Active Power Device Selection in High- and Very-High-Frequency Power Converters

• Published in: IEEE transactions on power electronics Vol. 34; no. 7; pp. 6818 - 6833
• Main Authors: Zulauf, Grayson, Tong, Zikang, Plummer, James D., Rivas-Davila, Juan Manuel
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.07.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Capacitors; Gallium nitride; Gallium nitrides; HEMTs; High electron mobility transistors; Internal energy; Loss measurement; MOSFET; Power converters; Power semiconductor devices; power transistors; resonant converters; semiconductor device modeling; Silicon; Silicon carbide
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2018.2874420

This paper aims to provide a road map for selecting power devices in soft-switched, megahertz (MHz) frequency power converters. Minimizing <inline-formula><tex-math notation="LaTeX">{C_{\text{OSS}}}</tex-math></inline-formula> losses, which occur when charging and discharging the parasitic output capacitor of power semiconductors, is critical to efficient operation. These losses are excluded from manufacturer-provided information, and measurements are either sparse or not reported at all in the existing literature. We report the first high-frequency <inline-formula><tex-math notation="LaTeX">{C_{\text{OSS}}}</tex-math></inline-formula> loss data from silicon carbide (SiC) power mosfet s, with a range of devices tested from 1 to 35 MHz and up to 800 V. In contrast to GaN HEMTs, <inline-formula><tex-math notation="LaTeX">{C_{\text{OSS}}}</tex-math></inline-formula> losses in SiC mosfet s do not increase with <inline-formula><tex-math notation="LaTeX">{dV/dt}</tex-math></inline-formula> at these frequencies. A total of 3%-10% of the stored energy is dissipated in the measured SiC mosfet s. We report new <inline-formula><tex-math notation="LaTeX">{C_{\text{OSS}}}</tex-math></inline-formula> loss measurements for vertical silicon mosfet s and expand on existing measurements for superjunctions, finding high variance in <inline-formula><tex-math notation="LaTeX">{C_{\text{OSS}}}</tex-math></inline-formula> losses between devices for both constructions. High <inline-formula><tex-math notation="LaTeX">{C_{\text{OSS}}}</tex-math></inline-formula> losses preclude the tested silicon mosfet s from efficient operation at MHz frequencies. Lastly, we compare devices in soft-switched applications using a loss calculation that includes these <inline-formula><tex-math notation="LaTeX">{C_{\text{OSS}}}</tex-math></inline-formula> losses, and demonstrate a 100 W, 17 MHz dc-RF inverter using a custom-packaged SiC mosfet .