The Digital Vector Control Of Asynchronous Motor

With the development of social productive forces, the research aiming at the AC motor speed control technology expecially the vector control technology become more and more important. In order to realize the digital vector control of asynchronous motor, this paper studies the vector control technology based on rotor flux field oriented, the research content including the vector control with speed sensor and without the speed sensor.In the aspect of control strategy, in order to conditioning the speed of the asynchronous motor, this paper uses vector control technology based on indirect rotor flux field oriented, and uses current model to accomplish the rotor flux observation. For speedsensorless vector control, this paper uses the vector control technology based on model reference adaptive system which uses modified voltage model as the reference model and current model as the adjustable model, consitituding a self-adaptive control.In the aspect of simulation, this paper uses PISM9.0software to modeling for the two kinds of digital scheme, mainly including the design of SVPWM calculating block, power inverter, the acquisition of current and voltage, the presetvalue and PI adjustment block. The performance of the experiments show that the vector control with speed sensor can obtain perfect control performance, and the speedsensorless vector control can estimate the speed of motor and has a certain engineering use value.In hardware design, this paper uses high cost performance floating point digital signal processor TMS320F28069of TI company to consititute a minimum system for the control circuit, also uses hall current sensor and linear light coupling components to constitute a current and voltage sampling circuit. Besides, this paper uses incremental photoelectric encoder to accomplish the acquisition of speed, and calculated the SVPWM to control the state of inverter, achiving the goal of VVVF to asynchronous motor.Finally, system experimental apparatus and experimental waveforms are given. Results show that the overall design of the vector control with speed sensor is reasonable, and there is no obvious distortion of current signal. Besides, the speed and torque of asynchronous motor response quickly, the motor speed is smooth, and the system’s performance is stable.