Modeling Eccentric Squirrel-Cage Induction Motors With Slotting Effect and Saturable Teeth Reluctances

Abstract

This paper mainly proposes a general model of eccentric squirrel-cage induction motor (SCIM), which includes the stator and rotor slotting effect as well as their individual tooth reluctance effect. Considering open slots on the stator and rotor, their rather exact shape is included in the machine's air gap function. Then, the resulting air gap function is used for evaluating various inductances of SCIM by the winding function approach (WFA). A simple general technique is used for adding eccentricity effect, including static, dynamic, and mixed eccentricities, on the air gap function and, therefore, on the inductances. Using a novel technique, saturable reluctance of each tooth of the stator and rotor is evaluated in every simulation step. Then, these reluctances are added to the model by equivalent increase of the air gap in front of the teeth; this reflects the teeth saturable reluctance effect on the inductances of the SCIM. In effect, dynamic simulation of SCIM with all aforementioned effects using WFA becomes possible. Simulation results compared to corresponding experimental results show accuracy and exactness of the proposed model.