圧粉コアを用いたハイブリッド界磁モータ

Abstract

This paper presents a hybrid excitation motor which enables to realize both high torque capability at low speed and wide speed operating range employing field-strengthening and weakening control by mmf of field winding excitation. The origin of the proposed machine construction is from a hybrid stepper machine, but the uniqueness lies in the utilization of powdered iron core as magnet flux bypass core and filed-pole core with toroidal coil. Because of the magnetically three-dimensional isotropic nature of powdered iron core, the magnet flux bypass core makes it possible to avoid unnecessary magnet mmf loss due to a passage through inter-lamination airgap. For the same reason, the field pole core can deliver three-dimensional flux and the mmf of the fitted field toroidal coil can theoretically contribute to providing independent field strengthening/weakening capability. Using an existing prototype of 300 rpm-12.7Nm-hybrid stepper machine as a point of departure, the basic working principle how to achieve both the field strengthening and weakening in the proposed machine is described. The performance predictions of the proposed machine based on three-dimensional finite element analysis are demonstrated.