Research And Application Of Vector Control Strategy For Asynchronous Motor Speed-adjusting System

With the development of modern power electronics and control technology based on computer, the technical revolution of electrical drive is promoted. It is a trend that AC drive replaces DC drive and computer-aided digital control takes the place of traditional analog control. Speed-adjusting has become the major mean to improve energy efficiency, the production processes, quality of products and operational environment. Therefore, this paper researched on the asynchronous motor, and the vector control system of speed-adjusting was established. The strategy of vector control for asynchronous motor was researched and implemented in this paper.The organization and characteristic of asynchronous motor was introduced. Using the Space Vector Pulse Width Modulation (SVPWM) as the control algorithm, the thesis used Digital Signal Processor (DSP) TMS320LF2407A special for digital motor control of TI Corporation as the control core, and developed the software and hardware of the full-digital vector control for asynchronous motor, achieved the speed adjustment.This paper can be divided into three parts:Firstly, this paper induced the current condition and future trend of AC speed-adjustment system and its main control strategies, analyzed the mathematical model of asynchronous motor and the principle of vector control, gave the general control scheme and strategy for asynchronous motor speed regulation according to the principle of vector control. Besides, simulation had been conducted in this paper and the result showed the ability of fast response and high robust.Secondly, this paper introduced the design of the circuit (including main circuit, control unit, detection unit, protection unit and auxiliary power supply) and control program which is in C or assembly way (including main program and subprograms for PWM interrupt service, malfunction protection service, series communication and anti-jamming), achieving double closed loop control of speed and current. Experimental waves were also given in this paper and testified the rationality and effectiveness of the control method.Finally, this paper summarized the system and gave the analysis and prospect for the future research.