Noninvasive Quality Assurance Testing for Magnetization Defects in Surface PM Synchronous Machines

초록

Imperfections in the magnetization or assembly processes or PM material of surface permanent magnet synchronous motors (PMSMs) can reduce torque production and cause torque pulsations. Quality assurance (QA) tests are performed by the manufacturer at the production stage to screen out defective units with degraded performance. However, the QA tests currently applied in production for detecting rotor defects such as back-emf or flux measurement lack sensitivity or are too costly to perform on all individual rotors. To address this limitation, a new inverter-embedded QA test method based on the differential inductance is proposed. Finite element (FE) analysis is performed to analyze the causes and patterns of magnetization defects due to misaligned or eccentric rotor during magnetization. An experimental study under emulated magnetization and PM defects is performed to validate the effectiveness of the proposed method. Existing QA tests commonly used in the field are also performed for comparing fault detection performance. The results show that the proposed QA test can be embedded in the inverter available in the QA system to provide fast and sensitive detection of magnetization defects in surface PM rotors at low cost. © 1972-2012 IEEE.

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