The Design Of Induction Motor Vector Control Of Speed-adjusting System Based On DSP

Today, there is a lack of sufficien energy resources, energy conservation has very important significance. In our country, Much energy is being consumed by some motors. The traditional speed-adjusting methods cause energy waste because of narrow speed range and low energy efficiency, so high-effect speed-adjusting methods are in urgent need.In the past, the control law is based on the steady-state model, so the dynamical performance is not satisfactory. The vector control which is based on dynamic model is the advanced control method for its high dynamical performance.This paper researches on the asynchronous squirrel-cafe induction motor and the vector control system of speed-adjusting is established. Firstly, the mathematics model of asynchronous motor is developed, the stator current is decoupled into the flux and torque-producing stator current according to the coordinate transform ation and the rotor-flux orientation. Secondly, the circuit construction of the speed-adjusting system is introduced, the principle of the inverter is also analyzed in detailed. The realization of flux-orientation is very important in the speed-adjusting system. In this paper, the method of how to obtain the flux is introduced, the flux monitor in rotor-flux-oriented reference frame is also analyzed.The flux monitor is presented and simulated, which sets a good foundation for further studying.Using DSP of TI inc.-TMS320F2812,this thesis develops a general AC Variable-Speed system,and then carries out the research on various new control strategies for induction motor based on it. As for hardware, TMS2812 is the control unit. Digital signal board mainly implements frequency giving, data display, communication and so on. Analog signal board mainly detects current signals, voltage signals and implements fault protect. Main circuit adopts the AC-DC-AC structure as main switch. The software implements sine Pulse Width Modulation(SPWM),Space Vector Pulse Width Modulation(SVPWM) using assembly language of TMS320F2812 and achieves the purpose of variable-frequency adjusting-speed for induction motor.The experimental results indicate that the scheme of software and hardware is successful. Using Digital signal processor(DSP),TMS320F2812,which is special for motor control we develop a suit of speed adjustable, reliable and highly effective induction drive based on FOC principle. Realization of the whole hardware and the whole software is described. At the same time, a new Pulse Width Modulation(PWM) named Speed Vector Pulse Width Modulation(SVPWM)method is introduced Which is more effective.