The Halbach array structure rotor of the aero motor can satisfy the requirements of high power density and high air-gap flux for aeronautical motors. The size parameters of the rotor are determined by the power rating of the motor based on an analytic method. Producing a Halbach array structure is difficult. Comparison and analysis of the structure of the aero motor showthat the overall structure of the rotor adopts a three-axial-section classic Halbach-array hollow structure, and the rotor magnetic steel adopts a discrete structure of 4 blocks per pole and a single 45◦ magnetisation mode, which reduces the processing difficulty of the rotor magnetic steel. The finite element method was used to analyse the magnetic flux density distribution of the aeronautical motor under various working conditions. The results show that the motor can produce uniform air-gap flux density at various working conditions and present good sinusoidal periodicity. Furthermore, the axial segment did not produce obvious magnetic flux leakage. Finally, considering the eddy current loss of the stator under the rated power-generation condition with high-frequency magnetic field, we conducted coupling analysis of electromagnetic and heat flows to verify that the thermal characteristics of the rotor magnetic steel material could meet the requirements for the aero motor.

The concentrated winding (CW) is obviously different from the traditional distributed winding (DW) in the arrangement of windings and the calculation of winding factors, which will inevitably lead to different performances of the permanent magnet synchronous motor (PMSM). In order to analyze the differences between the CW and the DW in the performance, a 3 kW, 1500 r/min PMSM is taken as an example to establish a 2-D finite element model. The correctness of the model is verified by comparing experimental data and calculated data. Firstly, the finite element method (FEM) is used to calculate the electromagnetic field of the PMSM, and the performance parameters of the PMSM are obtained. On this basis, the influences of the two winding structures on the performance are quantitatively analyzed, and the differences between the two winding structures on the performance of the PMSM will be determined. Finally, the differences of efficiency between the two winding structures are obtained. In addition, the influences of the winding structures on eddy current loss are further studied, and the mechanism of eddy current loss is revealed by studying the eddy current density. The analysis of this paper provides reference and practical value for the optimization design of the PMSM.