Design modelling and development of gate driver circuits for WBG devices for green energy application

Abstract

The rapid adoption of wide bandgap (WBG) devices such as Gallium Nitride High Electron Mobility Transistors (GaN-HEMTs) has enabled the realization of high-efficiency, high-frequency power converters for green energy applications. Despite the numerous advantages offered by GaN devices, several challenges arise, such as the risks of false turnon, reverse conduction, high dv/dt stress, and increased electromagnetic interference (EMI). These challenges necessitate further investigation into the design of various gate driver circuit topologies, intended at mitigating dv/dt stress and EMI, while effectively suppressing false turn-on phenomena and reverse conduction. In this work, various driver circuit topologies for GaN-HEMTs are investigated, which motivates the proposal of two novel gate driver circuits. The proposed circuits are modelled and validated as innovative resonant gate driver configurations, specifically optimized for GaN-HEMTs. The research begins with an LTspice-based comparative loss analysis of GaN-HEMTs and Si-MOSFETs in Class-E resonant inverters, demonstrating reduction in switching losses results in enhanced efficiency of GaN devices. The first proposed gate driver circuit, i.e. Single-Switch Resonant Gate Driver (SSRGD), achieved approximately 96.25% efficiency and better suppression in EMI. The second proposed gate driver circuit, i.e. Multi-Resonant Current Source Gate Driver (MRCSGD), which combines current-source and resonant topologies providing intrinsic negative turn-off capability, false turn-on suppression, and enhanced efficiency of 95.14% at 10 MHz operating frequency. The proposed circuits are analyzed through detailed steady-state modelling, power loss estimation, and simulation in LTspice. An experimental testbench is setup for testing the designed gate driver prototypes. Experimental results validate the theoretical findings and simulation studies.