The influence of the squirrel cage rotor in the estimation of the IM flux linkage at standstill

Recent developments in the field of controls for asynchronous induction motors require a precise knowledge of the parameters of the machine. In particular, the estimation of the stator flux is a matter of highest importance, and many solutions can be found in literature, with different degrees of accuracy and complexity. The present paper deals with an industry-oriented estimation technique, performed at complete standstill, to let the estimation be performed even without disconnecting the motor from the load. In particular, the paper carries out a complete study on the influence of the squirrel cage rotor during the integration usually adopted for the flux linkage determination. A full experimental validation is included, to investigate a problem yet little known. In this regard, two twin machines have been designed and manufactured, with and without rotor cage die casting.