A Study on MHz Switching Operation in Flyback Converter for Lithium Ion Battery and its Parallelization

Lithium-ion batteries (LiBs) have been widely used as consumer rechargeable batteries. We use the flyback topology, which is a type of isolated DC/DC converter, as the boosting circuit for an LiB. In this study, the flyback converter is operated with a single LiB in both the main and gate drive circuits. The switching frequency of conventional flyback converters is in the range of several hundred kHz. However, we aim to drive the flyback converter at 2.1MHz. Accordingly, Si and GaN devices are compared, and Liqualloy magnetic materials are investigated. Then, the components suitable for our field of use are reexamined. Additionally, our approach for the parallelization of the circuit to compensate for the drop in the output voltage of the LiB is described.