Design and Implementation of a GaN-Based, 100-kHz, 102-W/in3 Single-Phase Inverter

High power density is a desirable feature of power electronics design, which prompts economic incentives for industrial applications. In this paper, a gallium nitride (GaN)-based 2-kVA single-phase inverter design was developed for the Google Little Box Challenge, which achieves a 102-W/in³ power density. First, the static and dynamic temperature-dependent characteristics of multiple SiC and enhancement-mode GaN FETs are investigated and compared. Based on the device testing results, several topologies of the inverter stage and different power decoupling solutions are compared with respect to the device volume, efficiency, and thermal requirements. Moreover, some design approaches for magnetic devices and the implementation of gate drives for GaN devices are discussed in this paper, which enable a compact and robust system. Finally, a dc notch filter and a hard switching full-bridge converter are combined as the proposed design for the prototype. A 2-kVA prototype is demonstrated, which meets the volume, efficiency, and thermal requirements. The performance of the prototype is verified by the experimental results.

I. Introduction

New wideband gap (WBG) power devices, such as silicon carbide (SiC) and gallium nitride (GaN) transistors, exhibit unique physical characteristics that enable power conversion with higher switching frequency, higher efficiency, and higher power density than their silicon counterparts [1].