| This is a dissertation on the analysis and reduction of stray rotor losses in high-speed synchronous machines. Attention is focused on the surface-mounted permanent-magnet (PM) machine with a non-magnetic steel sleeve that contains the rotor magnets. A review of the literature on this and related topics is presented, covering various analytical and numeric techniques for computation; the loss mechanisms of interest; and means for reducing the loss or impact thereof. Axial segmentation of the rotor sleeve is considered as a prime means to reduce the eddy currents.; This research presents a method for determining the eddy losses in the conductive sleeve of a high-speed PM machine suitable for power-dense aerospace applications that includes three-dimensional end effects, stator slotting, inverter-current time-harmonic content, and stator-winding harmonics. The proposed method incorporates commercial finite-element (FE) software and achieves a lower computational burden than a full 3D-transient, nonlinear rotating-grid FE model, while at the same time achieving greater accuracy than existing methods.; Optimizing the system (power converter, filter, feeders, machine) under the combined constraints of current and voltage limits, system weight maximum and cooling limitations relies on an accurate rotor loss model. A numerical example is presented to demonstrate the benefits to a practical application achieved by applying this design methodology that allows such an optimization. |
