Steady-State FE Modelling of Induction Machines: the Harmonic-Balance Approach versus the Classical Fundamental-Frequency Phasor Approach

In this paper three different approaches for the steady-state finite-element (FE) modelling of induction machines (IMs) are discussed and compared regarding their (spectral) accuracy and computational cost; to this end a 3-phase 3kW squirrel-cage IM with sinusoidal voltage supply is considered. The reference approach is plain time-stepping; its drawback is the possibly very long transient and time interval to traverse. The well-known phasor approach, which involves only the fundamental stator and rotor frequency, is much quicker but may be insufficiently accurate. In the Harmonic Balance (HB) method, two sets of frequencies are to be fixed a priori, for stator- and rotor-side variables respectively, with a view to an adequate compromise between accuracy and computational cost.