Effect of Magnets Asymmetry on Stray Magnetic Flux Based Bearing Damage Detection in PMSM

Vigneshwaran Gurusamy,Wai Lee,Bilal Akin,Mohsen Zafarani,Kudra H Baruti

doi:10.1109/access.2021.3076779

Abstract

In this paper, it is shown that stray magnetic flux is a highly reliable condition monitoring variable which is rich in motor health related information and it is superior to motor current. It is well-known that the magnetic field distribution in permanent magnet (PM) rotors exhibit asymmetry due to magnet manufacturing process. It is shown that, in addition to the clear characteristic bearing signatures, the magnet imperfections induce multiple new bearing fault signatures in the stray magnetic flux. Different than current, the signatures in stray flux are more immune to noise, consistent and independent of load and speed. It is also shown that the stray flux-based detection method can locate the faulty bearing. To justify the proposed approach, comparative simulations and experiments are carried out on a surface mounted PM synchronous motor (PMSM) and an interior permanent magnet motor (IPM) with outer raceway bearing fault and different degree of magnet field asymmetry.

Highlights

The market share of permanent magnet motors in high-end applications have been increasing drastically due to its high-power density and high efficiency
4) DISCUSSION AND SUMMARY OF EXPERIMENTAL RESULTS The bearing fault signatures related to magnetic asymmetry and fundamental electrical frequency are present in stray magnetic flux spectrum
In this paper, it is shown that stray flux enables highly reliable bearing fault detection

Summary

Introduction

The market share of permanent magnet motors in high-end applications have been increasing drastically due to its high-power density and high efficiency. This rapid and widespread deployment raises reliability concerns, for mission and safety critical systems. Continuously monitoring these systems is essential to prevent unexpected shutdowns and catastrophic failures that may result in fatal accidents or significant operation loss. Among the various faults in electric motors, bearing faults are statistically most common failure at about 41% [1]. The majority of bearing related failures are reported for induction motors due to their long history. The authors in [2] investigate a PM servo motor with damaged bearing from field to detect

Results

Discussion

Conclusion