Development of repetitive pulsed power generators using power semiconductor devices

Power semiconductor devices have been used in development of various pulsed power generators for industrial applications. A repetitive pulsed high-voltage modulator using power MOSFETs has been developed for accelerator applications. It is capable of high-speed switching of 2kV at repetition rate of I MHz. This modulator, operating in continuous mode at average power level of 30 kW, has played an important role in the experimental demonstration of Induction Synchrotron. In the same time, SIThy is also tested for the same application since it has higher power capability than MOSFET. Initial experiments have demonstrated 1-MHz operation of SIThy at 2kV in burst mode. A pulsed high-voltage generator using SIThy has been developed for applications in flue-gas treatment. This generator uses a newly developed inductive-energy-storage circuit to achieve both output-voltage multiplication and pulse-width compression. It is very compact and it needs a 12-V (DC) battery as the only power supply to give output of 12 W with pulse width of 100 ns at repetition rate of 2 kHz in continuous mode. A pulsed high-current modulator has been developed for extreme-ultraviolet generation. It uses IGBTs as the main switch and employs magnetic-pulse-compression to achieve pulsed high current. The output reaches 40 kA with pulse width of 240 ns while operating at repetition rate of I kHz in burst mode. This modulator is used in light source development for next-generation lithography. Semiconductor opening switches (SOS) are used in pulsed power generators for excimer laser pumping and flue-gas treatment. These developments are mostly international collaboration with Russian scientists, while efforts are being made to develop SOS devices in Japan.