Permanent Magnet Linear Synchronous Machines Equipped with a Longitudinal Edge Effect Minimization Device

Abstract

The present invention relates to linear permanent magnet synchronous machines equipped with a device for minimizing the longitudinal edge effect. Intrinsically, this phenomenon gives rise to several limitations, such as: (i) a fairly marked amplification of the tooth force, which affects the quality of the force developed, (ii) an imbalance of the fluxes cut by the phases, resulting in unbalanced electromotive forces, and (iii) a local increase in transverse magnetic forces, which generates a vibration of the slider and annoying acoustic noise. The present invention proposes a device for minimizing the longitudinal edge effect in the case of long-stroke machines, whether tubular or planar in topology. It consists of two laminated ferromagnetic pieces having an "L"-shaped cross-section, mounted near the ends of the stator ferromagnetic circuit. Such a device allows for the collection of a portion of the flux generated by the slider poles located at the stator ends and its injection into the extreme stator teeth. The shape and location of these components are determined using a numerical dimensioning procedure. The proposed device improves the performance of long-stroke permanent magnet linear synchronous machines. Their integration into various sectors, such as energy, mobility, and robotics, is at stake.