Analytical Calculation and Experimental Validation of 3D Rotor Eddy Current Loss in High-Speed Permanent Magnet Synchronous Motors

This article proposes an analytical method for 3-D rotor eddy current loss (RECL) calculation of high-speed permanent magnet synchronous motors (HSPMSMs), which provides more accurate RECL prediction than 2-D analytical and finite-element analysis (FEA) methods. First, an accurate subdomain model for the two-pole ring magnet HSPMSM is established in which the stator slotting effect and eddy current reaction field are considered simultaneously. A rotation factor is introduced to account for both synchronous and unsynchronous state. Based on the equivalent impedance method, 3-D RECL is computed by correcting each harmonic component in 2-D RECL prediction. Second, the influence of dimension and frequency on RECL prediction is analyzed in FEA. The characteristic of eddy current distribution and the source of the error in 2-D method are analyzed. Finally, a loss separation method is presented and carried out which eliminates the impact of mechanical loss and considers high frequency additional electromagnetic losses to improve the accuracy. The effectiveness of the proposed analytical method is verified by both FEA and experimental result.