2026-09-20T01:21:41Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/458602022-01-13T07:54:29Zcom_1721.1_7582com_1721.1_7581col_1721.1_131022
Jeffrey H. Lang and Zoltan S. Spakovszky.
Yen, Bernard Chih-Hsun, 1981-
Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
2009-06-30T16:27:49Z
2009-06-30T16:27:49Z
2008
2008
http://hdl.handle.net/1721.1/45860
320081432
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.
Includes bibliographical references (p. 331-336).
The energy density available from batteries is increasingly becoming a limiting factor in the capabilities of portable electronics. As a result, there is a growing need for compact, high energy density sources. This thesis presents the design, fabrication, and testing of a fully-integrated permanent-magnet turbine generator based on silicon MEMS technology envisioned to replace batteries. The air-driven device, supported on gas bearings, has been experimentally shown to deliver 19 mW to matched resistive loads of 0.33 [omega] while operating at a rotational speed of 40 krpm. With an active volume of 41 mm³, this translates to a power density of 0.46 mW/mm³. By extrapolating the experimental data up to the design speed of 360 krpm, it is expected that the integrated generator can deliver 1.5 W of output power.This research represents the first batch-fabricated permanent-magnet generator shown to generate milliwatt-level power, with a further potential to deliver watt-level power. To achieve full integration, a broad range of topics are examined, including the design of gas bearings, high-speed mechanical analysis using non-ideal material interfaces, magnetic rotor balancing, and novel fabrication techniques.A major challenge unique to the integrated device is the need for both silicon and non-silicon components on the same die. While the silicon components are precision micromachined using DRIE and can withstand high temperatures, the permanent magnets are laser-machined separately and rapidly demagnetize when exposed to heat. Similar problems exist for the copper surface windings. The differences are reconciled with the use of a novel drop-in technique, which involves placing nonsilicon components into the die after all the silicon fabrication is complete.
by Bernard Chih-Hsun Yen.
Ph.D.
336 p.
eng
Massachusetts Institute of Technology
M.I.T. theses are protected by
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http://dspace.mit.edu/handle/1721.1/7582
Electrical Engineering and Computer Science.
A fully-integrated multi-watt permanent-magnet turbine generator
Thesis
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