Research On The Controller Of Four In-wheel Driven Electric Vehicles

Because energy and environmental problems becomes more and more serious, electric car industry increasingly has been receiving more and more attention. The hub-motor electric vehicle has simple and light structure, is easy to realize all wheel drive, and also has a good control, so the hub-motor electric vehicle gets high attention. Hub-motor electric vehicle is studied in this thesis respectively, analysis the theory of BLDCM and build its simulation models. In-depth study hub-moter automobile electronic differential control strategy and its controller, and optimizates electronic differential control strategy, in addition, make a detailed description for sel-diagnosis system.The electronic differential is a key technology of electric vehicle's wheel drive system; we use a section of a systematic comprehensive modeling and simulation analysis. For the four-wheel drive vehicles, left and right wheel differential speed algorithms are crucial.Four-wheel differential driven electric vehicle has not traditional, so the electronic differential control algorithm needs a rational allocation of the speed difference between left and right wheels in order to achieve the shift differential. The algorithm based on steering angle sensor signal and the current speed to get a reasonable allocation of the front and rear wheels, it can prevent sliding friction and steering tail flick and so on. In this article the electronic differential is based torque distribution and a combination of electronic slip, the entire wheel electric vehicle control system structure is divided into two layers, the inner layer is a wheel electric vehicle control system, the outer layer is steering wheel control system, it can achieve the four wheels wheel electric vehicle torque and speed distribution.The controller has two parts, one is core board and the other is expansion board. The expansion board composes by the power supply module, the encoder signal processing circuit, and so on. In the dashboard it can display throttle angle, speed, torque, gear, speed, voltage, current, and mileage and other parameters, also can adjust the PMW parameters to control the motor's speed, in addition,the data can display Refresh in real-time. The final chapter introduces the electrical theory and design of performance test system based on graphic language LABVIEW and wireless transmission. This system makes use of wireless transmission and computer serial port, and has the fuctions of dynamic performance test and real-time monitoring all the status of the system. This system has a high test precision and reliability.