Browsing by Author "Wills, Dominic A."

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    Analytical prediction of rotor eddy current loss due to stator slotting in PM machines
    (IEEE Xplore, 2001-08) Wills, Dominic A.; Kamper, Maarten J.
    Certain types of PM electric machines are particularly susceptible to the proliferation of eddy currents flowing within the solid conducting regions in the rotor. These eddy currents can be induced by current winding harmonics, but also by the interaction of the static rotor magnetic field with the permeance variation of the slotted stator known as ‘slotting’. This work focuses on the analytical calculation of eddy current loss that occurs in the conducting regions within a rotor under no-load conditions. The results are compared with finite element analysis and measured results from a machine test. Good agreement is achieved between the three methods of comparison.
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    Reducing PM eddy current rotor losses by partial magnet and rotor yoke segmentation
    (IEEE Xplore, 2010-09) Wills, Dominic A.; Kamper, Maarten J.
    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.