Study On Drive Motor Control System For Electric Vehicle

Vehicle is driven by electricity. It will be the direction of car development and it has the advantages of low noise, clean energy and easily automatic control. Induction motor is used widely for its advantages of small volume, low cost, performance reliable, light weight and free maintenance. Direct torque control is a new AC speed control technique which is based on the stator field oriented. It has no complex vector transform and produces PWM signals by the bang-bang control principle. It controls the inverter switch state directly, so the dynamic performance of the torque response is improved. Apparently, the directly control to the torque is simple and the responses are more quickly. However, the bang-bang Control produces torque ripple inevitably. Therefore, studying how to reduce the ripple of the induction motor direct torque control is important both in theoretical research and engineering.The paper integrates theories of control, vehicle and motion control to study the drive motor control system of vehicle, and analyzes the structure and function of the system. The fuzzy control has the characteristics of Strong robustness, adaptive. It can deal with problems of controlled object which is nonlinear and hardly to build up mathematical models. On the one hand, hysteresis controller is replaced by the fuzzy controller to reduce the torque ripple which obtained better voltage vector by using fuzzy reasoning. On the other hand, the traditional speed regulator is replaced by the adaptive fuzzy PI controller. Then the drive motor direct torque control system which is based on double fuzzy control algorithm is designed and the system dynamic performances are improved. The system simulation model is established and carried out in MATLAB. The simulation results show that the algorithms are correct and advanced. Finally, the software and hardware design of the control system are realized based on TMS320F2812.