High step-up flyback with low-overshoot voltage stress on secondary GaN rectifier
Document Type
Article
Publication Date
7-1-2022
Abstract
This paper presents a new technique to mitigate the high voltage stress on the secondary gallium nitride (GaN) transistor in a high step-up flyback application. GaN devices provide a means of achieving high efficiency at hundreds (and thousands) of kHz of switching frequency. Presently however, commercially available GaN is limited to only a 650 V absolute voltage rating. Such a limitation is challenging in high step-up flyback applications due to the secondary leakage. The leakage imposes high voltage stress on the secondary GaN rectifier during its turn-off transient. Such stress may cause irreversible damage to the GaN device. A new method of leakage bypass is presented to mitigate the high voltage stress issue. The experimental results suggest that when compared to conventional secondary active clamp, a 2.3-fold reduction in overshoot voltage stress percentage is achievable with the technique. As a result, it is possible to utilize GaN as the rectifier while keeping the peak voltage stress within the 650 V limitation with the technique.
Keywords
High gain converter, High step-up, flyback, Gallium nitride, GaN, Silicon carbide, SiC, Rectifier, Voltage stress, Leakage
Divisions
umpedac
Funders
UMPEDAC-2020 (MOHE HICOE-UMPEDAC), Ministry of Education Malaysia (Grant No: IF006-2021 & RU002-2021)
Publication Title
Energies
Volume
15
Issue
14
Publisher
MDPI
Publisher Location
ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND