Abstract
This paper introduces the loss reduction technology for power supply. Design and manufacture of the power supply for JT-60 was carried out using the high-power thyristor. Although the power supply for JT-60 was high-voltage and large-current, the power supply for ITER or a future nuclear fusion reactor system will be a low-voltage large-current type. It is very important to study the latest technical trend in low loss electric power conversion equipment using turn-off type power devices.