Optimal Dead-time Setting and Loss Analysis for GaN-based Voltage Source Converter

The dead-time in voltage source converters can have significant impact on power quality and efficiency, and because these losses scale proportionally with switching frequency, it is important to study the impact of these losses in wide bandgap based converters, like SiC and GaN. This paper focuses on the impact of dead-time on the total loss of a 5 kW, single phase, GaN-based inverter, and an experimental model of dead-time losses for various dead-times was developed based on static and dynamic characterization results. The results show that in a GaN-based voltage source inverter (VSI), a 100 ns dead-time setting can attribute up to 30% additional switching loss and is a strong function of load current level and temperature. A comparison of losses between fixed and adaptive dead-time was studied, and an optimal fixed dead-time setting based on the analysis was implemented and verified in experiment.