Comparison analysis of AC PM transverse-flux machines of different designs in terms of power density and cost

This paper compares four different configurations of PM transverse-flux machines. The permanent magnet transverse flux machines with: internal rotor; outer rotor with magnetic shunts; double coil; and outer rotor without magnetic shunts with optimal average air-gap diameter — are designed, analyzed and tested in the laboratory. The study implies that each design has its own advantages and disadvantages in terms of power density, cogging torque, and cost. Special attention is given to the manufacturing process of the machines, materials, and components, which determine the total cost of the machine. Power densities, cogging torque, and cost of the machines are compared and discussed. Conclusions on practical use of the proposed configurations are provided in the paper.