Esitmation of Performance of PM Type LPM using Permeance Method

Abstract

A linear pulse motor (LPM) has been examined, for application to actuators of floppy disk drives, hard disk drives, printers, etc. A permanent magnet (PM) type LPM is superior in thrust force to other variable reluctance (VR) type LPMs and hybrid (HB) type LPMs. However it is difficult to calculate performance of the PM type LPM, because the electromagnetic fields in an air gap between a magnet and the teeth have to be estimated with a finite element method.
We propose a simple method, in which magnetic paths in the air gap are assumed to be straight lines and circles, to estimate the magnetic flux in the air gap and an iron core with winding coils, thrust force and inductance. This method is shown useful for estimating the thrust force of PM type LPMs, especially assuming the width of the magnet pole to be narrower than the real one and when compensating magnetic paths with a leakage magnetic path.