Identifier

etd-07082004-150137

Degree

Master of Science in Mechanical Engineering (MSME)

Department

Mechanical Engineering

Document Type

Thesis

Abstract

Active magnetic bearings (AMBs) are being increasingly employed in the aerospace industry in a variety of devices including compressors, turbines, pumps, and flywheels. One application of great interest to future space missions is the Integrated Power and Attitude Control System (IPACS). The IPACS consists of an arrangement of flywheels that integrates the energy storage and attitude control functions into a single system; thereby, reducing the spacecraft mass, volume, launching cost, and maintenance. Like any energy storage system, flywheels need to be operated with low power losses. AMBs are ideally suited for flywheels because they eliminate mechanical losses (friction). Nevertheless, AMBs are subject to electrical losses, which are proportional to the bias flux. We recently developed an innovative solution to the problem of AMB control with reduced electrical power losses. The controller incorporates a smart, time-varying bias flux that reduces power losses without affecting the rotor stabilization. The novelty of the smart-bias controller strongly motivated the pursuit of the next step in this research – an experimental validation. To that end, the objectives of this project were: · Design and build an experimental AMB test rig. · Conduct tests to validate the smart-bias controller and its power-loss reduction mechanism in comparison to a standard constant-bias AMB controller. The experimental results show that the smart-bias controller clearly reduces the electrical power losses and energy dissipation of the AMB system in comparison to the constant-bias approach, without significantly affecting the stabilization performance. These results confirm, in a qualitative manner, the theoretical and numerical results obtained earlier.

Date

2004

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Marcio de. Queiroz

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