Magnetic Field Distortion Analysis and Suppression for the Minimum Unit Winding Segmented Moving-Magnet Linear Motor

Abstract

Segmented power supply is frequently utilized for long-stroke moving-magnet linear synchronous motors to lessen the issue of large loss and heating brought on by long-stroke power supply. However, the driving mode of partial excitation in segmented power supply brings some problems, such as unbalanced parameters of three-phase, the transient inductance of winding changing with secondary position, and distortion of armature reaction magnetic field. This paper proposes a new topology with the minimum unit winding segmented to solve the problems of unbalanced inductance parameters and distortion of armature reaction magnetic field in winding segmented permanent magnet linear synchronous motors (WS-PMLSM). An analytical model of inductance distortion in the end coils of a moving-magnet PMLSM is established and compared with the non-end coil inductance to summarize the mechanism of inductance unbalance in WS-PMLSM. Based on the model of winding transient inductance changing with secondary position, the changing law of transient inductance is expounded. An analytical method of the air gap magnetic field based on virtual winding is proposed, and the formation mechanism of magnetic field distortion caused by partial excitation is revealed. Aiming at the topology of the minimum unit winding segmented moving-magnet PMLSM, an optimized drive strategy of n+3 is proposed.