Estimação e controle em acionamentos com máquinas assíncronas em campo orientado.

Abstract

This work is a contribution to the study and implementation of a real time microcomputerbased control system for an induction motor drive. The system hardware includes a bipolar transistor three phase inverter, which is used to supply a machine with a PWM voltage waveform and an IBM compatible microcomputer Machine currents and shaft position are obtained with the help of a Hall effect sensor and an absolute optical encoder, respectively. The static drive system, includes current regulator, flux/conjugate field oriented approach and speed regulator. Two different current control schemes in field oriented control, which use hysteresis and discret time current controllers arc discussed However, the PI controller is used for both current controller and speed controller in system implementation. In the design and caractcrization of several parameters dependent system, static estimation and dynamic estimation are analized These estimation techniques are both based on the least square method Two new approaches for parameter estimation are developed in which the i l l - conditioned matrices problem is avoided In one of this techniques the algoritm execution time is independent on the data quantity. Finally, a digital program for drive motors is developed The program structure and the use of high-level language make its use very flexibe in the sense that control strategies, in the test procedure, may be easily changed.