Simulation Research On Direct Torque Control Technology Of Electric Vehicles

Electric Vehicles (EV) use vehicle power supply as their power, using motor to drive the wheels to run. They are vehicles that conform to the road traffic rules and the safety regulations. Asynchronous motor has become the mainstream of power drive system, because of its simple structure, easy manufacture, low price, sturdiness, durability, small rotary inertia, reliable operation, easy maintenance, and other merits. Direct Torque Control (DTC) technology of asynchronous mo-tor is a new type of high-performance AC drive control technology that is quickly developed following Vector Control (VC) technology. It is an excellent AC drive control technique which has high static and dynamic performance for its novel control idea, simple structure and direct means of control. So it has become the research hot spot in the AC drive system.In this paper, AC asynchronous motor was used as the drive engine of EV. Considering the operating characteristic of the electric vehicle drive system, the idea of DTC technology was applied in the electric vehicle drive system. Com-bining with the real conditions of EV, the whole DTC system of EV was modeled and simulated. The simulation research for the entire system is progressive. In DTC technology, DTC theory was fully analysed. In view of inaccurate problem on flux linkage observed at low-speed range of traditional DTC system, a new flux linkage observation method was proposed. Then, the improved scheme more accurately than the traditional one to reflect the changes in flux linkage at low speed run-time was proved through the simulation confirmation. In the aspect of applying DTC technology in EV, the dynamics mathematical model of EV was built, combining DTC technology with the electric vehicle dynamics mathemati-cal model. According to the typical drive condition of EV, the operating charac-teristic of EV is simulated at full speed range. The result validated the superiority of DTC scheme.