Winding Function-Based Analytical Modeling of Core Loss in an Induction Machine Considering Slotting Effects and the Frequency-Dependent B-H Curve Characteristics

The flux density distribution in an induction machine (IM) can be obtained by a conventional winding function-based (CWFB) model for being incorporated in the machine’s core loss calculation using the Bertotti core loss function. However, in this CWFB analytical core loss prediction method, the slotting effects, magneto-motive-force (MMF) drops in the stator and rotor cores, and frequency-dependent $B$ –$H$ characteristics of the core are ignored for simplicity. In this article, an extended winding function-based (EWFB) model is proposed to overcome these shortcomings present in the existing analytical core loss prediction methods by sectioning the teeth, tooth tips, and yoke parts of the IM’s stator and rotor and accurately calculating the flux and core loss densities of each section taking into account the corresponding MMF drops and frequency-dependent $B$ –$H$ curve changes. The effectiveness of the proposed EWFB model over the CWFB model in predicting the total core loss of a laboratory 11 kW IM is validated via experiments at various operating points.