Torque ripple reduction in a flux-switching permanent magnet machine targeted at elevator door applications by minimizing space harmonics

摘要

A flux-switching permanent magnet (FSPM) machine using ferrite magnet is proposed to replace the permanent magnet synchronous motors (PMSMs) in elevator doors. In order to improve both mechanical robustness and manufacturability, bridges around permanent magnet (PM) slots have been adopted in the C-shaped core of an FSPM machine. The optimization of the C-shaped stator is conducted, and its prototype has been built up for experimental validation. Back-electromotive force (EMF) is estimated to prove that simulated results are correct and reliable. Compared to a PMSM designed for elevator doors, the efficiency of an FSPM machine is significantly improved in spite of using ferrite PM that is utilized in the PMSM, but there is a disadvantage in torque ripple due to the interaction of harmonic components between back-EMF and magneto-motive force (MMF). However, most of researches on an FSPM machine have been focused on eliminating harmonic components of back-EMF. In this paper, the design process of an FSPM machine based on winding function theory will be given to diminish torque ripple by considering the harmonics of back-EMF and MMF in air gap.