Improved 2-D Analytical Model for Rotor Eddy Current Loss of HS PMSMs With Rotor Retaining Sleeve Based on Accurate Subdomain Method

The existing two-dimensional (2-D) analytical models for rotor eddy current loss (RECL) cannot consider the influence of the three-dimensional (3-D) distribution of the eddy current, so the calculation accuracy is limited. Based on the accurate subdomain method, this article proposes an improved 2-D analytical model for the RECL of high-speed (HS) permanent magnet (PM) motors with sleeve. Based on the load magnetic field, the model considers the influence of stator slotting and time harmonic of each current. The 3-D distribution of the eddy current is considered by expanding the radial component of the flux density axially. The eddy current reaction is considered by introducing the attenuation coefficient. The eddy current distribution on the surface of the PM and the RECL under the load magnetic field are verified by finite element (FE) method. The effect of the PM axial segmentation and thickness of sleeve on the RECL is also analyzed by the proposed analytical model. Finally, the correctness of the analytical model is verified by the loss separation experiment and the C-shape core experiment.