A coupled thermal-magnetic finite element model for high frequency transformers

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 experimental measurement.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1990

Author dc:creator

• Jessee, J. Patrick

Chair dc:contributor.committeechair

• Nelson, Douglas J.

Committee members dc:contributor.committeemember

• Vick, Brian L.
• Thomas, James R. Jr.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-12172008-063409

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/46291