新能源汽车驱动电机用烧结钕铁硼磁体的热稳定性

通过对两种不同尺寸、不同磁导(P_c=0.26和P_c=0.57)的磁体进行分析,考察在最高工作温度下长时间保持的耐久性能,即实验前后的磁体开路磁通变化、材料磁性能变化以及磁体的温度系数。实验发现,同样性能(牌号)、但不同磁导的磁体在磁路中所处的工作点不同,抗热退磁能力也不同,即使经历相同的实验条件,磁性能下降也不同。相对于P_c=0.26的样品,P_c=0.57的样品其热稳定性和抗热退磁能力更好,即使长时间的高温作用,仍然保持较高的磁性能。这不仅对电机设计提供了指导,同时为电机设计时校核磁体退磁风险提供依据和参考。

Thermal stability of the sintered Nd-Fe-B magnet for drive motors for new energy automobiles

The magnets with two different size and two different permeance were analyzed in this paper.The durability of the magnets kept long at the maximum working temperature were studied,that is,changes of the flux,magnetic properties and temperature coefficients between before and after the experiment were studied.The experimental results indicate that the same grade magnets with different permeance were at different working points in the magnetic path so that the ability of thermal demagnetization was different although exposed at the same experimental conditions.The drop rate of the magnetic properties were not the same,specifically,the thermostability and the ability to resistance to thermal demagetization of the magnet with permeance of 0.57 were preferable compared to one with permeance of 0.26.Even though,the magnet was applied at high temperature for a long time,it could maintain higher magnetic properties.The results provide for not only guidance to moter design but gist and reference for checking demagnetization risk in the electric design.