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 position estimation using high-frequency (HF) signal injection. Standard SPM machines with cylindrical rotors are analyzed. It is shown that the magnet eddy current loss due to the superimposed HF signal should be considered for SPM-machine injection-based position estimation. With a proper machine design, the resulting HF armature flux linkage in the magnet can convert to the HF leakage flux in the stator. The decreased magnet eddy current loss can be achieved, leading to better performance on both power conversion and injection-based position estimation. This paper includes the experimental evaluation of two SPM machines with different winding configurations.