Theoretical investigations of stator iron losses in a 15 MW induction motor equipped with fractional conductor windings

Sammanfattning: Iron loss calculation in AC machines has aroused great interest over the years, in an attempt to make electrical machines more efficient. However, different iron loss models yield different results for the same machine, owing to their individual limitations. This element of uncertainty associated with obtained values is further enhanced in cases where knowledge of the flux density’s behavior is very elementary.  This thesis gives an overview of different iron loss models and applies them to a 15 MW induction motor equipped with fractional conductor winding. The aim is to analyze the results acquired using various models and determine the suitability of the investigated models. The two main categories of iron loss models implemented are the Steinmetz models and the loss separation model. Iron loss results confirmed that the basic Steinmetz equation is only suitable for sinusoidal flux density waveforms and its accuracy diminishes as the waveform becomes increasingly non-sinusoidal. Furthermore, parts of the stator where the magnetic field is most rotational were identified as the roots of stator teeth. However, rotational magnetic fields were found to have a small effect on stator yoke iron losses.