dissipation per IGBT has been estimated to be 30 W per IGBT
or 180 W total, with approximately 100–200 CFM airflow at
25 ◦C. Cooling can be provided by forced air between the heat
sinks for a horizontal cross flow. The switch design currently
assumes operation in a controlled laboratory environment. The
IGBTs are not isolated from each aluminum cooling plate, so
the plates serve as the collector and emitter contacts.
Each IGBT is voltage-protected by six transient voltage suppressors
(TVSs) diodes in series. The six diodes in series limit
each IGBT collector-emitter voltage to 1200 V. This simple
method of voltage protection prevents overvoltage of an IGBT
that may switch asymmetrically.