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PhD Thesis Defense: Bradley A. Reese

Friday, January 18, 2019, 1:00–3:00pm

Jackson Conference Rm, Cummings Hall

“Alternative Winding and Magnetic Core Fabrication Methods for High Frequency Magnetic Components”


Recent advances in power semiconductor devices allow for reduced size and power loss of power converters. A key feature of these converters is the use of high switching frequencies to reduce the size and cost of capacitors and magnetic components (inductors and transformers). However, as the frequency increases, power losses in these components also tend to increase, limiting the maximum operating frequency. This limitation can be extended for magnetic components with new winding and magnetic core technologies.

At high frequencies, the performance of windings is constrained by the minimum practical diameter of the wires. In some cases, the optimal wire diameter is too expensive for the application or even impossible to manufacture. This work explores new methods of arranging individual strands of wire within a bundle that can reduce power loss while using the currently available wire manufacturing technology.

Magnetic core materials are also significant contributors to the power loss of magnetic components. Composite materials composed of magnetic flakes embedded in an insulating binder have the potential to achieve low power loss at high frequency, while maintaining low cost and scalability. This work also investigates the use of a freeze-casting process to reduce power loss in composite materials by aligning magnetic flakes with controlled ice crystal growth.

Thesis Committee

For more information, contact Daryl Laware at