Study of eddy-current loss in the sleeves and Sm-Co magnets of a high-performance SMPM synchronous machine (10Â kRPM, 60Â kW)

•Experimental study of rotor eddy-current loss in high-speed PM synchronous machine.•Testing of Inconel718 and carbon-fiber retaining sleeves.•Effect of slot opening width on rotor eddy-current loss.•Magnetic shielding effect on rotor eddy-current loss.

The goal of this paper is to analyze and evaluate the eddy-current losses due to stator slotting in conductive and non-conductive retaining sleeves mounted on the rotor of a high-speed SMPMSM: 60 kW, 10 kRPM, designed for an aeronautical application. Roughly speaking, there are two groups of sleeves: composite sleeves (carbon-fiber or fiberglass + resin) and metallic sleeves (Inconel718, titanium, stainless steel). For both types of sleeves losses are estimated by two means: a 2D finite-element model (AnsysMaxwell) and experimental tests. According to test bench results, the use of a composite sleeve reduces losses by 330 W (370 W found with the FEM), showing reduction equal to 0.6% of the machine's rated power. The eddy-current losses in the magnets are equal to 60 W. The final section of the paper proposes an optimization study of eddy-current loss and an analysis of the shielding effect induced by the high-conductivity sleeve (aluminum, etc.).