为了准确计算永磁同步电机(PMSM)转子的挠度，降低电机的生产制造成本，基于理论解析和有限元法，分析与计算了转子偏心电磁力和挠度。推导了PMSM不平衡磁拉力的解析表达式，详细介绍了不平衡磁拉力和转子挠度的有限元计算方法。以355 kW 1 500 r/min PMSM为例，对比了不平衡磁拉力、转子挠度的有限元和解析法的计算结果，验证了有限元法的可靠性，对PMSM转子机械的准确计算和振动噪声分析具有一定的参考意义。

In order to accurately calculate the deflection of permanent magnet synchronous motor (PMSM) rotor and reduce the production cost of motor, the eccentric electromagnetic force and deflection of the rotor are analyzed and calculated based on theoretical analysis and finite element method. The analytical expression of unbalanced magnetic pull of PMSM is derived, and the finite element calculation methods of unbalanced magnetic pull and rotor deflection are introduced in detail. Taking a 355 kW 1 500 r/min PMSM as an example, the calculation results of finite element method and analytical method of unbalanced magnetic pull and rotor deflection are compared, which verifies the reliability of finite element method and has certain reference significance for the accurate calculation of rotor machinery and the study of vibration and noise of PMSM.