Analysis and Test of the Sensorless Capability of Induction Motors With Created Saliency

This paper presents various experimental tests on the sensorless capability of induction motors (IM). An intentionally created saliency is introduced in the rotor so as to allow the rotor position to be estimated by means of a high-frequency (HF) injected signal in the stator winding. Experimental measurements are carried out on three prototypes, two with saliency and the third without saliency, as reference. The critical aspects in the prototype realization are discussed in this paper. Suggestion on how to solve them from the machine design point of view is included. The rotor saliency has been measured by means of an HF injection. Then, the steady-state performance has been measured, together with the mechanical characteristic of the three prototypes. FE analysis is used to predict the variation of the IM parameters with rotor position. The results are compared with those achieved from measurements.