Novel rotors with low eddy current loss for high speed permanent magnet machines

Due to the large rotor eddy current loss and low thermal conductivity of carbon fiber sleeve, the high temperature usually occurs in high speed permanent magnet machines (HSPMMs) at the rated operation condition, resulting in irreversible demagnetization of the permanent magnet (PM). To obtain low rotor temperature, two novel rotor structures with low rotor eddy current loss are proposed in this paper. With the output torque and air gap flux density unchanged, the performance of HSPMMs with the two proposed rotor structures are analyzed based on finite element algorithm (FEA), including eddy current loss and temperature. Finally, the appropriate parameters of the proposed rotor structures are selected, and the electromagnetic (EM) performance, rotor stress and temperature are compared with those of the conventional rotor structure.