| At first,this paper introduces the development of the AC transferring speed in recent years,the mode of speed regulation and vector control idea .The advantage and the disadvantage of the AC transferring speed are discussesed,including the direct current speed,the development of power electronic device, the research status of the vector control technology and the characteristic and the application of the DSP chip. The purpose and the main content of the project are given in this paper.For vector control, the mathematical model of the induction motor is analyzed, drawn the conclusion that the mathematical model of the AC induction motor is an unlinear system with multi_input and multioutput. Compared with methods of vector control used in AC transferring speed,the mode of vector control and flux oriented are analyzed,which involved with the vector control equivalent circuit and fundamental equation of three-phase coordinate systems, two static and revolution coordinate systems, the fundamental formula,and then charting for vector control is obtained.According to the fundamental equations induction motor for the field oriented control, a new rotor flux model combine with the merits of voltage model and current model is presented.At the same time, this paper uses the Space Vector Pulse Width Modulation( SVPWM) method to control the induction motor. Then using DSP,which is special for motor control,a speed sensorless vector control system for induction motor is developed which is based on vector control principle.This paper introduces the main circuit of the inverter,the main function of the DSP, and the detect circuit of the current in detail. The paper gives the software chart of the system. Making use of the DSP with high-speed capability,the fully digital vector control for induction motor is implemented, and some experiment results are given. The results show that the speed sensorless vector control system for induction motor based on DSP has beter synamic and static performance. |
