Adaptive torque control of indirect-field oriented induction drive by stator current matching and rotor flux positioning

In this paper, an adaptive controller using the identification process proposed by Holtz and Thimm (1991) is simulated at zero speed. The controller uses the spatial error between the identified rotor flux vector and the reference flux vector to control the switching pattern of a voltage PWM inverter. Simulation results show that when measured current accuracy allows proper identification, the convergence of the identified rotor time-constant to the "real\´ parameter is rapid. They also show that by using the flux obtained from this identification process as a controlled state, stable and rapid torque control is achieved even at the unfavourable zero speed and torque condition. These results show that the technique of identification by current matching and technique of control by rotor flux positioning could be promising in low speed and torque conditions for field oriented induction drives working under nonsaturated magnetic condition