永磁同步电机具有高效率、高功率密度和运行稳定的优点，是液化天然气（LNG）泵核心驱动部件的理想选择，其在低温环境下的电磁性能至关重要。本文首先分析了低温永磁同步电机关键材料在−161 ℃工作环境下的电磁特性；然后，建立了一台额定功率为6.5 kW的低温永磁同步电机瞬态电磁场有限元模型，对比研究了低温环境和室温环境下电机电磁性能和电磁损耗，并分析了永磁体厚度对低温永磁同步电机性能的影响。与室温工作环境相比，在−161 ℃环境下，电机空载反电动势和电磁转矩分别增加了8.93%和6.03%；定子铁耗增加为2.5倍，铜损耗减小为65.3%，铁耗占总电磁损耗比例显著增大。

Permanent magnet synchronous motor (PMSM) with advantages of high efficiency, high power density and stable operation is ideal core drive component for liquefied natural gas (LNG) pumps, where its electromagnetic performance is critical in cryogenic environments. This article firstly analyses the electromagnetic properties of key materials of cryogenic permanent magnet synchronous motors under the operating environment of −161 ℃. Then, a transient electromagnetic field finite element model of a cryogenic permanent magnet synchronous motor with a rated power of 6.5 kW is established. The electromagnetic performance and losses of the motor under cryogenic and room temperature environments are studied comparatively, and the influence of permanent magnet thickness on the performance of the cryogenic permanent magnet synchronous motor is analyzed Compared with the room temperature environment, the no-load back electromotive force and electromagnetic torque of the motor increase by 8.93% and 6.03%, respectively, at the temperature of −161 ℃; the stator iron loss increases by 2.5 times, the copper loss decreases by 65.3%, and the proportion of iron loss to total electromagnetic loss significantly increases.