I can't find an easy way to add dragon soul so for now, the best way is to spawn a dragon, kill it, and absorb its soul. Rinse and repeat.
1) Use help command to get dragon ID.
2) Use player.placeatme [ID] to spawn dragon.
@awakendjay Dragon souls are not place in inv consumable. It's the same as perk point. I think it's listed in magick.
[Edited by iosa, 11/10/2011 6:21:40 PM]
i absorbed this way a dragon soul ancient one, elders seem to be tough