Demagnetization Characteristics Diagnosis of Permanent Magnet Synchronous Motors

Permanent magnet synchronous motors (PMSM) are widely used in various fields due to their small size, high efficiency and power density, and simple structure. However, during the application process, it may cause demagnetization of the motor's permanent magnet (PM), resulting in poor or even damaged output performance of the drive system. This article conducts research and comparison on several different demagnetization characteristics diagnosis methods. This includes algebraic identification methods that can identify motor related parameters, voltage model flux estimation methods that use the integration of stator voltage to achieve flux estimation, and sliding mode observers based on motor current signals and rotor speed. The validation results of these three methods for motor flux estimation are presented. Finally, based on the design process and the results obtained, the advantages and disadvantages of three different magnetic flux monitoring methods were summarized.