Brushless Doubly-Fed Machines have potential benefits in variable speed
generation and adjustable speed drive applications by combining a robust machine
structure with a reduced power converter rating. While recent work has demonstrated
feasibility, steady-state performance has not been optimized. The nature of doubly-fed
operation causes rotor currents of varying, relatively high frequency. Moreover, the rotor
structure deviates from conventional squirrel cages. Consequently, induction machine
rotor bar geometries need to be carefully examined and refined for applicability in the
doubly-fed system.
The present thesis uses finite element analysis to investigate alternative rotor bar
design. Two-dimensional finite element analysis is used to investigate basic rotor bar
characteristics. Interface with a detailed simulation program enables investigation of
assembled rotors, otherwise a three-dimensional analysis problem.
Rotor bar geometries for a high speed alternator are investigated. Bar shapes are
kept simple to allow manufacturing of the rotor in the absence of the-casting equipment.
Rotor prototypes are constructed using custom, laser-cut laminations and experimental
results for the alternator verify improved line-to-shaft efficiencies over conventional rotor
geometries as well as off-the-shelf alternators. / Graduation date: 1994
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37050 |
| Date | 13 April 1993 |
| Creators | Salim, Mohamed Ali, 1968- |
| Contributors | Spee, Rene |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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