Higher efficiency three-level inverter employing IEGTs

A higher efficiency is one of the important features required on large capacity converters. As high voltage and large capacity power semiconductor devices replacing conventional GTO thyristors, 4.5 kV IEGTs (injection enhanced gate transistors) and IGBTs have been placed on the market, for use in inverters for driving large motors of rolling mills, pumps, compressors, etc and in converters for SVCS for power systems. This paper describes an 8 MVA three-level converter-inverter that employs an improved 4.5 kV - 5.5 kA press-packaged IEGT, featuring 99% in measured efficiency.