Hitachi IGBT Module Application Manual

5.8.4 Short-circuit Current and Gate Voltage Increase

Collector voltage increases with short-circuit current, at the same time gate voltage increase due to dv/dt

current flows to gate through reverse transfer capacitance ( C

res

). The increase in gate voltage can be

estimated by examination of the Q

res

electric charge characteristics. (Refer to Figure 51.)

Figure 51. Example of Gate Charge Characteristics

voltage increases due to short circuit current,

Q

res

conducts to the gate through

C

res

.

Figure 52. Dependency of Gate Voltage upon C

res

In this case, gate current ( i

gsc

) can be calculated as shown in Equation 42.

Equation 42:

i

gsc

= (v

ge

(i) - V

GP

â€™ )/ R

G

and Q

res

can be calculated using Equation 43:

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