Minimization of Commutation Losses in LLC Resonant Converter with GaN HEMTs and Si based MOSFETs

Abstract

Highly efficient and high-power density power electronics applications require semiconductor devices with minimized power losses. Traditional Si based MOSFET transistors are limited by maximum operating frequency unlike GaN transistors. The combination of high critical breakdown field and high electron velocity and mobility in the GaN material system provided a path to highly efficient end compact power conversion applications. This paper provides brief comparation of Si MOSFETs and GaN transistors in high-frequency high- power density application as LLC resonant converter which is increasingly represented in the industry. Overlapping gate to source signals method for commutation losses reduction is presented. The same method is examined on couple of Si and GaN transistors available on the market first in LTspice simulation package and further on LLC GaN HEMT’s resonant converter developed prototype. The experimental results of commutation loss reduction are presented.