GaN-GIT power transistor switching behavior and application in a motor drive inverter

Abstract:
GaN Gate injection transistors exhibit no reverse recovery current peak and therewith possess promising properties for the development of hard switching converters with higher energy densities and higher switching frequencies. This paper presents an investigation of the switching behavior of 650 V GaN-GITs in the development of a motor drive inverter. Extensive switching tests were carried out in two different commutation loop designs. One design enabled the measurement of the drain current by using a coaxial shunt. The measurement results show steep voltage gradients up to 100 V/ns and marginal voltage overshoot and ringing. The results show the influence of the parasitic inductance on the switching behavior caused by different commutation loop design as well as the effect of the gate-resistance. Finally, a design for a three-phase-inverter is proposed and measurements in continuous DC/AC operation with a switching frequency of 100 kHz and 200 kHz and a DC link voltage of 400 V and an output power of 520 W are presented.