Analytical Calculation of Rotor Eddy Current Loss of High Speed Permanent Magnet Machines With Shielding Layer

This paper proposes an accurate analytical calculation method for rotor eddy current loss of high-speed machines with the shield layer and retaining sleeve. The calculation model includes six subdomains, such as permanent magnet, shield layer, retaining sleeve, air gap, slot opening, winding. Considering the eddy current reaction of the permanent magnet, shield layer, and retaining sleeve, the vector magnetic potential equation derivation model for each subdomain is established, and the eddy current loss of the permanent magnet and shield layer caused by current harmonics and slot openings is accurately calculated. The model is used to study the factors affecting the rotor eddy current loss, including carrier ratio, modulation ratio, slot opening length, and thickness of permanent magnet and protective retaining sleeve. The results of model analysis and calculation are compared with the results of finite element and machine experiments to verify the correctness and regularity of model analysis and calculation.