Core Loss Equivalent Resistance Modeling of Small- and Medium-Sized Converter-Fed Induction Motors Considering Supply and Spatial Harmonics

In order to estimate the core loss resistance of converter-fed induction motor accurately and efficiently, an analytical piecewise variable-coefficient core loss model is proposed. By introducing two voltage harmonics related coefficients, the influence of converter harmonics on core loss is simply and effectively considered. In addition, the surface and pulse loss caused by slot harmonics and the additional harmonic core loss caused by harmonic magnetic potential of stator winding under load condition are also considered. Based on the proposed model, an advanced core loss equivalent resistance model of converter-fed induction motor considering supply and spatial harmonics is proposed. The effectiveness of the proposed model is validated by comparisons with the measured core losses of 5.5 kW induction motor under no-load condition. In addition, compared with the finite-element method under load condition, the proposed analytical model reduces the computational time significantly while maintaining high accuracy.