Multigap Toroidal Transformer and Inductors for Overcoming Fringing Losses in High Frequency Converters

Abstract:
This paper offers an overview of achieving a reduction in fringing losses in high-frequency magnetics for resonant converter applications. Through the utilization of ferrite toroidal cores with split gaps into several smaller gaps, resulting in a multi-gap ferrite toroidal core, substantial reductions in fringing losses can be achieved, leading to higher efficiency or size reduction of magnetics. The study presents practical examples of multi-gap toroidal transformer and resonant inductor designs, including optimization of the number of gaps and gap sizes using finite element analysis. Additionally, the paper discusses wire selection strategies to minimize losses and provides comparative results against designs in E or PQ format. Overall, this study demonstrates the effectiveness of the multi-gap toroidal approach in mitigating fringing losses and improving the performance of high-frequency magnetics in resonant converter applications.