Sponsor
Portland State University. Department of Electrical and Computer Engineering
First Advisor
Jonathan Bird
Term of Graduation
Winter 2023
Date of Publication
3-20-2023
Document Type
Dissertation
Degree Name
Doctor of Philosophy (Ph.D.) in Electrical and Computer Engineering
Department
Electrical and Computer Engineering
Language
English
Subjects
Magnetic devices -- Design and construction, Gearing, Torque, Magnetic flux, Electromagnetism
DOI
10.15760/etd.8200
Physical Description
1 online resource (xviii, 207 pages)
Abstract
This dissertation is devoted to investigating the performance potential of coaxial radial flux modulating magnetic gears for use in propulsive thruster applications. The research has focused on studying magnetic gear designs suitable for use in electric aircraft drivetrains and electric boat thrusters. Consequent pole, flux concentration and Halbach rotor magnetic gear typologies have been analyzed and compared with respect to their torque density performance for the first time. It is shown that the Halbach rotor magnetic gear holds the greatest potential with respect to achieving volumetric and mass torque densities parity with an equivalent mechanical gear.
A high volumetric torque density Halbach rotor coaxial magnetic gear with a 1:5.67 gear ratio was designed, fabricated, and experimentally tested. The radial flux prototype achieved a volumetric torque density of 279 Nm/L at a torque of 190 Nm. This design validated the high torque density performance of a Halbach rotor coaxial magnetic gear.
A high mass torque density 1:12.4 gear ratio Halbach rotor radial flux coaxial magnetic gear was also designed for an electric vertical take-off and landing vehicle. The design was computed using 3-D finite element analysis to have a mass torque density of 53 Nm/kg at a torque of 240 Nm. The design was experimentally verified with a prototype. This design demonstrated the feasibility of a lightweight magnetic gear for the use in an electric aircraft. A thermal and electrical loss analysis was conducted by using 3-D finite element analysis, where the hysteresis loss and eddy current loss was used as heat source in the thermal model. It was shown that a magnetic gear efficiency greater than 99% at rated torque is feasible.
Prior research indicated that when using a high gear ratio (> 1:10), the torque density of coaxial magnetic gear is greatly reduced. This research used a comprehensive finite element analysis geometric sweep method to demonstrate for the first time that by increasing the magnetic gear diameter, a magnetic gear can simultaneously achieve a high torque density and a high gear ratio. Using 3-D finite element analysis, it was shown that a single-stage 1:33.3 gear ratio coaxial magnetic gear can operate with an active region volumetric torque density of 336 Nm/L or an active region mass torque density of 92 Nm/kg.
A magnetic equivalent circuit analytical modeling approach that allows the characterization of the spatial and temporal harmonic components in a magnetic gear was also developed and its accuracy was compared with an equivalent finite element analysis model.
Rights
©2023 Ho Yin Wong
In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
Persistent Identifier
https://archives.pdx.edu/ds/psu/39803
Recommended Citation
Wong, Ho Yin, "Design and Analysis of High Performance Magnetic Gears for Magnetomechanical Thrusters" (2023). Dissertations and Theses. Paper 6346.
https://doi.org/10.15760/etd.8200