Masahiro Nagasu

3.3 kV punchthrough IGBT with low loss and fast switching

This paper presents a new punchthrough (PT) IGBT with a high blocking voltage of 3.3 kV. We numerically show that a high injection efficiency with a p+layer and local lifetime control in an n-layer are more effective in reducing the turn-on and turn-off losses, respectively. A p+epitaxial layer at the collector has been made in order to realize a high injection efficiency, which greatly reduced the turn-on loss, experimentally. When a local lifetime control technique is applied to this new PT IGBT, the turn-off loss is decreased by approximately 50% compared to a conventional PT IGBT with uniform lifetime control of electron irradiation. The new PT IGBT provides fast switching with rise and fall times of about 1 /spl mu/s at 125/spl deg/C. In addition, in this PT IGBT it is easy to apply a high resistivity n-layer without increasing its thickness or losing high blocking voltage in comparison with non-punchthrough (NPT) IGBT, which can get low failure rate (FIT) with cosmic ray.

Traction inverter that applies hybrid module using 3-kV SiC-SBDs

We have developed SiC-Schottky barrier diodes with a JBS structure that have characteristics of low forward voltage and low leakage current at 3 kV. Further, we have built a prototype of a 3 kV/200 A SiC hybrid module, equipped with Si-IGBTs and SiC-Schottky barrier diodes. We have achieved to reduce the recovery loss and the turn-on loss, by using the SiC hybrid module and a high-speed drive circuit. Moreover, we estimated that the total energy loss of the converter and inverter using the developed SiC hybrid module was reduced to about 30%. Additionally, the inverter succeeded in driving an induction motor for a train.

Inverter Loss Reduction Using 3kV SiC-JBS Diode and High-Speed Drive Circuit

We developed a JBS diode with characteristics of a low forward voltage and a low leakage current at 3kV. Further, we built a prototype of a 3kV/200A hybrid module, equipped with Si-IGBTs and SiC-JBS diodes. We attempted to decrease the recovery loss, and the decrease in the turn-on power loss, by using a hybrid module and a high-speed drive circuit. Moreover, we estimated that the total energy loss of the converter and the inverter were reduced to about 33%.