Analysis of iron and magnet losses in surface permanent magnet machines resulting from injection-based self-sensing position estimation

This paper presents a systematic analysis of iron and magnet losses in surface permanent magnet (SPM) machines for the self-sensing (sensorless) position estimation using HF signal injection. It is shown that the magnet eddy current losses due to the superimposed HF signal are significant and should be considered for SPM machine injection-based self-sensing drives. When a SPM machine uses concentrated windings (CW), the resulting HF armature flux linkage component is reduced because of the rich HF armature leakage fluxes in the stator. The decreased magnet eddy current losses can be achieved, resulting in better performance on both power conversion and self-sensing estimation. Two SPM machine prototypes with different winding configurations are used for experimental evaluation.