Research On DSP-Based Vector Control System Of Induction Motor

Nowadays, the vector control strategy of Induction Motor becomes a hot subject, and a lot of successes have been achieved. But the real products of vector controller for induction motor are very rare, they aren't mature enough yet. Aiming at the AC vector control system industrialization, cooperating with a Heilongjiang electric Ltd, we deeply studied control strategies and practicality system of Induction Motor Vector control system and implemented a high performance digital AC vector control system.In an induction motor drive system with field oriented vector control, the key to improve its performance is accurate flux estimate. To resolve the problems of DC drift and inaccurate estimation of the rotor flux linkage at very low speed using conventional flux observer, a new adaptive perpendicular rotor flux observer with compensation was presented. Compensation feedback flux was automatically adjusted by checking the perpendicular degree of flux vector with back EMF vector. Simulation and experimental results verified that the proposed observer could accurately estimate the rotor flux linkage by reducing the estimate error due to the DC drift, parameter perturbation and measurement noise.Two kinds of control schemes were proposed in this paper according to the different requirements for current and speed response performance in vector control system. The current regulator which adopt PI controller with integral anti-windup, can effectively restrain the influence of integrator saturation. In the speed loop, Fuzzy self-adjusting PID controller has been designed. It can realize the online automatic tuning by the control method of fuzzy inference method, and improve the system steady-state precision and dynamic performance. A detailed design procedure has been proposed in this paper. The simulation and experimental result show the effectiveness of the method.In this paper the formation of SVPWM in the Cartesian coordinate system is introduced particularly on the basis of the principle of space vector pulse width modulation (PWM) of the three-phase AC motor. A method compensating the dead-time in a synchronous rotating reference frame is also proposed, which fits for vector control system of induction motor. The compensation results show that the method achieved a better compensation conclusion.Based on above work, a set of induction motor vector control system with high performance and full digits based on DSP TMS320F2812 structure has been developed. This system is helpful to the further research of AC motor vector control system. The experimental results show that the system designed by the method mentioned above has an excellent control performance.