III. DESIGN OF THE IGBT STACK
The University of Missouri—Columbia and Loree Engineering
have designed and built the custom IGBT stack for a
5 kV dc, 1 kW output boost converter as a primary design
application. However, the stack’s switching ability also lends
itself well as a pulsed power solid-state switch, where it can be
modularized for higher voltage or current capability. To characterize
the switch for pulse power applications, resistive-load
pulse tests were utilized to determine the stack’s turn-on time.
The IGBT stack uses six international rectifier (IRF)
IRGP30B120KD-E IGBTs rated at 1200 V and 60 A continuous
current. This IGBT is an NPT-type IGBT, in a TO-247AD
package. The NPT-type IGBTs have been shown to be nearly
ideal for series stack assemblies due to consistent switching
times among NPT devices and minor changes in switching
performance from thermal variations [10]. The stack can theoretically
handle 120-A single-pulse pulses according to the IRF
datasheet ratings. A diagram of the IGBT stack is shown below
in Fig. 1, and a photograph is shown in Fig. 2.