Reducing PM eddy current rotor losses by partial magnet and rotor yoke segmentation

In order to reduce the losses caused by eddy currents in the magnets and rotor yoke of a PM electric machine, a number of effective methods can be used. One method that imposes the least restrictions on machine performance is segmentation, which can be difficult to implement as magnets need to be cut, insulated and re-glued, which is a laborious and costly process. This paper presents methods of partial segmentation in magnets and the rotor yoke that aim to improve machine performance by reducing eddy current loss, while also suggesting realistic manufacturing possibilities. Results are obtained using analytical, numerical and experimental methods and good agreement is achieved.