The Design On Control System Of Electric Vehicles With Double Near-wheel Motor Driving

With the natural resources shrinking fast, the human beings have to face theproblem that energy sources will dry up soon. China is a country less of energy andimports lots of petroleum, natural gas every year for developing national economy.However, the price hikes of the energy puts more burden on China’s modernizationand the uncertainty of international situation makes our country have to value thestable supply of energy. On the other hand, the extensive use of fossil-fuel takes themain responsibility to damaging our environment. Nowadays, a serious haze in theeast-central China let everybody have to face the environment problem straight andeverybody has the urge to improve our living environment. Therefore, developingelectric vehicles has become a main trend in the world and the automotive industry.The main content of this paper is the research and design on the control systemof electric vehicles with double near-wheel motor driving. This paper gives detailanalysis about the situation driving in a straight line. For the requirement of towmotors’ precise synchronized operation, this paper presents an improved method oncontrolling torque current in order to overcome the load-perturbation and takesadvantage of cross-coupling algorithm to implement synchronized control.Firstly, this paper compares different motor and distributed forms of electricvehicles, chooses the near-wheel form as the structure. After analysis on thecharacteristic of near-wheel structure, this paper selects the exterior permanentmagnet synchronous motor as driven motor and presents the mathematical model ond-q axes. Then, this paper analyzes the ordinary method on controlling tor que currentand paraphrases the factors that influence the response speed of torque current. Inorder to improve this problem, this paper presents a fast response of torque currentcontrol method. Simulation results show that the proposed method is right andefficacious.Secondly, this paper analyzes different ways and different control objects onsynchronized control for double motors, selects the rotation speed as the controlobject and cross-coupling as synchronized algorithm. Simulation results show that thecontrol system is right and efficacious.Finally, this paper designs a hardware platform of the double near-wheel motorsynchronized control system. In the hardware design, this paper briefly introducescontrol circuit, sampling circuit, inverting circuit and the principle of selecting some devices. This paper designs a software program based on this platform, and gives theflow chart of the software program.