Review of secondary magnetic field detection technology for permanent magnet synchronous linear motor
ZHAO Jiwen
YIN Le
SONG Juncai
PAN Zhenbao
YU Zixiang
WANG Lijun
Abstract：[Objective]Permanent magnet synchronous linear motors(PMSLMs)eliminate the need for intermediate transmission devices,thus having a simple structure and being able to achieve direct-drive reciprocating motion.They possess advantages such as high thrust density,high efficiency,and the ability to meet the demands of high-speed long-stroke motion and micron-level and nanometer-level dynamic precision.These characteristics make them widely applicable in high-precision processing fields such as laser cutting machines,CNC machines,and 3D printers.As an essential component of PMSLMs,permanent magnets provide a constant magnetic field environment in the air gap of the motors.The uniformity of the magnetic field distribution is closely related to motor performance.Hence,there is a need for timely detection and replacement of faulty permanent magnets to ensure the stability of motor thrust and power density.[Methods]This paper provided a comprehensive introduction to the secondary magnetic field detection of PMSLMs.It began with an introduction to the topological structure and working principle of the motors and analytical formulas for the magnetic field.It then summarized the mechanisms of magnetic field changes and common causes of magnetic field failures.The paper also introduced different permanent magnet faults including local demagnetization,uniform demagnetization,defects,and cracks and the modeling methods for magnetic fields subject to different faults,such as analytical method,finite element method,and Matlab modeling method.Finally,it discussed the fault signals chosen for secondary magnetic field detection of PMSLMs,such as current signals,magnetic flux signals,electromotive force signals,vibration signals,and magnetic field signals,and points out their advantages and disadvantages.[Results]After sorting and summarizing various methods and key technologies,the paper finds that current PMSLMs magnetic field detection mainly relies on magnetic field signals and feature extraction methods to achieve offline diagnosis of magnetic field failures.[Conclusion]To achieve real-time fault diagnosis and improve motor reliability,future trends in magnetic field fault diagnosis should focus more on the study of signals collected in real time such as electromotive force,current,and magnetic flux,so that demagnetization failures can be detected on line.At the same time,high fault-tolerant adaptive control strategies need to be developed to ensure that the motors can maintain output performance and thereby reliable operation even when demagnetization failures occur.
Keywords：permanent magnet synchronous linear motordemagnetization of permanent magnetpermanent magnet defectpermanent magnet crackmagnetic field detectiondirect-drive reciprocating motionair gap of motorsecondary magnetic field
Publication Date：2025-01-24
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：13( 1-13 )