Compensation of Stray Load Loss Induced Detuning in Rotor Flux Oriented Induction Machines

Stray load loss (SLL) is a phenomenon that is neglected in standard d-q axis models of induction machines. Hence it appears as a source of detuned operation in rotor flux oriented machines, since vector controllers are not aware of its existence. Recent studies have shown that the detuning caused by the SLL is rather small. Nevertheless, provided that the necessary motor data are available, it is possible to provide a full compensation of SLL induced detuning in a simple manner. This paper at first illustrates quantitatively detuning effects due to stray load losses in vector controlled induction machines during transient mode of operation. It further develops a modified indirect rotor flux oriented (IRFO) controller that compensates detuning and verifies its operation by simulation. Iron losses are included at all times, so that the modified IRFO controller fully compensates both SLL and iron losses in steady state operation