The Technology Research Of Direct Torque Control Of Asynchronous Motor Used In Electric Vehicle

With the global fossil energy decreases gradually and the continuous deterioration of environment, the development of electric vehicle is becoming more and more important and the emergence of electric vehicle has putted the automotive industry into a new space. The research for control system of motor and the development of electric vehicle has become a focus of attention of many automobile manufacturers. This paper selects the asynchronous motor as the driving system for electric vehicle and uses the direct torque control(DTC)as control method of asynchronous motor. Direct torque control technology can reduce the torque ripple in the process of motor running effectively and increase the starting torque of the motor, also It has simple structure. DTC has a little influence from the parameters of motor and it can improve the dynamic performance of the motor. The design of asynchronous motor direct torque control system has full consideration of the characteristics of driving electric vehicle, also spend much time in researching the theory of DTC in detail. The key introductions are as follows:1) Introduce the model of asynchronous motor briefly and explain the principle of direct torque control technology.Put forward the design scheme of direct torque control system according to the characteristics of the actual operation of electric vehicles.2) Research the design scheme of the direct torque control system, also provide the demonstration and reasoning for the important parts,algorithm of the system.3) DTC system has been designed in MATLAB/SIMULINK environment and get the simulation results.It shows that the system at low speed has the problem of fluctuation in torque and flux. Get the solution to this problem and prove mean is right by simulation.4) The core chip for asynchronous motor is the micro controller STM32F051 produced by ST, get the platform for experiments and experimental verification.In summary, we have chose asynchronous motor drive system and put forward DTC control technology in the application of driving system. Provide more theoretical basis and more options for DTC system of asynchronous motor.