O. Winter, Ch. Kral, E. Schmidt:
"Design Study of Magnet Shapes for Axial Halbach Arrays using 3D Finite Element Analyses";
Poster: International Conference on Electrical Machines ICEM, Marseille France; 09-02-2012 - 09-05-2012; in: "Proceedings of the 20th International Conference on Electrical Machines", (2012), ISBN: 978-1-4673-0142-8; 1 - 6.

Axial ironless in-wheel motors are promising candidates for future light weight vehicles. Therefore, possibilities to reduce the manufacturing cost without adversely affecting the performance are studied in this paper. Both static and transient 3D finite element analyses are applied to calculate flux density distribution, output torque and induced back EMF. Based on experimental measurements with linear Halbach magnet arrays, the prerequisites for the manufacturing of axial magnet arrays are given.
Finally, a full-scale prototype in-wheel hub motor is presented.
Experimental measurements prove the viability of the design and the good agreement between the computations and reality.

http://publik.tuwien.ac.at/files/PubDat_214559.pdf