Date of Award
Fall 2025
Document Type
Thesis (Ph.D.)
Department or Program
Engineering Sciences
First Advisor
Charles R. Sullivan
Abstract
As magnetics have always taken up a large portion of the total volume of power electronic devices, miniaturization of the magnetics is important. Past works have studied how magnetic components can be miniaturized. In this thesis, we will follow the path of using air-core magnetics at high-frequency and explore how to design good miniaturized magnetic components under certain constraints. We studied toroid, solenoid, staple and spiral air-core inductor geometries; and concentric, end-to-end, interleaved, side-by-side, and stacked transformer topologies. For inductors in a buck converter at 30 $\si{\mega\hertz}$, solenoid inductors outperform toroid and staple inductors for a wide range of design parameters including footprint area and height. Solenoid inductors can also outperform spiral inductors with enough height. For transformers in an isolated DC-DC converter, the concentric solenoid is the best topology under 1 $\si{\milli\meter}^2$ area when height is greater than 0.7 $\si{\milli\meter}$. For stacked spiral transformers with the same area constraint, a pair of ground planes with 1.5 $\si{\milli\meter}$ distance can provide EMI shielding with little performance impact. An isolated DC-DC converter with concentric toroid transformer is designed to achieve high efficiency, good thermal performance, and low EMI. This work presents a method for designing good magnetic components under constraints.
Recommended Citation
Wu, Yue, "Design and Comparison of Air-core Miniaturized Magnetics" (2025). Dartmouth College Ph.D Dissertations. 447.
https://digitalcommons.dartmouth.edu/dissertations/447
