[Objective] The canned permanent magnet synchronous motor (CPMSM) is widely used in critical fields such as chemical processing

nuclear power

and medical applications due to its high power density

superior efficiency

and excellent dynamic performance. However

research on the impact of batch-produced permanent magnet performance variations on long-term motor stability remains insufficient. Therefore

this study aims to analyze the influence of permanent magnet variations on CPMSM performance and reveal its multi-physics field coupling mechanisms. [Methods] Firstly

a load backs electromotive force-based real-time detection method for permanent magnet magnetic properties was proposed

enabling dynamic post-assembly monitoring without additional sensors. Then

the influence of permanent magnet performance variations on CPMSM electromagnetic fields

temperature distribution

and shield-can thermal stress/deformation was analyzed using finite element models. Finally

experimental validation of the proposed method was subsequently conducted. [Results] The results demonstrated that when compared with the N30-grade

the motor with N38-grade permanent magnets exhibited a 2.56% difference in power factor

a 1.76% difference in efficiency

a 5 ℃ difference in winding temperature

and a 5.82 ℃ difference in casing temperature. [Conclusion] A decline in the magnetic performance of permanent magnets leads to nonlinear deterioration in motor performance metrics

and the performance difference is solely related to the quantity of permanent magnets

independent of their distribution. This study provides theoretical references for the optimized design of CPMSM

the evaluation of permanent magnet deviation impacts

and the enhancement of reliability in harsh environments.