What is the meaning of collector current pulse in the datasheet?
Here's a guide published by On Semiconductor on how to interpret their IGBT datasheets. It says that:


  The pulsed collector current describes the peak collector current
  pulse above the rated collector current specification that can flow
  while remaining below the maximum junction temperature. The maximum
  allowable pulsed current in turn depends on the pulse width, duty
  cycle and thermal conditions of the device. (P. 2)