Principles and implementation of direct torque control by stator flux orientation of an induction motor

The field oriented control of an induction motor is sensitive to machine parameters and some detuning is expected in most rotor flux oriented systems. Consequently, direct torque control has been introduced to reduce parameter sensitivity problems, which are negligible at high speed. The authors of this paper present principles and implementation, with a digital signal processor, of the control system. They propose solutions to correct integrators, which cause some drift and operation errors, and they estimate the possibilities of the proposal. They describe the methods used to obtain good performance, even in the low speed range, where the stator resistance influence becomes critical