Efficient PM Power Loss Mapping for Brushless AC PM Machines With Surface-Mounted PM Rotor Construction. IEEE Transactions on Industrial Electronics, 62(12), 7391-7401. DOI: 10.1109/TIE.2015.2455062

This paper describes a computationally efficient approach for mapping the rotor power loss in permanent magnet (PM) machines. The PM loss mapping methodology discussed here utilises a small number of time-step finite element analyses (FEA) to determine the parameters of a functional representation of the loss variation with speed (frequency) and stator current, and is intended for a rapid evaluation of machine performance over entire torque-speed envelope. The research focus is placed on field-oriented controlled brushless AC PM machines with surface-mounted PM rotor construction, although the method could be adapted for other rotor formats. The loss mapping procedure accounts for the axial-segmentation of PM array through the use of an equivalent electrical resistivity of the segmented PM array, obtained from 3D FEA. The PM loss can be accurately mapped across the full operational envelope, including the field weakened mode, through a single three-dimensional (3D) and four two-dimensional (2D) time-step FEAs. The proposed methodology is validated on an 18 slots, 16 poles surfacemounted brushless AC PM machine design. The loss mapping procedure results agree closely with the computationally demanding alternative of direct 3D FE prediction of the PM power loss undertaken at each of the machine’s operating points.