Research on Magnetic-Thermal Coupling of High-Permeability Soft Magnets in SynRMs

Synchronous reluctance motors (SynRMs) without rare Earths have attracted the attention of many researchers as rare Earth permanent magnet materials are being consumed in large quantities and prices are increasing. In this article, a high-permeability core material, Fe-Ni alloy (1J50), is proposed for SynRMs. With the property of ultrahigh permeability, it is able to increase the convex pole ratio of SynRMs at lower magnetic field intensity, thus improving the torque performance of the motors. To further verify the feasibility of 1J50 in SynRMs, a magneto-thermal coupling experimental setup was established in this paper, and variable frequency and variable temperature tests were conducted on 1J50 and conventional silicon steel (CSS). It is found that the permeability of 1J50 is higher than that of CSS, and it is quite sensitive to high-frequency magnetic fields. The permeability of 1J50 gains an enhancement and the loss tends to decrease under high-temperature conditions. The results of the study were also applied to the motor model to effectively increase the motor's reluctance torque by 15.89% and verify the feasibility of the material.