Optimal design of a high power density PM motor with discrete halbach array and concentrated windings

The objective of this paper is to develop a high power density PM motor for the strict dimension applications. Halbach array which has potential to offer high air-gap flux density and concentrated windings which has short winding end regions are considered. The discrete Halbach array and concentrated windings configurations are introduced first. Then feathers of air-gap flux density in discrete Halbach array are investigated and the air-gap flux densities varied with the structure parameters are discussed. After that, winding factors of concentrated windings are researched and the results show that the pitch factor and distributed factor reduce only part of EMF waveform harmonics. Later suggestion is that with careful design of the slot width, the EMF waveform of the concentrated windings can also be sinusoidal with high power density. Finally, prototype motors are presented and the results validate the analysis in this paper.