Exampleof aDC-bus construction
For IGBTmodules with several terminals for the DC+ and the DC- potential of the DC-
bus a balanced current distribution between the terminals is essential. This depends on
the module design and the DC-bus construction. The DC-bus construction and the
positioning of the capacitors have to be such that the currents will distribute
symmetrically over themodule terminals. Severe asymmetry could lead to temperature
problems at the module terminals and to an asymmetric current distribution inside the
13.6 Snubber capacitors
During operation is has to be assured that the maximum blocking voltages of the
semiconductors (IGBT and associated freewheeling diode) will not be exceeded.
Additionally to the DC-bus voltage the turn-on and turn-off switching sequences cause
, which result from an addition of the DC-bus voltage U
Uof the stray inductance of the commutationpath.
The stray inductance L
consists of the portions L