Title page for ETD etd-12172008-063409
|Type of Document
||Jessee, J. Patrick
||A coupled thermal-magnetic finite element model for high frequency transformers
||Master of Science
|Nelson, Douglas J.
|Thomas, James R. Jr.
|Vick, Brian L.
|Date of Defense
A new method for analyzing axisymmetric, high-frequency transformers is presented. The method
is based on the simultaneous solution of the coupled, nonlinear thermal and electromagnetic
equations using the finite element method. A novel technique for modeling the reluctivity of the
soft-ferrite core material permits a time-harmonic transformation of the electromagnetic equations.
This eliminates the need to step through time while maintaining the effects of hysteresis losses.
Also, a quasi-steady formulation of the heat-conduction equation eliminates the time dependency
on the thermal problem. A direct substitution iterative scheme is used in conjunction with the finite
element method to compensate for the coupled and nonlinear nature of the equations. To verify
the magnetics portion of the finite element code numerically, a linear, uncoupled test case is given
which compares the magnetic results from the present method to those from a commercial software
package. To investigate the accuracy of the fully coupled and nonlinear model, an example is presented
which compares the results from the numerical analysis of an inductor to those obtained by
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