Development of 1000 AMPERE RMS, 4 KHZ, 1500 volt thyristors and rectifiers

This paper describes the design and development of 1500 volt, 1000 amp rms, 4 kHz triode thyristors and companion rectifiers for high frequency power conditioning. In order to obtain devices with the objective specifications, programs were conducted on selection of emitter profiles and geometries, on lifetime evaluation and control, on encapsulation development, and on interdigitation optimization of the thyristor cathode and gate. Spreading velocity measurements of the on-region of the thyristors and use of a rating model which was computerized established the interdigitation required to obtain the objective current rating at 4 kHz. An auxilliary built-in amplifying thyristor was used to provide high gate drive to the highly interdigitated cathode emitter of the thyristor. Uniformity of turn-on was determined by observations of infrared radiation during turn-on and determinations of the spreading of the on plasma.