Proposal for Design Method of Shared Rotor to Improve Eddy Current Loss in SPM Type Magnetic Geared Motor

Abstract

When integrating a magnetic gear and a motor into a single unit, the shared rotor simultaneously incorporates permanent magnets used for the input-side rotor of the magnetic gear and those utilized in the motor. This design results in both components sharing the same rotor structure. This integration marks a critical juncture where the magnetic gear and motor unite into a single device. However, it has been observed that this area experiences significant losses due to the extensive use of permanent magnets, leading to high eddy current losses in the shared rotor. In addition, the iron core of the shared rotor contributes significantly to losses from iron losses in the magnetic gear section. Therefore, this article discusses various design approaches aimed at reducing losses occurring in the shared rotor. The design approach used methods to maintain the torque density of conventional magnetic gears while reducing the usage of permanent magnets and decreasing eddy current losses from the permanent magnets. In addition, to improve iron losses originating from the iron core of the shared rotor, the approach involved dividing the iron core into segments.