Research on the Magnetic Properties of High-Saturation Magnetically Induced Alloy Motors under Magnetocaloric Coupling

Abstract

In the face of the rapid development of the motor industry, some motors with traditional soft magnetic materials can no longer meet the needs of the market. Using new high-saturation magnetic density materials has become a new breakthrough to improve the torque density of motors. Fe-Co alloys (1J22) have high-saturation magnetic induction strength, which can effectively improve the motor’s magnetic field strength and increase its torque density. At the same time, the temperature rise of the motor is also an important factor to consider in the motor design process. In particular, the change in core temperature caused by loss makes the coupling of the internal temperature field and the electromagnetic field of the motor more common. Therefore, it is necessary to test the temperature and magnetic properties of 1J22 together. In this paper, a coupling measurement device for magnetic properties of soft magnetic materials is built, and a 1J22 temperature field–electromagnetic field coupling experiment is completed. It is found that the maximum loss of 1J22 decreases by 4.44% with the increase in temperature; the maximum loss is 6.41% less than that of traditional silicon steel. Finally, a finite element simulation model is built to simulate the actual working conditions of the motor, and it is verified that the magnetic properties of the material at high temperature will have a certain impact on the performance of the motor.

Optimization of PM Slotless Brushless DC Motors Considering Magnetic Saturation and Temperature Limitation

“…Therefore, limiting the temperature rise of the stator of the PM is a necessary condition for preventing the insulation from deteriorating and demagnetization of the PM when the motor torque is boosted [21,22]. Asef et al [23] carried out a PM motor threedimensional finite element thermal analysis and reduced the temperature rise at the stator core by investigating radial and circumferential airflow ducts; Guo et al [24] proposed a temperature rise calculation method based on a reduced-order model for variable-condition PM motors in order to accurately carry out the temperature rise calculations and verified that the method can predict the temperature rise at key nodes of PM motors under variable conditions in real time; Li et al [25] simultaneously considered the temperature rise of the motor as well as the effect of high saturation on the motor. The magnetic properties of the motor under magnetic-thermal coupling were investigated, and it was verified that the magnetic properties of the material at high temperatures would have a certain impact on the performance of the motor, but no optimization of the motor was carried out accordingly; Liu et al [26] carried out magnetic-thermal coupling after verifying a thermal equivalent circuit model in order to facilitate the reduction of the motor quality while controlling the temperature rise, and provided a reference for the magnetic-thermal coupling of slotless brushless DC motors; Li et al [27] proposed a shunt ratio optimization method considering winding temperature limitation to improve the torque, but did not explore the effect of other factors of the motor size on the electromagnetic torque; Lekić et al [28] proposed a new method for analyzing the shunt ratio optimization of a high-torque-density PM brushless DC motor, which considered leakage of the magnetic field and was applicable to large high-pole-count motors with limited copper loss density.…”