Anti-Demagnetization Analysis of Fractional Slot Concentrated Windings Interior Permanent Magnet Motor Considering Effect of Rotor Design Parameters

This work investigates the effect of design parameters of permanent magnets (PMs) and flux barriers (FBs) in the rotor on the anti-demagnetization ability (ADA) of fractional slot concentrated windings interior PM (IPM) motors for electric scooters. A 2.5 kW IPM motor (12 slots and 8 poles) is designed for a wide speed range, and its ADA associated with different PM and FB arrangements is studied under high temperature and high current density operations. The analysis shows the relationship between the ADA and characteristic current ( $I_{\mathrm {ch}}$ , defined as the ratio of PM flux linkage to $d$ -axis inductance). It is also found that proper designs of FBs can significantly improve the ADA of the IPM motor without much affecting $I_{\mathrm {ch}}$ . Thus, the motor ADA and performance can be simultaneously improved. Finite element analysis is used for evaluation, and experiments are conducted to validate the analysis.