Loss Suppression and Strength Optimization of Semi-Inserted High-Speed PM Rotor With Double-Layer Hybrid Sleeve

The surface-mounted high-speed permanent magnet motor suffers from such issues as large eddy current losses and unstable rotor strength. To solve these problems, many novel rotor structures have been proposed. In this study, a novel rotor structure with a double-layer hybrid sleeve and semi-inserted permanent magnets is proposed to enhance the rotor strength, reduce the rotor eddy current losses, and optimize the electromagnetic parameters of the motor. First, an analytical model of the eddy current losses of the double-layer hybrid sleeve is established, and it is verified through finite element analysis. Then, by changing the size structure of the rotor, the variation law of the eddy current losses is obtained, and the dimensions such as the insertion depth of the permanent magnets in the rotor and the thickness of the sleeve are analyzed and optimized. Finally, the rotor strength is studied based on the dimensions when the rotor losses are minimum. The influence fit of the interference amount on the rotor stress is analyzed, and the optimal interference fit is determined. By considering the stress distribution of each part of the rotor, the reliability of the novel rotor structure is verified.