The Design On Intellectualized Field-oriented Control (FOC) System Of Induction Motor

According to induction motor field-oriented control (FOC) system , the research on speed controller and speed identification is popular now. In this paper, the structure and the speed control and speed identification methods of speed sensor-less field-oriented control (FOC) system are discussed. A theory of field-oriented control based on model reference adaptive system (MRAS) and PID controller for induction motor is presented. The math model of the induction motor is nonlinear, time varying and coupled. From the simulation results, we can find the performance of the system using PID controller is not ideal because it is influenced by external disturbance or uncertainty. Based on the neural network with the capability of self-study and self-adaptive we present the speed control and speed identification new methods of speed sensor-less field-oriented control (FOC). The new system has a better performance than the PID controller system. It has many performances such as faster dynamic response, strong in robustness, strong anti-interference and so on. At last a new instantaneous reactive power model hybrid speed identification method is also proposed, which based on the neural network, combines the open loop estimator and the instantaneous reactive power model reference adaptive system (MRAS). The simulation results show that the vector control system based on this improved scheme has better dynamic and static performance. It solves a lot of problems such as larger error in the MRAS based on the back electromotive force when the motor runs across the zero speed and the instability based on the instantaneous reactive power in the regenerating mode and has high estimating precision.In this paper, the design method of the induction motor full digital AC control system is also introduced. The software and hardware implementation of the system is discussed in detail. The industry computer controls the DSP TMS320F240, DSP output the space vector pulse width modulation voltage wave (SVPWM) onto the induction motor. Frequency and voltage conversion control are achieved. We have finished the vector control experiments on digital AC motor experiment platform.