No-Load Additional High-order Space Harmonic Losses of Squirrel Cage Induction motor Based on General Airgap Field Modulation Theory

This paper proposes the analytical methods for calculating no-load additional losses induced by high-order space harmonics of airgap magnetic flux density. Firstly, amplitudes and rotation speeds of prominent space harmonics of airgap magnetic flux density are calculated based on the general airgap field modulation theory (GAFMT). Secondly, the loss formulas are deduced, where the surface losses and the pulsation losses in the stator and rotor and the bar joule loss induced in the rotor bars are considered. At last, the results obtained by the proposed method are compared with those obtained by finite element analysis (FEA), showing a good agreement.