving is better than single motor about 5%.In a word,multi-mode driving of dual motor can meet the requirements of low speed with high torque and high speed with high power.Therefore,dual motor driving or multi-motor driving is a better choice in the design of electric vehicles.