The irreversible demagnetization phenomenon that may occur in the permanent magnets serving inside the motor under the influence of high operating temperature and strong demagnetization magnetic field is the main bottleneck for the high reliability operation of permanent magnet synchronous motor (PMSM). This article summarizes the demagnetization process and identification methods of permanent magnets in the rotor of PMSM

including the physical process of demagnetization of permanent magnets in the motor

the influencing factors and analysis methods of the demagnetization process

the characteristic parameters and identification methods of demagnetization faults

the preventive measures for demagnetization faults

and the testing and experimental methods for demagnetization research. Finally

the development direction and solution ideas of key technologies such as the improvement of permanent magnet materials

precise design of motors

high-precision identification and diagnosis of demagnetization processes

and operation strategies for demagnetization protection are proposed

providing a reference for further developing high- reliability designs of PMSM.