Design And Study On Driving Control System For Electric Vehicle

Since January2013, Beijing and several provinces were shrouded in fog haze. Thisfog haze is a wake-up call for Chinese traditional auto industry. The whole society isrecognized that the traditional car is the culprit of air pollution; perhaps this fog willbring opportunities to the development of clean energy vehicles. Unlike theconventional cars with serious pollution, pure electric vehicles as one of clean energyvehicles will enter the technical breakthrough stage in the next few years, and thetechnology breakthroughs will make electric vehicles have great prospects fordevelopment.This paper describes the inadequate of the conventional cars compared to electricvehicles, such as short driving range, long charging time, charging facilities are notcomplete and so on. These are restricting the popularity of electric vehicles. In thiscondition that the battery technology did not get a breakthrough, through using motoreffectively, full recovery of braking energy and charge to the battery, it can increase thedriving range. Secondly, this paper discusses the status of the existing electric vehicledrive system and the vehicle controller.Under the different road conditions, we can use the vehicle controller to controlthe automatic gearbox and make sure the motor is in the high efficiency range. Atpresent, the traditional low-end electric vehicle drive system only installed the reducerand not equipped with a gearbox system. In this case, the vehicle speed change isachieved by changing the output power of the drive motor in the drive system. Theconsequence of this practice is the motor is not working in the best efficiency point. Itdoes not make full use of the characteristics of the motor and traction drive performancealso showed general. Gearbox also plays an important role in the energy recoveryprocess. Through the gearbox, the motor speed will increases, so the motor can increasethe generating capacity, and recycle more mechanical energy.The main research task of this thesis is to design a vehicle traveling control system,and achieve the basic driving functions of electric cars, according to the road conditionsto achieve automatic transmission shift function, mechanical braking energy recovery when braking and downhill, and other functions. Due to the addition of the automaticgearbox, so the speed synchronization problem when automatic shift is the core ofvehicle controls system. Because the shift strategy design is good or bad is also relatedto the efficient use of the motor, so the shift strategy is the research task. Different fromthe existing electric vehicles, plus another generator to recover braking energy, in thesubject, the drive motor can also be used as a generator, to achieve a motor use in twousages. This method simplifies the automobile structure, reduces the weight and costs.Therefore, this design requires the support of the vehicle control system and it does notsimple. In order to be recovered more braking energy; this requires the motor to beswitched from the drive state to the power generation state in a few milliseconds. Thiswill undoubtedly improve the system’s hardware and real-time requirement. The motorused in the subject is a three-phase AC induction motor, and about the generation ofthree-phase induction motor is the important research content in the paper.