Reactive power model used for adaptive and indirect field orientated induction motor control.

This paper studies the use of reactive power for the indirect-field-orientated control (IFOC) of induction motors and a method to achieve a simple and robust drive control in spite of rotor resistance variations. Firstly, the reactive power model is presented showing how the rotor-flux vector velocity can be calculated without using the rotor resistance. Secondly, a Model Reerence Adaptive Controller (MRAC) in reviewed to perform IFOC while estimating the rotor resistance on-line. The convergence of the rotor resistance estimator is presented in detail. Finally, an algorithm to achieve power “consumed” by the induction motor. It is shown how two different algorithms must be used during braking and motoring for correct IFOC convergence. Experimental results for the MRAC and the proposed controller are presented and compared with results obtained using both a tuned and de-tuned IFOC.