pulsed power switches, require fast switching while a certain
level of conduction loss may be acceptable, especially with
lower duty ratio switching applications
An alternative to high-voltage COTS IGBTs, for high-speed
switching, is to assemble a stack of lower voltage-rated IGBTs
in series. Theoretically, an entire stack of high speed, lower
voltage-rated, IGBTs will switch similar to each individual
IGBT. This concept has motivated the design and study of a
7.2-kV rated stack that has been built using six, 1200-V rated
NPT IGBTs in series. This IGBT-stack design divides the total
voltage hold off capacity among six IGBTs, and eliminates the
large drift region of a single IGBT to support the OFF-state
voltage. Therefore, faster switching is achieved. The six IGBTstack
switching performance is experimentally compared to a
single 6.5-kV IGBT module, which utilizes the field-stop technology,
in a single-shot pulsed resistive-load application, and is
also compared to two 3.3-kV NPT IGBT modules in series in a
5-kV dc output boost converter circuit operating at 9 kHz.