Advances in High-Frequency Magnetics for High-Efficiency, High-Density Power Electronic Systems

Power electronics -- electronic circuits that process energy -- plays a key enabling role in a wide range of energy-efficient and renewable-energy technologies, and is also essential for powering other types of electronic systems. Smaller, more efficient, and less costly power electronics are critical to continued improvement of all these systems. Magnetic components such as inductors and transformers are typically the largest and usually lossy components in power electronics. Moreover, limitations in magnetic component design have been a major obstacle to realizing substantial improvements in miniaturization. To date, advances in power electronics have been enabled by increases in operating frequency, but limitations in magnetics technologies are inhibiting continuation of this trend. This project will develop design methods for high-frequency magnetics, mitigating these limitations, and will apply them to develop miniaturized, high-efficiency power electronics. The results will be useful across many different applications in electronic systems, efficient end-use of energy, and renewable energy systems, reducing their cost and improving their energy efficiency. The project will engage undergraduate and graduate students in the research, strengthening their skills in this important area. Participation of under-represented groups will be sought, and research participants will be carefully mentored. An ongoing research collaboration between Dartmouth and MIT will be strengthened and extended to include educational activities, including outreach to K-12 students to promote science and engineering.

A key route to improvement of power electronics is the development of converters that operate efficiently at substantially higher switching frequencies than are presently used (e.g., in the High-Frequency, or HF, range of 3-30 MHz). Higher switching frequencies result in reduced energy storage requirements of the passive components (including magnetic components), which can be leveraged to reduce size and cost of power electronics, and to improve performance (e.g., higher bandwidth.) Joint advances in high-frequency power circuits and magnetic component design are needed to realize these benefits. Advances have been hindered both by a lack of performance data for HF magnetic materials and a poor understanding of how to design power magnetics for HF. Recent work has revealed that some commercial low-permeability magnetic materials have high performance in this frequency range, enabling substantial miniaturization of power electronics (e.g., factors of 2-10 reduction in overall size) if magnetic component and circuit designs leveraging these materials can be developed. The proposed research program will develop design methods for power magnetic components at HF frequencies utilizing low-permeability materials, and will further investigate how these components can best be applied to realize high-density, high-efficiency power electronics. The research will develop design techniques for achieving reduced core and winding losses with low permeability materials; investigate optimized core and winding geometries; create improved models and designs for high-frequency windings, and develop new self-shielding HF magnetic structures. Moreover, power converter designs that can effectively leverage the capabilities of these HF magnetic components will be investigated and applied to realize miniaturized power electronics operating at HF.