Cogging Torque Characteristics of a Magnetic‐Geared Motor

Abstract

This paper describes the cogging torque characteristics of a magnetic-geared motor with permanent magnets only on the high-speed rotor. The operational principle, which is different from that of the magnetic-geared motor with permanent magnets on the high-speed rotor and stator, is described. The torque characteristics, especially the order of the cogging torque, are mathematically formulated and verified by conducting 3D finite element analysis and carrying out measurements on a prototype. A novel cogging torque reduction method is proposed and verified as well.

Design and Analysis of Magnetic-Geared Motor With Field Windings

“…Therefore, we adjusted the position of the permanent magnets [3]. The maximum transmission torque of these magnetic-geared motors is larger than the magnetic-geared motor shown in [2]. In addition, the maximum transmission torque per permanent magnet weight is almost the same as Atallah et al's magnetic-geared motor.…”

“…This is because permanent magnets mounted at the tip of the teeth of the stator obstruct the magnetic flux from the coils. To solve this problem, we proposed a magneticgeared motor with permanent magnets only on the high-speed rotor [2]. This magnetic-geared motor has a high excitation torque density, but the maximum transmission torque density is very low.…”

Magnetic‐geared motor with a continuously variable transmission gear ratio and its control method

“…Atallah and colleagues have proposed a magnetic‐geared motor in which magnetic gears are integrated in a motor . This magnetic‐geared motor is a motor that contains a reduction gear and, as such, it has gathered attention as a next‐generation high‐torque density actuator.…”

Performance Evaluation of an Axial‐Type Magnetic‐Geared Motor

“…Magnetic-geared motors that combine a magnetic reduction gears using harmonics with a brushless motor have also been proposed [4][5][6]. A magnetic-geared motor combines into one unit a conventional drive motor composed of three elements: a motor, reduction gears, and a torque limiter.…”

“…To address this problem, we proposed a magneticgeared motor with permanent magnets only on the highspeed rotor [5,6]. In this configuration, the permanent magnets on the stator are removed and the conduction torque is greatly increased.…”