Minimizing High-Frequency Switching Losses in Wideband Gan Hemts for Flyback Converters

Abstract

Background. In the realm of pulse power supplies, flyback converters play a pivotal role in efficient voltage conversion and providing electrical isolation. Typically, these converters utilize silicon transistors. However, they encounter several issues that hinder their energy efficiency and operational stability. A primary concern is the increase in switching losses at high frequencies. This is attributed to the lower switching speed and higher on-state resistance characteristic of silicon transistors. Such inefficiency leads to substantial power dissipation, thereby reducing overall efficiency. Additionally, the heat generated from these losses necessitates complex temperature control systems, increasing operational burden and affecting the reliability and longevity of the converters. Furthermore, the operational frequency of these converters is limited. While operating at higher frequencies is beneficial for reducing the size of passive components, it exacerbates the problems of switching losses and heat dissipation in silicon transistors.
 Objective. This article aims to conduct a comprehensive study and optimization of flyback converters based on High Electron Mobility Transistors (HEMT) made of Gallium Nitride (GaN), focusing on minimizing losses in high-frequency switching. The study delves into the intrinsic properties of GaN HEMTs, highlighting their superior characteristics compared to traditional silicon counterparts, and emphasizes the circuit design methods for minimizing losses and their features.
 Method. The research involved a detailed analysis of the switching losses of GaN HEMTs under high-frequency switching conditions. Using computer simulation models, the study examines the impact of various parameters, such as currents and voltages on the GaN transistor, power dissipation, and the output characteristics of the device with different circuit topologies on the performance and efficiency of switching.
 Results. The results provide insights into the optimization strategies of topology, particularly the use of transistor gate drivers and snubber circuits, which are crucial for enhancing the overall efficiency and reliability of flyback converters.
 Conclusions. The article offers an in-depth analysis into optimizing high-frequency flyback converters using GaN HEMTs, providing valuable guidance for devices requiring compact power sources, such as in small aircraft systems and telecommunications networks.