DTC of induction machines considering the iron loss

The existence of iron loss is normally neglected in derivation of induction machine models. Consequently. all the model-based high-performance control schemes are characterized with a certain amount of iron loss-induced detuning. Consequences of iron loss on. operation of vector-controlled induction machines have been examined in detail recently. and numerous methods of iron loss compensation have been suggested. In contrast to such a situation with regard to vector control, it appears that a corresponding Study has never been done in conjunction with direct torque, control (DTC) of induction machines. The purpose of this paper is twofold. A detailed simulation study is at first performed so that the impact of iron loss on accuracy of the control is examined in detail. Torque mode of operation in the base speed region is considered. It is shown that the net consequence of the iron loss is a substantial difference between the torque reference and the average motor output torque. In Contrast to Such a situation with regard to motor torque, stator flux estimation is not affected by the iron loss existence. On the basis of the results of detuning investigation, a simple iron loss compensation method is developed. Its accuracy is verified by simulation, Further simplifications of the iron loss compensation scheme are investigated. and it is shown that, for certain machines. iron loss can be effectively compensated by simple deduction. of a constant, iron loss-related torque component from the initial torque estimate.