AC Copper Loss Analytical Models of High-Power-Density Axial Flux Permanent Magnet Motor With Different Wire Types

Axial flux permanent magnet (AFPM) motor has many advantages such as compact structure and high power density and is suitable for electric vehicles, aerospace, renewable energy, and other fields that require high motor performance and installation space. However, the ac copper loss will affect the power density, torque density, and efficiency of the motor. Therefore, this article presents the analytical models of ac copper loss, which can accurately calculate different wire types and different winding methods. First, the conditions affecting ac copper loss are analyzed by finite element (FE) and analytical models. Second, the ac copper loss of different wire types under different working conditions is compared, and the efficiency difference is analyzed. Then, the armature reaction ac resistance of different wire types of windings is measured by the experimental platform. Finally, two prototypes with a rated power of 55 kW are manufactured, and the windings are made of flat and round copper wire. The prototype efficiency is measured experimentally based on loss separation.