IGBT Modules - Technologies, Driver and Application (Second Edition) - page 281

Fig. 6.63
Circuit concept of DynamicActiveClamping
6.7.3 Gate clamping
As alreadymentioned, adisplacement current can flow through theMiller capacitance of
the IGBT, charging the gate. This process may increase the voltage at the gate of the
IGBT. Especiallywhen switching over currents and short circuit currents. In the event of
a short circuit, the transfer characteristic of the IGBTmeans that:
) U(f
Eq. 6.23
: Short circuit current [A]
It is therefore important to limit the gate voltage to a certainmaximum value, so that the
value of the short circuit current is not too high and themaximum short circuit energy is
not exceeded. The relationship between the gate voltage, the short circuit current and
the maximum short circuit time for a 1.2kV IGBT is presented in
The gate
clamping limits themaximum gate voltage and therefore also themaximum short circuit
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